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Abtahi MA, Beheshtnejad AH, Latifi G, Akbari-Kamrani M, Ghafarian S, Masoomi A, Sonbolastan SA, Jahanbani-Ardakani H, Atighechian M, Banan L, Nouri H, Abtahi SH. Corneal Epithelial Thickness Mapping: A Major Review. J Ophthalmol 2024; 2024:6674747. [PMID: 38205099 PMCID: PMC10776199 DOI: 10.1155/2024/6674747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/27/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
The corneal epithelium (CE) is the outermost layer of the cornea with constant turnover, relative stability, remarkable plasticity, and compensatory properties to mask alterations in the underlying stroma. The advent of quantitative imaging modalities capable of producing epithelial thickness mapping (ETM) has made it possible to characterize better the different patterns of epithelial remodeling. In this comprehensive synthesis, we reviewed all available data on ETM with different methods, including very high-frequency ultrasound (VHF-US) and spectral-domain optical coherence tomography (SD-OCT) in normal individuals, corneal or systemic diseases, and corneal surgical scenarios. We excluded OCT studies that manually measured the corneal epithelial thickness (CET) (e.g., by digital calipers) or the CE (e.g., by confocal scanning or handheld pachymeters). A comparison of different CET measuring technologies and devices capable of producing thickness maps is provided. Normative data on CET and the possible effects of gender, aging, diurnal changes, refraction, and intraocular pressure are discussed. We also reviewed ETM data in several corneal disorders, including keratoconus, corneal dystrophies, recurrent epithelial erosion, herpes keratitis, keratoplasty, bullous keratopathy, carcinoma in situ, pterygium, and limbal stem cell deficiency. The available data on the potential role of ETM in indicating refractive surgeries, planning the procedure, and assessing postoperative changes are reviewed. Alterations in ETM in systemic and ocular conditions such as eyelid abnormalities and dry eye disease and the effects of contact lenses, topical medications, and cataract surgery on the ETM profile are discussed.
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Affiliation(s)
| | | | - Golshan Latifi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Sadegh Ghafarian
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Masoomi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | | | - Laleh Banan
- Sunshine Coast University Hospital, Brisbane, Queensland, Australia
| | - Hosein Nouri
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed-Hossein Abtahi
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Heidari Z, Mohammadpour M, Hajizadeh F, Fotouhi A, Hashemi H. Corneal layer thickness in keratoconus using optical coherence tomography. Clin Exp Optom 2024; 107:32-39. [PMID: 37121670 DOI: 10.1080/08164622.2023.2201369] [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: 02/28/2021] [Accepted: 04/05/2023] [Indexed: 05/02/2023] Open
Abstract
CLINICAL RELEVANCE Accurate thickness measurement of corneal layers using anterior segment OCT can be used to improve visual outcomes. Understanding its applications is essential for optometric practices to enhance eye care procedures. BACKGROUND To evaluate the thicknesses of different corneal layers for identifying keratoconus (KCN) and subclinical keratoconus (SKCN) using spectral-domain optical coherence tomography (SD-OCT). METHODS This prospective study analyzed 60 eyes with KCN, 48 eyes with SKCN, and 53 normal eyes. The central corneal thickness (CCT) and thicknesses of the epithelium, Bowman, stroma, and Descemet-endothelium layers were measured using SD-OCT. One way analysis of variance and the area under the curve (AUC) were used to evaluate the parameters. The Delong method was used to compare AUCs. RESULTS In KCN, CCT and thicknesses of epithelium, Bowman, stroma, and Descemet-endothelium layers were 495.5 ± 41.7, 52.6 ± 6.4,11.5 ± 1.4, 415.5 ± 38.9, and 12.3 ± 1.7 µm, respectively. These thickness values were respectively 524.5 ± 33.3, 56.8 ± 6.8, 11.5 ± 1.6, 439.8 ± 30.6, and 12.4 ± 1.7 µm in SKCN and 563.8 ± 37.9, 57.7 ± 6.9, 12.2 ± 1.6, 469.5 ± 33.7, and 12.8 ± 2.1µm in normal group. Total cornea and stroma in KCN and SKCN, and epithelium in KCN were significantly thinner compared to the normal group (P < 0.001). The highest AUC values were observed for CCT in KCN (AUC 0.90) and SKCN (AUC 0.782). The diagnostic accuracy was significantly higher for stromal thickness in KCN (sensitivity 81.7%, specificity 73.6%, AUC 0.871) and SKCN (sensitivity 80.0%, specificity 56.6%, AUC 0.751) than other individual corneal layers (Delong, P < 0.001) . CONCLUSION CCT can accurately distinguish keratoconus from normal eyes. However, central corneal stromal thinning was the most sensitive diagnostic index for early detection of SKCN. Developing standardized stromal maps may be helpful for detecting SKCN.
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Affiliation(s)
- Zahra Heidari
- Department of Ophthalmology, Bu-Ali Sina Hospital, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Mehrdad Mohammadpour
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
- Department of Ophthalmology, Farabi Eye Hospital and Eye Research Center, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Fedra Hajizadeh
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Akbar Fotouhi
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Hassan Hashemi
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
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Salman A, Mazzotta C, Kailani O, Ghabra M, Omran R, Balamoun AA, Darwish T, Shaaban R, Alhaji H. Diagnostic Accuracy of Corneal and Epithelial Thickness Map Parameters to Detect Keratoconus and Suspect Keratoconus. J Ophthalmol 2023; 2023:6677932. [PMID: 37842327 PMCID: PMC10575749 DOI: 10.1155/2023/6677932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 09/22/2023] [Accepted: 09/28/2023] [Indexed: 10/17/2023] Open
Abstract
Aim To establish the diagnostic accuracy of corneal and epithelial thickness measurements obtained by spectral-domain optical coherence tomography (SD-OCT) in detecting keratoconus (KC) and suspect keratoconus (SKC). Methods This retrospective study reviewed the data of 144 eyes separated into three groups by the Sirius automated corneal classification software: normal (N) (n = 65), SKC (n = 43), and KC (n = 36). Corneal thickness (CT) and epithelial thickness (ET) in the central (0-2 mm) and paracentral (2-5 mm) zones were obtained with the Cirrus high-definition OCT. Areas under the curve (AUC) of receiver operator characteristic (ROC) curves were compared across groups to estimate their discrimination capacity. Results ROC curve analysis revealed excellent predictive ability for ET variables: minimum (Min) ET (0_2), minimum-maximum (Min-Max) ET (0_2), superonasal-inferotemporal (SN-IT) ET (2_5), Min-Max ET (2_5), and Min ET (2_5) to detect keratoconus (AUC > 0.9, all). Min-Max CT (0_2) was the only CT parameter with excellent ability to discriminate between KC and N eyes (AUC = 0.94; cutoff = ≤-32 μm). However, both ET and CT variables were not strong enough (AUC < 0.8, all) to differentiate between SKC and N eyes, with the highest diagnostic power for Min-Max ET (2_5) (AUC = 0.71; cutoff = ≤-9 μm) and central corneal thickness (CCT) (AUC = 0.76; cutoff = ≤533 μm). Conclusion These results demonstrate that OCT-derived CT and ET are able to differentiate between KC and N eyes, with a high level of certainty. However, Min-Max ET (2_5) was the parameter with the highest ability to detect suspect keratoconus.
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Affiliation(s)
| | - Cosimo Mazzotta
- Departmental Ophthalmology Unit, AUSL Toscana Sudest, Siena, Italy
- Ophthalmology School, University of Siena, Siena, Italy
- Siena International Crosslinking Centre, Siena, Italy
| | - Obeda Kailani
- Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Marwan Ghabra
- Whipps Cross University Hospital, Leytonstone, London, UK
| | | | - Ashraf Armia Balamoun
- Watany Eye Hospital (WEH), Cairo, Egypt
- Watany Research and Development Centre, Cario, Egypt
- Ashraf Armia Eye Clinic, Giza, Egypt
| | - Taym Darwish
- Department of Ophthalmology, Tishreen University, Latakia, Syria
| | | | - Hala Alhaji
- Department of Ophthalmology, Tishreen University, Latakia, Syria
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Zhang J, Liu S, Shao T, Li H, Wang H, Long K. Impact of Corneal Toricity on the Distribution of Corneal Epithelial Thickness. J Refract Surg 2023; 39:482-490. [PMID: 37449507 DOI: 10.3928/1081597x-20230609-02] [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: 07/18/2023]
Abstract
PURPOSE To investigate the impact of corneal toricity on the distribution characteristics of corneal epithelial thickness (CET). METHODS A total of 330 eyes in 330 healthy participants were included in this study. They were divided into two groups based on the median of the corneal toricity value: low-toricity group (corneal toricity < 1.50 diopters) and high-toricity group (corneal toricity ≥ 1.50 diopters). The CET within a 9-mm-diameter area of the central cornea was obtained using optical coherence tomography. The difference of CET value between flat and steep meridians (F-S CET) was defined to evaluate the CET distribution. The F-S CET between the two groups was compared, and the correlations between F-S CET and the corneal toricity were analyzed. RESULTS The CET was thinner in the superior-peripheral area than in other areas. A slight intergroup difference was noted in terms of the F-S CET at the paracentral (0.11 ± 0.93 vs 0.32 ± 0.92, P = .038), midperipheral (0.45 ± 0.78 vs 0.77 ± 0.89, P = .001), and peripheral (3.11 ± 2.18 vs 4.10 ± 2.38, P < .001) zone. In each zone, the difference in F-S CET between the two groups was less than 1 μm. As the area expanded, the F-S CET continued to increase (F = 850.303, P < .001). A weak correlation was observed between F-S CET and corneal toricity (r = 0.103 to 0.240); however, this correlation was not significant in the paracentral zone. Covariance analysis demonstrated that F-S CET was slightly correlated with age, refractive state, and intraocular pressure. CONCLUSIONS The corneal toricity did not significantly affect the distribution of the corneal epithelium in normal corneas. [J Refract Surg. 2023;39(7):482-490.].
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Dubinsky-Pertzov B, Segal O, Hecht I, Gazit I, Or L, Shemer A, Pras E, Einan-Lifshitz A. Predictive accuracy of the ABCD progression display among patients with keratoconus: A historic cohort analysis. Eye (Lond) 2023; 37:1834-1839. [PMID: 36127423 PMCID: PMC10275891 DOI: 10.1038/s41433-022-02242-9] [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: 01/15/2022] [Revised: 06/30/2022] [Accepted: 09/05/2022] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE To evaluate the accuracy of the ABCD Progression Display and the ABCD grading system in a population of adult patients with keratoconus. METHODS A retrospective cohort analysis of all adult patients with keratoconus followed at the Shamir Medical Center between 2012 and 2017. A recommendation by the cornea specialist to undergo corneal crosslinking (CXL) was used as a surrogate of ectasia progression. The ABCD grading was not available to the treating physician and was computed post-hoc. Sensitivity and specificity of the ABCD Progression Display was calculated, and multivariate regression was used to estimate the risk to undergo CXL when the ABCD Progression Display indicated progression. The ABCD grading was compared between patients who required CXL to those who did not. A single eye of each patient was included. Sensitivity and specificity of the ABCD Progression Display were 82% and 73%, respectively. A multivariable model adjusted for possible confounders, found that ABCD Progression was associated with a 7-fold risk of undergoing CXL compared to a patient in whom progression was not recorded in the ABCD Progression Display (OR = 7.55; 95% CI = 3.82-14.93, p < 0.001). RESULTS 293 eyes of 293 patients were analysed. Mean age at presentation was 26.92 ± 6.12 years. In 68 eyes, progression of keratoconus was recorded and CXL was performed (CXL-group). CONCLUSION The ABCD Progression Display demonstrated adequate sensitivity and specificity and high predictive capabilities of keratoconus progression. It can be effectively utilized as an initial screening test in adults with keratoconus.
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Affiliation(s)
- Biana Dubinsky-Pertzov
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel.
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Omri Segal
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Idan Hecht
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Inbal Gazit
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Lior Or
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Asaf Shemer
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eran Pras
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Adi Einan-Lifshitz
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Nobl M, Gerhardt M, Kassumeh S, Mohr N, Mayer W, Dirisamer M, Priglinger S, Luft N. [Steering clear of "corneal red disease"-epithelial thickness mapping for differential diagnosis of corneal ectatic disease]. DIE OPHTHALMOLOGIE 2023; 120:430-436. [PMID: 35925332 DOI: 10.1007/s00347-022-01663-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 05/04/2022] [Accepted: 05/11/2022] [Indexed: 04/29/2023]
Affiliation(s)
- Matthias Nobl
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Maximilian Gerhardt
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Stefan Kassumeh
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Niklas Mohr
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Wolfgang Mayer
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
| | - Martin Dirisamer
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
- Auge-Laser-Chirurgie, Linz, Österreich
| | - Siegfried Priglinger
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland
- Auge-Laser-Chirurgie, Linz, Österreich
| | - Nikolaus Luft
- Augenklinik und Poliklinik, Klinikum der Universität München, LMU München, Mathildenstr. 8, 80336, München, Deutschland.
- Auge-Laser-Chirurgie, Linz, Österreich.
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Abstract
PURPOSE To enumerate the various diagnostic modalities used for keratoconus and their evolution over the past century. METHODS A comprehensive literature search including articles on diagnosis on keratoconus were searched on PUBMED and summarized in this review. RESULTS Initially diagnosed in later stages of the disease process through clinical signs and retinoscopy, the initial introduction of corneal topography devices like Placido disc, photokeratoscopy, keratometry and computer-assisted videokeratography helped in the earlier detection of keratoconus. The evolution of corneal tomography, initially with slit scanning devices and later with Scheimpflug imaging, has vastly improved the accuracy and detection of clinical and sub-clinical disease. Analyzing the alteration in corneal biomechanics further contributed to the earlier detection of keratoconus even before the tomographic changes became evident. Anterior segment optical coherence tomography has proven to be a helpful adjuvant in diagnosing keratoconus, especially with epithelial thickness mapping. Confocal microscopy has helped us understand the alterations at a cellular level in keratoconic corneas. CONCLUSION Thus, the collective contribution of the various investigative modalities have greatly enhanced earlier and accurate detection of keratoconus, thus reducing the disease morbidity.
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Affiliation(s)
- Akhil Bevara
- Department of Cornea and Anterior segment, Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Pravin K Vaddavalli
- Department of Cornea and Anterior segment, Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
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Decision taking in corneal refractive surgery. J Cataract Refract Surg 2023; 49:325-330. [PMID: 36867474 DOI: 10.1097/j.jcrs.0000000000001161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
A 27-year-old woman who wants to get rid of contact lenses and spectacles was seen at our clinic. She had strabismus surgery as a child and was patched for the right eye but now shows mild nondisturbing exophoria. Infrequently, she likes to box in the sports school. Her corrected distance visual acuity at presentation in the right eye was 20/16 with -3.75 -0.75 × 50 and in the left eye 20/16 with -3.75 -1.25 × 142. Her cycloplegic refraction in the right eye was -3.75 -0.75 × 44 and in the left eye was -3.25 -1.25 × 147. The left eye is the dominant eye. The tear break-up time was 8 seconds in both eyes, and the Schirmer tear test was 7 to 10 mm in right and left eyes, respectively. Pupil sizes under mesopic conditions were 6.62 mm and 6.68 mm. The anterior chamber depth (ACD) (measured from the epithelium) in the right eye was 3.89 mm and in the left eye was 3.87 mm. The corneal thickness was 503 μm and 493 μm of the right and left eye, respectively. Corneal endothelial cell density was on average 2700 cells/mm2 for both eyes. Slitlamp biomicroscopy showed clear corneas and a normal flat iris configuration. Supplemental Figures 1 to 4 (available at http://links.lww.com/JRS/A818, http://links.lww.com/JRS/A819, http://links.lww.com/JRS/A820, and http://links.lww.com/JRS/A821) show the corneal topography and Belin-Ambrósio deviation (BAD) maps at presentation of the right eye and left eye, respectively. Would you consider this patient a candidate for corneal refractive surgery (eg, laser-assisted subepithelial keratectomy, laser in situ keratomileusis [LASIK], or small-incision lenticule extraction [SMILE] procedure)? Has your opinion changed given the recent opinion of the U.S. Food and Drug Administration (FDA) regarding LASIK?1 The patient herself is slightly favoring an implantation of a phakic intraocular lens (pIOL), as she prefers something reversible. Would you implant a pIOL, and which type of IOL, for this level of myopia? What is your diagnosis or are additional diagnostic methodologies needed to establish a diagnosis? What is your treatment advice for this patient? REFERENCES 1. U.S. Food and Drug Administration, HHS. Laser-assisted in situ keratomileusis (LASIK) lasers-patient labeling recommendations; draft guidance for industry and food and drug administration staff; availability. July 28, 2022, Federal Register; 87 FR 45334. Available at: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/laser-assisted-situ-keratomileusis-lasik-lasers-patient-labeling-recommendations Accessed January 25, 2023.
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Yücekul B, Dick HB, Taneri S. Systematic detection of keratoconus in OCT: corneal and epithelial thickness maps. J Cataract Refract Surg 2022; 48:1360-1365. [PMID: 35714335 DOI: 10.1097/j.jcrs.0000000000000990] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/08/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE To detect keratoconus (KC) only by analyzing the corneal and epithelial map parameters and patterns in optical coherence tomography (OCT). SETTING Tertiary care refractive surgery center. DESIGN Retrospective data collection. METHODS Corneal and epithelial thickness maps of normal, manifest, and subclinical keratoconic eyes (according to the Belin-Ambrosio display, Pentacam) were evaluated using spectral-domain OCT (Zeiss Cirrus 5000 HD). A new 2-step decision tree was developed based on previous studies with another OCT device. In the first step, if at least 1 of the 4 independent parameters (pachymetry minimum, pachymetry minimum-median, pachymetry superonasal-inferotemporal, and epithelial superonasal-inferotemporal) overruns the cutoff values, the eye was suspicious for KC. In the second step, if the epithelial map showed concentric thinning and the thinnest point of the cornea and epithelium is coincident, the eye was classified as keratoconic. RESULTS 172 manifest keratoconic eyes (108 patients), 21 subclinical keratoconic eyes (20 patients), and 172 normal eyes (90 age-matched participants) were included in this study. Step 1 captured 100% of manifest and subclinical keratoconic eyes. Step 2 ruled out all suspicious but normal cases and, falsely, 2 subclinical keratoconic eyes. Our 2-step decision tree reached 100% specificity, 100% sensitivity in manifest KC, and 90.4% sensitivity in subclinical KC. CONCLUSIONS Pachymetric and epithelial map parameters and patterns in OCT can be used in the diagnosis of KC, including subclinical cases, yielding a high level of agreement with the commonly used diagnostic reference, the Belin-Ambrosio display. Further improvements by refining our algorithm and including an automated evaluation in the software are desirable.
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Affiliation(s)
- Burcu Yücekul
- From the Department of Ophthalmology, Haseki Training and Research Hospital, Istanbul, Turkey (Yücekul); Ruhr University, Bochum, Germany (Dick, Taneri); Zentrum für Refraktive Chirurgie, Augenzentrum am St. Franziskus Hospital, Muenster, Germany (Taneri)
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Alghamdi A, Khan MS, Dakhil TA. Understanding Corneal Epithelial Thickness Mapping. Middle East Afr J Ophthalmol 2022; 29:147-155. [PMID: 37408717 PMCID: PMC10319081 DOI: 10.4103/meajo.meajo_207_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/31/2022] [Accepted: 03/06/2023] [Indexed: 07/07/2023] Open
Abstract
Corneal epithelial thickness (CET) and the regional variations in response to changes in corneal architecture and biomechanics have recently drawn the interest of corneal surgeons. Corneal epithelium possesses the tremendous capability of remodeling and changing its thickness. This remodeling of corneal epithelium takes place in response to underlying stromal irregularities which can result from a variety of corneal disorders including corneal ectasia. Measurement of CET can reveal the underlying stromal abnormalities and supplement in early diagnosis of corneal disorders especially corneal ectasia which has been one of the leading challenges in planning corneal refractive surgery. A significant number of patients ends up in ectasia after refractive surgery and the most common cause of this complication is the presence of preoperative subclinical keratoconus. Furthermore, postoperative complications of corneal refractive surgery are partly masked by epithelial remodeling and make the diagnosis and management difficult and extremely challenging. This leads not only to unpredictable visual and refractive outcome but also the need of multiple interventions to treat these complications. Although corneal tomography is considered as gold standard in the detection and diagnosis of corneal ectasia, a small number of subclinical cases may still go undetected. In this review, we have highlighted the underlying mechanism of epithelial remodeling, the devices and imaging modalities used to measure CET, and application of epithelial mapping in the diagnosis and management of various corneal disorders.
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Affiliation(s)
- Abdullah Alghamdi
- Department of Ophthalmology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Muhammad S. Khan
- Department of Ophthalmology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Turki A. Dakhil
- Department of Ophthalmology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
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Kasıkcı M, Karalezli A, Eroğul Ö, Gobeka HH. Quantifying contact lens-related changes in keratoconus corneal topographic indices: an updated Pentacam Scheimpflug imaging analysis. Rom J Ophthalmol 2022; 66:245-256. [PMID: 36349169 PMCID: PMC9585500 DOI: 10.22336/rjo.2022.47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2022] [Indexed: 06/16/2023] Open
Abstract
Purpose: Slowing ectasia progression is critical for maintaining visual potential in keratoconus (KC), for which various therapeutic approaches have been implemented. A Pentacam Scheimpflug imaging device was used to quantify contact lens (CL)-related changes in keratoconus corneal topographic indices. Methods: Thirty KC patients (group 1; 60 eyes) were using one of the three CL (rigid gas-permeable CL (RGPCL)-10, hybrid CL (HCL)-10, and scleral CL (SCL)-10 patients). A control group included 30 KC patients (group 2; 60 eyes) not using CLs due to intolerance or inappropriateness. The Pentacam® HR Scheimpflug imaging device was used to measure topographic indices such as Km anterior, Km posterior, K max, corneal thickness (CT, corneal central, apex, and thinnest), corneal volume (CV), anterior chamber volume (ACV), and anterior chamber depth (ACD) at baseline, 3rd, 6th, and 12th months. Results: The mean ages for groups 1 and 2 were 32±10 and 31±09 years, respectively. Group 1 had a lower but statistically significant change in K max than group 2 (p<0.038). Also, group 1 had a minor but non-significant decrease in anterior and posterior keratometry values compared to group 2 (pKm ant. right/ left eye = 0.063/ 0.065 and 0.087/ 0.094, respectively). RGPCL users had significant changes in central CT, thinnest CT and ACD (p<0.041). SCL users had more stable changes than other CLs for the thinnest CT along with significant changes in K max, pachy apex and ACV (p<0.036). HCL users had significantly higher K max stability (p<0.039). Conclusion: Regular use of appropriate therapeutic CLs may help to stabilize corneal deformity, thereby slowing changes in corneal topographic indices in KC.
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Affiliation(s)
- Murat Kasıkcı
- Department of Ophthalmology, Mugla Sitki Kocman University Education and Research Hospital, Mugla, Turkey
| | - Aylin Karalezli
- Department of Ophthalmology, Mugla Sitki Kocman University Education and Research Hospital, Mugla, Turkey
| | - Özgür Eroğul
- Department of Ophthalmology, Afyonkarahisar Health Sciences University Faculty of Medicine, Afyonkarahisar, Turkey
| | - Hamidu Hamisi Gobeka
- Department of Ophthalmology, Afyonkarahisar Health Sciences University Faculty of Medicine, Afyonkarahisar, Turkey
- Department of Ophthalmology, Agri Ibrahim Cecen University Faculty of Medicine, Agri, Turkey
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12
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Abdolalizadeh P, Karimi M, Latifi G, Nouri L, Hashemian MN, Hashemian H, Mehrpour M, Alipour F. Role of Different Types of Contact Lenses in Epithelial Thickness. Eye Contact Lens 2022; 48:210-216. [PMID: 35333790 DOI: 10.1097/icl.0000000000000878] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2021] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To evaluate the potential role of different types of contact lenses, such as soft (SCL), hard (HCL), and mini scleral (SCCL), in corneal epithelial thickness with anterior segment optical coherence tomography (AS-OCT). METHODS In this cross-sectional study, patients who used contact lens at recent 6 months were recruited consecutively from September 2019 to October 2019, and the epithelial thicknesses of the cornea were obtained by AS-OCT and compared with control subjects who did not use contact lens. RESULTS In total, 184 eyes (115 subjects) were included; of them, 75 eyes were keratoconic (KCN) and 109 eyes were nonkeratoconic (non-KCN). Twenty eyes in KCN and 79 eyes of non-KCN group had no history of contact lens use and were included for comparison with KCN and non-KCN contact lens users, respectively. Mean duration of contact lens wearing was 75.63±50.42 months. The epithelial thickness of non-KCN SCL group was thinner than that of non-KCN control subjects all over the cornea, whereas the epithelium of non-KCN HCL was thinner at central site as well as nasal and temporal paracentral and midperipheral areas. Epithelial thickness of the KCN HCL group was not different from the KCN control subjects in all sectors. The KCN SCCL group had thinner epithelium at nearly all peripheral sectors as well as inferior, inferotemporal, inferonasal, and nasal midperipheral sectors compared with KCN control subjects. CONCLUSION The corneal epithelium was thinner at the peripheral zones in KCN SCCL users; at both peripheral and central zones in non-KCN SCL users and in central zones in non-KCN HCL users.
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Affiliation(s)
- Parya Abdolalizadeh
- Eye and Skull Base Research Centers (P.A.), The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran; and Eye Research Center (M.K., G.L., L.N., M.-N.H., H.H., M.M., F.A.), Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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13
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Kong AW, Ahmad TR, Turner ML, Barnett J, Kaur G, Pasricha ND, Indaram M. Trends in Corneal Topography and Tomography Imaging for Keratoconus Management. Clin Ophthalmol 2022; 16:1357-1363. [PMID: 35510272 PMCID: PMC9059983 DOI: 10.2147/opth.s361352] [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: 02/06/2022] [Accepted: 03/31/2022] [Indexed: 11/23/2022] Open
Abstract
Purpose To describe trends in the use of corneal topography and tomography for the management of keratoconus patients at a single academic institution and to identify how these trends may be associated with different procedural interventions. Patients and Methods In this retrospective cohort study, keratoconus patients treated from 2012 to 2019 were identified. The electronic health record was reviewed for the presence of corneal topography or tomography imaging completed within seven days of the first visit and the highest level of intervention at the first and most recent visit. Patients were grouped as pediatric (<18 years) or adult (≥18 years). Chi-square tests and linear regressions were used to evaluate trends and to determine which factors were predictive for receiving corneal collagen cross-linking (CXL) versus other surgical interventions (intrastromal corneal ring segments, lamellar keratoplasty, or penetrating keratoplasty) by the most recent visit. Results A total of 873 keratoconus patients met inclusion criteria. The use of corneal topography at the first visit remained relatively consistent from 2012 to 2019, while corneal tomography usage at the first visit increased from 3.9% in 2015, when corneal tomography was introduced, to 52.8% in 2019. Each year was associated with an 11.2% ± 1.9% increase in the use of corneal tomography at the first visit in pediatric patients and 6.7% ± 0.5% in adult patients. Use of corneal tomography at the first visit was a significant predictor for receiving CXL procedures (P < 0.001) and a negative predictor for requiring other surgical interventions (P = 0.032) when controlling for the year of the first visit. Conclusion Obtaining corneal tomography at the first visit has become the standard of care in keratoconus, especially for pediatric patients. Moreover, the increase in corneal tomography imaging has coincided with an increase in CXL procedures and decrease in other surgical interventions.
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Affiliation(s)
- Alan W Kong
- School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Tessnim R Ahmad
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA
| | - Marcus L Turner
- School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Jackson Barnett
- School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Gurbani Kaur
- School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Neel D Pasricha
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA,Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA
| | - Maanasa Indaram
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA,Correspondence: Maanasa Indaram, Department of Ophthalmology, University of California San Francisco, 490 Illinois Street, San Francisco, CA, 94158, USA, Email
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14
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Avetisov SE, Gridin VN, Bubnova IA, Lebedev AS, Novikov IA. [Prospects for early detection of keratoconus based on systems built for computer-assisted diagnostics of structural changes in the cornea]. Vestn Oftalmol 2022; 138:100-106. [PMID: 35234428 DOI: 10.17116/oftalma2022138011100] [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
The article is devoted to the problem of diagnosing subclinical keratoconus (KK). The need to identify early signs of KK is primarily associated with the potential for the development of iatrogenic keratoectasia in cases of underdiagnosis of the disease when determining the conditions for laser keratorefractive surgery involving a decrease in the thickness of the cornea. Today generally accepted algorithms for early computer-assisted diagnosis of KK are mainly based on the analysis of various morphometric parameters of the cornea, reflecting changes in its shape and thickness induced by structural abnormalities. Direct detection of structural changes in the cornea characteristic of early KK requires the use of high-tech imaging methods that are not always applicable in everyday clinical practice. The promising approach proposed in this study is based on the fact that a digital image of a corneal «slice» obtained using serial analyzers such as the Scheimpflug camera widely used in clinical practice provides indirect information about the structure of the epithelial layer, the local thickening of which takes place in the initial stages KK. It is this criterion that underlies the proposed system of computer-assisted diagnosis of KK. The carried out studies have shown the high sensitivity of this algorithm, and its specificity can be increased by involving the known diagnostic indicators of KK.
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Affiliation(s)
- S E Avetisov
- Research Institute of Eye Diseases, Moscow, Russia.,I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - V N Gridin
- Center of Information Technologies in Design Russian Academy of Sciences, Odintsovo, Russia
| | - I A Bubnova
- Research Institute of Eye Diseases, Moscow, Russia.,Center of Information Technologies in Design Russian Academy of Sciences, Odintsovo, Russia
| | - A S Lebedev
- Center of Information Technologies in Design Russian Academy of Sciences, Odintsovo, Russia
| | - I A Novikov
- Research Institute of Eye Diseases, Moscow, Russia.,Center of Information Technologies in Design Russian Academy of Sciences, Odintsovo, Russia
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15
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Asroui L, Dupps WJ, Randleman JB. Determining the Utility of Epithelial Thickness Mapping in Refractive Surgery Evaluations. Am J Ophthalmol 2022; 240:125-134. [PMID: 35247335 DOI: 10.1016/j.ajo.2022.02.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 02/18/2022] [Accepted: 02/20/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE To determine the impact of corneal epithelial thickness maps on screening for refractive surgery candidacy in a single refractive surgical practice. DESIGN Comparison of screening methods. METHODS A total of 100 consecutive patients who presented for refractive surgery screening were evaluated. For each patient, screening based on Scheimpflug tomography, clinical data, and patient history was performed and a decision on eligibility for laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE)was independently made by 2 masked examiners. Examiners were then shown patients' epithelial thickness maps derived from optical coherence tomography (OCT). The percentage of screenings that changed after evaluating the epithelial thickness maps, with regard to candidacy for surgery, and ranking of surgical procedures from most to least favorable was determined. RESULTS Candidacy for corneal refractive surgery changed in 16% of patients after evaluation of the epithelial thickness maps, with 10% of patients screened in and 6% screened out. Surgery of choice changed for 16% of patients, and the ranking of surgical procedures from most to least favorable changed for 25% of patients. A total of 11% of patients gained eligibility for LASIK, whereas 8% lost eligibility for LASIK. No significant difference was found between the evaluations of the 2 examiners. CONCLUSIONS Epithelial thickness mapping derived from optical coherence tomography imaging of the cornea altered candidacy for corneal refractive surgery, as well as choice of surgery, in a substantial percentage of patients in our practice, and was thus a valuable tool for screening evaluations. Overall, the use of epithelial thickness maps resulted in screening in a slightly larger percentage of patients for corneal refractive surgery.
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Affiliation(s)
- Lara Asroui
- From the Cole Eye Institute (L.A., W.J.D., J.B.R.), Department of Biomedical Engineering, Lerner Research Institute (W.J.D.), Cleveland Clinic, Department of Biomedical Engineering, Case Western Reserve University (W.J.D.), and the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (W.J.D, J.B.R) Cleveland, Ohio, USA
| | - William J Dupps
- From the Cole Eye Institute (L.A., W.J.D., J.B.R.), Department of Biomedical Engineering, Lerner Research Institute (W.J.D.), Cleveland Clinic, Department of Biomedical Engineering, Case Western Reserve University (W.J.D.), and the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (W.J.D, J.B.R) Cleveland, Ohio, USA
| | - J Bradley Randleman
- From the Cole Eye Institute (L.A., W.J.D., J.B.R.), Department of Biomedical Engineering, Lerner Research Institute (W.J.D.), Cleveland Clinic, Department of Biomedical Engineering, Case Western Reserve University (W.J.D.), and the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (W.J.D, J.B.R) Cleveland, Ohio, USA.
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16
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Pavlatos E, Harkness B, Louie D, Chamberlain W, Huang D, Li Y. Differentiating Between Contact Lens Warpage and Keratoconus Using OCT Maps of Corneal Mean Curvature and Epithelial Thickness. J Refract Surg 2022; 38:112-119. [PMID: 35156455 PMCID: PMC8870421 DOI: 10.3928/1081597x-20211116-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To formulate an Epithelial Modulation index to differentiate between eyes with contact lens warpage and keratoconus. METHODS Normal eyes and eyes with either contact lens warpage or keratoconus were scanned by a Fourier-domain optical coherence tomography (OCT) system. Maps of epithelial thickness and anterior surface mean curvature were generated and converted to deviation maps by subtracting the average maps from a healthy population. The Epithelial Modulation index was defined as the covariance between the two types of deviation maps. A logistic regression model was used to classify eyes as non-keratoconus (normal or warp-age) or keratoconus (manifest, subclinical, or forme fruste). RESULTS The average Epithelial Modulation index value for normal eyes was -0.6 ± 1.0 µm/m. Eyes with keratoconus were characterized by coincident high anterior surface mean curvature and low epithelial thickness, resulting in a high Epithelial Modulation index (manifest: 103.0 ± 82.9 µm/m, subclinical: 37.0 ± 23.0 µm/m, forme fruste: 7.3 ± 13.2 µm/m). The Epithelial Modulation index was closer to normal for eyes with warpage (-1.9 ± 4.0 µm/m). The classification accuracy of the Epithelial Modulation index during five-fold cross-validation of the logistic regression model was 100 ± 0% for normal eyes and 99.0 ± 2.0% for eyes with warpage. The accuracy was 100 ± 0%, 100 ± 0%, and 53.1 ± 1.5% for the manifest, subclinical, and forme fruste keratoconus groups, respectively. CONCLUSIONS The Epithelial Modulation index is useful in distinguishing eyes with secondary epithelial modulation (keratoconus) from those with primary epithelial deformation (contact lens-related warpage). [J Refract Surg. 2022;38(2):112-119.].
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17
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Abe K, Miyai T, Toyono T, Aixinjueluo W, Inoue T, Asano S, Ishii H, Yoshida J, Shirakawa R, Usui T. Comparison of efficacy and safety of accelerated trans-epithelial crosslinking for keratoconus patients with corneas thicker and thinner than 380µm. Curr Eye Res 2021; 47:511-516. [PMID: 34898348 DOI: 10.1080/02713683.2021.2018466] [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: 10/19/2022]
Abstract
PURPOSE Accelerated trans-epithelial cross-linking (ATE-CXL), a therapy to halt keratoconus progression, has the merit of widening the indications for thinner corneas (<380 μm). Since a hypotonic solution affects the swollen cornea, corneas of <380 μm thickness at preoperative measurement can be an indication for ATE-CXL. The aim of this retrospective study was to compare the efficacy and safety of ATE-CXL for keratoconus between corneas with thicknesses <380 μm and ≥380 μm. MATERIALS AND METHODS Thirty-four eyes of 27 patients who underwent ATE-CXL (30 mW/cm2; 3 minutes) with completion of a 24-month follow-up, were enrolled and divided into two groups: Group 1, thinnest corneal thickness (TCT), <380 μm (n = 10) and Group 2, TCT, ≥380 μm (n = 24). A hypotonic solution was administered to Group 1 until the corneal thickness increased by >380 μm before UV-A irradiation. We measured uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), maximum and average keratometric values (Kmax and AveK), central corneal thickness (CCT), TCT by anterior segment optical coherence tomography, and corneal endothelial cell density (ECD) using specular microscopy. The changes from baseline to 24 months postoperatively between the two groups were compared accordingly. RESULTS The changes in Kmax and AveK from baseline to 24 months in Group 1 (ΔKmax: -7.8±7.7 D, ΔAveK: -4.3±6.1 D) showed significant decreases compared to those in Group 2 (ΔKmax: 0.2±3.0 D, ΔAveK: 0.6±2.7 D) (p = 0.004 and p = 0.001), and there were no significant changes from baseline to 24 months postoperatively in UCVA, BCVA, CCT, TCT, and ECD in both groups. CONCLUSION ATE-CXL is effective and safe for keratoconic corneas in both groups. The effect of reducing keratometric values was greater in the group with thinner corneas.
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Affiliation(s)
- Kentaro Abe
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan
| | - Takashi Miyai
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan
| | - Tetsuya Toyono
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan
| | - Wei Aixinjueluo
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan.,Department of Ophthalmology, Tokyo Teishin Hospital, Japan
| | - Tatsuya Inoue
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan
| | - Shotaro Asano
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan
| | - Hitoha Ishii
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan.,Department of Ophthalmology, Saitama Red Cross Hospital, Japan
| | - Junko Yoshida
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan
| | - Rika Shirakawa
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan
| | - Tomohiko Usui
- Department of Ophthalmology, the University of Tokyo, Graduate School of Medicine, Japan
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18
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Krause D, Mohr N, Shajari M, Mayer WJ, Priglinger S, Luft N. Reliability of Corneal, Epithelial, and Stromal Thickness Mapping for a 9-mm Zone Using Spectral-Domain Optical Coherence Tomography. Klin Monbl Augenheilkd 2021; 238:1213-1219. [PMID: 34528231 DOI: 10.1055/a-1535-1685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE To evaluate the reliability of spectral-domain optical coherence tomography (SD-OCT; RTVue XR; Optovue, Inc., Fremont, CA, USA) for thickness mapping of the entire cornea (CT), corneal epithelium (ET). and corneal stroma (ST) over a 9-mm zone in healthy eyes. We sought to develop reference values for different age groups and elucidate potential sex- and age-dependent characteristics of corneal sublayer pachymetry maps. METHODS Three consecutive SD-OCT scans were obtained in 166 healthy right eyes (mean age = 50 ± 20 years). The thickness maps contain 25 sectors over a 9-mm diameter zone. To test measurement reliability, intraclass correlation coefficients (ICC), coefficients of variation (CoV), and within-subject standard deviations (WSSD) were calculated. RESULTS CT, ET, and ST ICCs ranged from 0.961 to 0.998, 0.896 to 0.945, and 0.955 to 0.998, respectively. CoV values for CT, ET, and ST ranged between 0.3 and 1.5%, 1.6 and 4.2%, and 0.4 and 1.7%, respectively. WSSD ranged from 6 to 41, 4 to 8, and 7 to 46 µm, respectively. A negative correlation was found between age and ET (p < 0.05) but not between age and ST or CT. No gender-related differences in CT, ET, or ST were detected. CoV of CT, ET, and ST measurements showed a positive correlation with age in 28, 64, and 28% of the sectors, respectively. CONCLUSION SD-OCT is a rapid and noninvasive technique that provides excellent reliability for corneal sublayer thickness measurements over a 9-mm zone. The reliability of the ET measurement seems to be negatively affected by age. Peripheral CT and global ET thin with age.
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Affiliation(s)
- Daniel Krause
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
| | - Niklas Mohr
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
| | - Mehdi Shajari
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
| | - Wolfgang J Mayer
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
| | | | - Nikolaus Luft
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
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19
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Diagnostic Value of Corneal Epithelial and Stromal Thickness Distribution Profiles in Forme Fruste Keratoconus and Subclinical Keratoconus. Cornea 2021; 40:61-72. [PMID: 32769675 DOI: 10.1097/ico.0000000000002435] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To assess the diagnostic values of corneal epithelial and stromal thickness distribution characteristics in forme fruste keratoconus (FFKC) and subclinical keratoconus (KC). METHODS This cross-sectional study was conducted at VISSUM Innovation and Miguel Hernandez University, Alicante, Spain. Twenty-seven eyes (27 subjects) with FFKC, 50 eyes (50 subjects) with subclinical KC with a best spectacle corrected distance visual acuity ≥20/20 (Snellen) (grade zero KC according to the Red Temática de Investigación Cooperativa en Salud classification), and 66 control eyes (66 subjects) were included. Epithelial and stromal thicknesses and epithelium/stroma (E/S) thickness ratio at center, thinnest point, 5-, and 8-mm circles obtained from the MS-39 device (CSO, Firenze, Italy) were compared among the control, FFKC, and subclinical KC groups. RESULTS The FFKC group had thinner 8-mm superior-nasal epithelium and higher central E/S ratio compared with the control group (P < 0.05). In the subclinical KC group, the E/S ratios in the 5-mm temporal and superior zones were higher than those in the control group (P < 0.05). The FFKC and subclinical KC groups had thinner stroma compared with the control group (P < 0.05). A two-parameter formula correctly classified 94% of the eyes with subclinical KC and 98.5% of the normals, whereas another three-parameter model had 75% sensitivity and 94.3% specificity for discriminating FFKC from normals. CONCLUSIONS This study identified different epithelial distributional and behavioral patterns in eyes with FFKC and subclinical KC. Eyes with FFKC seem to have increased central E/S ratio and asymmetric superior-nasal epithelial thinning, whereas keratometric and volumetric alterations seem to be more prominent in subclinical KC.
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20
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Hu L, Li Y, Liu Q, Xu Z, Gu J, Li A, Wang Y, Lin K, Xia J, Chen S, Lu F. Corneal Vertical and Horizontal Thickness Profiles Generated by UHR-OCT for Suspected and Subclinical Keratoconus Diagnosis. J Refract Surg 2021; 37:438-445. [PMID: 34236909 DOI: 10.3928/1081597x-20210330-01] [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: 12/13/2022]
Abstract
PURPOSE To verify the diagnostic power of vertical and horizontal thickness profiles of the corneal sublayers generated by ultra-high resolution optical coherence tomography (UHROCT) in subclinical and suspected keratoconus. METHODS In this cross-sectional study, 25 eyes with confirmed keratoconus, 63 eyes with suspected keratoconus, 15 eyes with subclinical keratoconus, and 42 normal eyes were investigated. Vertical and horizontal thickness profiles of the corneal epithelium, Bowman's layer, and stroma were measured by UHR-OCT. Diagnostic indices included ratios of thickness distribution and multimeric discriminant functions calculated by multiple logistic regression based on them. Receiver operating characteristic curves were used to verify the predictive accuracy by the area under the curve (AUC). RESULTS Function consisting of two indices (vertical maximum ectasia index of epithelium and horizontal maximum ectasia index of Bowman's layer) performed well to discriminate subclinical keratoconus (AUC = 0.967) and suspected keratoconus (AUC = 0.932) from normal. In addition, when four indices were combined, the diagnostic power for subclinical keratoconus (AUC = 0.984) and suspected keratoconus (AUC = 0.971) was further increased. However, both binary and quaternary functions could not adequately discriminate suspected from subclinical keratoconus. CONCLUSIONS UHR-OCT-generated thickness indices from the vertical and horizontal thickness profiles of the corneal epithelium and Bowman's layer showed an evident diagnostic efficacy in discriminating suspected and subclinical keratoconus from normal eyes. The early changes in keratoconus might prefer thickness distribution in corneal sublayers rather than corneal thickness or topography. [J Refract Surg. 2021;37(7):438-445.].
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21
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Li Y, Gokul A, McGhee C, Ziaei M. Repeatability of corneal and epithelial thickness measurements with anterior segment optical coherence tomography in keratoconus. PLoS One 2021; 16:e0248350. [PMID: 34143790 PMCID: PMC8213071 DOI: 10.1371/journal.pone.0248350] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 02/24/2021] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To investigate the repeatability in corneal thickness (CT) and epithelial thickness (ET) measurements using spectral domain anterior segment optical coherence tomography (AS-OCT, REVO NX, Optopol) in keratoconus, and examine the effect of corneal crosslinking (CXL) on repeatability. METHODS A cross-sectional study of 259 eyes of 212 patients with keratoconus attending the corneal disease clinic at a university hospital tertiary referral center were enrolled. Two groups were analysed: eyes with no prior history of CXL (Group A) and eyes with prior CXL (Group B). Repeatability of measurements was assessed using the intraclass correlation coefficient (ICC) and coefficient of variation (CV). RESULTS In Group A, central corneal thickness (CCT) was 472.18 ± 45.41μm, and the ET was found to be the thinnest in the inferior-temporal aspect at 51.79 ± 5.97μm and thickest at the superior-nasal aspect at 56.07 ± 5.70μm. In Group B, CCT was 465.11± 42.28μm, and the ET was the thinnest at the inferior-temporal aspect at 50.63 ± 5.52μm and thickest at the superior aspect at 56.80 ± 6.39μm. When evaluating CT measurements, ICC was above 0.86 and 0.83 for Group A and Group B respectively. When evaluating ET measurements, ICC was above 0.82 for both groups. CXL had no statistically significant impact on the repeatability of measurements. CONCLUSIONS AS-OCT provides repeatable CT and ET measurements in the central and peripheral cornea in patients with keratoconus. Repeatability is not affected by a history of CXL.
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Affiliation(s)
- Ye Li
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Akilesh Gokul
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Charles McGhee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Mohammed Ziaei
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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22
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Lopes B, Padmanabhan P, Zhang H, Abass A, Eliasy A, Bandeira F, Bao F, Bühren J, Elmassry A, Faria-Correia F, Rocha K, Rechichi M, Romano V, Torres-Netto EA, Vinciguerra R, Vinciguerra P, Elsheikh A. Clinical Validation of the Automated Characterization of Cone Size and Center in Keratoconic Corneas. J Refract Surg 2021; 37:414-421. [PMID: 34170770 DOI: 10.3928/1081597x-20210315-03] [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: 12/17/2022]
Abstract
PURPOSE To evaluate an automated method for detecting the cone shape characteristics and to assess the cornea specialists' subjective variability of these measures using different maps. METHODS Topographic images of the anterior and posterior surface of each eye were presented to 12 clinicians in two different types of map: tangential curvature and relative elevation to the best-fit sphere. They were asked to mark the cone center and its boundaries in the two maps without knowing that they belonged to the same patient. The results between the maps were compared to assess the subjective variability dependent on the map type and the automated method was compared against both estimations to assess its accuracy. RESULTS Considering the results of anterior and posterior surfaces, there was low agreement between the cone center estimations using different types of maps for 10 of the 12 cases (P < .05), whereas the comparison between the automated method and the two map estimations did not show differences in 11 of the 12 cases (P > .05). There was high variability, up to 55%, among clinicians' estimations of the cone area. The results of the automated method were within the range of the expert's estimations. CONCLUSIONS An objective, mathematically derived method of determining morphological dimensions of the cone was consistent with clinicians' evaluations. Although there was high variability among the experts' subjective estimates, which were highly influenced by the type of map, the objective method provided a reliable evaluation of the keratoconus shape independent of maps or color scale. [J Refract Surg. 2021;37(6):414-421.].
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23
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Yang Y, Pavlatos E, Chamberlain W, Huang D, Li Y. Keratoconus detection using OCT corneal and epithelial thickness map parameters and patterns. J Cataract Refract Surg 2021; 47:759-766. [PMID: 33181629 PMCID: PMC8131403 DOI: 10.1097/j.jcrs.0000000000000498] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 10/20/2020] [Indexed: 01/03/2023]
Abstract
PURPOSE To detect keratoconus using optical coherence tomography (OCT) corneal map parameters and patterns. SETTING Casey Eye Institute, Oregon Health and Science University, Portland, Oregon. DESIGN Cross-sectional observational study. METHODS A spectral-domain OCT was used to acquire corneal and epithelial thickness maps in normal, manifest keratoconic, subclinical keratoconic, and forme fruste keratoconic (FFK) eyes. A 2-step decision tree was designed. An eye will be classified as keratoconus if both decision tree conditions are met. First, at least 1 of the 4 quantitative corneal thickness (minimum, minimum-maximum, and superonasal-inferotemporal) and epithelial thickness (standard deviation) map parameters exceed cutoff values. Second, presence of both concentric thinning pattern on the epithelial thickness map and coincident thinning patterns on corneal and epithelial thickness maps by visual inspection. RESULTS The study comprised 54 eyes from 29 normal participants, 91 manifest keratoconic eyes from 65 patients, 12 subclinical keratoconic eyes from 11 patients, and 19 FFK eyes from 19 patients. The decision tree correctly classified all normal eyes (100% specificity) and had good sensitivities for detecting manifest keratoconus (97.8%), subclinical keratoconus (100.0%), and FFK (73.7%). CONCLUSIONS The 2-step decision tree provided a useful tool to detect keratoconus, including cases at early disease stages (subclinical keratoconus and FFK). OCT corneal and epithelial thickness map parameters and patterns can be used in conjunction with topography to improve keratoconus screening.
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Affiliation(s)
- Yuli Yang
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University, Chongqing, China
| | - Elias Pavlatos
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
| | - Winston Chamberlain
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
| | - David Huang
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
| | - Yan Li
- The Center for Ophthalmic Optics and Lasers, Casey Eye Institute, and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, USA
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David C, Reinstein DZ, Archer TJ, Kallel S, Vida RS, Goemaere I, Cuyaubère R, Borderie M, Laroche L, Borderie V, Bouheraoua N. Postoperative Corneal Epithelial Remodeling After Intracorneal Ring Segment Procedures for Keratoconus: An Optical Coherence Tomography Study. J Refract Surg 2021; 37:404-413. [PMID: 34170769 DOI: 10.3928/1081597x-20210225-02] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess epithelial corneal remodeling by anterior segment optical coherence tomography (AS-OCT) after intracorneal ring segments (ICRS) implantation in keratoconic eyes. METHODS This prospective observational study included patients with keratoconus receiving ICRS of different arc lengths according to their tomographic pattern. AS-OCT and corneal topography (Scheimpflug camera) were performed before and 1, 3, and 6 months after surgery. Corneal pachymetry mapping was performed and total corneal and epithelial thicknesses (3-mm central and 16 points on 6-mm zone) were measured over the pupil center using AS-OCT. Topographic parameters were also assessed. RESULTS A total of 68 keratoconic eyes were analyzed (Amsler-Krumeich stages 1 to 4) in four groups of 17 eyes: 210° ICRS, 320° ICRS, double 160° ICRS, and single 160° ICRS. Corneal pachymetry mapping revealed that epithelial thickness increased significantly in the internal zones juxtaposed to the ICRS without smoothing during the postoperative period (P < .05). Mean maximum epithelial thickness increased from 67 ± 6 to 79 ± 7 µm for 210° ICRS, 66 ± 9 to 82 ± 4 µm for 320° ICRS, 63 ± 6 to 78 ± 7 µm for double 160° ICRS, and 62 ± 5 to 77 ± 5 µm for single 160° ICRS (P < .0001). Significant epithelial thickening at the apex of the cone was observed in all groups (P < .05). CONCLUSIONS Significant epithelial thickening occurs after ICRS implantation adjacent to the ICRS to compensate for the ridge created with a thickening of epithelium over the cone due to regularization of the stromal surface. [J Refract Surg. 2021;37(6):404-413.].
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Bassiouny RM, Awad EA, Gaafar W, Kyrillos FA, Abou Samra WA, Abdelhameed AG. Corneal Tomographic Analysis Among Patients With Thyroid Gland Dysfunction. J Refract Surg 2021; 37:192-197. [PMID: 34038304 DOI: 10.3928/1081597x-20210105-03] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To analyze the corneal tomographic parameters of patients with thyroid gland dysfunction. METHODS This case-control study included 100 eyes of 50 patients with thyroid gland dysfunction and 100 eyes of 50 healthy controls. All eyes were examined by Pentacam (Oculus Optikgeräte GmbH). Pentacam parameters were compared between patients with thyroid gland dysfunction and controls. Spearman's correlation coefficient between different Pentacam parameters and the serum level of free thyroxin (T4) and thyroid-stimulating hormone (TSH) was calculated. RESULTS Patients with hypothyroidism had significantly higher median values of steep and maximum simulated keratometric readings, central corneal thickness (CCT), and thinnest pachymetry (CTmin) than both patients with hyperthyroidism and controls (P⩽ .05). The median values of the average and maximum pachymetric progression index (PPI), posterior elevation, and back difference elevation were significantly higher in patients with hyperthyroidism than in patients with hypothyroidism and controls (P ⩽ .05). The Ambrósio Relational Thickness (ARTmax) was significantly reduced in patients with hyperthyroidism (P ⩽ .001). Both CCT and CTmin showed a moderately positive correlation with serum TSH level and a moderately negative correlation with serum free T4 level. Patients with non-autoimmune thyroid gland dysfunction had significantly thinner CCT, CTmin, and inferior vertical deviation than the autoimmune group (P ⩽ .05). CONCLUSIONS Thyroid gland dysfunction is associated with significant corneal tomographic changes. Patients with hyperthyroidism tend to have thinner corneas and more abnormal tomographic parameters correlating with keratoconus. No significant tomographic changes were found in association with autoimmune thyroid gland dysfunction. The authors recommend screening and regular follow-up of patients with thyroid gland dysfunction for early detection and management of keratoconus. [J Refract Surg. 2021;37(3):192-197.].
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Keratoconus concordance in monozygotic twins before and after combined CXL/PRK (Athens Protocol) using Scheimflung and OCT tomography. J Cataract Refract Surg 2021; 48:83-88. [PMID: 34091554 DOI: 10.1097/j.jcrs.0000000000000691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/24/2021] [Indexed: 11/26/2022]
Abstract
PUPOSE To describe the concordance of keratoconus expression in two pairs of monozygotic twins before and after a combined CXL/PRK procedure. SETTING Private Ambulatory Eye Surgery Unit. DESIGN Retrospective Interventional Twin Study. METHODS Two pairs of male monozygotic twins with keratoconus (KCN) were studied retrospectively. Improvement of flattest (k1) and steepest (k2) keratometry, Index of Height Decentration (IHD), corneal thickness at thinnest point and corneal epithelial thickness measured by AS-OCT and Scheimpflug tomography was compared between respective eyes of monozygotic twin siblings 1 to 5 years after the application of combined corneal cross linking (CXL) and topography guided photorefractive keratectomy (PRK) of part of the refractive error (the Athens Protocol). RESULTS Significant improvement was noted in all the keratometric indices of all 8 eyes after the combined CXL/PRK procedure.The difference in k1, k2, IHD corneal thickness at thinnest point and corneal epithelial thickness percentage improvement between the right eyes of each pair of twins was statistically significant 1 and 5 years post-operatively (P < .05). Statistically significant discordance in the aforementioned parameters percentage improvement was likewise observed between the left eyes of each pair of twins (P < .05). CONCLUSIONS Although a genetic predisposition in KCN is well documented, the discordance in keratometric indices improvement after a CXL/PRK procedure between respective eyes of monozygotic twins suggests that environmental influences may contribute to the disease expression as well. Variable degree of synergy in a combined CXL/PRK procedure may also explain the aforementioned discordant improvement.
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Abstract
A biomarker is a "characteristic that is measured as an indicator of normal biological processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions." Recently, calls for biomarkers for ocular surface diseases have increased, and advancements in imaging technologies have aided in allowing imaging biomarkers to serve as a potential solution for this need. This review focuses on the state of imaging biomarkers for ocular surface diseases, specifically non-invasive tear break-up time (NIBUT), tear meniscus measurement and corneal epithelial thickness with anterior segment optical coherence tomography (OCT), meibomian gland morphology with infrared meibography and in vivo confocal microscopy (IVCM), ocular redness with grading scales, and cellular corneal immune cells and nerve assessment by IVCM. Extensive literature review was performed for analytical and clinical validation that currently exists for potential imaging biomarkers. Our summary suggests that the reported analytical and clinical validation state for potential imaging biomarkers is broad, with some having good to excellent intra- and intergrader agreement to date. Examples of these include NIBUT for dry eye disease, ocular redness grading scales, and detection of corneal immune cells by IVCM for grading and monitoring inflammation. Further examples are nerve assessment by IVCM for monitoring severity of diabetes mellitus and neurotrophic keratitis, and corneal epithelial thickness assessment with anterior segment OCT for the diagnosis of early keratoconus. However, additional analytical validation for these biomarkers is required before clinical application as a biomarker.
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Belin MW, Alizadeh R, Torres-Netto EA, Hafezi F, Ambrósio R, Pajic B. Determining Progression in Ectatic Corneal Disease. Asia Pac J Ophthalmol (Phila) 2020; 9:541-548. [PMID: 33323708 DOI: 10.1097/apo.0000000000000333] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Before the advent of modern tomographic imaging and corneal cross-linking (CXL), diagnosis and treatment of ectatic disease were limited to disease severity where changes on the anterior corneal surface lead to visual complaints. Rigid contact lenses and/or penetrating keratoplasty addressed late stage disease, as identifying early or subclinical disease was not possible, or its need appreciated. The emergence of CXL as a viable treatment to alter the natural progression of keratoconus heightened the need for improved diagnostics.Several methods have been described in the literature to evaluate and document progression in keratoconus, but there has been no consistent definition of ectasia progression. Newer imaging techniques (ie, tomography) allowed the detection of earlier ectatic disease, before visual loss and subjective complaints. The Belin ABCD classification/staging system was introduced on a Scheimpflug imaging system [Pentacam, (Oculus GmbH, Wetzlar, Germany)] to address previous shortcomings. The ABCD system utilizes 4 parameters: Anterior ("A") and posterior ("B" for Back) radius of curvature taken from a 3.0 mm optical zone centered on the thinnest point, "C" is minimal Corneal thickness, and "D" best spectacle Distance visual acuity. The first 3 parameters (A, B, C) are machine-generated objective measurements that can be used to determine progressive change.The staging system is not limited to a specific commercial entity and can be incorporated in any tomographic imaging system. The ABCD Progression Display graphically displays each parameter and shows when statistical change above measurement noise is reached. This should allow the clinician the ability to diagnose progressive disease at a much earlier stage than was previously possible, with the confidence that earlier intervention could prevent visual loss.
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Affiliation(s)
- Michael W Belin
- University of Arizona, Department of Ophthalmology & Visual Science, Tucson, AZ
| | - Reza Alizadeh
- University of Arizona, Department of Ophthalmology & Visual Science, Tucson, AZ
| | - Emilio A Torres-Netto
- Laboratory for Ocular Cell Biology, Center for Applied Biotechnology & Molecular Medicine, University of Zurich, Zurich, Switzerland
- ELZA Institute, Dietikon/Zurich, Switzerland
- Federal University of Sao Paulo, Paulista School of Medicine, Department of Ophthalmology & Visual Sciences, Sao Paulo, Brazil
| | - Farhad Hafezi
- Laboratory for Ocular Cell Biology, Center for Applied Biotechnology & Molecular Medicine, University of Zurich, Zurich, Switzerland
- ELZA Institute, Dietikon/Zurich, Switzerland
- University of Geneva, Geneva, Switzerland
| | - Renato Ambrósio
- Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
- Federal University of Sao Paulo, Paulista School of Medicine, Department of Ophthalmology & Visual Sciences, Sao Paulo, Brazil
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Pavlatos E, Chen S, Yang Y, Wang Q, Huang D, Li Y. A Coincident Thinning Index for Keratoconus Identification Using OCT Pachymetry and Epithelial Thickness Maps. J Refract Surg 2020; 36:757-765. [PMID: 33170283 DOI: 10.3928/1081597x-20200925-01] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 09/10/2020] [Indexed: 02/02/2023]
Abstract
PURPOSE To develop a coincident thinning (CTN) index to differentiate between keratoconic and healthy corneas using optical coherence tomography (OCT) measurements of pachymetry and epithelial thickness. METHODS Pattern deviation maps of pachymetry and epithelial thickness were generated using Fourier-domain OCT images of the cornea. The co-localized thinning of the two maps was quantified using a novel CTN index, which was calculated from Gaussian fits of the regions of maximum relative thinning. The CTN index was validated using k-fold cross-validation, and its classification performance was compared to minimum pachymetry and maximum keratometry. RESULTS A total of 82 normal eyes and 133 eyes within three groups of keratoconus severity were evaluated. The pattern deviation maps for the keratoconic eyes showed relative thinning that was larger in magnitude and more strongly correlated with the Gaussian function compared to normal eyes (all P < .01). The distance between the pachymetric and epithelial maximum relative thinning locations was significantly smaller for the keratoconic eyes than for the normal eyes (all P < .02). The CTN index was significantly larger for all three keratoconus groups compared to normal eyes (all P < .0001). The CTN index demonstrated a sensitivity of 100% in detecting manifest keratoconus, 100% for subclinical keratoconus, and 56% for forme fruste keratoconus. The overall classification accuracy was better for the CTN index (93%) than for minimum pachymetry (86%) and maximum keratometry (86%). CONCLUSIONS The CTN index is a highly sensitive measure of coincident pachymetric and epithelial thinning. It provides valuable information for detecting and monitoring early to moderate keratoconus. [J Refract Surg. 2020;36(11):757-765.].
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Kanellopoulos AJ. Scheimpflug vs Scanning-Slit Corneal Tomography: Comparison of Corneal and Anterior Chamber Tomography Indices for Repeatability and Agreement in Healthy Eyes. Clin Ophthalmol 2020; 14:2583-2592. [PMID: 32943840 PMCID: PMC7481306 DOI: 10.2147/opth.s251998] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 08/14/2020] [Indexed: 12/11/2022] Open
Abstract
Purpose To evaluate and compare the repeatability and agreement of Scheimpflug vs scanning-slit tomography of the cornea and the anterior chamber in terms of keratometric and tomographic indices in healthy eyes. Methods The 20 eyes of 10 healthy participants underwent 3 consecutive measurements using both Scheimpflug-tomography and scanning-slit tomography, diagnostic devices. Multiple corneal and anterior chamber tomographic parameters were recorded and evaluated to include corneal keratometry and its axis; corneal best-fit sphere (BFS), pachymetry mapping, angle kappa, anterior chamber depth (ACD), pupil diameter, and location. Repeatability for each device was assessed using the within each subject standard deviation of sequential exams, the coefficient variation (CV) and the intraclass correlation coefficient (ICC). Agreement between the two devices was assessed using Bland-Altman plots with 95% limits of agreement (LoA) and correlation coefficient (r). Results Both devices were found to have high repeatability (ICC>0.9) both in keratometric and other tomographic measurements. Scheimpflug tomography's repeatability though appeared superior in the average keratometry values, anterior and posterior BFS, thinnest corneal pachymetry value and location (p<0.05). Agreement: Statistically significant inter-device differences were noted in the mean values of K1, K2, BFS, ACD and thinnest corneal pachymetry (p<0.05). Despite the agreement differences noted, the two devices were well correlated (r>0.8) in respective measurements with Scheimpflug delivering consistently lower values than the scanning-slit tomography device. Conclusion Scheimpflug-tomography repeatability was found to be superior to that of scanning-slit tomography in this specific study, in most parameters evaluated. Inter-device agreement evaluation suggests that reading from the two devices may not be used interchangeably in absolute values, yet they are well correlated with Scheimpflug delivering consistently lower values in most.
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Affiliation(s)
- Anastasios John Kanellopoulos
- Department of Ophthalmology, The LaserVision Clinical and Research Eye Institute, Athens, Attiki, Greece.,Department of Ophthalmology, New York University Medical School, New York City, NY, USA
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Ziaei M, Gokul A, Vellara H, Patel DV, McGhee CNJ. Measurement of refractive, wavefront, topographic, and keratometric changes attributable to epithelial removal in keratoconus. Can J Ophthalmol 2020; 56:6-11. [PMID: 32777204 DOI: 10.1016/j.jcjo.2020.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/20/2020] [Accepted: 06/29/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The corneal epithelium is able to mask topographic and keratometric abnormalities of the underlying Bowman layer in keratoconus, but its contribution to refractive and wavefront parameters has not yet been studied. This study compared the refractive and aberrometric features of the corneal epithelium and Bowman layer in eyes with keratoconus before and after epithelial debridement. METHODS Corneal refractive and wavefront variables were measured in patients with keratoconus undergoing corneal crosslinking-immediately before and after epithelial debridement using a third-generation combined corneal topographer, autorefractor, and aberrometer. RESULTS After epithelial debridement, there were significant changes in spherical equivalent (-1.37 D; p < 0.01) and asphericity (-0.64; p = 0.03). The mean difference in the magnitude of epithelium-induced astigmatism in the 3rd and 5th central millimeter rings was 0.44 ± 3.20 D × 8 and 0.43 ± 2.75 D × 21 (positive cylinder), respectively. Corneal astigmatism axis shifted in the against-the-rule orientation after epithelial debridement. There were no significant changes in any corneal higher-order aberration parameter after epithelial debridement (p > 0.05). CONCLUSIONS In eyes with keratoconus, epithelial debridement increased the magnitude of anterior corneal prolateness and tended to increase astigmatism and shift its axis toward the against-the-rule orientation. This study supports the notion that the corneal epithelium smooths underlying Bowman layer irregularity in keratoconus.
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Affiliation(s)
- Mohammed Ziaei
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand..
| | - Akilesh Gokul
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Hans Vellara
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Dipika V Patel
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Charles N J McGhee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Pircher N, Beer F, Holzer S, Gschließer A, Donner R, Pircher M, Hitzenberger CK, Schmidinger G, Lammer J. Large Field of View Corneal Epithelium and Bowman's Layer Thickness Maps in Keratoconic and Healthy Eyes. Am J Ophthalmol 2020; 209:168-177. [PMID: 31170392 DOI: 10.1016/j.ajo.2019.05.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/19/2019] [Accepted: 05/15/2019] [Indexed: 11/29/2022]
Abstract
PURPOSE To assess differences between epithelium thickness (ET) and Bowman's layer thickness (BLT) maps in keratoconic eyes and healthy eyes. DESIGN Cross-sectional study. METHODS Setting: institutional. STUDY POPULATION 47 patients (1 eye) with keratoconus (KC) and 20 healthy subjects (1 eye). OBSERVATION PROCEDURE epithelium and Bowman's layer measurements were performed by using custom-designed polarization-sensitive optical coherence tomography (PS-OCT) with a conical scanning optics design. En face corneal ET and BLT maps with a diameter of 11 mm were computed. Main outcome measurements were mean ET and BLT of 25 sectors; the thinnest (minET, minBLT) and thickest sectors (maxET, maxBLT) were assessed. Ratios between thinnest/thickest sectors (R1) and between mean ET and BLT of the inferior temporal quadrant/superior nasal quadrant (R2) were calculated (R1ET, R1BLT; R2ET, R2BLT). Receiver operator characteristic (ROC) curve analysis was used to assess the diagnostic power of statistically different parameters. RESULTS In healthy eyes, smooth ET maps were observed. KC eyes showed a "doughnut pattern." The BLT maps of healthy eyes had a smooth appearance, but highly irregular "moth"-like damage pattern could be observed in keratoconic eyes. Highest area under the curve values were found for the thinnest sector of the BLT map, the R1ET, and the thinnest sector of the ET map. CONCLUSIONS PS-OCT imaging enables the visualization of significant differences of the corneal epithelium and the Bowman's layer in en face maps covering almost the entire cornea. ET and BLT profiles could clearly show their diagnostic importance for the distinguishing of keratoconic eyes and healthy eyes.
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Affiliation(s)
- Niklas Pircher
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Florian Beer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Stephan Holzer
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Andreas Gschließer
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Ruth Donner
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Michael Pircher
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Christoph K Hitzenberger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Gerald Schmidinger
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Jan Lammer
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria.
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El Wardani M, Hashemi K, Aliferis K, Kymionis G. Topographic changes simulating keratoconus in patients with irregular inferior epithelial thickening documented by anterior segment optical coherence tomography. Clin Ophthalmol 2019; 13:2103-2110. [PMID: 31802839 PMCID: PMC6827357 DOI: 10.2147/opth.s208101] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 08/06/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose To present six patients with keratoconus-like topographic changes due to inferior inhomogenous epithelial thickening, demonstrated by AS-OCT epithelium map. Patients and methods We present twelve eyes of six patients evaluated in the refractive surgery consultation with Pentacam® HR Scheimpflug rotating camera system, presenting topographical irregularities suggestive of keratoconus. Slit-lamp examination, best-corrected visual acuity, Scheimpflug tomography and anterior segment optical coherence tomography epithelium map (Optovue® ) were conducted and analyzed. Results The mean age was 42 years and the female:male ratio was 2:1. Mean Kmax was 45±2 D. The mean corneal thickness at apex was 560±33 µm and the mean thickness at the thinnest location was 555±34 µm. All patients had an abnormal index of height decentration (IHD) in at least one eye. In all cases, anterior segment OCT demonstrated relative epithelial thickening over the steep area measured by tomography. The mean thickness of the inferior epithelium over the suspicious area was 60±2 µm, whereas the mean thickness of the superior epithelium was 56±2 µm. Conclusion Epithelial irregularity, as measured by anterior segment OCT, should be considered as a possible contributing factor in the appearance of suspicious keratoconus-like topographies.
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Affiliation(s)
- Mohamad El Wardani
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Foundation Asile des Aveugles, Lausanne, Switzerland
| | - Kattayoon Hashemi
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Foundation Asile des Aveugles, Lausanne, Switzerland
| | - Konstantinos Aliferis
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Foundation Asile des Aveugles, Lausanne, Switzerland
| | - George Kymionis
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Foundation Asile des Aveugles, Lausanne, Switzerland.,Department of Ophthalmology, 'G. Gennimatas Hospital', National and Kapodistrian University of Athens, Athens, Greece
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Chen KJ, Eliasy A, Vinciguerra R, Abass A, Lopes BT, Vinciguerra P, Ambrósio R, Roberts CJ, Elsheikh A. Development and validation of a new intraocular pressure estimate for patients with soft corneas. J Cataract Refract Surg 2019; 45:1316-1323. [DOI: 10.1016/j.jcrs.2019.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 03/20/2019] [Accepted: 04/01/2019] [Indexed: 11/25/2022]
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Long-Term Stability With the Athens Protocol (Topography-Guided Partial PRK Combined With Cross-Linking) in Pediatric Patients With Keratoconus. Cornea 2019; 38:1049-1057. [PMID: 31169612 DOI: 10.1097/ico.0000000000001996] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the safety, efficacy, and stability of topography-guided partial PRK combined with corneal cross-linking (CXL) (the Athens Protocol [AP]) in pediatric patients with keratoconus over a 4-year follow-up period. METHODS This prospective study included 39 keratoconic eyes of 21 patients younger than 18 years with clinical and imaging evidence of keratoconus progression. Partial topography-guided excimer laser ablation in conjunction with high-fluence CXL was performed in all patients according to the AP. Uncorrected distance visual acuity, corrected distance visual acuity, refraction, keratometry, endothelial cell density, topography, and tomography using both Scheimpflug and optical coherence tomography (OCT) were evaluated for 4 years postoperatively. RESULTS At 4 years postoperative, there was significant improvement in mean uncorrected distance visual acuity from 0.51 ± 0.31 (decimal) to 0.65 ± 0.26 (decimal; P < 0.05). Mean corrected distance visual acuity improved from 0.71 ± 0.22 (decimal) preoperatively to 0.81 ± 0.19 (decimal; P < 0.05), respectively. Mean flat keratometry (K1) and mean steep keratometry (K2) readings reduced from 44.95 ± 3.71 D and 49.32 ± 5.05 D, respectively, preoperatively to 43.14 ± 2.95 D and 46.28 ± 4.87 D, respectively, (P < 0.05) at 4 years. The mean anterior maximum keratometry (Kmax) reading reduced from 56.81 ± 2.94 D preoperatively to 48.11 ± 3.17 D at 48 months. The mean index of height decentration was 0.105 ± 0.054 μm preoperatively and 0.049 ± 0.024 (P < 0.05) at 4 years postoperative. Mean preoperative corneal thickness at the thinnest point was 436.7 ± 42.6 μm preoperatively, 392.50 ± 45.68 μm at 12 months postoperative, and 418.42 ± 17.01 μm at 4-year follow-up. Late-onset deep corneal haze, a potential intrinsic complication of this technique in pediatric patients, was encountered in 2 cases at least 1 year after the procedure. CONCLUSIONS Long-term results of the AP seem to be safe and effective in pediatric patients, with marked improvement in visual function and keratometric symmetry indices.
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Distinguishing between contact lens warpage and ectasia: Usefulness of optical coherence tomography epithelial thickness mapping. J Cataract Refract Surg 2019; 43:60-66. [PMID: 28317679 DOI: 10.1016/j.jcrs.2016.10.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 09/22/2016] [Accepted: 10/16/2016] [Indexed: 11/22/2022]
Abstract
PURPOSE To distinguish between corneal ectasia and contact lens-related warpage by characteristic patterns on corneal topography and optical coherence tomography (OCT) epithelial thickness maps. SETTING Casey Eye Institute, Portland, Oregon, USA. DESIGN Prospective and retrospective case series. METHODS Axial and mean power maps were obtained on corneal topography systems. Epithelial thickness maps were generated using RTVue OCT. A sector divider was applied to all maps. The locations of the minimum epithelial thickness, maximum epithelial thickness, maximum axial power, and maximum mean power were determined based on sector averages. Agreement was defined as the extremums occurring in the same or adjacent sectors. RESULTS Twenty-one eyes with keratoconus, 6 eyes with forme fruste keratoconus (better eye of asymmetric keratoconus), and 15 eyes with contact lens-related warpage were identified. The keratoconus and forme fruste keratoconus eyes had coincident topographic steepening with epithelial thinning. The locations of minimum epithelial thickness and maximum axial power agreed in 90% of the keratoconic eyes, while the minimum epithelial thickness and maximum mean power agreed in 95% of them. Conversely, the warpage eyes had coincident topographic steepening with epithelial thickening and normal pachymetry maps. The locations of maximum epithelial thickness and maximum axial power agreed in 93% of the warpage eyes, while the maximum epithelial thickness and maximum mean power agreed in all warpage eyes. CONCLUSION Results show that epithelial thickness maps and corneal topographic maps are powerful synergistic tools in evaluating eyes with abnormal topography and can help differentiate between keratoconus and nonectatic conditions.
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Wang Q, Lim L, Lim SWY, Htoon HM. Comparison of Corneal Epithelial and Stromal Thickness between Keratoconic and Normal Eyes in an Asian Population. Ophthalmic Res 2019; 62:134-140. [PMID: 31266046 DOI: 10.1159/000500313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 04/10/2019] [Indexed: 11/19/2022]
Abstract
PURPOSE To assess corneal epithelial and stromal thickness in keratoconic and normal eyes by spectral domain optical coherence tomography (SDOCT) in an Asian population. METHODS Forty-three keratoconic and 24 normal eyes were studied and examined using SDOCT. Keratoconic eyes with corneal scarring were excluded. Epithelial and stromal thickness was assessed at 25 points, 0.5 mm apart, across the central 6 mm of the pupil centre in the horizontal and vertical meridians. The correlation between epithelial and stromal thickness in both keratoconic and normal eyes (at the corneal centre) was also assessed. RESULTS The corneal epithelium at the pupil centre was significantly thinner in keratoconic eyes (p < 0.05) than in controls. Epithelial thickness varied widely in keratoconic eyes compared to controls (p < 0.05). The epithelium and stroma were significantly thinner inferiorly and temporally in keratoconic eyes (p < 0.05). There was a significant correlation between epithelial and stromal thickness (at the pupil centre) in the keratoconus group (rs = 0.348, p < 0.001) but not the normal group (rs = 0.036, p = 0.376). CONCLUSIONS Corneal epithelial thickness was markedly thinner and varied in keratoconic eyes compared to controls. Epithelial thinning occurred secondary to the abnormal elevation of the stroma. These findings are useful in detecting early keratoconus and in the evaluation of refractive surgery candidates.
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Affiliation(s)
- Qing Wang
- Corneal and External Eye Disease Service, Singapore National Eye Centre, Singapore, Singapore.,Department of Ophthalmology, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Li Lim
- Corneal and External Eye Disease Service, Singapore National Eye Centre, Singapore, Singapore,
| | - Samuel Wen Yan Lim
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hla Myint Htoon
- National University of Singapore, Singapore Eye Research Institute, Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS, Singapore, Singapore
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False corneal ectasia in patients referred for corneal crosslinking, topography-guided photorefractive keratectomy, and intrastromal corneal rings. Can J Ophthalmol 2019; 54:374-381. [DOI: 10.1016/j.jcjo.2018.08.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 08/21/2018] [Accepted: 08/29/2018] [Indexed: 02/07/2023]
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Yip H, Chan E. Optical coherence tomography imaging in keratoconus. Clin Exp Optom 2019; 102:218-223. [PMID: 30793800 DOI: 10.1111/cxo.12874] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 12/23/2018] [Accepted: 01/01/2019] [Indexed: 11/28/2022] Open
Abstract
Optical coherence tomography (OCT) is being increasingly used as a tool in the diagnosis and management of keratoconus. While elevation-based topography remains essential, there is an expanding role for cross-sectional OCT imaging in the diagnosis of the disease. Images and measurements of corneal thickness, and in particular, epithelial thickness, may be important in diagnosing early cases, and following procedures such as intrastromal corneal ring segments, corneal transplants and corneal collagen cross-linking.
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Affiliation(s)
- Harry Yip
- School of Medicine, Monash University, Melbourne, Victoria, Australia
| | - Elsie Chan
- Ophthalmology, Royal Victorian Eye and Ear Hospital, Centre for Eye Research Australia, The University of Melbourne, Melbourne, Victoria, Australia
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Comparison of Corneal Epithelial Remodeling Over 2 Years in LASIK Versus SMILE: A Contralateral Eye Study. Cornea 2018; 38:290-296. [DOI: 10.1097/ico.0000000000001821] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Evaluation of the Repeatability and Reproducibility of Corneal Epithelial Thickness Mapping for a 9-mm Zone Using Optical Coherence Tomography. Cornea 2018; 38:67-73. [DOI: 10.1097/ico.0000000000001806] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Lautert J, Doshi D, Price FW, Price MO. Corneal Epithelial Remodeling After Standard Epithelium-off Corneal Cross-linking in Keratoconic Eyes. J Refract Surg 2018; 34:408-412. [PMID: 29889294 DOI: 10.3928/1081597x-20180402-03] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 04/02/2018] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate remodeling of the corneal epithelium after epithelium-off corneal cross-linking (CXL). METHODS In this prospective single-center study, 93 eyes of 93 patients with progressive keratoconus underwent standard CXL. The maximum keratometry was assessed before and after CXL with Scheimpflug imaging, and the epithelial thickness profile across the central 5 mm of the cornea was assessed with spectral-domain optical coherence tomography anterior segment imaging. RESULTS The mean patient age was 27 ± 11 years; 76 patients (81%) were male and 17 (19%) were female. Between baseline and 6 months after CXL, the mean corneal maximum keratometry flattened from 58.90 to 57.80 diopters (P < .0001). The mean minimum epithelial thickness increased slightly (from 41 ± 6 to 42 ± 7 μm, P = .12), whereas the mean maximum epithelial thickness decreased slightly (from 65 ± 6 to 64 ± 7 μm, P = .067), reducing the net difference between the minimum and maximum epithelial thickness (from 24 ± 9 to 22 ± 9 μm, P = .0023). The difference between the minimum and maximum epithelial thickness was strongly positively correlated with the maximum keratometry reading at baseline (R2 = 0.38) and at 6 months after CXL (R2 = 0.59). CONCLUSIONS Epithelium-off CXL resulted in modest regularization of the epithelial thickness profile across the central 5 mm of the cornea at 6 months. This could slightly mask flattening of the underlying stroma. [J Refract Surg. 2018;34(6):408-412.].
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Pircher N, Schwarzhans F, Holzer S, Lammer J, Schmidl D, Bata AM, Werkmeister RM, Seidel G, Garhöfer G, Gschließer A, Schmetterer L, Schmidinger G. Distinguishing Keratoconic Eyes and Healthy Eyes Using Ultrahigh-Resolution Optical Coherence Tomography-Based Corneal Epithelium Thickness Mapping. Am J Ophthalmol 2018; 189:47-54. [PMID: 29458037 DOI: 10.1016/j.ajo.2018.02.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 12/17/2017] [Accepted: 02/08/2018] [Indexed: 10/18/2022]
Abstract
PURPOSE To find differences in epithelial thickness (ET) maps of eyes with keratoconus (KC) and healthy eyes. DESIGN Institutional cross-sectional study. METHODS In this study 40 keratoconic eyes and 76 healthy eyes were scanned using a custom-built ultrahigh-resolution optical coherence tomography system. Automated segmentation ET maps with 17 subsectors were calculated (central, temporal inferior, temporal superior, nasal inferior, and nasal superior area). The thinnest point of the epithelium (minET), the thickest point of the epithelium (maxET), and the thinnest point diagonally opposing the thickest point (ETmax/op) were additional parameters. Ratios were calculated as follows: minET/diagonally opposing point (R1), maxET/diagonally opposing point (R2), inferior temporal area/superior nasal area (RTI/NS), and inferior/superior hemisphere (RI/S). Furthermore, collected parameters were analyzed regarding their diagnostic accuracy (area under the curve; AUC). RESULTS Statistically significant differences were as follows: central ET, 46.25 ± 2.56/50.91 ± 1.66; minET, 38.50 ± 2.10/46.79 ± 1.27; ETmax/op, 47.14 ± 2.45/49.60 ± 1.57; temporal inferior area: 43.93 ± 2.95/51.04 ± 1.51 (all mean ± standard deviation, μm); R1, 0.76 ± 0.09/0.93 ± 0.04; R2, 1.08 ± 0.04/1.21 ± 0.16; RTI/NS, 0.85 ± 0.08/1.02 ± 0.04; RI/S: 0.92 ± 0.07/0.99 ± 0.02. AUC values were R1: 0.979 (confidence interval [CI]: 0.957-1.000), RTI/NS: 0.977 (CI: 0.951-1.000), and minET: 0.928 (CI: 0.880-0.977). CONCLUSIONS Epithelial thickness maps could clearly visualize different ET patterns. Parameters with the highest potential of diagnostic discrimination between eyes with KC and healthy eyes were, in descending order, R1, RTI/NS, and minET. Consequently, epithelial thickness irregularity and asymmetry seem to be the most promising diagnostic factor in terms of discriminating between keratoconic eyes and healthy eyes.
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Moschos MM, Nitoda E, Georgoudis P, Balidis M, Karageorgiadis E, Kozeis N. Contact Lenses for Keratoconus- Current Practice. Open Ophthalmol J 2017; 11:241-251. [PMID: 28932340 PMCID: PMC5585463 DOI: 10.2174/1874364101711010241] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/29/2017] [Accepted: 06/13/2017] [Indexed: 12/14/2022] Open
Abstract
Background: Keratoconus is a chronic, bilateral, usuallly asymmetrical, non-inflammatory, ectatic disorder, being characterized by progressive steepening, thinning and apical scarring of the cornea. Initially, the patient is asymptomatic, but the visual acuity gradually decreases, resulting in significant vision loss due to the development of irregular astigmatism, myopia, corneal thinning and scarring. The classic treatment of visual rehabilitation in keratoconus is based on spectacles and contact lenses (CLs). Objective: To summarize the types of CLs used in the treatment of keratoconus. This is literature review of several important published articles focusing on the visual rehabilitation in keratoconus with CLs. Method: Gas permeable (GP) CLs have been found to achieve better best corrected visual acuity than spectacles, eliminating 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS, and higher-order RMS. However, they have implicated in reduction of corneal basal epithelial cell and anterior stromal keratocyte densities. Soft CLs seem to provide greater comfort and lower cost, but the low oxygen permeability (if the lens is not a silicone hydrogel), and the inability to mask moderate to severe irregular astigmatism are the main disadvantages of them. On the other hand, scleral CLs ensure stable platforms, which eliminate high-order aberrations and provide good centration and visual acuity. Their main disadvantages include the difficulties in application and removal of these lenses along with corneal flattening and swelling. Result: The modern hybrid CLs are indicated in cases of poor centration, poor stability or intolerance with GP lenses. Finally, piggyback CL systems effectively ameliorate visual acuity, but they have been related to corneal neovascularization and giant papillary conjunctivitis. Conclusion: CLs seem to rehabilitate visual performance, diminishing the power of the cylinder and the high-order aberrations. The final choice of CLs is based on their special features, the subsequent corneal changes and the patient’s needs.
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Affiliation(s)
- Marilita M Moschos
- Department of Ophthalmology, Medical School, National & Kapodistrian University of Athens, Greece
| | - Eirini Nitoda
- Department of Ophthalmology, Medical School, National & Kapodistrian University of Athens, Greece
| | | | - Miltos Balidis
- Institute of Ophthalmology and Ocular Microsurgery 'Ophthalmica', Thessaloniki, Greece
| | | | - Nikos Kozeis
- Institute of Ophthalmology and Ocular Microsurgery 'Ophthalmica', Thessaloniki, Greece
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Andreanos KD, Hashemi K, Petrelli M, Droutsas K, Georgalas I, Kymionis GD. Keratoconus Treatment Algorithm. Ophthalmol Ther 2017; 6:245-262. [PMID: 28755306 PMCID: PMC5693837 DOI: 10.1007/s40123-017-0099-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Indexed: 11/25/2022] Open
Abstract
Keratoconus management has significantly changed over the last two decades. The advent of new interventions such as cornea cross-linking, intrastromal corneal ring segments, and combined treatments provide corneal clinicians a variety of treatment options for the visual rehabilitation of keratoconus patients. This review summarizes current evidence for these treatments and highlights their place in keratoconus management while new promising emerging therapies are being investigated.
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Affiliation(s)
- Konstantinos D Andreanos
- 1st Department of Ophthalmology, 'G. Gennimatas Hospital', National and Kapodistrian University of Athens, Athens, Greece.
| | - Kate Hashemi
- Faculty of Biology and Medicine, Jules Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
| | - Myrsini Petrelli
- 1st Department of Ophthalmology, 'G. Gennimatas Hospital', National and Kapodistrian University of Athens, Athens, Greece
| | - Konstantinos Droutsas
- 1st Department of Ophthalmology, 'G. Gennimatas Hospital', National and Kapodistrian University of Athens, Athens, Greece
| | - Ilias Georgalas
- 1st Department of Ophthalmology, 'G. Gennimatas Hospital', National and Kapodistrian University of Athens, Athens, Greece
| | - George D Kymionis
- 1st Department of Ophthalmology, 'G. Gennimatas Hospital', National and Kapodistrian University of Athens, Athens, Greece
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Belin MW, Meyer JJ, Duncan JK, Gelman R, Borgstrom M. Assessing Progression of Keratoconus and Cross-linking Efficacy: The Belin ABCD Progression Display. ACTA ACUST UNITED AC 2017. [DOI: 10.5005/jp-journals-10025-1135] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
ABSTRACT
Several methods have been described to both evaluate and document progression in keratoconus and to show efficacy of cross-linking, however, there are no consistent generally accepted parameters. Modern corneal tomography, including both anterior and posterior elevation and pachymetric data can be used to screen for ectatic progression, be employed to detect earlier change and additionally to show efficacy of new treatment modalities, such as crosslinking.
To describe specific quantitative values that can be used as progression and efficacy determinants, the normal noise measurements of the three parameters used in the ABCD keratoconus classification (corneal thickness at the thinnest point, anterior and posterior radius of curvature taken from the 3.0 mm optical zone centered on the thinnest point), were determined. Values were obtained from both a normal population and a known keratoconic population. The 80 and 95% one-sided confidence intervals for all three parameters were surprisingly small, suggesting that they may perform well as progression and efficacy determinants.
How to cite this article
Belin MW, Meyer JJ, Duncan JK, Gelman R, Borgstrom M, Ambrósio Jr R. Assessing Progression of Keratoconus and Cross-linking Efficacy: The Belin ABCD Progression Display. Int J Kerat Ect Cor Dis 2017;6(1):1-10.
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Tang M, Li Y, Chamberlain W, Louie DJ, Schallhorn JM, Huang D. Differentiating Keratoconus and Corneal Warpage by Analyzing Focal Change Patterns in Corneal Topography, Pachymetry, and Epithelial Thickness Maps. Invest Ophthalmol Vis Sci 2017; 57:OCT544-9. [PMID: 27482824 PMCID: PMC4978086 DOI: 10.1167/iovs.15-18938] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To differentiate between keratoconus and contact lens-related corneal warpage by combining focal change patterns in anterior corneal topography, pachymetry, and epithelial thickness maps. Methods Pachymetry and epithelial thickness maps of normal, keratoconus, and warpage, and forme fruste keratoconus (FFK) eyes were obtained from a Fourier-domain optical coherence tomography (OCT). Epithelial pattern standard deviation (PSD) was calculated and combined with two novel indices, the Warpage Index and the Anterior Ectasia Index, to differentiate between normal, keratoconus, and warpage eyes. The values of the three parameters were compared between groups. Results The study included 22 normal, 31 keratoconic, 11 warpage, and 8 FFK eyes. The epithelial PSD was normal (< 0.041) for 100% normal eyes and abnormal (> 0.041) for 100% of keratoconic eyes, 81.8% of warpage eyes, and 87.5% of FFK eyes. The Anterior Ectasia Index of normal eyes (1.66 ± 0.74) was significantly lower than that for the keratoconus eyes (17.5 ± 7.17), the warpage eyes (2.98 ± 1.69), and the FFK eyes (6.95 ± 5.86). The Warpage Index was positive in all warpage eyes and negative for all keratoconic and FFK eyes except three wearing rigid gas-permeable contact lens. Conclusions The epithelial PSD can distinguish normal from keratoconus or warpage, but does not distinguish between these two conditions. The Anterior Ectasia Index is abnormal in keratoconus but not warpage. The Warpage Index is positive for warpage and negative for keratoconus, except in cases where keratoconus and warpage coexist. Together, the three parameters are strong tripartite discriminators of normal, keratoconus, and warpage.
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Ryu IH, Kim BJ, Lee JH, Kim SW. Comparison of Corneal Epithelial Remodeling After Femtosecond Laser–Assisted LASIK and Small Incision Lenticule Extraction (SMILE). J Refract Surg 2017; 33:250-256. [DOI: 10.3928/1081597x-20170111-01] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 01/03/2017] [Indexed: 11/20/2022]
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Semiautomated SD-OCT Measurements of Corneal Sublayer Thickness in Normal and Post-SMILE Eyes. Cornea 2016; 35:972-9. [DOI: 10.1097/ico.0000000000000799] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Detection of ectatic corneal diseases based on pentacam. Z Med Phys 2016; 26:136-42. [DOI: 10.1016/j.zemedi.2015.11.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 11/13/2015] [Accepted: 11/13/2015] [Indexed: 11/20/2022]
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