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Niazi S, Doroodgar F, Nazari SH, Rahimi Y, Del Barrio JLA, Gatzioufas Z, Findl O, Vinciguerra P, Vinciguerra R, Moshirfar M, Ambrósio R, Alio JL. Refractive surgical approaches to keratoconus: A systematic review and network meta-analysis. Surv Ophthalmol 2024:S0039-6257(24)00045-6. [PMID: 38710236 DOI: 10.1016/j.survophthal.2024.04.008] [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: 10/25/2023] [Revised: 04/25/2024] [Accepted: 04/29/2024] [Indexed: 05/08/2024]
Abstract
Advancements in diagnostic methods and surgical techniques for keratoconus (KC) have increased non-invasive treatment options. Successful surgical planning for KC involves a combination of clinical science, empirical evidence, and surgical expertise. Assessment of disease progression is crucial, and halting the progression should be the focus if it is progressive. While surgeons used to rely on experience alone to decide the surgical method, comparing the network of primary factors, such as visual acuity, across studies can help them choose the most appropriate treatments for each patient and achieve optimal outcomes. Meticulous tabulation methods facilitate interpretation, highlighting the importance of selecting the correct surgical and rehabilitation approach based on each patient's condition and stage of the disease. We detail the outcomes of a comprehensive network meta-analysis comparing the effectiveness of various combined therapeutic refractive treatments for KC at identical stages of the disease, spanning four distinct follow-up intervals. Additionally, the comprehensive analysis suggests that for corneas with optimal best corrected visual acuity (BCVA) preoperatively (classified as regular), combining phakic intraocular lenses with intracorneal ring segments (ICRS) and corneal cross-linking (CXL) could offer the best therapeutic approach provided the disease stage does not exceed stage 3. For irregular corneas, although initial follow-ups show a significant difference in BCVA with surface ablation, longer-term follow-ups recommend combining surface ablation with ICRS and CXL, especially at higher stages.
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Affiliation(s)
- Sana Niazi
- Negah Aref Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Farideh Doroodgar
- Negah Aref Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Saeed Hashemi Nazari
- Prevention of Cardiovascular Disease Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Yekta Rahimi
- Student Research Committee, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Jorge L Alió Del Barrio
- Vissum Miranza, Alicante, Spain; Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain
| | | | - Oliver Findl
- Vienna Institute for Research in Ocular Surgery (VIROS), A Karl Landsteiner Institute, Hanusch Hospital, 1140, Vienna, Austria
| | - Paolo Vinciguerra
- Biomedical Sciences, Humanitas University, Milan, Italy; IRCCS Humanitas Research Hospital, Rozzano, Italy
| | | | - Majid Moshirfar
- John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | - Renato Ambrósio
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil; Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil; BrAIN: Brazilian Artificial Intelligence Networking in Medicine, Rio de Janeiro & Maceió, Brazil; Department of Ophthalmology, Federal University the state of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil; Department of Ophthalmology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Jorge L Alio
- Vissum Miranza, Alicante, Spain; Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain
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Fard AM, Patel SP, Nader ND. The efficacy of 2 different phakic intraocular lens implant in keratoconus as an isolated procedure or combined with collagen crosslinking and intra-stromal corneal ring segments: a systematic review and meta-analysis. Int Ophthalmol 2023; 43:4383-4393. [PMID: 37470861 DOI: 10.1007/s10792-023-02813-z] [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: 07/31/2022] [Accepted: 07/10/2023] [Indexed: 07/21/2023]
Abstract
PURPOSE To compare the efficacy of phakic intra-ocular lenses in isolation or in combination with corneal crosslinking (CXL) and/or intra-stromal corneal ring segments (ICRS) in keratoconus. METHODS Data extracted from the publications meeting the selection. The outcome parameters included mean pre- and post-operative uncorrected distance visual acuity, corrected distance visual acuity (CDVA), sphere and cylinder of refraction and complications. Available data analyzed with Cochrane Review Manager. RESULTS A total of 23 studies including 464 eyes were included. All the parameters showed significant improvement in all subgroups other than CDVA in ACPIOL + CXL subgroup and cylinder in PIOL + CXL subgroups. There was not a significant difference between PCPIOL and ACPIOL in the outcomes, exception was more improvement of CDVA in "ACPIOL only" than" PCPIOL only" subgroup. CONCLUSION Both PCPIOLs and ACPIOLs are comparably safe and efficient options in management of KCN and their efficacy significantly improves when combined with CXL/ICRS.
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Affiliation(s)
- Ali Mahdavi Fard
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
- Department of Ophthalmology, Doheny Eye Center of UCLA, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Sangita P Patel
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
- Research and Ophthalmology Services, Veterans Administration of Western New York Healthcare System, Buffalo, NY, USA
| | - Nader D Nader
- Department of Anesthesiology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA.
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De Rosa G, Rossi S, Santamaria C, Boccia R, De Rosa L, D'Alterio FM, Simonelli F. Combined photorefractive keratectomy and corneal collagen cross-linking for treatment of keratoconus: a 2-year follow-up study. Ther Adv Ophthalmol 2022; 14:25158414221083362. [PMID: 35340750 PMCID: PMC8949731 DOI: 10.1177/25158414221083362] [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] [Received: 09/14/2021] [Accepted: 02/04/2022] [Indexed: 11/22/2022] Open
Abstract
Background: Corneal collagen cross-linking (CXL) is considered an effective procedure for slowing down or eliminating the progression of keratoconus. New techniques, in combination with CXL, have been proposed to stop the evolution of keratoconus and improve the visual function. Objective: To evaluate the effectiveness of combined photorefractive keratectomy (PRK) with mitomycin-C (MMC) application and CXL in the management of grade 1–2 keratoconus over a 2-year follow-up. Methods: Fifteen eyes underwent topography-guided PRK with 0.02% MMC application immediately followed by standard CXL. Results: Best corrected visual acuity improved from 0.15 ± 0.11 logMAR to 0.08 ± 0.09 logMAR at 24 months (p < 0.0001) in treated eyes. Mean steepest meridian keratometry reduced from 48.79 ± 3.22 D at baseline to 46.16 ± 3.11 D at 24 months (p < 0.0001). Mean flattest meridian keratometry reduced from 45.18 ± 2.17 D preoperatively to 44.35 ± 2.19 D at 24 months (p < 0.0001). Conclusion: Simultaneous topography-guided PRK with MMC 0.02% application and standard CXL is a safe, promising and effective procedure in the treatment of mild and moderate keratoconus.
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Affiliation(s)
- Giuseppe De Rosa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Settimio Rossi
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Carmine Santamaria
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Rosa Boccia
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Luigi De Rosa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Francesco Maria D'Alterio
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania 'Luigi Vanvitelli', Via Sergio Pansini 5, 80131 Naples, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania 'Luigi Vanvitelli', Naples, Italy
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Sakla HF, Altroudi W, Sakla YFR, Muñoz G, Pineza C. Visual and Refractive Outcomes of Toric Implantable Collamer Lens Implantation in Stable Keratoconus After Combined Topography-Guided PRK and CXL. J Refract Surg 2021; 37:824-829. [PMID: 34914551 DOI: 10.3928/1081597x-20210920-02] [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 evaluate the safety and efficacy of toric implantable Collamer lens (ICL) (STAAR Surgical) implanted at least 6 months after combined topography-guided photorefractive keratotomy (TG-PRK) and corneal cross-linking (CXL) in keratoconus. METHODS This retrospective study included 46 eyes with keratoconus of 31 patients who underwent toric ICL implantation after previous TG-PRK+CXL. Patients were examined for uncorrected (UDVA) and corrected (CDVA) distance visual acuity, flat and steep keratometry, and manifest refraction spherical equivalent preoperatively and 12 months postoperatively. RESULTS At 12 months postoperatively, there was a statistically significant improvement in visual and refractive outcomes (all P < .001). Mean UDVA improved to 0.17 ± 0.14 logMAR (vs 1.00 ± 0.38 logMAR preoperatively) and mean manifest refraction spherical equivalent improved to -0.32 ± 1.42 diopters (D) (vs -7.35 ± 5.20 D preoperatively). At 12 months, 63% of eyes achieved UDVA of 20/32 or better and 60.9% of eyes were within ±0.50 D of manifest refraction spherical equivalent. Mean refractive astigmatism improved from -2.90 ± 2.21 D preoperatively to -1.47 ± 1.46 D at postoperative 12 months (P < .001), with 30.4% and 45.7% of eyes having a postoperative astigmatic error within ±0.50 and ±1.00 D, respectively. No complications were observed. CONCLUSIONS Toric ICL implantation was found to be safe and effective for the correction of myopia and myopic astigmatism in patients with stable keratoconus who had undergone TG-PRK+CXL, as revealed by the statistically significant improvement in visual and refractive outcomes at 12 months after toric ICL implantation. [J Refract Surg. 2021;37(12):824-829.].
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Ormonde S. Refractive surgery for keratoconus. Clin Exp Optom 2021; 96:173-82. [DOI: 10.1111/cxo.12051] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 01/31/2013] [Accepted: 02/03/2013] [Indexed: 11/28/2022] Open
Affiliation(s)
- Sue Ormonde
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand,
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Sinjab MM, Rubinfeld RS, Wagner K, Parsons Jnr EC, Cummings AB, Belin MW. Outcomes of Conductive Keratoplasty Combined with Corneal Crosslinking in Advanced Ectatic Corneal Disease. Clin Ophthalmol 2021; 15:1317-1329. [PMID: 33824576 PMCID: PMC8018415 DOI: 10.2147/opth.s259012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 01/15/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose To assess the effectiveness of a novel treatment for patients with advanced corneal ectasia and loss of visual acuity (VA). Conductive keratoplasty (CK) is performed to improve VA followed by epithelium-on (epi-on) corneal crosslinking (CXL) to stabilize the cornea after CK. Methods Retrospective, exploratory cohort study. Patients with keratoconus or postsurgical ectasia and best spectacle-corrected distance VA (CDVA) ≤ 20/40 were included. Conductive keratoplasty was performed (ViewPoint CK System, Refractec, Inc., Bloomington, MN); followed a day later by epi-on CXL (CXLUSA/CXLO, Bethesda, MD/CXLO Encinitas, CA). Measures included uncorrected distance visual acuity (UDVA) and CDVA, as well as refractive and tomographic measures and tomographic indices. Results Data from 50 eyes of 45 patients were analyzed. Mean follow-up was 15.1 ± 12.2 months (range: 2 to 51). Overall, UDVA and CDVA improved postoperatively. Subjective refraction and tomographic metrics did not show consistent changes, but changes in tomographic indices were associated with treatment follow-up time. At the 1-year visit, mean UDVA significantly improved over baseline (P = 0.009) by approximately 3 lines; mean CDVA improved significantly (P = 10−5) by approximately 2 lines. No eye lost lines of CDVA. Change in the Index of Surface Variance (ISV) was associated with treatment, and the D-Index trended over follow-up time. Conclusion Conductive keratoplasty with a proprietary epi-on CXL treatment improved vision in patients with advanced ectasia This CK/epi-on CXL treatment offers the possibility of improved VA for patients with compromised vision due to ectasia.
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Affiliation(s)
- Mazen M Sinjab
- Dr. Mazen Eye Clinic, Medcare Hospitals and Centres, Dubai, United Arab Emirates.,Al Zahra Medical Group, Damascus, Syria
| | - Roy S Rubinfeld
- Department of Ophthalmology, Georgetown University Medical School/Washington Hospital Center, Washington, DC, USA.,Re:Vision Private Practice, Rockville, MD, USA
| | - Kirsten Wagner
- Department of Ophthalmology, Medstar Georgetown University Hospital, Washington, DC, USA.,Department of Ophthalmology, Medstar Washington Hospital Center, Washington, DC, USA
| | | | | | - Michael W Belin
- Department of Ophthalmology, University of Arizona, Tucson, AZ, USA
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Mazzotta C, Ferrise M, Gabriele G, Gennaro P, Meduri A. Chemically-Boosted Corneal Cross-Linking for the Treatment of Keratoconus through a Riboflavin 0.25% Optimized Solution with High Superoxide Anion Release. J Clin Med 2021; 10:jcm10061324. [PMID: 33806928 PMCID: PMC8004796 DOI: 10.3390/jcm10061324] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/13/2021] [Accepted: 03/18/2021] [Indexed: 11/28/2022] Open
Abstract
The purpose of this study was to evaluate the effectiveness and safety of a novel buffered riboflavin solution approved for corneal cross-linking (CXL) in progressive keratoconus and secondary corneal ectasia. Following the in vivo preclinical study performed on New Zealand rabbits comparing the novel 0.25% riboflavin solution (Safecross®) containing 1% hydroxypropyl methylcellulose (HPMC) with a 0.1% riboflavin solution containing 0.10% EDTA, accelerated epithelium-off CXL was performed on 10 patients (10 eyes treated, with the contralateral eye used as control) through UV-A at a power setting of 9 mW/cm2 with a total dose of 5.4 J/cm2. Re-epithelialization was evaluated in the postoperative 7 days by fluorescein dye test at biomicroscopy; endothelial cell count and morphology (ECD) were analyzed by specular microscopy at the 1st and 6th month of follow-up and demarcation line depth (DLD) measured by anterior segment optical coherence tomography (AS-OCT) one month after the treatment. We observed complete re-epithelization in all eyes between 72 and 96 h after surgery (88 h on average). ECD and morphology remained unchanged in all eyes. DLD was detected at a mean depth of 362 ± 50 µm, 20% over solutions with equivalent dosage. SafeCross® riboflavin solution chemically-boosted corneal cross-linking seems to optimize CXL oxidative reaction by higher superoxide anion release, improving DLD by a factor of 20%, without adverse events for corneal endothelium.
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Affiliation(s)
- Cosimo Mazzotta
- Departmental Ophthalmology Unit and USL Toscana Sud-Est, 53100 Siena, Italy;
- Post Graduate Ophthalmology School, Siena University, 53100 Siena, Italy
- Siena Crosslinking Center, Via Sandro Pertini 7, 53100 Siena, Italy
| | - Marco Ferrise
- Siena Crosslinking Center, Via Sandro Pertini 7, 53100 Siena, Italy
- Studio Oculistico Ferrise, 88046 Lamezia Terme, Italy
- Correspondence:
| | - Guido Gabriele
- Department of Oral and Maxillofacial Surgery, “Le Scotte” Hospital, Viale M. Bracci, 53100 Siena, Italy; (G.G.); (P.G.)
| | - Paolo Gennaro
- Department of Oral and Maxillofacial Surgery, “Le Scotte” Hospital, Viale M. Bracci, 53100 Siena, Italy; (G.G.); (P.G.)
| | - Alessandro Meduri
- Unit of Ophthalmology, Department of Biomedical Sciences, Dentistry, Morphological and Functional Imaging, University of Messina, 98100 Messina, Italy;
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Femtosecond laser-assisted stromal keratophakia for keratoconus: A systemic review and meta-analysis. Int Ophthalmol 2021; 41:1965-1979. [PMID: 33609200 DOI: 10.1007/s10792-021-01745-w] [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: 08/18/2020] [Accepted: 02/06/2021] [Indexed: 10/22/2022]
Abstract
PURPOSE Femtosecond lasers have revived the possibility of stromal keratophakia or tissue additive keratoplasty, a technique originally introduced by Prof. Jose Ignacio Barraquer in the 1960s. The surgical technique offers a unique solution to treat keratoconus. In the current study, we reviewed and performed a meta-analysis of the clinical outcomes of the femtosecond laser-assisted stromal keratophakia in the treatment of keratoconus. METHODS This is a systematic review and meta-analysis of the estimated outcome difference between pre- and post-lenticule implantations. RESULTS A total of related 10 studies were found in the literature. No studies reported adverse events, such as persistent haze or graft rejection, at last patients' visits. We further narrowed down the article selection in accordance to our inclusion criteria to report the composite outcomes (9 studies) and meta-analysis (4 studies). In the composite analysis, we demonstrated that lenticule implantation in keratoconus and post-LASIK ectasia patients appeared to expand the stromal volume of the thin corneas, flattened the cones, and significantly improved uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA) and spherical equivalent (SE). The meta-analysis showed that the random estimated UCVA, BCVA, SE and mean keratometry (Km) differences following the lenticule implantation was -0.214 (95% CI: -0.367 to 0.060; p = 0.006), -0.169 (-0.246 to 0.091; p < 0.001), -2.294 D (-3.750 to -0.839 D; p = 0.002), and 2.909 D (0.805 to 5.012 D; p = 0.007), respectively. CONCLUSIONS Femtosecond laser-assisted stromal keratophakia is a feasible technique to correct the refractive aberrations, expand corneal volume and regularize corneal curvature in patients with keratoconus. However, there is a need to standardize the technique (e.g., whether to crosslink or not or to use convex or concave lenticules) and to formulate a mathematical model that accounts for the long-term epithelial thickness changes and stromal remodeling to determine the shape or profile of the lenticules, in order to improve the efficacy of the keratophakia further.
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Toric phakic IOLs in keratoconus-evaluation of preoperative parameters on the outcome of phakic anterior chamber lens implantation in patients with keratoconus. Graefes Arch Clin Exp Ophthalmol 2021; 259:1643-1649. [PMID: 33464378 PMCID: PMC8166703 DOI: 10.1007/s00417-020-05041-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/01/2020] [Accepted: 12/04/2020] [Indexed: 11/30/2022] Open
Abstract
Purpose To evaluate the influence of the type of the keratectasia and preoperative keratometry readings on the efficacy of implantation of iris-fixated phakic anterior chamber intraocular lenses (pIOL) in patients with keratoconus. Methods In this retrospective study, iris-fixated pIOLs (Artisan/Artiflex (Ophtec®), Verisyse/Veriflex (AMO®)) were implanted in 38 eyes of 22 patients with stable keratoconus. Thirty-six eyes underwent corneal crosslinking (CXL) prior to the lens implantation. The refractive outcome was evaluated 6 weeks postoperatively and the influence of preoperative refraction and topo- and tomographical factors were analyzed. Results The mean postoperative uncorrected distance visual acuity (UDVApost) was 0.25 ± 0.15 logMAR and was not statistically different from the mean preoperative corrected distance visual acuity (CDVApre), which was 0.24 ± 0.13 logMAR. Twenty-seven eyes (71%) reached UDVApost/CDVApre ≥ 1 (efficacy index), whereas patients with PMD-like ectasia (n = 14) showed significantly (p = 0.003) higher efficacy index (100%) than patients diagnosed with keratoconus (n = 24) (54%). Higher eccentricity of the maximum posterior elevation showed a significant beneficial influence on the efficacy index (p = 0.021). Furthermore, a higher Amsler-Krumeich stage and preoperative MAE were correlated with a worse UDVApost. The mean absolute spherical equivalent was significantly decreased from 5.71 ± 4.96 D to 1.25 ± 1.20 D (p < 0.001). No significant difference was found in endothelial cell count. Conclusion The results indicate that the implantation of phakic iris-fixated anterior chamber IOLs is a reasonable refractive option for patients with keratoconus. Keratoconus patients with a pellucidal marginal degeneration (PMD)-like appearance ectasia seem to benefit most from such procedures.
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Kankariya VP, Dube AB, Grentzelos MA, Kontadakis GA, Diakonis VF, Petrelli M, Kymionis GD. Corneal cross-linking (CXL) combined with refractive surgery for the comprehensive management of keratoconus: CXL plus. Indian J Ophthalmol 2020; 68:2757-2772. [PMID: 33229651 PMCID: PMC7856931 DOI: 10.4103/ijo.ijo_1841_20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The past two decades have witnessed an unprecedented evolution in the management of keratoconus that demands a holistic approach comprising of inhibiting the ectatic progression as well as visual rehabilitation. The advent of corneal cross-linking (CXL) in the late 1990s resulted in long-term stabilization of the ectatic cornea along with limited reduction in corneal steepening and regularization of corneal curvature. However, CXL as a standalone procedure does not suffice in rehabilitating the functional vision especially in patients who are unwilling or intolerant towards contact lenses. The concept of “CXL plus” was proposed which incorporates adjunctive use of refractive procedures with CXL in order to overcome the optical inefficiency due to corneal irregularity, decrease the irregular astigmatism, correct the residual refractive error and improve functional visual outcome in keratoconus. Several refractive procedures such as conductive keratoplasty (CK), photorefractive keratectomy (PRK), transepithelial phototherapeutic keratectomy (t-PTK), intrastromal corneal ring segments (ICRS) implantation, phakic intraocular lens (PIOL) implantation and multiple other techniques have been combined with CXL to optimize and enhance the CXL outcome. This review aimed to summarize the different protocols of CXL plus, provide guidelines for selection of the optimum CXL plus technique and aid in decision-making for the comprehensive management of cases with primary keratoconus in addition to discussing the future and scope for innovations in the existing treatment protocols.
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Affiliation(s)
| | - Ankita B Dube
- Asian Eye Hospital and Laser Institute, Pune, Maharashtra, India
| | - Michael A Grentzelos
- Asian Eye Hospital and Laser Institute, Pune, Maharashtra, India; Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, Lausanne, Switzerland
| | - George A Kontadakis
- Laboratory of Vision and Optics, Medical School, University of Crete, Heraklion, Greece
| | | | - Myrsini Petrelli
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, Lausanne, Switzerland
| | - George D Kymionis
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, Lausanne, Switzerland
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Accelerated corneal collagen crosslinking: Technique, efficacy, safety, and applications. J Cataract Refract Surg 2018; 42:1826-1835. [PMID: 28007116 DOI: 10.1016/j.jcrs.2016.11.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/16/2016] [Accepted: 05/25/2016] [Indexed: 11/22/2022]
Abstract
Corneal collagen crosslinking (CXL) is an approach used to increase the biomechanical stability of the stromal tissue. Over the past 10 years, it has been used to halt the progression of ectatic diseases. According to the photochemical law of reciprocity, the same photochemical effect is achieved with reduced illumination time and correspondingly increased irradiation intensity. Several new CXL devices offer high ultraviolet-A irradiation intensity with different time settings. The main purpose of this review was to discuss the current use of different protocols of accelerated CXL and compare the efficacy and safety of accelerated CXL with the efficacy and safety of the established conventional method. Accelerated CXL proved to be safe and effective in halting progression of corneal ectasia. Corneal shape responses varied considerably, as did the demarcation line at different irradiance settings; the shorter the exposure time, the more superficial the demarcation line. FINANCIAL DISCLOSURE Dr. Santhiago is a consultant to Ziemer Ophthalmic Systems AG and Alcon Laboratories, Inc. None of the authors has a financial or proprietary interest in any material or method mentioned.
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Surgical Options for the Refractive Correction of Keratoconus: Myth or Reality. J Ophthalmol 2017; 2017:7589816. [PMID: 29403662 PMCID: PMC5748308 DOI: 10.1155/2017/7589816] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/28/2017] [Indexed: 01/14/2023] Open
Abstract
Keratoconus provides a decrease of quality of life to the patients who suffer from it. The treatment used as well as the method to correct the refractive error of these patients may influence on the impact of the disease on their quality of life. The purpose of this review is to describe the evidence about the conservative surgical treatment for keratoconus aiming to therapeutic and refractive effect. The visual rehabilitation for keratoconic corneas requires addressing three concerns: halting the ectatic process, improving corneal shape, and minimizing the residual refractive error. Cross-linking can halt the disease progression, intrastromal corneal ring segments can improve the corneal shape and hence the visual quality and reduce the refractive error, PRK can correct mild-moderate refractive error, and intraocular lenses can correct from low to high refractive error associated with keratoconus. Any of these surgical options can be performed alone or combined with the other techniques depending on what the case requires. Although it could be considered that the surgical option for the refracto-therapeutic treatment of the keratoconus is a reality, controlled, randomized studies with larger cohorts and longer follow-up periods are needed to determine which refractive procedure and/or sequence are most suitable for each case.
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13
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Hashmani S, Hashmani N, Memon RS. Corneal Collagen Cross-Linking Combined with an Artiflex Iris-Fixated Anterior Chamber Phakic Intraocular Lens Implantation in a Patient with Progressive Keratoconus. Case Rep Ophthalmol 2017; 8:482-488. [PMID: 29118708 PMCID: PMC5662956 DOI: 10.1159/000480728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 08/28/2017] [Indexed: 01/04/2023] Open
Abstract
We present here the case of a 24-year-old male who experienced progressive keratoconus and vision loss which adversely affected his ability to carry out everyday tasks. This landed him in the Hashmanis Hospital for consultation. He had a preoperative best corrected visual acuity of 6/12. He underwent multiple Oculus Pentacam examinations, which showed progressive keratoconus. Corneal collagen cross-linking (CXL) was performed to stabilize his cornea and, subsequently, an Artiflex anterior chamber iris-fixated phakic intraocular lens (ACIF-PIOL) was implanted to alleviate his refractive errors. The patient achieved a postoperative uncorrected visual acuity of 6/12. This report shows that CXL combined with ACIF-PIOL can be safe and effective in those with progressive keratoconus.
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Updates on corneal collagen cross-linking: Indications, techniques and clinical outcomes. J Curr Ophthalmol 2017; 29:235-247. [PMID: 29270469 PMCID: PMC5735256 DOI: 10.1016/j.joco.2017.07.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 07/18/2017] [Accepted: 07/22/2017] [Indexed: 12/17/2022] Open
Abstract
Purpose To review the historical background and basic principles of collagen cross-linking, to bring together the data regarding the outcomes and complications of collagen cross-linking and finally to explore the efficacy and safety of new variations of this technique. Methods A literature review was performed using PubMed and Scopus. The following keywords were used for literature search: cross linking, crosslinking, cross-linking, keratoconus, keratectasia. Results In contrast to traditional treatment modalities for keratoconus (KCN), this new technique addresses the progression of the disease. Several clinical studies have been conducted to assess the efficacy of corneal collagen cross-linking (CXL) in the last decade. The results were promising as collagen cross-linking showed significant improvement in visual acuity and keratometric values. Moreover, initial results show that it is a safe procedure with few reported complications. Conclusion CXL is an emerging treatment method in ophthalmology that offers the possibility to effectively treat progressive KCN.
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Abdelmassih Y, el-Khoury S, Chelala E, Slim E, Cherfan CG, Jarade E. Toric ICL Implantation After Sequential Intracorneal Ring Segments Implantation and Corneal Cross-linking in Keratoconus: 2-Year Follow-up. J Refract Surg 2017; 33:610-616. [DOI: 10.3928/1081597x-20170621-02] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Accepted: 05/24/2017] [Indexed: 11/20/2022]
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Tiveron MC, Alió del Barrio JL, Kara-Junior N, Plaza-Puche AB, Abu-Mustafa SK, Zein G, Alió JL. Outcomes of Toric Iris-Claw Phakic Intraocular Lens Implantation After Deep Anterior Lamellar Keratoplasty for Keratoconus. J Refract Surg 2017; 33:538-544. [DOI: 10.3928/1081597x-20170616-02] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/16/2017] [Indexed: 11/20/2022]
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Efficacy of Corneal Collagen Cross-Linking for the Treatment of Keratoconus: A Systematic Review and Meta-Analysis. Cornea 2016; 35:417-28. [PMID: 26751990 DOI: 10.1097/ico.0000000000000723] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To examine the efficacy of corneal collagen cross-linking (CXL) for the treatment of keratoconus (KCN). METHODS A systemic literature review and meta-analysis of ocular functional and structural parameters of patients with KCN undergoing cross-linking procedures were performed using PubMed and the web of science. A literature search was performed for relevant peer-reviewed publications on population-based studies. Data were analyzed with R software (Meta library), and heterogeneity was assessed with the Cochran Q and I. A random-effects model was used for high heterogeneity; otherwise a fixed model was used. Sensitivity analysis of particular tested groups was used to explain high heterogeneity. The main outcome measures extracted from the articles were corrected distance visual acuity, uncorrected distance visual acuity, and maximum K. RESULTS An improvement in visual acuity of 1 to 2 Snellen lines was found 3 months or more after undergoing CXL. Changes were more pronounced in uncorrected visual acuity. Some topography parameters were found to be improved (0.6-1 diopters) 12 to 24 months after CXL. The refractive cylinder improved by 0.4 to 0.7 diopters. Endothelial cell density decreased by 225 cells per square millimeter in the first 3 months and thereafter returned to normal. Corneal thickness was reduced by 10 to 20 μm in the year following CXL but not after 24 months. No changes in intraocular pressure were noted. CONCLUSIONS CXL is a safe and effective method for halting the deterioration of KCN, while slightly improving visual function.
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Abstract
Phakic intraocular lenses revolutionize refractive surgery and continue to serve as an excellent option for vision correction in patients who are not ideal candidates for laser vision correction. This article will review special indications of phakic intraocular lenses in the clinical practice.
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Affiliation(s)
- Roberto Pineda
- Keratorefractive Surgery Service, Massachusetts Eye and Ear Infirmary, Boston MA, USA
| | - Tulika Chauhan
- Keratorefractive Surgery Service, Massachusetts Eye and Ear Infirmary, Boston MA, USA
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One-Year Results of Simultaneous Topography-Guided Photorefractive Keratectomy and Corneal Collagen Cross-Linking in Keratoconus Utilizing a Modern Ablation Software. J Ophthalmol 2015; 2015:321953. [PMID: 26366293 PMCID: PMC4561114 DOI: 10.1155/2015/321953] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 08/04/2015] [Indexed: 11/30/2022] Open
Abstract
Purpose. To evaluate effectiveness of simultaneous topography-guided photorefractive keratectomy and corneal collagen cross-linking in mild and moderate keratoconus. Methods. Prospective nonrandomized interventional study including 20 eyes of 14 patients with grade 1-2 keratoconus that underwent topography-guided PRK using a Custom Ablation Transition Zone (CATz) profile with 0.02% MMC application immediately followed by standard 3 mw/cm2 UVA collagen cross-linking. Maximum ablation depth did not exceed 58 μm. Follow-up period: 12 months. Results. Progressive statistically significant improvement of UCVA from 0.83 ± 0.37 logMAR preoperative, reaching 0.25 ± 0.26 logMAR at 12 months (P < 0.001). Preoperative BCVA (0.27 ± 0.31 logMAR) showed a progressive improvement reaching 0.08 ± 0.12 logMAR at 12 months (P = 0.02). Mean Kmax reduced from 48.9 ± 2.8 to 45.4 ± 3.1 D at 12 months (P < 0.001), mean Kmin reduced from 45.9 ± 2.8 D to 44.1 ± 3.2 D at 12 months (P < 0.003), mean keratometric asymmetry reduced from 3.01 ± 2.03 D to 1.25 ± 1.2 D at 12 months (P < 0.001). The safety index was 1.39 at 12 months and efficacy index 0.97 at 12 months. Conclusion. Combined topography-guided PRK and corneal collagen cross-linking are a safe and effective option in the management of mild and moderate keratoconus. Precis. To our knowledge, this is the first published study on the use of the CATz ablation system on the Nidek Quest excimer laser platform combined with conventional cross-linking in the management of mild keratoconus.
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Randleman JB, Khandelwal SS, Hafezi F. Corneal cross-linking. Surv Ophthalmol 2015; 60:509-23. [PMID: 25980780 DOI: 10.1016/j.survophthal.2015.04.002] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 04/28/2015] [Accepted: 04/30/2015] [Indexed: 12/26/2022]
Abstract
Since its inception in the late 1990s, corneal cross-linking has grown from an interesting concept to a primary treatment for corneal ectatic disease worldwide. Using a combination of ultraviolet-A light and a chromophore (vitamin B2, riboflavin), the cornea can be stiffened, usually with a single application, and progressive thinning diseases such as keratoconus arrested. Despite being in clinical use for many years, some of the underlying processes, such as the role of oxygen and the optimal treatment times, are still being worked out. More than a treatment technique, corneal cross-links represent a physiological principle of connective tissue, which may explain the enormous versatility of the method. We highlight the history of corneal cross-linking, the scientific underpinnings of current techniques, evolving clinical treatment parameters, and the use of cross-linking in combination with refractive surgery and for the treatment of infectious keratitis.
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Affiliation(s)
- J Bradley Randleman
- Department of Ophthalmology, Emory University, Atlanta, Georgia, USA; Emory Vision, Emory Eye Center, Atlanta, Georgia, USA.
| | | | - Farhad Hafezi
- ELZA Institute, Zurich, Switzerland; Laboratory for Ocular Cell Biology, University of Geneva, Geneva, Switzerland; Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA; Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland
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Le crosslinking du collagène dans le kératocône. J Fr Ophtalmol 2015; 38:445-62. [DOI: 10.1016/j.jfo.2014.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 12/07/2014] [Accepted: 12/09/2014] [Indexed: 11/20/2022]
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Safety and Visual Outcome of Visian Toric ICL Implantation after Corneal Collagen Cross-Linking in Keratoconus: Up to 2 Years of Follow-Up. J Ophthalmol 2015; 2015:514834. [PMID: 25874116 PMCID: PMC4383407 DOI: 10.1155/2015/514834] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 10/14/2014] [Accepted: 10/27/2014] [Indexed: 11/17/2022] Open
Abstract
Purpose. To evaluate the long-term safety and clinical outcome of phakic Visian toric implantable collamer lens (ICL) insertion after corneal collagen cross-linking (CXL) in progressive keratoconus. Methods. This was a retrospective study of 30 eyes (19 patients), with progressive keratoconus, who underwent sequential CXL followed by Visian toric ICL implantation after 6 months. Results. At baseline, 6 eyes had stage I, 14 eyes stage II, and 10 eyes stage III keratoconus graded by Amsler-Krumeich classification. At 6 months after CXL, only K (steep) and K (max) decreased significantly from baseline, with no change in visual acuity or refraction. Flattening in keratometric readings was stable thereafter. There was significant improvement in mean uncorrected distance visual acuity (1.57 ± 0.56 to 0.17 ± 0.06 logMAR, P < 0.001) and mean corrected distance visual acuity (0.17 ± 0.08 to 0.11 ± 0.05 logMAR, P < 0.001) at 12 months after ICL implantation that was maintained at the 2-year follow-up. Mean cylinder power and mean spherical equivalent (SE) also decreased significantly after ICL implantation. A small hyperopic shift in SE (+0.25 D) was observed at 2 years that did not alter visual outcomes. Conclusions. Visian toric ICL implantation following CXL is an effective option for improving visual acuity in patients with keratoconus up to 2 years.
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Kamiya K, Shimizu K, Kobashi H, Igarashi A, Komatsu M, Nakamura A, Kojima T, Nakamura T. Three-year follow-up of posterior chamber toric phakic intraocular lens implantation for the correction of high myopic astigmatism in eyes with keratoconus. Br J Ophthalmol 2014; 99:177-83. [PMID: 25147365 DOI: 10.1136/bjophthalmol-2014-305612] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
AIM To assess the clinical outcomes following the use of toric implantable collamer lenses (toric ICL, STAAR Surgical) for the correction of high myopic astigmatism with keratoconus. METHODS This retrospective study evaluated 21 eyes of 11 patients with spherical equivalents of -9.70±2.33 D (mean±SD) and astigmatism of -3.21±1.56 D who underwent toric ICL implantation for keratoconus. Preoperatively, and at 1, 3 and 6 months and 1, 2 and 3 years postoperatively, we assessed the safety, efficacy, predictability, stability and adverse events of the surgery. RESULTS The logarithm of the minimum angle of resolution (logMAR) uncorrected distance visual acuity (UDVA) and the logMAR corrected distance visual acuity (CDVA) were -0.06±0.11 and -0.12±0.09, respectively, at 3 years postoperatively. At 3 years, 67% and 86% of the eyes were within ±0.5 and ±1.0 D, respectively, of the targeted correction. Manifest refraction changes of 0.04±0.33 D occurred from 1 month to 3 years postoperatively. No significant change in manifest refraction (analysis of variance, p=0.989) or keratometry (p=0.951), or vision-threatening complications occurred during the observation period. CONCLUSIONS Toric ICL implantation is beneficial according to measures of safety, efficacy, predictability and stability for the correction of refractive errors for keratoconus during a 3-year observation period. The disease did not progress even in the late-postoperative period, suggesting the viability of this procedure as a surgical option for the treatment of such eyes.
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Affiliation(s)
- Kazutaka Kamiya
- Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan
| | - Kimiya Shimizu
- Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan
| | - Hidenaga Kobashi
- Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan
| | - Akihito Igarashi
- Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan
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Kymionis GD, Grentzelos MA, Portaliou DM, Kankariya VP, Randleman JB. Corneal Collagen Cross-linking (CXL) Combined With Refractive Procedures for the Treatment of Corneal Ectatic Disorders: CXL Plus. J Refract Surg 2014; 30:566-76. [DOI: 10.3928/1081597x-20140711-10] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 06/02/2014] [Indexed: 12/17/2022]
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Assaf A, Kotb A. Simultaneous corneal crosslinking and surface ablation combined with phakic intraocular lens implantation for managing keratoconus. Int Ophthalmol 2014; 35:411-9. [DOI: 10.1007/s10792-014-9963-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/05/2014] [Indexed: 10/25/2022]
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Li N, Peng XJ, Fan ZJ. Progress of corneal collagen cross-linking combined with refractive surgery. Int J Ophthalmol 2014; 7:157-62. [PMID: 24634883 DOI: 10.3980/j.issn.2222-3959.2014.01.29] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 09/23/2013] [Indexed: 01/27/2023] Open
Abstract
As a photochemical reaction that can stiffen the cornea, corneal collagen cross-linking (CXL) is the only promising method of preventing the progress of keratectasia, such as keratoconus and secondary ectasia following refractive surgery. The aim of CXL is to stabilize the underlying condition, with a small chance of visual improvement. Combining CXL with refractive surgery targeting both stabilization and reshaping of the corneal tissue for visual function improvement is a good treatment option. This review aims to provide a comprehensive and unbiased summary of the published research regarding combined CXL and refractive surgery, including measures and results, to help elucidate the future direction of CXL.
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Affiliation(s)
- Na Li
- Department of Ophthalmology, Navy General Hospital of Chinese PLA, Beijing 100048, China
| | - Xiu-Jun Peng
- Department of Ophthalmology, Navy General Hospital of Chinese PLA, Beijing 100048, China
| | - Zheng-Jun Fan
- Department of Ophthalmology, Navy General Hospital of Chinese PLA, Beijing 100048, China
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Comparison of iris-claw and posterior chamber collagen copolymer phakic intraocular lenses in keratoconus. J Cataract Refract Surg 2014; 40:383-94. [DOI: 10.1016/j.jcrs.2013.07.052] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 07/25/2013] [Accepted: 07/30/2013] [Indexed: 02/07/2023]
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Abstract
Keratoconus is characterized by progressive corneal protrusion and thinning, leading to irregular astigmatism and impairment in visual function. The etiology and pathogenesis of the condition are not fully understood. However, significant strides have been made in early clinical detection of the disease, as well as towards providing optimal optical and surgical correction for improving the quality of vision in affected patients. The past two decades, in particular, have seen exciting new developments promising to alter the natural history of keratoconus in a favorable way for the first time. This comprehensive review focuses on analyzing the role of advanced imaging techniques in the diagnosis and treatment of keratoconus and evaluating the evidence supporting or refuting the efficacy of therapeutic advances for keratoconus, such as newer contact lens designs, collagen crosslinking, deep anterior lamellar keratoplasty, intracorneal ring segments, photorefractive keratectomy, and phakic intraocular lenses.
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Affiliation(s)
- Jayesh Vazirani
- Cornea and Anterior Segment Services, LV Prasad Eye Institute, Hyderabad, India
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Kymionis GD, Mikropoulos DG, Portaliou DM, Voudouragkaki IC, Kozobolis VP, Konstas AGP. An overview of corneal collagen cross-linking (CXL). Adv Ther 2013; 30:858-69. [PMID: 24170589 DOI: 10.1007/s12325-013-0065-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Indexed: 11/27/2022]
Abstract
Corneal collagen cross-linking (CXL) was first described over a decade ago and is now considered to be one of the most important surgical innovations of modern ophthalmology. Prior to its introduction, no interventions were available to arrest, or slow down ectatic disease progression, with corneal transplantation required in the majority of cases. Unlike earlier treatments of corneal ectasias that attempted to only improve the consequences of the disease, CXL aims to address the corneal biomechanical weakening itself. The long-term safety and efficacy of CXL have been established in several studies that have documented significant improvements in all outcome measures (visual acuity, spherical equivalent, astigmatism, and keratometric findings). The emerging combination of CXL with other interventions (termed 'CXL plus') optimizes the visual and topographic outcomes. This, along with the expansion of the techniques' indications for other clinical conditions, such as microbial keratitis, highlights the continuous improvement of the initial technique and confirms its wide acceptance. Overall, CXL has already demonstrated much promise and has several clinical indications, representing a clear example of recent advances in ocular therapy.
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Affiliation(s)
- George D Kymionis
- Faculty of Medicine, Institute of Vision and Optics, University of Crete, Heraklion, Greece
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Jaimes M, Ramirez-Miranda A, Graue-Hernández EO, Navas A. Keratoconus therapeutics advances. World J Ophthalmol 2013; 3:20-31. [DOI: 10.5318/wjo.v3.i3.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 09/04/2013] [Indexed: 02/06/2023] Open
Abstract
Keratoconus is a progressive, usually bilateral disease of the cornea that significantly diminishes visual acuity, secondary to a progressive corneal deformity which is characterized by corneal thinning, variable degrees of irregular astigmatism and specific abnormal topographic patterns. Normally it initiates during puberty and is progressive until the third or fourth decade of life, when normally the progression rate is diminished or waned. There are multiple scales to clinically classify keratoconus. One of the most commonly used is Amsler-Krumeich and recently with the development of morphometric and aberrometric techniques, additional scales have been created that allow keratoconus to be classified according to its severity. Despite certain etiology of keratoconus remains unknown, current treatment options are available in patients with ectatic corneas and they vary depending on the severity of the disease and they include spectacles, contact lenses, intrastromal rings, keratoplasty both penetrant or lamellar, cross-linking, refractive lens exchange with intraocular lens implant, phakic intraocular lenses and the combination of these alternatives. Some authors have been using excimer laser in patients with keratoconus but the safety of the procedure is controversial. Currently, the techniques for the management of keratoconus can be classified in 3 types: corneal strengthening techniques, optical optimization techniques and combined techniques.
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Fadlallah A, Dirani A, El Rami H, Cherfane G, Jarade E. Safety and Visual Outcome of Visian Toric ICL Implantation After Corneal Collagen Cross-linking in Keratoconus. J Refract Surg 2013; 29:84-9. [DOI: 10.3928/1081597x-20130117-01] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 11/27/2012] [Indexed: 11/20/2022]
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Raiskup F, Spoerl E. Corneal crosslinking with riboflavin and ultraviolet A. Part II. Clinical indications and results. Ocul Surf 2013; 11:93-108. [PMID: 23583044 DOI: 10.1016/j.jtos.2013.01.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2012] [Indexed: 11/29/2022]
Abstract
Changes in the biomechanical properties of the human cornea play an important role in the pathogenesis of corneal ectatic diseases. A variety of conditions in primary acquired (keratoconus and pellucid marginal degeneration) or secondary induced (iatrogenic keratectasia after excimer refractive laser surgery) corneal ectatic disorders lead to reduced biomechanical resistance. Corneal collagen crosslinking (CXL) has emerged as a promising technique to slow or even to stop the progression of these corneal ectatic pathologies. In this procedure, riboflavin (vitamin B2) is administered in conjunction with ultraviolet A light (UVA, 365 nm). This interaction causes the formation of reactive oxygen species, leading to the formation of additional covalent bonds between collagen molecules, with consequent biomechanical stiffening of the cornea. Although this method is not yet accepted as an evidence-based medicine modality for the treatment of corneal primary or secondary ectasias, the results of prospective, randomized studies of CXL used in the treatment of these pathologic entities show significant changes in the properties of corneal tissue. This procedure is currently the only etiopathogenetic approach in ectatic eyes that can delay or stop the process of cornea destabilization, reducing the necessity for keratoplasty. Despite promising results, CXL is associated with issues that include long-term safety and duration of the stabilizing effect. Combination of CXL with vision-improving procedures, such as topography-guided custom ablation and implantation of intracorneal ring segments of phakic intraocular lenses, may expand the indications for this procedure.
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Affiliation(s)
- Frederik Raiskup
- Department of Ophthalmology, Carl Gustav Carus University Hospital, Dresden, Germany.
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Abstract
Pre-2000, the clinical management of keratoconus centred on rigid contact lens fitting when spectacle corrected acuity was no longer adequate, and transplantation where contact lens wear failed. Over the last decade, outcome data have accumulated for new interventions including corneal collagen crosslinking, intracorneal ring implantation, topographic phototherapeutic keratectomy, and phakic intraocular lens implantation. We review the current evidence base for these interventions and their place in new management pathways for keratoconus under two key headings: corneal shape stabilisation and visual rehabilitation.
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Affiliation(s)
- D M Gore
- Moorfields Eye Hospital, London, UK.
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Bevel toric multicurve rigid gas-permeable lens for keratoconus. Jpn J Ophthalmol 2012; 57:199-205. [DOI: 10.1007/s10384-012-0216-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 10/17/2012] [Indexed: 10/27/2022]
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Tuwairqi WS, Sinjab MM. Safety and efficacy of simultaneous corneal collagen cross-linking with topography-guided PRK in managing low-grade keratoconus: 1-year follow-up. J Refract Surg 2012; 28:341-5. [PMID: 22443804 DOI: 10.3928/1081597x-20120316-01] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 02/21/2012] [Indexed: 01/14/2023]
Abstract
PURPOSE To evaluate 1-year visual and topographic outcomes and safety and efficacy of corneal collagen cross-linking (CXL) combined with topography-guided photorefractive keratectomy (TG-PRK) to achieve near emmetropia in eyes with low-grade keratoconus. METHODS Twenty-two eyes from 15 patients (11 women, 4 men) were included in a prospective, nonrandomized, noncontrolled clinical study. Mean patient age was 26.6±6.07 years (range: 19 to 40 years). Inclusion criteria were low-grade keratoconus with evidence of progression, transparent cornea, corrected distance visual acuity (CDVA) 0.8 (decimal) or better, corneal thickness >440 μm, and maximum keratometry readings (K-max) <51.00 diopters (D). All patients underwent simultaneous TG-PRK with CXL. Study parameters were uncorrected distance visual acuity, CDVA, manifest refractive error, manifest and topographic (corneal) astigmatism, patient satisfaction, and efficacy and safety of the treatment. Follow-up was 1 year. RESULTS After 1 year, statistically significant improvement was noted in all study parameters (P<.01). The safety and efficacy indices were 1.6 and 0.4, respectively. Patient satisfaction questionnaire showed that 91% were satisfied, 9% were not completely satisfied but believed they improved, and none were dissatisfied. Corneal topography demonstrated significant improvement in 55%, improvement in 36%, and minor improvement in 9% of cases. No cases progressed as evidenced by keratometry readings. CONCLUSIONS Simultaneous TG-PRK with CXL is an effective and safe treatment with remarkable visual and topographic outcomes in patients with low-grade keratoconus who meet the recommended inclusion criteria.
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Güell JL, Morral M, Malecaze F, Gris O, Elies D, Manero F. Collagen crosslinking and toric iris-claw phakic intraocular lens for myopic astigmatism in progressive mild to moderate keratoconus. J Cataract Refract Surg 2012; 38:475-84. [PMID: 22261324 DOI: 10.1016/j.jcrs.2011.10.031] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Revised: 09/28/2011] [Accepted: 10/04/2011] [Indexed: 01/06/2023]
Abstract
PURPOSE To report the long-term results of combined collagen crosslinking (CXL) and toric phakic intraocular lens (pIOL) implantation to correct myopic astigmatism in patients with progressive mild to moderate keratoconus. SETTING Instituto de Microcirugia Ocular, Barcelona, Spain. DESIGN Case series. METHODS From November 2006 to July 2009, CXL was performed in eyes with proven progressive keratoconus. Once refraction and topography stabilized, toric Artiflex/Artisan pIOL implantation was performed to correct residual myopic astigmatism. A complete ophthalmologic examination, including manifest refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, biomicroscopy, tonometry, fundoscopy, keratometry, corneal tomography, and central endothelial cell count (ECC), was performed before each procedure and postoperatively at 3 months and at yearly intervals up to 5 years. Main outcome measures were accuracy and stability of the spherical equivalent (SE) and cylinder, keratometry, UDVA (efficacy), CDVA (safety), central ECC, and complications. RESULTS The median follow-up in the 9 patients (17 eyes) was 36.9 months ± 15.0 (SD). The median interval between CXL and pIOL implantation was 3.9 ± 0.7 months. Fourteen eyes (82%) were within ± 0.50 diopter (D) of the attempted SE correction and 13 eyes (76%) were within ± 1.00 D of the attempted cylinder correction. The mean difference in simulated keratometry between preoperatively and the last follow-up was 0.17 ± 0.45 D (range -0.55 to 1.45 D). The postoperative UDVA was 20/40 or better in 16 eyes (94%). No eye lost lines of CDVA. No significant decrease in central ECC occurred (P>.05). CONCLUSION Combined CXL and toric iris-claw pIOL implantation effectively and safely corrected myopic astigmatism in progressive mild to moderate keratoconus. FINANCIAL DISCLOSURE Dr. Güell is a consultant to Ophtec. No other author has a financial or proprietary interest in any material or methods mentioned.
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Affiliation(s)
- José L Güell
- Instituto Microcirugia Ocular, Barcelona, Spain.
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Hardten DR. The expanding role of phakic intraocular lenses-not just for the rare patient anymore. J Refract Surg 2011; 27:471-2. [PMID: 21732574 DOI: 10.3928/1081597x-20110621-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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