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Cehelyk EK, Syed ZA. Long-term outcomes of corneal crosslinking. Curr Opin Ophthalmol 2024; 35:315-321. [PMID: 38700950 DOI: 10.1097/icu.0000000000001054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
PURPOSE OF REVIEW This manuscript summarizes contemporary research from 2018 to 2023 evaluating long-term (≥2 years) outcomes of corneal crosslinking (CXL) for progressive keratoconus (KCN). RECENT FINDINGS The standard Dresden protocol (SDP) has been utilized clinically since the early 2000 s to treat ectatic disorders, primarily progressive KCN and postrefractive ectasia. Various modifications have since been introduced including accelerated and transepithelial protocols, which are aimed at improving outcomes or reducing complications. This review summarizes data demonstrating that the SDP halts disease progression and improves various visual and topographic indices (UDVA, CDVA, Kmax, K1, K2) up to 13 years postoperatively. Accelerated and transepithelial protocols have been found to be well tolerated alternatives to SDP with similar efficacy profiles. Studies focusing on pediatric populations identified overall higher progression rates after CXL. All protocols reviewed had excellent safety outcomes in adults and children. SUMMARY Recent studies revealed that SDP successfully stabilizes KCN long term, and a variety of newer protocols are also effective. Pediatric patients may exhibit higher progression rates after CXL. Further research is required to enhance the efficacy and ease of these protocols.
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Affiliation(s)
| | - Zeba A Syed
- Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania, USA
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2
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Li JPO, Maile HP, Bunce C, Kandakji L, Leucci MT, Allan BD, Tuft SJ, Pontikos N, Gore DM. A comparison of keratoconus progression following collagen cross-linkage using standard or personalised keratometry thresholds. Eye (Lond) 2024; 38:1681-1686. [PMID: 38409307 PMCID: PMC11156642 DOI: 10.1038/s41433-024-02994-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 02/04/2024] [Accepted: 02/13/2024] [Indexed: 02/28/2024] Open
Abstract
OBJECTIVE To define how estimates of keratoconus progression following collagen cross-linking (CXL) vary according to the parameter selected to measure corneal shape. MATERIALS AND METHODS We estimated progression following CXL in 1677 eyes. We compared standard definitions of keratoconus progression based on published thresholds for Kmax, front K2, or back K2, or progression of any two of these three parameters, with the option of an increased threshold for Kmax values ≥ 55D. As corneal thickness reduces unpredictably after CXL, it was excluded from the principal analysis. We then repeated the analysis using novel adaptive estimates of progression for Kmax, front K2, or back K2, developed separately using 6463 paired readings from keratoconus eyes, with a variation of the Bland-Altman method to determine the 95% regression-based limits of agreement (LoA). We created Kaplan-Meier survival plots for both standard and adaptive thresholds. The primary outcome was progression five years after a baseline visit 9-15 months following CXL. RESULTS Progression rates were 8% with a standard (≥ 1.5D) threshold for K2 or 6% with the static multi-parameter definition. With a ≥ 1D threshold for Kmax, the progression was significantly higher at 29%. With adaptive Kmax or K2, the progression rates were similar (20%) but less than with the adaptive multi-parameter method (22%). CONCLUSIONS Estimates of keratoconus progression following CXL vary widely according to the reference criteria. Using adaptive thresholds (LoA) to define the repeatability of keratometry gives estimates for progression that are markedly higher than with the standard multi-parameter method.
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Affiliation(s)
- Ji-Peng Olivia Li
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London, EC1V 2PD, UK
| | - Howard P Maile
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Catey Bunce
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London, EC1V 2PD, UK
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
- National Institute for Health and Care Research (NIHR) BRC at the Royal Marsden NHS Foundation Trust and the Institute of Cancer Research, London, UK
| | - Lynn Kandakji
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Marcello T Leucci
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London, EC1V 2PD, UK
| | - Bruce D Allan
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London, EC1V 2PD, UK
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Stephen J Tuft
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London, EC1V 2PD, UK.
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK.
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Daniel M Gore
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London, EC1V 2PD, UK
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
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Raiskup F, Herber R, Lenk J, Pillunat LE, Spoerl E. Crosslinking with UV-A and riboflavin in progressive keratoconus: From laboratory to clinical practice - developments over 25 years. Prog Retin Eye Res 2024:101276. [PMID: 38830532 DOI: 10.1016/j.preteyeres.2024.101276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/05/2024]
Abstract
Changes in the biomechanical and biochemical properties of the human cornea play an important role in the pathogenesis of ectatic diseases. A number of conditions in primarily acquired (keratoconus or pellucid marginal degeneration) or secondarily induced (iatrogenic keratectasia after refractive laser surgeries) ectatic disorders lead to decreased biomechanical stability. Corneal collagen cross-linking (CXL) represents a technique to slow or even halt the progression of ectatic pathologies. In this procedure, riboflavin is applied in combination with ultraviolet A radiation. This interaction induces the production of reactive oxygen species, which leads to the formation of additional covalent bonds between collagen molecules and subsequent biomechanical corneal strengthening. This procedure is so far the only method that partially interferes etiopathogenetically in the treatment of ectatic diseases that slows or stops the process of corneal destabilization, otherwise leading to the need for corneal transplantation. Besides, CXL process increases markedly resistance of collagenous matrix against digesting enzymes supporting its use in the treatment of corneal ulcers. Since the discovery of this therapeutic procedure and the first laboratory experiments, which confirmed the validity of this method, and the first clinical studies that proved the effectiveness and safety of the technique, it has been spread and adopted worldwide, even with further modifications. Making use of the Bunsen-Roscoe photochemical law it was possible to shorten the duration of this procedure in accelerated CXL and thus improve the clinical workflow and patient compliance while maintaining the efficacy and safety of the procedure. The indication spectrum of CXL can be further expanded by combining it with other vision-enhancing procedures such as individualized topographically-guided excimer ablation. Complementing both techniques will allow a patient with a biomechanically stable cornea to regularise it and improve visual acuity without the need for tissue transplantation, leading to a long-term improvement in quality of life.
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Affiliation(s)
- Frederik Raiskup
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.
| | - Robert Herber
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Janine Lenk
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Lutz E Pillunat
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Eberhard Spoerl
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
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Amaral DC, Menezes AHG, Vilaça Lima LC, Faneli AC, Neto PFS, Canedo ALC, Mora-Paez DJ, Guedes JAF, Louzada RN, Fontes BM. Corneal Collagen Crosslinking for Ectasia After Refractive Surgery: A Systematic Review and Meta-Analysis. Clin Ophthalmol 2024; 18:865-879. [PMID: 38525385 PMCID: PMC10960511 DOI: 10.2147/opth.s451232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 02/26/2024] [Indexed: 03/26/2024] Open
Abstract
Introduction Corneal ectasia leads to progressive irregular corneal curvature and reduced visual acuity. Objective To assess the safety and effectiveness of corneal collagen cross-linking (CXL) for managing corneal ectasia resulting from refractive laser surgery (RSL). Methods A systematic review and meta-analysis were realized according to PRISMA guidelines. We searched PubMed, EMBASE, Cochrane, and Web of Science databases for studies on CXL in patients with ectasia after RLS. The outcomes of interest included visual acuity, refractive outcomes, topographic parameters (Kmax, index surface variance (ISV), index of Vertical Asymmetry (IVA), keratoconus index (KI), central keratoconus index (CKI), index of height asymmetry (IHA), index of height decentration (IHD) and Rmin (minimum sagittal curvature)), central corneal thickness, endothelial cell count, and possible adverse events. Statistical analysis was performed using the R software (version 4.2.3, R Foundation for Statistical Computing, Vienna, Austria). Results 15 studies encompassing 421 patients (512 eyes) were included. The mean age was 32.03 ± 4.4 years. The pooled results showed a stable uncorrected visual acuity post-CXL, with a significant improvement in corrected distance visual acuity (SMD = 0.09; 95% CI: -0.07 to 0.26). The spherical equivalent decreased significantly (SMD = -0.09; 95% CI: -0.35, -0.02). The topographic parameter Kmax decreased significantly (SMD = 0.15; 95% CI:0.01 to 0.28); however, the other parameters, ISV, IVA, KI, CKI, IHA, IHD, and Rmin, did not change significantly. Central corneal thickness decreased significantly (SMD = 0.24; 95% CI:0.07 to 0.41), and the endothelial cell count remained stable The complications were rare. Conclusion CXL is a safe and effective technique for managing corneal ectasia after RLS.
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Affiliation(s)
- Dillan Cunha Amaral
- Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Hacıağaoğlu S, Akkaya Turhan S, Toker E. A comparison of conventional and accelerated corneal crosslinking: corneal epithelial remodeling and in vivo confocal microscopy analysis. Int Ophthalmol 2024; 44:87. [PMID: 38363414 DOI: 10.1007/s10792-024-03020-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 01/09/2024] [Indexed: 02/17/2024]
Abstract
PURPOSE To evaluate the effect of conventional and accelerated corneal crosslinking (CXL) on visual acuity, corneal topography, corneal epithelial thickness, and subbasal nerve morphology in progressive keratoconus patients. METHODS In this prospective and randomized study, twenty eyes of 20 patients were treated with conventional CXL (3 mW/cm2, 30 min, C-CXL) and 19 eyes of 19 patients were treated with accelerated CXL (9 mW/cm2, 10 min, A-CXL). The spherical equivalent, uncorrected visual acuity, best-corrected visual acuity, keratometric measurements, demarcation line measurement and epithelial thickness mapping analyses, and subbasal nerve morphology with in vivo confocal microscopy (IVCCM) were evaluated at baseline and at postoperative months 1, 3 and 6. RESULTS At postoperative 6 months, a significant improvement was observed in all keratometric values in both treatment groups (p < 0.05). All epithelial thickness indices, except central, temporal, and inferotemporal thickness, were reduced at 1 month postoperatively in both treatment groups. The epithelial map uniformity indices (standard deviation and difference between min-max thickness) were significantly lower than the baseline values at all time points after CXL in both treatment groups (p < 0.001). Compared with the preoperative values, there was a significant decrease in all IVCCM parameters at 1 month postoperatively (p < 0.05). At 6 months postoperatively, corneal nerve fiber density and corneal nerve branch density recovered to preoperative values in the A-CXL group, whereas corneal nerve regeneration was not complete in the C-CXL group. CONCLUSION Both conventional and accelerated CXL treatments appear to be effective in halting the progression of KC. Corneal epithelial irregularity slightly improves after CXL. The regeneration of subbasal nerves is faster after A-CXL treatment.
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Affiliation(s)
- Sezer Hacıağaoğlu
- Department of Ophthalmology, Bahçeşehir University, Sahrayıcedit Mah. Batman Sk. No:66, 34734 Kadıköy, Istanbul, Turkey.
| | - Semra Akkaya Turhan
- Department of Ophthalmology, Marmara University, Marmara Üniversitesi Pendik Eğitim ve Araştırma Hastanesi, Fevzi Çakmak Mah. Muhsin Yazıcıoğlu Cad. No:10 Pendik, Istanbul, Turkey
| | - Ebru Toker
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, United States
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Prinz J, Kuerten D, Schellhase H, Koutsonas A, Djalali-Talab Y, Walter P, Fuest M. Clinical, Anatomical, and Densitometric Changes following Dresden vs. Accelerated Corneal Cross-Linking in Progressive Keratoconus. Klin Monbl Augenheilkd 2024; 241:209-220. [PMID: 38232738 DOI: 10.1055/a-2206-1420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
BACKGROUND To compare clinical, anatomical, and densitometric changes following Dresden (DCXL) vs. accelerated (ACXL) corneal UVA cross-linking (CXL; Avedro KXL, Geuder, Heidelberg, Germany) in progressive keratoconus (KC). METHODS AND MATERIAL In this retrospective study, we analyzed 20 patients following DCXL (3 mW/cm², 30 min, 5.4 J/cm²) and 44 patients following ACXL (9 mW/cm², 10 min, 5.4 J/cm²) between January 2016 and February 2020. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), central corneal thickness (CCT), steepest keratometry (Kmax), keratoconus index (KI), thinnest pachymetry (Pthin), and corneal densitometry (CD) were measured before and 3, 6, 12, and 24 months after CXL. RESULTS During the follow-up period, no changes in UCVA, BSCVA, Kmax, KI, or Pthin occurred. CCT significantly decreased 3 months after DCXL (p = 0.032) and ACXL (p = 0.006). At the 12- and 24-month follow-up, CCT remained decreased in the DCXL (p = 0.035, 0.036, respectively) but not in the ACXL group. At the 12-month follow-up, the reduction in CCT was significantly greater in DCXL compared to ACXL (p = 0.012). At the 3-, 6-, 12-, and 24-month follow-ups, we found a significant increase in the anterior stroma CD following DCXL (p = 0.019, 0.026, 0.049, 0.047, respectively) but not ACXL. The CD changes were localized in the central concentric zones (0.0 to 6.0 mm). No intra- or postoperative complications occurred. CONCLUSION ACXL and DCXL effectively halted KC progression. ACXL proved to be a safe time-saving alternative to conventional DCXL. DCXL led to a reduction in CCT and an increment in the CD of the central anterior stroma during 24 months of follow-up.
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Affiliation(s)
- Julia Prinz
- Clinic of Ophthalmology, University Hospital Aachen, Aachen, Germany
| | - David Kuerten
- Clinic of Ophthalmology, University Hospital Aachen, Aachen, Germany
| | - Hannah Schellhase
- Clinic of Ophthalmology, University Hospital Aachen, Aachen, Germany
| | - Antonis Koutsonas
- Clinic of Ophthalmology, University Hospital Aachen, Aachen, Germany
| | | | - Peter Walter
- Clinic of Ophthalmology, University Hospital Aachen, Aachen, Germany
| | - Matthias Fuest
- Clinic of Ophthalmology, University Hospital Aachen, Aachen, Germany
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Khanjian AT, Ivanova AV, Sklyarova AS, Khodzhabekyan NV, Manukyan IV. [Comparative analysis of clinical and functional parameters in patients with stable stage II-III keratoconus after implantation of corneal segments and fitting of scleral rigid contact lenses]. Vestn Oftalmol 2024; 140:72-77. [PMID: 38742501 DOI: 10.17116/oftalma202414002172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The modern treatment strategy for keratoconus (KC) involves sequential application of medical technologies aimed at stabilizing pathological changes in the cornea and restoring visual acuity. PURPOSE This study compares the effect of implantation of intrastromal corneal ring segment (ICRS) and fitting of individual scleral rigid contact lenses (RCLs) on visual functions in patients with stage II-III KC after previously performed corneal collagen cross-linking. MATERIAL AND METHODS The Helmholtz National Medical Research Center of Eye Diseases examined and treated 34 patients (69 eyes) aged 18 to 33 years with stage II-III KC. The study included patients who had previously undergone standard corneal collagen cross-linking. Depending on the type of optical correction, the patients were divided into two groups: patients in group 1 underwent ICRS implantation using a femtosecond laser; patients in group 2 were fitted with individual scleral RCLs. RESULTS Improvement in clinical and functional parameters was observed in both groups. A higher clinical and functional result was achieved in group 2. CONCLUSION For patients with stable stage II-III KC, it is advisable to recommend fitting of individual scleral RCLs for visual rehabilitation.
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Affiliation(s)
- A T Khanjian
- Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - A V Ivanova
- Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - A S Sklyarova
- Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - N V Khodzhabekyan
- Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - I V Manukyan
- Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
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Kandel H, Abbondanza M, Gupta A, Mills R, Watson AS, Petsoglou C, Kerdraon Y, Watson SL. Comparison of standard versus accelerated corneal collagen cross-linking for keratoconus: 5-year outcomes from the Save Sight Keratoconus Registry. Eye (Lond) 2024; 38:95-102. [PMID: 37369766 PMCID: PMC10764350 DOI: 10.1038/s41433-023-02641-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 06/07/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
OBJECTIVE To compare long-term effectiveness of Standard (UV intensity: 3 mW/cm2, duration: 30 min) vs Accelerated (UV intensity: 9 mW/cm2, duration: 10 min) corneal cross-linking (CXL) for stabilising keratoconus. METHODS Data for this observational study were captured through a web-based registry system from the routine clinical practice (15 sites across Australia, New Zealand and Italy). The outcomes were compared using mixed-effects regression models. A total of 100 eyes (75 patients) who had standard CXL and 76 eyes (66 patients) who had accelerated CXL, with a follow-up visit at five-year post-CXL were included. RESULTS Both CXL protocols were effective and safe in stabilising keratoconus and improving outcomes. The adjusted mean changes (95% CI) in outcomes were better in standard CXL than in accelerated CXL [visual acuity gain, 10.2 (7.9-12.5) vs 4.9 (1.6-8.2) logMAR letters; pinhole visual acuity 5.7 (3.5-7.8) vs 0.2 (-2.2 to 2.5) logMAR letters; Kmax -1.8 (-4.3 to 0.6) vs 1.2 (-1.5 to 3.9)D; K2 -0.9 (-2.2 to 0.3) vs 0.1 (-1.3 to 1.6)D; MCT -3.0 (-13.7 to 7.7) vs -11.8 (-23.9 to 0.4) µm (p values for visual acuity, pinhole visual acuity, Kmax: <0.05; for K2 and MCT: >0.05)]. The frequency of adverse events at the 5-year follow-up visit was low in both groups [standard, 5 (5%; haze 3; scarring 1, epithelial defect 1) and accelerated 3 (3.9%; haze 2, scarring 1)]. CONCLUSIONS Both standard and accelerated CXL were safe and effective procedures for stabilising keratoconus in the long term. The standard CXL resulted in greater improvements in visual acuity and keratometry.
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Affiliation(s)
- Himal Kandel
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute, Sydney, NSW, Australia.
| | | | - Aanchal Gupta
- Adelaide Eye & Laser Centre, Adelaide, SA, Australia
- South Australian Institute of Ophthalmology, Adelaide, SA, Australia
| | - Richard Mills
- Flinders Medical Centre, Flinders University, Adelaide, SA, Australia
| | | | - Constantinos Petsoglou
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute, Sydney, NSW, Australia
| | - Yves Kerdraon
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute, Sydney, NSW, Australia
| | - Stephanie L Watson
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute, Sydney, NSW, Australia
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Herber R, Francis M, Spoerl E, Pillunat LE, Raiskup F, Roy AS. Evaluation of Biomechanical Changes After Accelerated Cross-Linking in Progressive Keratoconus: A Prospective Follow-Up Study. Cornea 2023; 42:1365-1376. [PMID: 36727878 DOI: 10.1097/ico.0000000000003219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 11/15/2022] [Indexed: 02/03/2023]
Abstract
PURPOSE The aim of this study was to analyze the biomechanical effect of accelerated corneal cross-linking (9*10) in progressive keratoconus (KC) in comparison to untreated fellow eyes using Scheimpflug-based tonometry (Corvis ST, CVS). METHODS Forty-three eyes of 43 patients with KC showed progressive KC and were treated using accelerated corneal cross-linking. Twenty-five untreated fellow eyes were used as the control group. All eyes were examined biomechanically (CVS) and tomographically (Pentacam) at baseline, after 1-month, 6-month, and 12-month follow-up. Statistical analysis was performed using a linear mixed model. A logistic regression was performed to attribute the effects of changes in each parameter to treatment status (treated or untreated). RESULTS Maximum keratometry values decreased statistically significantly at 12 months by -1.1 D (95 confidence interval: -2.0 to -0.1, P = 0.025) compared with baseline. Thinnest corneal thickness decreased significantly after 1 month ( P < 0.001) and recovered to baseline after 12 months ( P = 0.752). In the corneal cross-linking (CXL) group, biomechanical changes were observed by an increased bIOP, a shorter A2 time, and a lower integrated radius after 1 month (all P < 0.05). No biomechanical and tomographical changes were observed in the control group (all P > 0.05). Logistic regression pointed out that treated eyes can be separated from untreated eyes by differences in bIOP, corneal thickness, A1 velocity, integrated radius, and Kc mean at 1, 6, and 12 months. CONCLUSIONS The alterations in biomechanical parameters indicated a corneal stiffening effect after CXL treatment, which was mostly detectable 1 month after treatment, although corneal thickness was reduced. The logistic regression model showed an adequate separation between CXL-treated and untreated eyes.
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Affiliation(s)
- Robert Herber
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Germany; and
| | - Mathew Francis
- Imaging, Biomechanics and Mathematical Modeling Solutions Lab, Narayana Nethralaya Foundation, Bangalore, India
| | - Eberhard Spoerl
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Germany; and
| | - Lutz E Pillunat
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Germany; and
| | - Frederik Raiskup
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Germany; and
| | - Abhijit Sinha Roy
- Imaging, Biomechanics and Mathematical Modeling Solutions Lab, Narayana Nethralaya Foundation, Bangalore, India
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10
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Ding L, Sun L, Zhou X. Network meta-analysis comparing efficacy and safety of different protocols of corneal cross-linking for the treatment of progressive keratoconus. Graefes Arch Clin Exp Ophthalmol 2023; 261:2743-2753. [PMID: 36944752 DOI: 10.1007/s00417-023-06026-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 02/13/2023] [Accepted: 02/25/2023] [Indexed: 03/23/2023] Open
Abstract
PURPOSE This study aimed to determine the preferred protocol of corneal collagen cross-linking (CXL) in the treatment of progressive keratoconus. METHODS Relevant studies were retrieved in PubMed, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL). Maximum keratometry value (Kmax), best spectacle-corrected visual acuity (BSCVA), manifest refraction spherical equivalent (MRSE), and endothelial cell density (ECD) were evaluated in network meta-analysis. RESULTS Eight randomized controlled trials (RCTs) were included. Low-level evidence suggested that aCXL with 30mW/cm2 for 3 min (aCXL-3) might be the best protocol for reducing BSCVA (65.22%) but worst protocol for reducing MRSE (51.53%). aCXL with 18mW/cm2 for 5 min (aCXL-5) might be the best protocol for reducing Kmax (39.58%) and MRSE (77.85%) but might be the worst for preserving ECD (50.98%). aCXL with 9mW/cm2 for 10 min (aCXL-10) might be the best protocol for preserving ECD (31.53%). CONCLUSION Overall, three protocols of aCXL are comparable in therapeutic efficacy and safety for treating progressive keratoconus. Despite no direct data comparing the efficacy of each technique according to different patients' profiles, it is reasonable to state that aCXL-5 may be the best for patients at early-stage to reduce Kmax and MRSE, aCXL-3 may be the best for patients at mid-stage to improve BSCVA, and aCXL-10 may be the best for patients at late-stage to preserve DEC.
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Affiliation(s)
- Lan Ding
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Ling Sun
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xingtao Zhou
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.
- Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
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Clahsen T, Hadrian K, Notara M, Schlereth SL, Howaldt A, Prokosch V, Volatier T, Hos D, Schroedl F, Kaser-Eichberger A, Heindl LM, Steven P, Bosch JJ, Steinkasserer A, Rokohl AC, Liu H, Mestanoglu M, Kashkar H, Schumacher B, Kiefer F, Schulte-Merker S, Matthaei M, Hou Y, Fassbender S, Jantsch J, Zhang W, Enders P, Bachmann B, Bock F, Cursiefen C. The novel role of lymphatic vessels in the pathogenesis of ocular diseases. Prog Retin Eye Res 2023; 96:101157. [PMID: 36759312 DOI: 10.1016/j.preteyeres.2022.101157] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/13/2022] [Accepted: 12/17/2022] [Indexed: 02/10/2023]
Abstract
Historically, the eye has been considered as an organ free of lymphatic vessels. In recent years, however, it became evident, that lymphatic vessels or lymphatic-like vessels contribute to several ocular pathologies at various peri- and intraocular locations. The aim of this review is to outline the pathogenetic role of ocular lymphatics, the respective molecular mechanisms and to discuss current and future therapeutic options based thereon. We will give an overview on the vascular anatomy of the healthy ocular surface and the molecular mechanisms contributing to corneal (lymph)angiogenic privilege. In addition, we present (i) current insights into the cellular and molecular mechanisms occurring during pathological neovascularization of the cornea triggered e.g. by inflammation or trauma, (ii) the role of lymphatic vessels in different ocular surface pathologies such as dry eye disease, corneal graft rejection, ocular graft versus host disease, allergy, and pterygium, (iii) the involvement of lymphatic vessels in ocular tumors and metastasis, and (iv) the novel role of the lymphatic-like structure of Schlemm's canal in glaucoma. Identification of the underlying molecular mechanisms and of novel modulators of lymphangiogenesis will contribute to the development of new therapeutic targets for the treatment of ocular diseases associated with pathological lymphangiogenesis in the future. The preclinical data presented here outline novel therapeutic concepts for promoting transplant survival, inhibiting metastasis of ocular tumors, reducing inflammation of the ocular surface, and treating glaucoma. Initial data from clinical trials suggest first success of novel treatment strategies to promote transplant survival based on pretransplant corneal lymphangioregression.
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Affiliation(s)
- Thomas Clahsen
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Karina Hadrian
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Maria Notara
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Simona L Schlereth
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Antonia Howaldt
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Verena Prokosch
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Thomas Volatier
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Deniz Hos
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Falk Schroedl
- Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Alexandra Kaser-Eichberger
- Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Ludwig M Heindl
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Philipp Steven
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Cluster of Excellence: Cellular Stress Responses in Ageing-Associated Diseases, CECAD, University of Cologne, Cologne, Germany
| | - Jacobus J Bosch
- Centre for Human Drug Research and Leiden University Medical Center, Leiden, the Netherlands
| | | | - Alexander C Rokohl
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Hanhan Liu
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Mert Mestanoglu
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Hamid Kashkar
- Institute for Molecular Immunology, Center for Molecular Medicine Cologne (CMMC), CECAD Research Center, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Björn Schumacher
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany; Cluster of Excellence: Cellular Stress Responses in Ageing-Associated Diseases, CECAD, University of Cologne, Cologne, Germany
| | - Friedemann Kiefer
- European Institute for Molecular Imaging (EIMI), University of Münster, 48149, Münster, Germany
| | - Stefan Schulte-Merker
- Institute for Cardiovascular Organogenesis and Regeneration, Faculty of Medicine, WWU Münster, Münster, Germany
| | - Mario Matthaei
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Yanhong Hou
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, 83 Fenyang Road, Xuhui District, Shanghai, China
| | - Sonja Fassbender
- IUF‒Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany; Immunology and Environment, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Jonathan Jantsch
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Wei Zhang
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Philip Enders
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Björn Bachmann
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Felix Bock
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Claus Cursiefen
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany; Cluster of Excellence: Cellular Stress Responses in Ageing-Associated Diseases, CECAD, University of Cologne, Cologne, Germany.
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Fischinger I, Reifeltshammer SA, Seiler TG, Nambiar MH, Komninou MA, Büchler P, Wendelstein J, Langenbucher A, Bolz M. Analysis of Biomechanical Response After Corneal Crosslinking with Different Fluence Levels in Porcine Corneas. Curr Eye Res 2023; 48:719-723. [PMID: 37144469 DOI: 10.1080/02713683.2023.2205612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 04/14/2023] [Indexed: 05/06/2023]
Abstract
PURPOSE To evaluate corneal stiffening of porcine corneas induced by corneal crosslinking (CXL) with constant irradiance as a function of total fluence. METHODS Ninety corneas from freshly enucleated porcine eyes were divided into five groups of 18 eyes. Groups 1-4 underwent epi-off CXL using a dextran-based riboflavin solution and an irradiance of 18 mW/cm2, group 5 served as the control group. Groups 1 to 4 were treated with a total fluence of 20, 15, 10.8, and 5.4 J/cm2, respectively. Thereafter, biomechanical measurements were performed on 5 mm wide and 6 mm long strips using an uniaxial material tester. Pachymetry measurements were performed on each cornea. RESULTS At 10% strain, the stress was 76, 56, 52, and 31% higher in groups 1-4, respectively compared to the control group. The Young's modulus was 2.85 MPa for group 1, 2.53 MPa for group 2, 2.46 MPa for group 3, 2.12 MPa for group 4, and 1.62 MPa for the control group. The difference between groups 1 to 4 and the control group 5 were statistically significant (p = <0.001; p = <0.001; p = <0.001; p = 0.021). In addition, group 1 showed significantly more stiffening than group 4 (p = <0.001), no other significant differences were found. Pachymetry measurements revealed no statistically significant differences among the five groups. CONCLUSION Additional mechanical stiffening can be achieved by increasing the fluence of the CXL. There was no threshold detected up to 20 J/cm2. A higher fluence could compensate the weaker effect of accelerated or epi-on CXL procedures.
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Affiliation(s)
- Isaak Fischinger
- Augentagesklinik Spreebogen Berlin, Berlin, Germany
- Klinik für Augenheilkunde, Kepler Universitätsklinikum, Linz, Austria
- Medizinische Fakultät, Johannes Kepler Universität Linz, Linz, Austria
| | - Sophia A Reifeltshammer
- Klinik für Augenheilkunde, Kepler Universitätsklinikum, Linz, Austria
- Medizinische Fakultät, Johannes Kepler Universität Linz, Linz, Austria
| | - Theo G Seiler
- Klinik für Augenheilkunde, Universitätsklinkum Düsseldorf, Düsseldorf, Germany
- Institut für Refraktive und Ophthalmo-Chirurgie (IROC), Zurich, Switzerland
- Department of Ophthalmology, Inselspital Bern, University of Bern, Bern, Switzerland
| | - Malavika H Nambiar
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Maria A Komninou
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Philippe Büchler
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Jascha Wendelstein
- Klinik für Augenheilkunde, Kepler Universitätsklinikum, Linz, Austria
- Medizinische Fakultät, Johannes Kepler Universität Linz, Linz, Austria
| | - Achim Langenbucher
- Department of Experimental Ophthalmology, Saarland University, Homburg, Germany
| | - Matthias Bolz
- Klinik für Augenheilkunde, Kepler Universitätsklinikum, Linz, Austria
- Medizinische Fakultät, Johannes Kepler Universität Linz, Linz, Austria
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Farrokhpour H, Soleimani M, Cheraqpour K, Masoumi A, Tabatabaei SA, Shahriari M, Hobaby S, Baharnoori SM, Chaudhry A, Djalilian AR. A Case Series of Infectious Keratitis After Corneal Cross-linking. J Refract Surg 2023; 39:564-572. [PMID: 37578174 DOI: 10.3928/1081597x-20230717-03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
PURPOSE To present the 7-year experience of a tertiary eye hospital while exploring possible risk factors and incidence of infectious keratitis in patients undergoing standard corneal cross-linking (CXL). METHODS This retrospective cohort study included patients with progressive keratoconus undergoing standard CXL in the Farabi Eye Hospital and all other patients who had undergone CXL in other facilities and were diagnosed as having infectious keratitis in the 7-year period of the study. RESULTS Among the total of 4,863 eyes that underwent CXL, 6 eyes developed infectious keratitis, yielding an incidence rate of 0.12%. Additionally, 13 eyes from 10 patients with a CXL history in other facilities who developed infectious keratitis were included. The mean age was 23.75 years, and 75% of patients were men and 25% were women. Gram-positive bacteria and Staphylococcus aureus were the most prevalent pathogens. Meibomian gland dysfunction, dry eye disease, or blepharitis were present in 12 patients. Medical treatment did not arrest the disease progress in 5 patients, which eventually required cases to undergo keratoplasty. CONCLUSIONS This study supports the need for proper patient selection by using a comprehensive medical history. It also highlights the imperative role of rigorous patient education and follow-up, particularly in the first postoperative week. Finally, the study emphasizes aggressive early therapy for patients with suspicious findings. [J Refract Surg. 2023;39(8):564-572.].
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14
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Vidas Pauk S, Jandroković S, Lešin Gaćina D, Tomić M, Bulum T, Pupić Bakrač A, Kuzman T, Knežević J, Kalauz M. Short-Term Effect of Conventional Versus Accelerated Corneal Cross-Linking Protocol on Corneal Geography and Stability. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1043. [PMID: 37374247 DOI: 10.3390/medicina59061043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 05/20/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023]
Abstract
Purpose: To determine the 6-month effect of conventional (CXL30) and accelerated cross-linking with a UVA intensity of 9 mW/cm2 (CXL10) on corneal stability and to investigate whether there was a difference in ABCD grading system parameters regarding the two different procedures. Methods: Twenty-eight eyes of 28 patients with a documented keratoconus (KN) progression were included. Patients were selected to undergo either epi off CXL30 or CXL10. At the baseline and the follow-up visits after one (V1), three (V2), and six months (V3), the patients underwent complete ophthalmic examination and corneal tomography. Results: In the CXL30 group, all the parameters from the ABCD grading system significantly changed from baseline to V3; parameter A decreased (p = 0.048), B and C increased (p = 0.010, p < 0.001), and D decreased (p < 0.001). In the CXL10 group, there were no changes in parameters A (p = 0.247) and B (p = 0.933), though parameter C increased (p = 0.001) and D decreased (p < 0.001). After an initial decline after one month, visual acuity (VA) recovered on V2 and V3 (p < 0.001), and median maximal keratometry (Kmax) decreased in both groups (p = 0.001, p = 0.035). In the CXL30 group, there were significant changes in other parameters; average pachymetric progression index (p < 0.001), Ambrósio relational thickness maximum (ARTmax) (p = 0.008), front and back mean keratometry (p < 0.001), pachymetry apex (PA) (p < 0.001), and front elevation (p = 0.042). However, in the CXL10 group, there were significant changes only in ARTmax (p = 0.019) and PA (p < 0.001). Conclusion: Both epi-off CXL protocols showed similar short-term efficacy in improving VA and Kmax, halting the progression of KN, and both similarly changed tomographic parameters. However, the conventional protocol modified the cornea more significantly.
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Affiliation(s)
- Sania Vidas Pauk
- Department of Ophthalmology, Zagreb University Hospital Center, 10000 Zagreb, Croatia
| | - Sonja Jandroković
- Department of Ophthalmology, Zagreb University Hospital Center, 10000 Zagreb, Croatia
- School of Medicine, University of Zagreb, Šalata 2, 10000 Zagreb, Croatia
| | - Dina Lešin Gaćina
- Department of Ophthalmology, Zagreb University Hospital Center, 10000 Zagreb, Croatia
| | - Martina Tomić
- Vuk Vrhovac University Clinic for Diabetes, Endocrinology and Metabolic Diseases, Merkur University Hospital, Dugi dol 4a, 10000 Zagreb, Croatia
| | - Tomislav Bulum
- School of Medicine, University of Zagreb, Šalata 2, 10000 Zagreb, Croatia
- Vuk Vrhovac University Clinic for Diabetes, Endocrinology and Metabolic Diseases, Merkur University Hospital, Dugi dol 4a, 10000 Zagreb, Croatia
| | - Ana Pupić Bakrač
- Department of Ophthalmology, Zagreb University Hospital Center, 10000 Zagreb, Croatia
| | - Tomislav Kuzman
- Department of Ophthalmology, Zagreb University Hospital Center, 10000 Zagreb, Croatia
- School of Medicine, University of Zagreb, Šalata 2, 10000 Zagreb, Croatia
| | - Josip Knežević
- Department of Ophthalmology, Zagreb University Hospital Center, 10000 Zagreb, Croatia
| | - Miro Kalauz
- Department of Ophthalmology, Zagreb University Hospital Center, 10000 Zagreb, Croatia
- School of Medicine, University of Zagreb, Šalata 2, 10000 Zagreb, Croatia
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15
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Abdel-Radi M, Abdelmohsen N, Abdelmotaal H, Abd El-Moneim MT. The effect of accelerated pulsed high-fluence corneal cross-linking on corneal endothelium; a prospective specular microscopy study. BMC Ophthalmol 2023; 23:163. [PMID: 37072730 PMCID: PMC10114460 DOI: 10.1186/s12886-023-02912-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 04/07/2023] [Indexed: 04/20/2023] Open
Abstract
BACKGROUND Corneal collagen cross-linking (CXL) is a procedure utilized for halting keratoconus progression with different approved protocols. The current study aimed to assess the corneal endothelial changes following the relatively new accelerated pulsed high-fluence protocol of epithelium-off corneal cross-linking for the treatment of mild to moderate keratoconus. METHODS This prospective case series study enrolled 45 eyes of 27 patients with mild to moderate progressive keratoconus who underwent accelerated pulsed high-fluence CXL (pl-ACXL, 30 mW/ cm2 UVA at 365 nm wavelength, 8 min pulsed mode 1 s on / 1 s off with a total energy of 7.2 J/ cm2). The main outcome measures were corneal endothelial changes assessed by specular microscopy at 3 and 6 months postoperatively including endothelial cell density (ECD), coefficient of variation, percentage of hexagonal cells, average, minimum and maximum endothelial cell sizes. Demarcation line depth was assessed 1 month following surgery. RESULTS The mean age of the studied sample was 24.89 ± 7.21. The mean preoperative ECD (2944.6 ± 247.41 cell/mm2) showed non-significant reduction at 3 and 6 months postoperatively (2931.03 ± 253.82 and 2924.7 ± 224.88 cell/mm2, respectively, P-value = 0.361). There were no significant changes in the mean coefficient of variation, percentage of hexagonal cells, average, minimum and maximum endothelial cell sizes at 3 and 6 months following pl-ACXL (P-value > 0.05). The mean demarcation line depth 1 month after pl-ACXL was 214 ± 17.43 μm. CONCLUSIONS Corneal endothelial changes following accelerated pulsed high-fluence CXL were minimal with stability of endothelial cell count and non-significant morphological changes. TRIAL REGISTRATION Clinicaltrials.gov: NCT04160338 (13/11/2019).
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Affiliation(s)
- Mahmoud Abdel-Radi
- Department of Ophthalmology, Assiut University, Assiut University Hospital 6th floor, Assiut, 71516, Egypt.
| | - Naglaa Abdelmohsen
- Department of Ophthalmology, Assiut University, Assiut University Hospital 6th floor, Assiut, 71516, Egypt
| | - Hazem Abdelmotaal
- Department of Ophthalmology, Assiut University, Assiut University Hospital 6th floor, Assiut, 71516, Egypt
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Einan-Lifshitz A, Achiron A, Hed S, Hecht I, Dubinsky-Pertzov B, Knyazer B. Three-year follow-up of accelerated versus standard corneal cross-linking in paediatric Keratoconus. Eye (Lond) 2023; 37:1219-1224. [PMID: 35590103 PMCID: PMC10102302 DOI: 10.1038/s41433-022-02093-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/19/2022] [Accepted: 05/05/2022] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Standard corneal collagen cross-linking (S-CXL) is an effective treatment to arrest Keratoconus (KC) progression in children. Less is known on the long-term efficacy of accelerated CXL (A-CXL) in paediatric populations. METHODS A historical cohort analysis of paediatric patients (≤18 years) with KC who underwent S-CXL and A-CXL at two tertiary referral centres in Israel between 2010-2017. Preoperative and 3-year postoperative evaluation included changes in visual acuity (best spectacle corrected [BSCVA]) and uncorrected [UCVA]), refractive errors, and keratometric data. RESULTS Ninety-three eyes of 93 patients were analysed (A-CXL: n = 39; S-CXL: n = 54). Baseline characteristics were similar between groups. Both groups showed a significant improvement in visual acuity compared to baseline (S-CXL: 0.810-0.602 LogMAR UCVA; A-CXL: 0.890-0.306 LogMAR UCVA, p < 0.05 for both). Improvement in BSCVA and UCVA following A-CXL was non-inferior to S-CXL (< ± 0.2 LogMAR). Kmax decreased by a mean of 0.98 ± 5.56 dioptres following S-CXL (p = 0.02) and by 1.48 ± 8.4 dioptres following A-CXL (p = 0.015). Thinnest pachymetry decreased following both treatments (S-CXL: by 26.8 ± 40.7 µm, p = 0.001, A-CXL: by 10.2 ± 13.4 µm, p = 0.028), the difference between groups was within the non-inferiority margin (< ± 10 µm). CONCLUSIONS Paediatric patients followed for three years after A-CXL showed improved visual function, reduced corneal astigmatism and Kmax, and decreased thinnest corneal thickness. A-CXL was non-inferior to S-CXL at three years in terms of best-corrected and uncorrected visual acuity, thinnest pachymetry, and astigmatism. For Kmax, non-inferiority could not be concluded.
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Affiliation(s)
- Adi Einan-Lifshitz
- Ophthalmology Department, Shamir Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Asaf Achiron
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shira Hed
- Department of Ophthalmology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Idan Hecht
- Ophthalmology Department, Shamir Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Biana Dubinsky-Pertzov
- Ophthalmology Department, Shamir Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Boris Knyazer
- Department of Ophthalmology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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17
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Borgardts K, Menzel-Severing J, Fischinger I, Geerling G, Seiler TG. Innovations in Corneal Crosslinking. Curr Eye Res 2023; 48:144-151. [PMID: 36458595 DOI: 10.1080/02713683.2022.2146725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
PURPOSE Corneal Crosslinking (CXL) strengthens the keratoconus cornea and prevents further disease progression. Modified crosslinking protocols and different riboflavin solutions have been proposed to optimize the procedure and improve treatment success. METHODS PubMed research of relevant publications and report of own experiences with different CXL protocols. RESULTS Accelerated CXL shows comparable efficiency with shorter surgery time and similar complication rates. Customized CXL provides improved results with faster epithelial healing. CXL in a hyperoxic environment seems to be a safe and effective transepithelial alternative with presumably less complications and fewer side effects. Thin corneas (<400 µm) can be treated safely by corneal swelling using hypoosmolar riboflavin solutions and reducing the applied UV-energy. The combination of CXL with photorefractive keratectomy (PRK) can be considered in patients with contact lens intolerance improving visual acuity, however, with increased risk of visual loss compared to CXL alone. Two-Photon (2Ph) CXL is a promising new technology enabling three-dimensional CXL. DISCUSSION Recently developed CXL protocols offer advantages over the standard "Dresden-protocol" and should be considered in patients with progressive keratectasia.
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Affiliation(s)
- Klara Borgardts
- Department of Ophthalmology, University Hospital Düsseldorf, Düsseldorf, Germany
| | | | - Isaak Fischinger
- Institut für Refraktive and Ophthalmo-Chirurgie (IROC), Zürich, Switzerland.,Department of Ophthalmology, Kepler University Hospital, Linz, Austria.,Medical Faculty, Johannes Kepler University Linz, Linz, Austria
| | - Gerd Geerling
- Department of Ophthalmology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Theo G Seiler
- Department of Ophthalmology, University Hospital Düsseldorf, Düsseldorf, Germany.,Institut für Refraktive and Ophthalmo-Chirurgie (IROC), Zürich, Switzerland.,Department of Ophthalmology, Inselspital, Bern University Hospital, Bern, Switzerland
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18
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Zhang X, Sun L, Chen L, Zhang C, Xian Y, Aruma A, Wei R, Shen Y, Chen W, Zhou X. Corneal biomechanical stiffness and histopathological changes after in vivo repeated accelerated corneal cross-linking in cat eyes. Exp Eye Res 2023; 227:109363. [PMID: 36584907 DOI: 10.1016/j.exer.2022.109363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 11/09/2022] [Accepted: 12/20/2022] [Indexed: 12/29/2022]
Abstract
Corneal cross-linking (CXL) has been proved efficiency for treating progressive keratoconus and other corneal ectasia diseases by stabilizing corneal geometry and biomechanics. However, the necessity of repeated CXL treatment in patients is unknown. This study aimed to investigate corneal biomechanical stiffness and change in corneal histopathological characteristics after repeated accelerated CXL (A-CXL) in cat eyes. A-CXL was performed with 0.1% riboflavin applied for 10 min, followed by ultraviolet A irradiation at 30 mW/cm2 for 3 min at 365 nm in 15 domestic cats. Corneas (n = 30) were divided into three groups: one-time accelerated corneal cross-linking (A-CXL*1 group), repeated accelerated corneal cross-linking (A-CXL*2 group), and an untreated control group. In A-CXL*2 group, A-CXL was repeated at 1-month intervals. In vivo ocular examinations were performed pre- and postoperatively. Biomechanical analysis was performed using a biotester biaxial testing system. We used the Mooney-Rivlin strain-energy function to describe corneal material properties. No infection in any case after A-CXL was observed. Biomechanical tests showed that the stress-strain curves of the two A-CXL groups were significantly different from those of the control group (P < 0.01), whereas stress-strain curve of the A-CXL*2 group was similar to that of the A-CXL*1 group (P > 0.05). Delayed epithelial healing and haze were observed 1 month after surgery. Stromal demarcation line depth measured with anterior spectral-domain optical coherence tomography was 187.6 ± 20.4 and 197.1 ± 11.5 μm for the A-CXL*1 and A-CXL*2 groups, respectively (P > 0.05). These results show that A-CXL can increase corneal biomechanics in cat eyes. The biomechanical enhancement of cat corneas treated with repeated A-CXL at 1-month intervals was similar to that of performing a one-time A-CXL. Repeated cross-linking procedures at short intervals may increase the risk of adverse reactions, and more caution should be taken in clinical applications.
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Affiliation(s)
- Xiaoyu Zhang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Research Center of Ophthalmology and Optometry, Shanghai, 200031, China; Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, 200031, China
| | - Ling Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Research Center of Ophthalmology and Optometry, Shanghai, 200031, China; Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, 200031, China
| | - Lingfeng Chen
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024, China
| | - Chaoqin Zhang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024, China
| | - Yiyong Xian
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Research Center of Ophthalmology and Optometry, Shanghai, 200031, China; Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, 200031, China
| | - Aruma Aruma
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Research Center of Ophthalmology and Optometry, Shanghai, 200031, China; Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, 200031, China
| | - Ruoyan Wei
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Research Center of Ophthalmology and Optometry, Shanghai, 200031, China; Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, 200031, China
| | - Yang Shen
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Research Center of Ophthalmology and Optometry, Shanghai, 200031, China; Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, 200031, China
| | - Weiyi Chen
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024, China
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Research Center of Ophthalmology and Optometry, Shanghai, 200031, China; Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, 200031, China.
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19
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Karam M, Alsaif A, Aldubaikhi A, Aljebreen M, Alazaz R, Alkhowaiter N, Almudhaiyan T, Aljassar F. Accelerated Corneal Collagen Cross-Linking Protocols for Progressive Keratoconus: Systematic Review and Meta-analysis. Cornea 2023; 42:252-260. [PMID: 36156043 DOI: 10.1097/ico.0000000000003124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 07/11/2022] [Indexed: 01/05/2023]
Abstract
PURPOSE The aim of this study was to compare the outcomes of 18 mW/cm 2 (5 minutes) versus 9 mW/cm 2 (10 minutes) accelerated corneal collagen cross-linking protocols in patients with progressive keratoconus. METHODS A systematic review and meta-analysis were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, and electronic information was searched to identify studies comparing the outcomes of 5- versus 10-minute protocols in patients with progressive keratoconus. Mean changes in uncorrected visual acuity, best-corrected visual acuity, cylinder (diopters), thinnest corneal thickness, corneal keratometry values (K1 and K2), corneal high-order aberration (HOA), spherical aberration, coma, and trefoil were the primary outcome measures. Secondary outcome measures included the mean change in central corneal thickness and postoperative complications. Random effects modeling was used for the analysis. RESULTS Four studies that enrolled 329 eyes were included. The 10-minute protocol had significantly improved outcomes compared with the 5-minute protocol for the mean changes in K1 and K2 ( P < 0.00001), corneal total HOA ( P = 0.0002), and corneal coma ( P = 0.00001). However, no statistically significant differences were found between the 2 protocols in uncorrected visual acuity, best-corrected visual acuity, cylinder, thinnest corneal thickness, spherical aberration, or trefoil. The 5-minute protocol was associated with a significantly lower mean change in the central corneal thickness for secondary outcomes. In addition, no significant differences were found between the 2 protocols for postoperative complications. CONCLUSIONS The 10-minute protocol had better K1, K2, and HOA outcomes than the 5-minute protocol, but no statistically significant differences in the other outcomes.
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Affiliation(s)
- Mohammad Karam
- Cornea Unit, AlBahar Ophthalmology Center, Ibn Sina Hospital, Ministry of Health, State of Kuwait
| | - Abdulmalik Alsaif
- Department of Surgery, Walsall Healthcare NHS Trust, West Midlands, UK
| | - Ahmed Aldubaikhi
- Department of Radiology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
- Department of Radiology, Prince Mohammed Bin Abdulaziz Hospital, Riyadh, Saudi Arabia
| | | | - Rand Alazaz
- King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Nahlaa Alkhowaiter
- Department of Medicine, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Tariq Almudhaiyan
- Division of Ophthalmology, Department of Surgery, National Guard Hospital, Riyadh, Saudi Arabia; and
- Department of Ophthalmology, King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Faisal Aljassar
- Cornea Unit, AlBahar Ophthalmology Center, Ibn Sina Hospital, Ministry of Health, State of Kuwait
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20
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Li F, Wang K, Liu Z. In Vivo Biomechanical Measurements of the Cornea. BIOENGINEERING (BASEL, SWITZERLAND) 2023; 10:bioengineering10010120. [PMID: 36671692 PMCID: PMC9854753 DOI: 10.3390/bioengineering10010120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/18/2023]
Abstract
In early corneal examinations, the relationships between the morphological and biomechanical features of the cornea were unclear. Although consistent links have been demonstrated between the two in certain cases, these are not valid in many diseased states. An accurate assessment of the corneal biomechanical properties is essential for understanding the condition of the cornea. Studies on corneal biomechanics in vivo suggest that clinical problems such as refractive surgery and ectatic corneal disease are closely related to changes in biomechanical parameters. Current techniques are available to assess the mechanical characteristics of the cornea in vivo. Accordingly, various attempts have been expended to obtain the relevant mechanical parameters from different perspectives, using the air-puff method, ultrasound, optical techniques, and finite element analyses. However, a measurement technique that can comprehensively reflect the full mechanical characteristics of the cornea (gold standard) has not yet been developed. We review herein the in vivo measurement techniques used to assess corneal biomechanics, and discuss their advantages and limitations to provide a comprehensive introduction to the current state of technical development to support more accurate clinical decisions.
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Affiliation(s)
- Fanshu Li
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Health Science Center, Peking University, Beijing 100191, China
| | - Kehao Wang
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Engineering Medicine, Beihang University, Beijing 100191, China
| | - Ziyuan Liu
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Health Science Center, Peking University, Beijing 100191, China
- Correspondence:
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21
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Roszkowska AM, Lombardo G, Mencucci R, Scorcia V, Giannaccare G, Vestri A, Alunni Fegatelli D, Bernava GM, Serrao S, Lombardo M. A randomized clinical trial assessing theranostic-guided corneal cross-linking for treating keratoconus: the ARGO protocol. Int Ophthalmol 2022:10.1007/s10792-022-02628-4. [PMID: 36587174 DOI: 10.1007/s10792-022-02628-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 12/20/2022] [Indexed: 01/01/2023]
Abstract
The Assessment of theranostic guided riboflavin/UV-A corneal cross-linking for treatment of keratoconus (ARGO; registration number NCT05457647) clinical trial tests the hypothesis that theranostic-guided riboflavin/UV-A corneal cross-linking (CXL) can provide predictable clinical efficacy for halting keratoconus progression, regardless of treatment protocol, i.e., either with or without epithelial removal. Theranostics is an emerging therapeutic paradigm of personalized and precision medicine that enables real-time monitoring of image-guided therapy. In this trial, the theranostic software module of a novel UV-A medical device will be validated in order to confirm its accuracy in estimating corneal cross-linking efficacy in real time. During CXL procedure, the theranostic UV-A medical device will provide the operator with an imaging biomarker, i.e., the theranostic score, which is calculated by non-invasive measurement of corneal riboflavin concentration and its UV-A light mediated photo-degradation. ARGO is a randomized multicenter clinical trial in patients aged between 18 and 40 years with progressive keratoconus aiming to validate the theranostic score by assessing the change of the maximum keratometry point value at 1-year postoperatively. A total of 50 participants will be stratified with allocation ratio 1:1 using a computer-generated stratification plan with blocks in two treatment protocols, such as epithelium-off or epithelium-on CXL. Following treatment, participants will be monitored for 12 months. Assessment of safety and performance of theranostic-guided corneal cross-linking treatment modality will be determined objectively by corneal tomography, corneal endothelial microscopy, visual acuity testing and slit-lamp eye examination.
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Affiliation(s)
- Anna Maria Roszkowska
- Ophthalmology Department, Faculty of Medicine, Health Sciences of Andrzej Frycz Modrzewski Krakow University, Gustawa Herlinga-Grudzińskiego 1, 30-705, Krakow, Poland. .,Dipartimento BIOMORF, Università di Messina, Via Consolare Valeria 1, 98100, Messina, Italy.
| | - Giuseppe Lombardo
- CNR-IPCF, Istituto per I Processi Chimico-Fisici, Viale F. Stagno D'Alcontres 37, 98158, Messina, Italy
| | - Rita Mencucci
- SOD Oculistica, AOU Careggi, Università di Firenze, Largo Brambilla 3, 50134, Florence, Italy
| | - Vincenzo Scorcia
- UO Oculistica, AOU Mater Domini, Università Magna Graecia di Catanzaro, Viale Europa, 88100, Catanzaro, Italy
| | - Giuseppe Giannaccare
- UO Oculistica, AOU Mater Domini, Università Magna Graecia di Catanzaro, Viale Europa, 88100, Catanzaro, Italy
| | - Annarita Vestri
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma "La Sapienza", Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Danilo Alunni Fegatelli
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma "La Sapienza", Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Giuseppe Massimo Bernava
- CNR-IPCF, Istituto per I Processi Chimico-Fisici, Viale F. Stagno D'Alcontres 37, 98158, Messina, Italy
| | | | - Marco Lombardo
- Studio Italiano di Oftalmologia, Via Livenza 3, 00198, Rome, Italy
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22
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Seifert FK, Theuersbacher J, Schwabe D, Lamm O, Hillenkamp J, Kampik D. Long-Term Outcome of Corneal Collagen Crosslinking with Riboflavin and UV-A Irradiation for Keratoconus. Curr Eye Res 2022; 47:1472-1478. [PMID: 36173395 DOI: 10.1080/02713683.2022.2117383] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE To evaluate long-term outcomes of corneal collagen crosslinking (CXL) using riboflavin and UV-A irradiation and to determine when to repeat CXL. METHODS In this retrospective consecutive interventional case series 131 eyes of 131 patients (95 male, 36 female, mean age 29.7 ± 11.4 years) between 2006 and 2016 received standard CXL (Dresden protocol, epithelium-off) for progressive keratoconus. Corrected distance visual acuity (CDVA) and corneal tomography (K1, K2, Kmax) were repeatedly recorded 1 year (n = 103 eyes) to 10 years (n = 44) postoperatively. Only one eye per patient was included. Paired t-test or Wilcoxon matched-pairs signed rank test was used for parametric and nonparametric data, respectively. RESULTS 1-3 years preoperatively, median K2 significantly increased by 1.1 D (p < 0.001). Postoperatively, median K2 increased by 0.1 D after 1 year, then decreased over the remaining postoperative period by 0.85 D (p = 0.021). Kmax fluctuated without significant change. Median apical corneal thickness decreased by 16 µm (p = 0.012) after 5 years and then returned to preoperative values. Mean CDVA showed a significant improvement (decrease in logMAR 0.08 after 10 years, p = 0.010). CXL non-responders, defined by a postoperative increase in Kmax>2 D, increased from 16% after 5 to 33% after 10 years. Risk factors for non-response were young age, high astigmatism (>4.3 D), thin cornea (<480 µm), poor initial visual acuity (CDVA ≥0.3 D), and atopic dermatitis. 4 eyes were re-treated 3-4 years after first CXL without complications and keratoconus stabilized thereafter. CONCLUSIONS CXL can slow or stop keratoconus progression. However, as the number of responders declines after 5 years, especially patients with risk factors may require re-treatment.
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Affiliation(s)
- Franziska K Seifert
- Department of Ophthalmology, University Hospital Wuerzburg, Wuerzburg, Germany
| | | | - Dorothee Schwabe
- Department of Ophthalmology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Olga Lamm
- Department of Ophthalmology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Jost Hillenkamp
- Department of Ophthalmology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Daniel Kampik
- Department of Ophthalmology, University Hospital Wuerzburg, Wuerzburg, Germany
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23
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Debono C, Smadja D, Saunier V, Touboul D. Sequential intracorneal ring segment implantation followed by transepithelial phototherapeutic keratectomy and corneal cross-linking. J Fr Ophtalmol 2022; 45:1117-1125. [DOI: 10.1016/j.jfo.2022.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 11/05/2022]
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24
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Enders C, Vogel D, Dreyhaupt J, Wolf W, Garip-Kuebler A, Hall J, Neuhann L, Werner JU. Corneal cross-linking in patients with keratoconus: up to 13 years of follow-up. Graefes Arch Clin Exp Ophthalmol 2022; 261:1037-1043. [PMID: 36197498 DOI: 10.1007/s00417-022-05844-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/20/2022] [Accepted: 09/21/2022] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION To evaluate long-term safety and efficacy of corneal collagen cross-linking (CXL) in patients with keratoconus up to 13 years. MATERIALS AND METHODS In this mono-centre exploratory study, we included all consecutive patients who underwent CXL in our cornea centre from 01/01/2007 to 12/30/2011 and met the inclusion criteria. CXL was performed in all patients according to the Dresden protocol. Evaluation included best-corrected visual acuity (BCVA), topographic keratometry by Scheimpflug corneal tomography and endothelial cell count (ECC). Follow-up measurements were taken up to 13 years after treatment were compared with baseline values. RESULTS The study enrolled 168 eyes. The mean age of our patients was 26.3 years ± 7.8 years. A complete topographic dataset was available 1 year postoperatively for 142 eyes, 5 years postoperatively for 105 eyes, 10 years postoperatively for 61 eyes and 13 years postoperatively for 9 eyes. BCVA increased statistically significant after 1 year, 5 years and 10 years and non-significantly after 13 years. All keratometric parameters with exception of posterior astigmatism showed a statistically significant decrease after 1 year, 5 years and 10 years. After 13 years, the decrease was statistically significant only in Kmax, K2 and thinnest cornea. No significant changes in ECC were detected. Three eyes received Re-CXL, none of the eyes received penetrating keratoplasty and no infections occurred in this cohort. CONCLUSIONS CXL can slow down or even stop the progression of keratoconus in the majority of cases. The effect is long-lasting with excellent safety.
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Affiliation(s)
- Christian Enders
- MVZ Prof. Neuhann GmbH, Helene-Weber-Allee 19, 80637, Munich, Germany.
| | - Diana Vogel
- MVZ Prof. Neuhann GmbH, Helene-Weber-Allee 19, 80637, Munich, Germany
| | - Jens Dreyhaupt
- Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany
| | - Waltraud Wolf
- MVZ Prof. Neuhann GmbH, Helene-Weber-Allee 19, 80637, Munich, Germany.,MVZ Smileeyes Alte Boerse, Munich, Germany
| | | | - Jonathan Hall
- MVZ Prof. Neuhann GmbH, Helene-Weber-Allee 19, 80637, Munich, Germany
| | - Lukas Neuhann
- MVZ Prof. Neuhann GmbH, Helene-Weber-Allee 19, 80637, Munich, Germany
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25
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Somohano K, Alzaga-Fernandez AG. Controversies in Corneal Collagen Crosslinking: A Review of Investigational Crosslinking Protocols and Its Off-label Application. Int Ophthalmol Clin 2022; 62:51-62. [PMID: 36170222 DOI: 10.1097/iio.0000000000000426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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26
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Miao Y, Liu J, Akella SS, Wang J, Li S, Chuck RS, Zhang C. Changes in Rat Scleral Collagen Structure Induced by UVA-Riboflavin Crosslinking at Various Tissue Depths in Whole Globe Versus Scleral Patch. Transl Vis Sci Technol 2022; 11:2. [PMID: 35913416 PMCID: PMC9351595 DOI: 10.1167/tvst.11.8.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate structural changes in scleral collagen fibers at various tissue depths before and after photosensitized crosslinking (CXL) both isolated scleral patch versus whole globe using second-harmonic generation (SHG) imaging. Methods Scleral tissues were harvested from Sprague-Dawley rats and separated into three groups: untreated sclera (control), full-thickness scleral patch for CXL (Free Scleral CXL group), and sclera in intact globe for CXL (Globe CXL group). The CXL groups were soaked in 0.1% riboflavin and irradiated with 365 nm ultraviolet-A light (power, 0.45 mW/cm2) for 30 minutes. SHG images were acquired every 5 µm between 10 and 60 µm from the outer scleral surface. Collagen fiber waviness was calculated as the ratio of the total length of a traced fiber and the length of a straight path between the fiber ends. Results In the Free Scleral CXL group, collagen waviness was significantly increased compared to the control group at 35 to 50 µm (P < 0.05). In the Globe CXL group, collagen waviness was decreased compared to control at all depths with statistical significance (P < 0.05) achieved from 10 to 45 µm. Conclusions Depending upon its initial state (i.e., free scleral patch versus mechanically loaded intact globe under pressure), collagen may experience different structural changes after CXL. In addition, the extent of the CXL effects may vary at different depths away from the surface. Translational Relevance Understanding the CXL effects on collagen structure may be important in optimizing the scleral crosslinking protocol for future clinical applications such as preventing myopic progression.
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Affiliation(s)
- Yuan Miao
- Aier School of Ophthalmology, Central South University, Changsha, Hunan, China.,Department of Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Juan Liu
- Department of Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, USA.,Department of Ophthalmology, People's Hospital of Ningxia Hui Autonomous Region, Yinchuan, Ningxia, China
| | - Sruti S Akella
- Department of Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jessie Wang
- Department of Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Shaowei Li
- Aier School of Ophthalmology, Central South University, Changsha, Hunan, China
| | - Roy S Chuck
- Aier School of Ophthalmology, Central South University, Changsha, Hunan, China
| | - Cheng Zhang
- Aier School of Ophthalmology, Central South University, Changsha, Hunan, China
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27
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Chan TCY, Tsui RWY, Chow VWS, Lam JKM, Wong VWY, Wan KH. Accelerated corneal collagen cross-linking in progressive keratoconus: Five-year results and predictors of visual and topographic outcomes. Indian J Ophthalmol 2022; 70:2930-2935. [PMID: 35918946 PMCID: PMC9672700 DOI: 10.4103/ijo.ijo_2778_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Purpose: To analyze the 5-year results of accelerated corneal collagen crosslinking (CXL) for progressive keratoconus and identify preoperative characteristics predictive of visual and topographic outcomes. Methods: A prospective interventional case series. Nineteen eyes of 19 patients receiving accelerated CXL with settings of 18 mW/cm2 for 5 min were included. Clinical and topographic parameters were assessed. Linear regression and logistic regression were used to compare the R2 and odds ratio (OR), respectively, between baseline characteristics and postoperative outcomes. Results: Corrected distance visual acuity (CDVA) remained stable from 0.28 ± 0.21 to 0.25 ± 0.18 logMAR (P = 0.486). The mean cylindrical refraction was stable (P = 0.119). The maximal keratometry (Kmax) decreased from 61.99 ± 10.37 to 59.25 ± 7.75 D (P < 0.001), flattening in the flattest and steepest meridians and mean keratometry were also observed (P ≤ 0.040). The mean anterior elevation at the apex reduced from 21.42 ± 16.69 to 18.53 ± 12.74 mm (P = 0.013) and changes in posterior elevation were non-significant (P = 0.629). Preoperative Kmax best predicted the postoperative change in Kmax (R2 = 0.55, P < 0.001) compared to the other baseline characteristics (P ≤ 0.028), whereas preoperative CDVA was the only significant predictor of postoperative change in CDVA (R2 = 0.41, P = 0.003). Accelerated CXL is less likely to fail in eyes with a steeper preoperative Kmax (OR = 0.74, P = 0.040) or greater posterior elevation at the apex (OR = 0.91, P = 0.042). Conclusion: Kmax significantly decreased following accelerated CXL. Eyes with worse preoperative CDVA and higher Kmax were more likely to have an improvement in visual acuity and corneal flattening.
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Affiliation(s)
- Tommy C Y Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; Department of Ophthalmology, Hong Kong Sanatorium and Hospital, Hong Kong
| | - Rachel W Y Tsui
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; Hong Kong Eye Hospital, Hong Kong
| | - Vanissa W S Chow
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; Hong Kong Eye Hospital, Hong Kong
| | - Jasmine K M Lam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; Hong Kong Eye Hospital, Hong Kong
| | - Victoria W Y Wong
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; Hong Kong Eye Hospital; LKS Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Kelvin H Wan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; Hong Kong Eye Hospital, Hong Kong
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28
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Yang K, Xu L, Wang S, Zhu M, Fan Q, Gu Y, Wang Y, Wang Q, Zhao D, Pang C, Ren S. A Bibliometric Analysis of 100 Most-Cited Articles on Corneal Cross-Linking. Front Med (Lausanne) 2022; 9:904077. [PMID: 35721090 PMCID: PMC9199002 DOI: 10.3389/fmed.2022.904077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
Background Highly cited papers are expected to have high-quality data that significantly contribute to the body of knowledge. The study aimed to evaluate the characters of the 100 most-cited articles on corneal cross-linking (CXL) through a bibliometric analysis. Materials and Methods The Web of Science database was searched to identify papers published from 1950 to 2020. A bibliometric analysis of the top 100-cited articles was conducted in the current study. The citation differences between basic research, clinical research, and reviews were compared by Kruskal-Wallis test. The association between citations and publication year was evaluated by Spearman correlation analysis. The VOSviewer software was used to create networks of co-authorship and keywords map. Results The median values of the number of citations, citations/year since publication, and citations since 2013 were 101, 9.5, and 11.92, respectively. A total of 61% of articles were clinical research. The citations since 2013 of clinical research were lower than basic research and the reviews (all p < 0.001). The publication year was positively correlated with the number of publications (r = 0.665, p = 0.013), and the total number of citations decreased for basic research (r = -0.447, p = 0.017), and clinical research (r = -0.433, p < 0.001). The J REFRACT SURG publishes the highest number of articles. The corresponding authors were predominantly from the Italy (N = 17), Germany (N = 16), and United States (N = 15). Spoerl Eberhard has the highest number of citations and total link strength with 15 articles. Extensive collaboration existed among the main core nodes containing "cross-linking (N = 45)," "riboflavin (N = 44)," and "ultraviolet A (UVA) (N = 42)." Conclusion The present study focused on the comprehensive analysis of the top 100-cited articles on the CXL research, providing insight into research developments over the past decades.
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Affiliation(s)
- Kaili Yang
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Liyan Xu
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Shaopei Wang
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Meng Zhu
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Qi Fan
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Yuwei Gu
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Yawen Wang
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Qing Wang
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Dongqing Zhao
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Chenjiu Pang
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Shengwei Ren
- Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, China
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Hashemi H, Roberts CJ, Ambrósio R, Mehravaran S, Hafezi F, Vinciguerra R, Vinciguerra P, Panahi P, Asgari S. Comparative Contralateral Randomized Clinical Trial of Standard (3 mW/cm 2) Versus Accelerated (9 mW/cm 2) CXL in Patients With Down Syndrome: 3-Year Results. J Refract Surg 2022; 38:381-388. [PMID: 35686709 DOI: 10.3928/1081597x-20220329-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the long-term results of accelerated corneal cross-linking (CXL) (9 mW/cm2, 10 min) with standard CXL (3 mW/cm2, 30 min) in patients with Down syndrome who had keratoconus. METHODS In this contralateral randomized clinical trial, 27 patients with Down syndrome aged 15.78 ± 2.46 years (range: 10 to 19 years) were enrolled. CXL was performed using the KXL System (Avedro, Inc) under general anesthesia, and patients were followed up for 3 years. The main outcome measure was a change in average keratometry in the 3-mm zone around the steepest point (zonal Kmax-3mm). Secondary outcomes were changes in Corvis ST (Oculus Optikgeräte GmbH) biomechanical parameters and vision, refraction, and corneal tomography measurements. RESULTS Mean 3-year changes in zonal Kmax-3mm were not significantly different between the accelerated and standard groups (-0.06 ± 0.75 and -0.35 ± 0.94 diopters [D], respectively, P = .727). Despite the contralateral design of the study, based on most baseline biomechanical indices, corneas in the standard group were weaker before treatment. The standard group also showed significantly fewer 3-year changes in the stress-strain index (-0.11 ± 0.21 vs -0.30 ± 0.32), integrated radius (+0.99 ± 3.48 vs +3.14 ± 2.84), and deformation amplitude ratio-2mm (-1.38 ± 1.33 vs +0.30 ± 1.75) (all P < .0167). Corneal stiffness in the accelerated group was stable for 2 years, and the decline mainly occurred during the third year. CONCLUSIONS In young patients with Down syndrome who had keratoconus, accelerated and standard CXL showed a similar flattening effect. Standard CXL is better able to maintain corneal stiffness in weaker corneas. With accelerated CXL, despite stable results for 2 years, there was decreased corneal stiffness in the third year. Longer follow-up periods are warranted to study the decreased efficacy on keratoconus progression. [J Refract Surg. 2022;38(6):381-388.].
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Lee J, Son BK, Kim TG, Jin KH. Ten-year Results after Conventional Corneal Cross-linking in Korean Patients with Progressive Keratoconus. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2022. [DOI: 10.3341/jkos.2022.63.5.417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Purpose: To evaluate the long-term effects of conventional corneal cross-linking in patients with progressive keratoconus.Methods: A total of 18 eyes of 9 patients diagnosed with keratoconus were analyzed retrospectively. One eye was diagnosed with progressive keratoconus and conventional corneal crosslinking was performed. The other eye was classified as non-progressive and remained untreated. All patients were assessed with best corrected visual acuity (BCVA), maximum keratometry (Kmax), mean keratometry (Kmean), corneal astigmatism, and corneal thickness. Clinical data were collected before the procedure and at 1, 3, 6 months and 1 to 10 years after the procedure.Results: The BCVA significantly improved from 0.63 ± 0.18 logarithm of the minimum angle of resolution (logMAR) to 0.46 ± 0.25 logMAR at 10 years after conventional corneal crosslinking (p = 0.027). The Kmax and Kmean decreased from 65.90 ± 9.43 D and 52.82 ± 5.16 D to 62.83 ± 8.16 D and 51.52 ± 5.18 D, respectively (p = 0.021, p = 0.028, respectively). Corneal astigmatism decreased from 6.97 ± 2.21 D to 5.53 ± 1.64 D (p = 0.008). The thinnest corneal thickness decreased from 435.11 ± 53.37 μm to 369.22 ± 64.00 μm 1 month after the procedure (p = 0.008), and gradually improved over time. At 10 years, the thinnest corneal thickness increased to 410.11 ± 61.32 μm (p = 0.097). In the untreated eyes, the mean keratometry significantly increased after 4 years of follow-up, but other factors did not change significantly. Although corneal opacity persisted for up to 10 years in 3 eyes of the treatment group, there was no significant difference of BCVA compared to the treated eyes without corneal opacity (p = 0.714).Conclusions: In patients with progressive keratoconus, conventional corneal crosslinking is a safe and effective procedure that suppresses long-term progression.
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Ashena Z, Doherty S, Gokul A, McGhee CNH, Ziaei M, Nanavaty MA. Flattening of Central, Paracentral, and Peripheral Cones After Non-accelerated and Accelerated Epithelium-off CXL in Keratoconus: A Multicenter Study. J Refract Surg 2022; 38:310-316. [PMID: 35536708 DOI: 10.3928/1081597x-20220404-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the flattening of central, paracentral, and peripheral cones following non-accelerated (non-A-CXL) and accelerated (A-CXL) epithelium-off corneal cross-linking with 10 times higher intensity. METHODS In this multicenter study of 200 eyes (100 in each group), following 10 minutes of soak time with riboflavin 0.1%, continuous CXL was performed for 30 minutes (intensity: 3 mW/cm2, fluence: 5.4 J/cm2) in the non-A-CXL group and 3 minutes (intensity: 30 mW/cm2, fluence: 5.4 J/cm2) in the A-CXL group. Anterior and posterior cone flattening were compared at 12 months. Multiple regression analysis was performed to establish correlation of age, sex, cone location, and preoperative maximum keratometry (Kmax) values with postoperative flattening at 12 months. RESULTS In the non-A-CXL and A-CXL groups, central cones were the steepest, followed by paracentral and peripheral cones. Both groups showed significant flattening in central (1.54 ± 1.94 and 1.09 ± 1.79 diopters [D]) and paracentral (0.62 ± 1.59 and 0.55 ± 0.98 D) cones only. In the non-A-CXL group, there was a positive correlation between postoperative flattening and preoperative Kmax values, whereas paracentral and peripheral cone locations were negatively related. In the A-CXL group, only paracentral location was negatively correlated to postoperative flattening and showed posterior cone steepening at 12 months. CONCLUSIONS Although central cones were the steepest in both groups, there was no difference in postoperative flattening between the groups for all cone locations. In the non-A-CXL group, postoperative flattening was proportional to preoperative Kmax values in central cones and was less with paracentral and peripheral locations. With A-CXL, postoperative flattening was less only with paracentral location. In the A-CXL group, significant posterior cone steepening was noticed only in paracentral cones. [J Refract Surg. 2022;38(5):310-316.].
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Dettoraki M, Droutsas K, Lazaridis A, Moschos MM. Evaluation of macular function and morphology following accelerated collagen cross-linking in progressive keratoconus. Eur J Ophthalmol 2022; 32:2547-2553. [PMID: 35450449 DOI: 10.1177/11206721221094880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To assess any changes in macular function and morphology in patients with progressive keratoconus undergoing accelerated corneal cross-linking (CXL). METHODS This prospective case series included 9 eyes of 8 patients with progressive keratoconus undergoing CXL using a high intensity accelerated protocol (9 mW/cm2 for 14 min) with a total surface dose of 7.5 J/cm2. Visual acuity assessment, slit lamp biomicroscopy, dilated fundoscopy, corneal tomography, multifocal electroretinography (mfERG) and spectral domain optical coherence tomography scan were performed at baseline, 2 weeks and 6 weeks postoperatively. RESULTS Uncorrected and corrected distance visual acuity did not change significantly at 2 weeks and 6 weeks following accelerated CXL compared to baseline. Retinal response density (RRD) of mfERG significantly decreased at 2 weeks postoperatively compared to baseline (p = 0.008) but did not differ from the baseline value at 6 weeks postoperatively in the fovea (ring 1) (p = 0.95). Similarly, P1 latency significantly decreased at 2 weeks (p = 0.04) but did not change at 6 weeks (p = 1.00) postoperatively compared to baseline in the fovea. No changes in RRD or P1 latency were observed in the retinal rings surrounding the fovea (rings 2 to 5). Central foveal thickness did not change at 2 weeks and 6 weeks postoperatively compared to baseline (p = 0.53 and p = 0.93, respectively). CONCLUSIONS A short-term reversible decrease in macular electrical activity without any structural changes seems to occur after accelerated CXL in patients with progressive keratoconus. The return of macular response to the preoperative values shows the safety of the CXL protocol.
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Affiliation(s)
- M Dettoraki
- First Department of Ophthalmology, Medical School, 393206National and Kapodistrian University of Athens, Athens, Greece
| | - K Droutsas
- First Department of Ophthalmology, Medical School, 393206National and Kapodistrian University of Athens, Athens, Greece.,Department of Ophthalmology, 98594Philipps University of Marburg, Marburg, Germany
| | - A Lazaridis
- Department of Ophthalmology, 98594Philipps University of Marburg, Marburg, Germany
| | - M M Moschos
- First Department of Ophthalmology, Medical School, 393206National and Kapodistrian University of Athens, Athens, Greece
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Fırat M, Çınar A, Çankaya C, Fırat İT, Tuncer T. Prediction of Pentacam image after corneal cross-linking by linear interpolation technique and U-NET based 2D regression model. Comput Biol Med 2022; 146:105541. [PMID: 35525070 DOI: 10.1016/j.compbiomed.2022.105541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 04/13/2022] [Accepted: 04/16/2022] [Indexed: 11/03/2022]
Abstract
Keratoconus is a common corneal disease that causes vision loss. In order to prevent the progression of the disease, the corneal cross-linking (CXL) treatment is applied. The follow-up of keratoconus after treatment is essential to predict the course of the disease and possible changes in the treatment. In this paper, a deep learning-based 2D regression method is proposed to predict the postoperative Pentacam map images of CXL-treated patients. New images are obtained by the linear interpolation augmentation method from the Pentacam images obtained before and after the CXL treatment. Augmented images and preoperative Pentacam images are given as input to U-Net-based 2D regression architecture. The output of the regression layer, the last layer of the U-Net architecture, provides a predicted Pentacam image of the later stage of the disease. The similarity of the predicted image in the final layer output to the Pentacam image in the postoperative period is evaluated by image similarity algorithms. As a result of the evaluation, the mean SSIM (The structural similarity index measure), PSNR (peak signal-to-noise ratio), and RMSE (root mean square error) similarity values are calculated as 0.8266, 65.85, and 0.134, respectively. These results show that our method successfully predicts the postoperative images of patients treated with CXL.
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Affiliation(s)
- Murat Fırat
- Malatya Turgut Ozal University, Faculty of Medicine, Malatya, Turkey
| | - Ahmet Çınar
- Firat University, Faculty of Engineering, Computer Engineering, Elazig, Turkey
| | - Cem Çankaya
- Inonu University Faculty of Medicine, Malatya, Turkey
| | | | - Taner Tuncer
- Firat University, Faculty of Engineering, Computer Engineering, Elazig, Turkey.
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Herber R, Graehlert X, Raiskup F, Veselá M, Pillunat LE, Spoerl E. Statistical Evaluation of Correlated Measurement Data in Longitudinal Setting Based on Bilateral Corneal Cross-Linking. Curr Eye Res 2022; 47:995-1002. [PMID: 35354347 DOI: 10.1080/02713683.2022.2052105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE In ophthalmology, data from both eyes of a person are frequently included in the statistical evaluation. This violates the requirement of data independence for classical statistical tests (e.g. t-Test or analysis of variance (ANOVA)) because it is correlated data. Linear mixed models (LMM) were used as a possibility to include the data of both eyes in the statistical evaluation. METHODS The LMM is available for a variety of statistical software such as SPSS or R. The application was applied to a retrospective longitudinal analysis of an accelerated corneal cross-linking (ACXL (9*10)) treatment in progressive keratoconus (KC) with a follow-up period of 36 months. Forty eyes of 20 patients were included, whereas sequential bilateral CXL treatment was performed within 12 months. LMM and ANOVA for repeated measurements were used for statistical evaluation of topographical and tomographical data measured by Pentacam (Oculus, Wetzlar, Germany). RESULTS Both eyes were classified into a worse and better eye concerning corneal topography. Visual acuity, keratometric values and minimal corneal thickness were statistically significant between them at baseline (p < 0.05). A significant correlation between worse and better eye was shown (p < 0.05). Therefore, analyzing the data at each follow-up visit using ANOVA partially led to an overestimation of the statistical effect that could be avoided by using LMM. After 36 months, ACXL has significantly improved BCVA and flattened the cornea. CONCLUSION The evaluation of data of both eyes without considering their correlation using classical statistical tests leads to an overestimation of the statistical effect, which can be avoided by using the LMM.
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Affiliation(s)
- Robert Herber
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Germany
| | - Xina Graehlert
- Coordination Center for Clinical Studies - KKS Dresden, Faculty of Medicine Carl Gustav Carus, TU Dresden, Germany
| | - Frederik Raiskup
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Germany
| | - Martina Veselá
- Department of Ophthalmology, Faculty of Medicine Hradec Králové, Charles University, Prague, Czech Republic
| | - Lutz E Pillunat
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Germany
| | - Eberhard Spoerl
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Germany
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35
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Li Y, Lu Y, Du K, Yin Y, Hu T, Fu Y, Xiang A, Fu Q, Wu X, Wen D. Comparison of Efficacy and Safety Between Standard, Accelerated Epithelium-Off and Transepithelial Corneal Collagen Crosslinking in Pediatric Keratoconus: A Meta-Analysis. Front Med (Lausanne) 2022; 9:787167. [PMID: 35372437 PMCID: PMC8968048 DOI: 10.3389/fmed.2022.787167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/15/2022] [Indexed: 01/10/2023] Open
Abstract
Purpose The purpose of the study is to compare the efficacy of standard epithelium-off CXL (SCXL), accelerated epithelium-off CXL (ACXL), and transepithelial crosslinking CXL (TECXL) for pediatric keratoconus. Methods A literature search on the efficacy of SCXL, ACXL, and TECXL [including accelerated TECXL (A-TECXL)] for keratoconus patients younger than 18 years was conducted using PubMed, Cochrane Library, ClinicalTrials.gov, and EMBASE up to 2021. Primary outcomes were changes in uncorrected visual acuity (UCVA) and maximum keratometry (Kmax) after CXL. Secondary outcomes were changes in best-corrected visual acuity (BCVA), mean refractive spherical equivalent (MRSE), and central corneal thickness (CCT). Estimations were analyzed by weighted mean difference (WMD) and 95% confidence interval (CI). Results A number of eleven identified studies enrolled 888 eyes (SCXL: 407 eyes; ACXL: 297 eyes; TECXL: 28 eyes; A-TECXL: 156 eyes). For pediatric keratoconus, except for a significant greater improvement in BCVA at 24-month follow-up in SCXL (WMD = –0.08, 95%CI: –0.14 to –0.01, p = 0.03, I2 = 71%), no significant difference was observed in other outcomes between the SCXL and ACXL groups. SCXL seems to provide greater changes in UCVA (WMD = –0.24, 95% CI: –0.34 to –0.13, p < 0.00001, I2 = 89%), BCVA (WMD = –0.09, 95% CI: –0.15 to –0.04, p = 0.0008, I2 = 94%), and Kmax (WMD = –1.93, 95% CI: –3.02 to –0.85, p = 0.0005, I2 = 0%) than A-TECXL, with higher incidence of adverse events. Conclusion For pediatric keratoconus, both SCXL and ACXL appear to be comparable in the efficacy of visual effects and keratometric outcomes; SCXL seems to provide greater changes in visual and pachymetric outcomes than A-TECXL.
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Affiliation(s)
- Yuanjun Li
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Ying Lu
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Kaixuan Du
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yewei Yin
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Tu Hu
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yanyan Fu
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Aiqun Xiang
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Qiuman Fu
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaoying Wu
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Dan Wen
- Eye Center of Xiangya Hospital, Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Dan Wen,
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Jackson AJ, Anand V. Keratoconus: To conquer the cone. Cont Lens Anterior Eye 2022; 45:101578. [PMID: 35210169 DOI: 10.1016/j.clae.2022.101578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Vijay Anand
- Deputy Head of Optometry, Moorfields Eye Hospital NHSFT, United Kingdom.
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Borgardts K, Menzel-Severing J, Geerling G, Seiler TG. [Treatment indications for corneal crosslinking and clinical results of new corneal crosslinking techniques]. Ophthalmologe 2022; 119:350-357. [PMID: 35147774 DOI: 10.1007/s00347-022-01579-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2022] [Indexed: 10/19/2022]
Abstract
BACKGROUND Corneal crosslinking (CXL) is used in keratoconus to strengthen and stabilize the cornea and to prevent further progression with subsequent visual loss and the possible need for keratoplasty. Correct treatment indications is crucial in this context. Since the introduction of the initial Dresden protocol, other modified CXL protocols have been proposed to optimize treatment success. OBJECTIVE The relevant parameters for treatment indications are explained and the clinical results of new CXL protocols are presented. METHODS The currently valid criteria with respect to the indications for CXL in keratoconus, PubMed search for relevant publications and own experiences with different CXL protocols are presented. RESULTS The reproducibility of topographic parameters depends on the stage of the keratoconus. Accelerated CXL as well as transepithelial CXL with a hyperoxic environment show comparable efficiency with shorter surgery time and possibly lower complication rates. Customized CXL with an individualized UV irradiation profile provides improved results with faster epithelial healing. Lower UV energy doses enable CXL to be conducted in eyes with minimal stromal pachymetry of less than 400 µm before irradiation. The combination of CXL with photorefractive keratectomy (PRK) provides visual acuity improvements but also increases the risk of visual loss. CONCLUSION Current indication rules for CXL neglect the reduced reproducability of topographic and tomographic measurements in keratoconus. The latest CXL protocols presented here provide a safe alternative with similar and/or better efficacy compared to standard CXL. The combination of CXL with PRK offers an option for visual rehabilitation in patients with contact lens intolerance.
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Affiliation(s)
- Klara Borgardts
- Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - Johannes Menzel-Severing
- Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - Gerd Geerling
- Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - Theo G Seiler
- Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland. .,Institut für Refraktive und Ophthalmo-Chirurgie (IROC), Stockerstr. 37, 8002, Zürich, Schweiz. .,Klinik für Augenheilkunde, Universitätsspital Bern, Inselspital Bern, 3010, Bern, Schweiz.
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Ishii H, Yoshida J, Toyono T, Yamagami S, Usui T, Miyai T. Three-year results of accelerated transepithelial cross-linking (30 mW/cm2 × 3 min) for keratoconus: a prospective study. BMJ Open Ophthalmol 2022; 7:e000827. [PMID: 35224204 PMCID: PMC8830257 DOI: 10.1136/bmjophth-2021-000827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 01/21/2022] [Indexed: 11/04/2022] Open
Abstract
ObjectiveTo assess the long-term efficacy and safety of accelerated transepithelial corneal cross-linking (ATE-CXL) with 30 mW/cm2 × 3 min.Methods and AnalysisThirty-four eyes of 23 patients with progressive keratoconus (KCN) recruited within a single centre were enrolled in this prospective interventional study. Exclusion criteria included: history of Descemet’s membrane rupture, glaucoma, uveitis, severe dry eye, concurrent corneal infections, and systemic disease that could affect corneal healing. ATE-CXL was performed with 3 min of ultraviolet-A continuous irradiation (30 mW/cm2). Follow-up examinations were scheduled on postoperative day 1; 1 and 2 weeks; 1, 3 and 6 months; and 1, 2 and 3 years. Main outcome measures were maximum corneal power (Kmax), average corneal power (AvgK), steepest corneal power (Ks), central corneal thickness, thinnest corneal thickness, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA) and endothelial cell density.ResultsMean Kmax, AvgK, Ks, UCVA, BCVA and endothelial cell density did not significantly change over 3 years. The speed of progression obtained by linear regression analysis on corneal parameters (Kmax, AvgK, Ks) improved after ATE-CXL. All baseline parameters correlated with the postoperative Kmax slope. Two eyes underwent ATE-CXL redo because of continued progression after the primary CXL.ConclusionThis is the first report of 3-year results of ATE-CXL with 30 mW/cm2 × 3 min. ATE-CXL (30 mW/cm2 × 3 min) was safe and effective for slowing down KCN progression.Trial registration numberThis study was registered with ID UMIN000009372 in UMIN-Clinical Trials Registry.
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Affiliation(s)
- Hitoha Ishii
- The Department of Ophthalmology, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan
| | - Junko Yoshida
- The Department of Ophthalmology, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan
- Department of Ophthalmology, International University of Health and Welfare Mita Hospital, Minato-ku, Tokyo, Japan
| | - Tetsuya Toyono
- The Department of Ophthalmology, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan
| | - Satoru Yamagami
- Division of Ophthalmology, Department of Visual Sciences, Nihon Daigaku, Chiyoda-ku, Tokyo, Japan
| | - Tomohiko Usui
- Department of Ophthalmology, International University of Health and Welfare Mita Hospital, Minato-ku, Tokyo, Japan
| | - Takashi Miyai
- The Department of Ophthalmology, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan
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Wajnsztajn D, Shmueli O, Zur K, Frucht-Pery J, Solomon A. Predicting factors for the efficacy of cross-linking for keratoconus. PLoS One 2022; 17:e0263528. [PMID: 35113959 PMCID: PMC8812864 DOI: 10.1371/journal.pone.0263528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 01/20/2022] [Indexed: 11/19/2022] Open
Abstract
Purpose
To evaluate predictors for success in corneal crosslinking (CXL) for keratoconus in a large cohort and extended follow-up.
Design
A retrospective study based on a prospectively built database.
Methods
Participants underwent CXL for keratoconus from 2007 to 2018. Statistical analysis was performed for patients with at least 1-year follow-up. We analyzed effects of CXL type (Epithelium-on or Epithelium-off and Accelerated (9mW/cm2@10min) or Standard (3mW/cm2@30min)) and pre-operative factors including age, gender, baseline LogMAR visual acuity (LogMARpre), maximal corneal power (Kmaxpre), pachymetry, refractive and topographic cylinders, spherical equivalent (SEpre), mean corneal power (MeanK) and follow-up time on outcome measures. The outcome measures were the final change of Kmax (Delta Kmax) and the final change in LogMAR visual acuity (Delta LogMAR). A more negative Delta Kmax or Delta LogMAR represents a favorable effect of crosslinking.
Results
517 eyes had Kmax results, and 385 eyes had LogMAR results with more than one year follow-up. These eyes were included in the study. The mean follow-up time was 2.29 years. Mean Kmax decreased from 54.07±5.99 diopters to 52.84±5.66 diopters (p<0.001), and Mean LogMAR decreased from 0.28±0.20 to 0.25±0.21 (p<0.001). Non-accelerated epithelium-off CXL resulted in greater flattening of Kmax when compared with other protocols. Visual acuity improvement was similar when comparing different CXL protocols. Multivariate analysis showed four factors associated with negative Delta Kmax: high Kmaxpre, high SEpre, high MeanKpre, and non-accelerated procedure. Multivariate analysis showed three factors associated with negative Delta LogMAR: high LogMARpre, high SEpre, and Low MeanKpre. After excluding corneas with Kmaxpre >65 D or Pachymetry<400 microns, multivariate analysis showed that high Kmaxpre, high SEpre, and non-accelerated CXL were associated with negative Delta Kmax while high LogMARpre and high SEpre were associated with negative Delta LogMAR.
Conclusion
CXL for keratoconus is a highly effective treatment, as evident by its effects on the outcome measures: Delta Kmax and Delta LogMAR. CXL was more successful in eyes with high Kmaxpre, high SEpre, and high LogMARpre, which express disease severity. The non-accelerated epithelium-off protocol was associated with greater flattening of corneal curvature but did not show a better effect on visual acuity as compared to the other CXL protocols.
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Affiliation(s)
- Denise Wajnsztajn
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Or Shmueli
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Ken Zur
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Joseph Frucht-Pery
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Abraham Solomon
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
- * E-mail:
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Lenk J, Herber R, Oswald C, Spoerl E, Pillunat LE, Raiskup F. Risk Factors for Progression of Keratoconus and Failure Rate After Corneal Cross-linking. J Refract Surg 2021; 37:816-823. [PMID: 34914558 DOI: 10.3928/1081597x-20210830-01] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the occurrence of risk factors for progression of keratoconus and failure rate after corneal cross-linking (CXL) in patients with progressive keratoconus. METHODS This retrospective study observed 230 eyes of 173 patients with a minimum follow-up of 36 months after CXL. A total of 185 eyes underwent CXL once (80%) (control) and 45 (20%) underwent this treatment more than once (Re-CXL-group). Subgroup analysis included standard CXL with the Dresden protocol (S-CXL group, n = 120) and accelerated CXL with a reduced radiation time of 10 minutes and a higher radiation power of 9 mW/cm2 (A-CXL group, n = 110). Risk factors of interest were age, maximum keratometry (Kmax), minimum corneal thickness (MCT), sex, and atopy (including allergic bronchial asthma, food allergy, allergic rhinitis, and neurodermatitis). RESULTS Follow-up for the control group was 76.0 ± 33.2 months. Re-CXL was performed after 46.2 ± 34.1 months overall and after 62.6 ± 41.9 months in the S-CXL subgroup and 29.2 ± 19.2 months in the A-CXL subgroup (P = .02). Kaplan-Meier analysis revealed a cumulative prediction rate of success after CXL of 92.5% (S-CXL) and 86.4% (A-CXL) after 36 months (P = .103). A high preoperative Kmax value (odds ratio = 1.056, P = .003 and odds ratio = 1.067, P = .028) in both subgroups and the presence of neurodermatitis combined with other atopic diseases in the A-CXL group (odds ratio = 11.662, P = .003) were significant risk factors for new progression of keratoconus after CXL. CONCLUSIONS Risk factors for progression of keratoconus after CXL are both high preoperative Kmax values and the presence of neurodermatitis combined with other atopic diseases. Patients with severe atopy should receive the S-CXL procedure. [J Refract Surg. 2021;37(12):816-823.].
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Lenk J, Herber R, Raiskup F, Pillunat LE, Spörl E. [Principles of corneal cross-linking : Presentation based on the development of the various treatment protocols]. Ophthalmologe 2021; 119:332-341. [PMID: 34882268 DOI: 10.1007/s00347-021-01538-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Corneal cross-linking (CXL) is used to treat corneal ectatic diseases. The aim is to improve the reduced consolidation of the cornea in order to halt further corneal protrusion and therefore subsequent deterioration of the optical imaging proportions. MATERIAL AND METHODS In this article the principles of corneal cross-linking based on riboflavin and UV light are presented including recent research results. Furthermore, the most important treatment protocols including standard CXL (S-CXL), accelerated CXL (A-CXL), transepithelial CXL (TE-CXL) and the approach of the CXL procedure for thin corneas are explained. RESULTS The CXL method depends on four major components, the riboflavin solution, oxygen, UV light and the availability of cross-linking sites on the collagen tissue. According to the present state of knowledge, the photochemical process of the CXL method induces covalent bonds between the fibrils and proteoglycans and thus stabilizes the collagen fibers, resulting in corneal consolidation. In addition to the S‑CXL, which has proven its effectiveness and safety in a large number of studies, there are other treatment protocols that have been developed based on the Bunsen-Roscoe law of reciprocity. The A‑CXL protocol has the advantage of having a shorter irradiation time but it seems to be less effective than the S‑CXL protocol concerning the increase in corneal stiffness. The use of TE-CXL has so far not yet gained acceptance in the clinical practice. CONCLUSION The CXL procedures primarily aim to stabilize the cornea. In the future, in addition to stabilization of the cornea, simultaneous improvement of visual acuity will be the main focus.
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Affiliation(s)
- Janine Lenk
- Augenklinik, Universitätsklinikum Carl Gustav Carus, TU Dresden, Fetscherstr. 74, 01307, Dresden, Deutschland.
| | - Robert Herber
- Augenklinik, Universitätsklinikum Carl Gustav Carus, TU Dresden, Fetscherstr. 74, 01307, Dresden, Deutschland
| | - Frederik Raiskup
- Augenklinik, Universitätsklinikum Carl Gustav Carus, TU Dresden, Fetscherstr. 74, 01307, Dresden, Deutschland
| | - Lutz E Pillunat
- Augenklinik, Universitätsklinikum Carl Gustav Carus, TU Dresden, Fetscherstr. 74, 01307, Dresden, Deutschland
| | - Eberhard Spörl
- Augenklinik, Universitätsklinikum Carl Gustav Carus, TU Dresden, Fetscherstr. 74, 01307, Dresden, Deutschland
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Kandel H, Nguyen V, Ferdi AC, Gupta A, Abbondanza M, Sullivan L, Apel A, Watson SL. Comparative Efficacy and Safety of Standard Versus Accelerated Corneal Crosslinking for Keratoconus: 1-Year Outcomes From the Save Sight Keratoconus Registry Study. Cornea 2021; 40:1581-1589. [PMID: 33935236 DOI: 10.1097/ico.0000000000002747] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 03/04/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim of this study was to compare the efficacy and safety of standard [Ultraviolet (UV) light power: 3 mW/cm2, duration: 30 minutes] versus accelerated (UV power: 9 mW/cm2, duration: 10 minutes) corneal crosslinking (CXL) for stabilizing keratoconus. METHODS A total of 684 eyes (555 patients; mean age ± SD, 25.0 ± 7.9 years; women, 30.6%) from 24 international sites with epithelium-off CXL for keratoconus had follow-up data at 1-year and met the inclusion criteria. Two hundred sixty-six eyes (228 patients) had undergone standard CXL, and 418 eyes (327 patients) had undergone accelerated CXL. The outcome measures included changes in visual acuity, keratometry, minimum corneal thickness, and frequency of adverse events. The outcomes were compared using mixed-effects regression models adjusted for age, sex, visual acuity, keratometry, pachymetry, doctor, practice, and eye laterality. RESULTS The adjusted mean changes (95% confidence interval) in outcomes were similar in standard and accelerated CXL in visual acuity [6.5 (2.0, 11.1) versus 5.5 (0.4, 10.6) logMAR letters, respectively], Kmax [-0.9 (-1.4, -0.3) D versus -1.2 (-1.9, -0.4) D, respectively], K2 [-0.4 (-0.9, 0.2) D versus -0.4 (-1.1, 0.3), D respectively], or minimum corneal thickness [-13.3 (-20.3, -6.3) μm versus -16.6 (-24.5, -8.6) μm, respectively] (all P > 0.05). The frequency of adverse events at the 12-month visit was also similar between the CXL groups (standard, 8.3% vs. accelerated, 5.5%; P = 0.21). CONCLUSIONS This real-world observational study found that both standard and accelerated CXL were similarly safe and effective in stabilizing keratoconus at 1-year postsurgery in the real-world setting. The findings support the adoption of accelerated CXL for time and convenience.
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Affiliation(s)
- Himal Kandel
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute, Sydney, NSW, Australia
| | - Vuong Nguyen
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute, Sydney, NSW, Australia
| | - Alex C Ferdi
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute, Sydney, NSW, Australia
| | - Aanchal Gupta
- Adelaide Eye & Laser Centre, Adelaide, SA, Australia
- South Australian Institute of Ophthalmology, Adelaide, SA, Australia
| | | | | | - Andrew Apel
- The Eye Health Centre, Brisbane, QLD, Australia
| | - Stephanie L Watson
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute, Sydney, NSW, Australia
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Clinical Outcomes of Accelerated Corneal Cross-Linking for Pediatric Keratoconus. J Ophthalmol 2021; 2021:1851883. [PMID: 34840821 PMCID: PMC8616643 DOI: 10.1155/2021/1851883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/15/2021] [Accepted: 10/29/2021] [Indexed: 11/18/2022] Open
Abstract
Aim To assess the efficacy and safety of accelerated corneal cross-linking in the treatment of pediatric keratoconus. Method In this retrospective case series, 29 eyes of 20 pediatric patients with keratoconus underwent accelerated corneal cross-linking. Treatment was delivered at 10 mW/cm2 for 9 minutes with a total dose of 5.4 J/cm2. Clinical evaluation included visual acuities and refractive and Scheimpflug corneal tomography assessments. All patients with a minimum follow-up duration of 24 months were included in the study. Results Mean ± standard deviation age was 15.41 ± 2.13 years (range: 8 to 18 years). Uncorrected distance visual acuity improved significantly from 0.56 ± 0.28 to 0.42 ± 0.29 logMAR (P=0.0003), and corrected distance visual acuity improved significantly from 0.34 ± 0.23 to 0.28 ± 0.22 logMAR (P=0.014). The mean manifest refraction spherical equivalent value was significantly reduced (-0.59 ± 0.95 D, P=0.0024). While mean flat keratometry and steep keratometry values were not significantly altered (P > 0.05 for both), the mean maximum keratometry value was significantly decreased from 56.97 ± 5.24 D preoperatively to 55.84 ± 5.37 D at 24 months postoperatively (P=0.003). Maximum keratometry had progressed by >1 D in two eyes (6.89%). Permanent corneal haze was reported in one case (3.44%). Conclusion Our 24-month follow-up demonstrated that accelerated corneal cross-linking appears to halt the progression of keratoconus in pediatric patients without apparent complications. Uncorrected and corrected distance visual acuities were also improved.
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Seyyar SA, Mete A, Kimyon S, Tıskaoğlu NS. Outcomes of customized topographic guided epithelial debridement for corneal collagen cross-linking. Int Ophthalmol 2021; 42:1273-1280. [PMID: 34727264 DOI: 10.1007/s10792-021-02114-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 10/21/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE To evaluate the outcomes of corneal collagen cross-linking performed with customized epithelial debridement technique in progressive keratoconic corneas. MATERIALS AND METHODS Forty eyes of 40 patients were included in the study. We performed an ophthalmologic examination and recorded the uncorrected visual acuity, best corrected visual acuity (BCVA), central corneal thickness at the thinnest point (t-CCT), flat meridian keratometry (K1), steep meridian keratometry (K2), endothelial cell density (ECC), hexagonal cells (HEX), and coefficient of variation of cell areas (CV) measured preoperatively and at the 1st, 3rd, 6th and 12th months postoperatively. RESULTS The mean UCVA and BCVA were increased (p < 0.05). The mean flattest and steepest K readings were decreased (p < 0.05). The mean t-CCT decreased in the first months after treatment and increased after 6 months. The mean t-CCT was thicker at 12 months compared to pretreatment status (p < 0.05). The mean ECC and CV were not significantly different between follow-up intervals (p > 0.05). The mean HEX was statistically increased (p > 0.05). CONCLUSIONS Corneal collagen cross-linking performed with customized epithelial debridement technique is a successful alternative method for stopping the progression of keratoconus after 12 months of treatment.
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Affiliation(s)
- Sevim Ayca Seyyar
- Kocaeli Derince Education and Research Hospital Ophthalmology Department, İbni Sina, Lojman Sk., 41900, Derince, Kocaeli, Turkey.
| | - Alper Mete
- Gaziantep University Hospital Ophthalmology Department, Gaziantep, Turkey
| | - Sabit Kimyon
- Gaziantep University Hospital Ophthalmology Department, Gaziantep, Turkey
| | - Nesime Setge Tıskaoğlu
- Ersin Arslan Education and Research Hospital Ophthalmology Department, Gaziantep, Turkey
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Adverse events after riboflavin/UV-A corneal cross-linking: a literature review. Int Ophthalmol 2021; 42:337-348. [PMID: 34448966 DOI: 10.1007/s10792-021-02019-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 08/12/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Riboflavin/UV-A corneal cross-linking (CXL) for treating keratoconus and iatrogenic corneal ectasia has been well-established as first treatment option to stabilize corneal tissue biomechanical instability. Although the plethora of clinical studies has been published into the field, there is no systematic review assessing the type and frequency of adverse events after CXL. METHODS A systemic literature review on clinical safety and adverse events after CXL in patients with keratoconus and corneal ectasia was performed using PubMed. A literature search was performed for relevant peer-reviewed publications. The main outcome measures extracted from the articles were adverse events, endothelial cell density, corrected distance visual acuity and maximum simulated keratometry. RESULTS The most frequent adverse events after CXL were corneal haze and corneal edema, which were mild and transient. The severe adverse events were infrequent (cumulative incidence: < 1.3%) after CXL. The clinical benefits of CXL highly outweighed the risks for the treatment of keratoconus and corneal ectasia. CONCLUSIONS The severe adverse events with permanent sequelae are infrequent after CXL and all are associated with corneal de-epithelialization, such as infectious keratitis and corneal scarring.
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Murchison CE, Petroll WM, Robertson DM. Infectious keratitis after corneal crosslinking: systematic review. J Cataract Refract Surg 2021; 47:1075-1080. [PMID: 33769765 PMCID: PMC8298263 DOI: 10.1097/j.jcrs.0000000000000620] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 01/29/2021] [Indexed: 11/26/2022]
Abstract
Corneal crosslinking is a U.S. Food and Drug Administration--approved therapy to stiffen the cornea and prevent progression of corneal ectasia in patients with keratoconus. The standard procedure involves removal of the corneal epithelium (epithelial-off) prior to treatment. Variations to the standard procedure include accelerated crosslinking and transepithelial procedures. This study reviewed what is known regarding the risk for infection after epithelial-off crosslinking, the spectrum of pathogens, and clinical outcomes. 26 publications were identified. All eyes were fit with a bandage contact lens postoperatively. Available data indicate that the overall frequency of infectious keratitis after epithelium-off crosslinking is low. Bacterial infections are the most common, with a mean time of presentation of 4.8 days postoperatively. The use of steroids and bandage contact lenses in the immediate postoperative period and/or a history of atopic or herpetic disease were associated with infection. These patients require intense postoperative care with prophylactic antiviral therapy when appropriate.
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Affiliation(s)
- Caroline E Murchison
- From the Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas
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Systemic supplemental oxygen therapy during accelerated corneal crosslinking for progressive keratoconus: randomized clinical trial. J Cataract Refract Surg 2021; 47:773-779. [PMID: 33252568 DOI: 10.1097/j.jcrs.0000000000000513] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/04/2020] [Indexed: 02/03/2023]
Abstract
PURPOSE To investigate the potential additive effect of systemic supplemental oxygen administered during accelerated corneal crosslinking (CXL) for progressive keratoconus (KC). SETTING Academic center. DESIGN Randomized clinical trial. METHODS Eyes with progressive KC randomized to 3 different CXL protocols were included. The first group (OA-CXL) included 19 eyes that underwent an accelerated CXL protocol (9 mW/cm2 for 10 minutes) while receiving systemic oxygen at a rate of 5 L/min for 10 minutes. The second group consisted of 14 eyes undergoing the same accelerated CXL protocol without supplemental oxygen therapy (A-CXL). The third group (C-CXL) comprised 14 eyes undergoing conventional CXL according to the Dresden protocol. All subjects were followed up for at least 6 months. Visual acuity, keratometry and corneal biomechanical parameters including corneal hysteresis and corneal resistance factor (CRF) were measured preoperatively and 6 months postoperatively. RESULTS Reduction in maximum keratometry (Kmax) was significantly greater in the OA-CXL group (P = .01). At baseline, the mean Kmax was 54.31 ± 3.64 diopters (D) in the OA-CXL group, 54.66 ± 4.99 D in the A-CXL group, and 56.03 ± 5.28 D in the C-CXL group (P = .58), which reached 53.58 ± 3.24 D, 54.59 ± 4.65 D, and 55.87 ± 4.73 D at 6 months in the 3 study groups, respectively (P = .115). The mean CRF increased significantly only in the OA-CXL group from a baseline value of 6.32 ± 2.12 mm Hg to 7.38 ± 1.88 mm Hg at 6 months (P = .009). CONCLUSIONS This study suggests superior efficacy of an accelerated CXL protocol coupled with systemic oxygen supplementation when compared with the accelerated CXL protocol and the conventional protocol in eyes with progressive KC. In addition to greater reduction in Kmax as the primary outcome, improvement in corneal biomechanics was also observed at 6 months.
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Pasha H, Palazzolo L, Prakash G, Jhanji V. Update on corneal collagen crosslinking for ectasia. Curr Opin Ophthalmol 2021; 32:343-347. [PMID: 33966013 DOI: 10.1097/icu.0000000000000765] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Corneal collagen crosslinking (CXL) is a minimally invasive treatment that can stabilize corneal ectatic disorders including keratoconus, pellucid marginal degeneration, or postrefractive surgery ectasia. The benefits of CXL have been well documented. New research is focused on modifying current treatment protocols with the goals of maximizing corneal stability while also shortening overall procedure time. RECENT FINDINGS Accelerated CXL protocols have the goal of delivering the same ultraviolet A intensity as conventional protocols, but over a shorter time period. Accelerated protocols have shown success to date, but there are concerns for long-term corneal stability. Pulsed protocols may increase the long-term efficacy of the accelerated designs. In addition, transepithelial crosslinking protocols have been designed with the goal of reducing postoperative pain and lower the risk of infectious complications of epithelial-off conventional protocols. SUMMARY Newer CXL protocols attempt to make the procedure safer and more effective. Current research is promising, but long-term studies are essential to understand how the new protocols may affect corneal stability.
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Affiliation(s)
- Hamza Pasha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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Kobashi H, Hieda O, Itoi M, Kamiya K, Kato N, Shimazaki J, Tsubota K. Corneal Cross-Linking for Paediatric Keratoconus: A Systematic Review and Meta-Analysis. J Clin Med 2021; 10:jcm10122626. [PMID: 34203646 PMCID: PMC8232120 DOI: 10.3390/jcm10122626] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/28/2021] [Accepted: 06/03/2021] [Indexed: 12/20/2022] Open
Abstract
All corneal cross-linking techniques attenuated disease progression in patients with pediatric keratoconus for at least one year based on a meta-analysis. A standard and accelerated technique led to marked improvement in visual acuity. We determined the efficacy and safety of corneal cross-linking (CXL) in pediatric keratoconus by conducting a systematic review and meta-analysis. The PubMed and Cochrane databases were searched for relevant studies on the effects of standard, transepithelial, and/or accelerated CXL protocols in patients aged 18 years or younger. Standardized mean differences with 95% confidence intervals were calculated to compare the data collected at baseline and 12 months. The primary outcomes were maximum keratometry (Kmax) and uncorrected visual acuity (UCVA), and the secondary outcomes were the thinnest corneal thickness (TCT), best-corrected visual acuity (BCVA), and manifest refraction spherical equivalent or cylindrical refraction. Our search yielded 7913 publications, of which 26 were included in our systematic review and 21 were included in the meta-analysis. Standard CXL significantly improved the Kmax, UCVA, and BCVA, and significantly decreased the TCT. Accelerated CXL significantly improved UCVA and BCVA. In the transepithelial and accelerated-transepithelial CXL methods, each measurable parameter did not change after treatments. All CXL techniques attenuated disease progression in patients with pediatric keratoconus for at least one year. Standard and accelerated CXL led to marked improvement in visual acuity.
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Affiliation(s)
- Hidenaga Kobashi
- Department of Ophthalmology, School of Medicine, Keio University, Tokyo 160-8582, Japan; (N.K.); (K.T.)
- Tsubota Laboratory Inc., Tokyo 160-0016, Japan
- Correspondence: or
| | - Osamu Hieda
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan; (O.H.); (M.I.)
| | - Motohiro Itoi
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan; (O.H.); (M.I.)
| | - Kazutaka Kamiya
- Department of Ophthalmology, School of Medicine, University of Kitasato, Kanagawa 252-0329, Japan;
| | - Naoko Kato
- Department of Ophthalmology, School of Medicine, Keio University, Tokyo 160-8582, Japan; (N.K.); (K.T.)
- Department of Ophthalmology, Ichikawa General Hospital, Tokyo Dental College, Chiba 272-8513, Japan;
| | - Jun Shimazaki
- Department of Ophthalmology, Ichikawa General Hospital, Tokyo Dental College, Chiba 272-8513, Japan;
| | - Kazuo Tsubota
- Department of Ophthalmology, School of Medicine, Keio University, Tokyo 160-8582, Japan; (N.K.); (K.T.)
- Tsubota Laboratory Inc., Tokyo 160-0016, Japan
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Vinciguerra R, Fossati G, Sorrentino T, Legrottaglie EF, Piscopo R, Rosetta P, Vinciguerra P. Corneal Cross-linking for Progressive Keratoconus in Patients Older Than 40 Years: Long-term Follow-up. J Refract Surg 2021; 37:338-342. [PMID: 34044691 DOI: 10.3928/1081597x-20210210-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the long-term efficacy and safety of epithelium-off corneal cross-linking according to the standard (Dresden) protocol (S-CXL) in patients with progressive keratoconus older than 40 years. METHODS Seventy-six eyes of 64 patients with a mean age of 46.4 ± 5.2 years were included. At baseline and after 6, 12, 24, 36, 48, 60, 72, 84, and more than 96 months (when available) after S-CXL, all patients were assessed with distance-corrected visual acuity (DCVA) and corneal topography and tomography with Pentacam HR (OCULUS Optikgeräte GmbH). A generalized linear model was used to compare the groups. Outcome measures were maximum keratometry, thinnest point, coma, spherical, and higher order aberrations, and ABC values. Fixed and random factors were age, gender, atopy, laterality, and group. RESULTS The mean follow-up time was 62.1 ± 40.1 months (range: 12 to 144 months). The main outcome of the study was the evidence that S-CXL was able to safely stop the progression of keratoconus in all patients with none requiring repeat CXL. The generalized linear model analysis showed no significant change in DCVA over time (P = 1.000), but atopy was negatively associated with DCVA (P = .030, B = -0.69). The generalized linear model also showed that CXL was able to induce a significant flattening demonstrated as reduction of maximum keratometry (P = .001, B = -0.35) and A value (P =.001, B = -0.015) of the ABC display. Similarly, coma aberration was reduced over time (P = .006, B = -0.005). CONCLUSIONS S-CXL was confirmed to be a safe and effective treatment for progressive keratoconus even after the age of 40 years, inducing a significant flattening of the cone. [J Refract Surg. 2021;37(5):338-342.].
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