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Li J, Zhang BN, Jhanji V, Wang X, Li D, Du X. Parental Corneal Tomographic and Biomechanical Characteristics of Patients With Keratoconus. Am J Ophthalmol 2023; 256:146-155. [PMID: 37567431 DOI: 10.1016/j.ajo.2023.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 07/19/2023] [Accepted: 08/04/2023] [Indexed: 08/13/2023]
Abstract
PURPOSE To investigate the hereditability of corneal tomographic and biomechanical parameters in keratoconus (KC). DESIGN Prospective cohort study. METHODS This study was conducted at Qingdao Eye Hospital of Shandong First Medical University in Qingdao, China. Forty-four patients with KC and their biological parents (n = 88) were recruited as the study group. The control group consisted of 84 healthy adults with matched age and gender. Both eyes of each participant underwent clinical examinations, and 1 eye was selected for statistical analysis. Exclusion criteria were as follows: individuals with glaucoma, ocular surgery, systemic diseases known to affect the eyes, or poor cooperation during examination. Subjects were asked to discontinue soft contact lens (CL) wear for 2 weeks and rigid gas permeable CL wear for 4 weeks before ocular examination. All participants underwent a comprehensive assessment including Pentacam Scheimpflug tomography, Corvis ST, visual acuity, refraction examination, axial length, and slitlamp examination for both eyes. Individuals presenting with KC manifestations in at least 1 eye were classified as having KC. A total of 9 Pentacam indices including keratometry in the flat/steep meridian (K1/K2), maximal keratometry (Kmax), thinnest point pachymetry (TP), and maximum/average Ambrósio relational thickness (ARTmax/ARTave), anterior and posterior surfaces elevation of the cornea (Ef/Eb) and total deviation value (Final D), and 21 biomechanical indices were collected. Associations of these factors with KC were evaluated using multiple comparison and binary logistics regression analyses. RESULTS Two parents (2.27%) from 2 different families were diagnosed with KC. Parents of patients with KC had thinner corneas with altered corneal biomechanical parameters compared with healthy controls (P < .05). The combined tomographic and biomechanical index demonstrated the highest discriminatory power (area under the receiver operating characteristic curve 0.785) and strong specificity (84.5%). Parental corneal tomographic and biomechanical index, Corvis biomechanical index, and TP were identified as the major influential factors for KC in their offspring by logistic regression analysis, with a 73.3% accuracy in identifying offspring with KC. CONCLUSIONS Parental corneal tomographic and biomechanical properties of patients with KC suggest a possible predisposition to KC. A combination of tomography and corneal biomechanics can be helpful in predicting the incidence rate of KC in the offspring of patients with subclinical KC.
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Affiliation(s)
- Jie Li
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China
| | - Bi Ning Zhang
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China
| | - Vishal Jhanji
- Department of Ophthalmology (V.J.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Xiaochuan Wang
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China
| | - Dewei Li
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China
| | - Xianli Du
- From Eye Institute of Shandong First Medical University (J.L., B.N.Z., X.W., D.L., X.D.), Qingdao Eye Hospital of Shandong First Medical University, Qingdao, Shandong, China; State Key Laboratory Cultivation Base (J.L., B.N.Z., X.W., D.L., X.D.), Shandong Provincial Key Laboratory of Ophthalmology, Qingdao, Shandong, China; School of Ophthalmology (J.L., B.N.Z., X.W., D.L., X.D.), Shandong First Medical University, Qingdao, Shandong, China.
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Evaluation of Ocular Higher-Order Aberrations in First-Degree Relatives of Patients With Keratoconus. Cornea 2023; 42:308-312. [PMID: 35587897 DOI: 10.1097/ico.0000000000003055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 03/17/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE The aim of this study was to evaluate the corneal higher-order aberrations (HOAs) in first-degree relatives of patients with keratoconus (KCN) and compare with the normal population. METHODS In this prospective comparative study, 210 eyes from 105 family members of 28 patients with KCN and 210 normal eyes of 105 controls were enrolled. In each eye, corneal topography, tomography, and aberrometry were performed and compared between the 2 groups. RESULTS This study included 61 female (58.1%) and 44 male participants (41.9%) and 105 age-matched and sex-matched controls with normal topographic cornea. In 14 of 105 first-degree relatives (13.33%) of patients with KCN, KCN was diagnosed with a male preponderance (71.5% male, 28.5% female). Tomographic indices and irregularity indices in 3 and 5 mm zone in Orbscan were significantly higher in the relative group. In addition, other irregularity indices of TMS-4 topography including surface regularity index, surface asymmetry index, difference sector index, SDP, and irregular astigmatism index were significantly higher in family members of patients with KCN. The most prevalent topographic pattern in the control group was the symmetric bowtie (57.1%) and in the relative group was the asymmetric bowtie (39.5%). In addition, significantly thinnest corneal pachymetry was detected in the relative group. Root mean square of all HOAs including vertical trefoil, vertical coma, horizontal coma, horizontal trefoil, quadrifoil, and fourth-order spherical aberrations were significantly greater in the relative group than controls. CONCLUSIONS Owing to the high prevalence of undiagnosed KCN susceptibility in family members with KCN, keratorefractive surgery should be considered cautiously in these individuals. In addition, comprehensive preoperative examination should be considered to detect subtle topographic and HOAs in these individuals.
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Niazi S, Moshirfar M, Alizadeh F, Doroodgar F, Baradaran-Rafii A, Filutowski O, Niazi F, Ambrósio R. Association of 2 Lysyl Oxidase Gene Single Nucleotide Polymorphisms with Keratoconus: A Nationwide Registration Study. OPHTHALMOLOGY SCIENCE 2022; 3:100247. [PMID: 36748061 PMCID: PMC9898806 DOI: 10.1016/j.xops.2022.100247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 10/31/2022] [Accepted: 11/03/2022] [Indexed: 11/10/2022]
Abstract
Purpose Keratoconus (KC) is the most common primary ectatic corneal disease, characterized by progressive thinning of the cornea, affecting its shape and structure and leading to visual loss. Lysyl oxidase is an important component of the extracellular matrix and contributes to the homeostasis of corneal stromal extracellular matrix via enzymatic reaction. This nationwide registration study aims to examine the association of KC with 2 known single nucleotide polymorphisms, rs2956540 and rs10519694, in a population of Iranian descent. Design Case-control. Participants One hundred seventy-eight subjects with KC and 180 clinically healthy subjects participated in the study. Methods Genomic DNA was extracted from peripheral blood samples, and their genotypes were determined using tetra-primer amplification refractory mutation system-polymerase chain reaction. Main Outcome Measures Allele frequency for rs2956540 and rs10519694. Results Genotype frequency was significantly different between cases and controls for rs2956540 (P value = 0.019). The rs2956540 C allele carriers were significantly more frequent among KC cases than healthy controls (P valuechi-square = 0.015, P valueFisher exact = 0.017). There was a significant difference in genotype frequency between groups for rs10519694 (P value = 0.001). T allele carriers were significantly more frequent among KC patients (P valuechi-square = 0.002, P valueFisher exact = 0.001). Sex stratification revealed no significant differences in genotype frequency between males and females in cases and controls. Fitting the general linear model showed that rs10519694 could be considered a predictor for the development of KC (P value = 0.001); however, this was not observed for rs2956540 (P value = 0.323). Conclusions rs2956540 and rs10519694 are associated with KC in a population of Iranian descent. rs10519694 could potentially be used for KC risk prediction.
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Affiliation(s)
- Sana Niazi
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Majid Moshirfar
- John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Fatemeh Alizadeh
- Department of Genomic Psychiatry and Behavioral Genomics (DGPBG), Roozbeh Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Farideh Doroodgar
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran, Iran,Negah Specialty Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran,Correspondence: Farideh Doroodgar, MD; Address: Negah Specialty Ophthalmic Hospital and Research Center, No 3., Ketabi St., Shariati Ave., Tehran, Iran; Postal Code: 1544914599
| | - Alireza Baradaran-Rafii
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran,Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Oliver Filutowski
- Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Feizollah Niazi
- Clinical Research Development Center, Shahid Modarres Educational hospital, Shahid Behesht University of Medical Sciences, Tehran, Iran
| | - Renato Ambrósio
- Department of Ophthalmology, Federal University the State of Rio de Janeiro (UNIRIO), São Paulo, Brazil,Department of Ophthalmology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil,Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil,Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil,BrAIN: Brazilian Artificial Intelligence Networking in Medicine, Rio de Janeiro & Maceió, Brazil
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A Hospital-Based Study on the Prevalence of Keratoconus in First-Degree Relatives of Patients with Keratoconus in Central China. J Ophthalmol 2022; 2022:6609531. [PMID: 35663517 PMCID: PMC9162836 DOI: 10.1155/2022/6609531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/21/2022] [Accepted: 05/17/2022] [Indexed: 11/17/2022] Open
Abstract
Purpose The present study investigated the prevalence of keratoconus (KC) among first-degree relatives of KC patients in Central China. Methods From July 2018 to March 2022, 661 first-degree relatives of 384 KC patients were included in the present study. Corneal tomography, uncorrected distance visual acuity, manifest refraction with corrected distance visual acuity, intraocular pressure, slit-lamp microscopy, and fundus examination were performed. The diagnosis of KC was based on the Belin/Ambrosio enhanced ectasia total deviation value (BAD-D value) on the Pentacam® system (Oculus GmbH). BAD-D value <1.6 was diagnosed as healthy, 1.6≤ BAD-D value <2.6 was diagnosed as suspected KC, and BAD-D value ≥2.6 was diagnosed as KC. Results The present study included 337 (50.98%) female and 324 (49.02%) male subjects. The prevalence of KC and suspected KC in first-degree relatives was 8.77% (n = 58) and 29.05% (n = 192), respectively. The prevalence of KC was 9.70% among parents and 7.23% among siblings. Conclusions The higher prevalence of KC among first-degree relatives of patients with KC suggests that first-degree relatives of KC are at high risk of developing KC.
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de Barros MRM, Chakravarti S. Pathogenesis of keratoconus: NRF2-antioxidant, extracellular matrix and cellular dysfunctions. Exp Eye Res 2022; 219:109062. [PMID: 35385756 DOI: 10.1016/j.exer.2022.109062] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/19/2022] [Accepted: 03/30/2022] [Indexed: 11/04/2022]
Abstract
Keratoconus (KC) is a degenerative disease associated with cell and extracellular matrix (ECM) loss that causes gradual thinning and steepening of the cornea and loss of vision. Collagen cross linking with ultraviolet light treatment can strengthen the ECM and delay weakening of the cornea, but severe cases require corneal transplantation. KC is multifactorial and multigenic, but its pathophysiology is still an enigma. Multiple approaches are being pursued to elucidate the molecular changes that underlie the corneal phenotype to identify relevant genes for tailored candidate searches and to develop potential biomarkers and targets for therapeutic interventions. Recent proteomic and transcriptomic studies suggest dysregulations in oxidative stress, NRF2-regulated antioxidant programs, WNT-signaling, TGF-β, ECM and matrix metalloproteinases. This review aims to provide a broad update on the transcriptomic and proteomic studies of KC with a focus on findings that relate to oxidative stress, and dysregulations in cellular and extracellular matrix functions.
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Affiliation(s)
| | - Shukti Chakravarti
- Department of Ophthalmology, NYU Grossman School of Medicine, NY, 10016, USA; Department of Pathology, NYU Grossman School of Medicine, NY, 10016, USA.
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Teo AWJ, Mansoor H, Sim N, Lin MTY, Liu YC. In Vivo Confocal Microscopy Evaluation in Patients with Keratoconus. J Clin Med 2022; 11:393. [PMID: 35054085 PMCID: PMC8778820 DOI: 10.3390/jcm11020393] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 02/05/2023] Open
Abstract
Keratoconus is the most common primary corneal ectasia characterized by progressive focal thinning. Patients experience increased irregular astigmatism, decreased visual acuity and corneal sensitivity. Corneal collagen crosslinking (CXL), a minimally invasive procedure, is effective in halting disease progression. Historically, keratoconus research was confined to ex vivo settings. In vivo confocal microscopy (IVCM) has been used to examine the corneal microstructure clinically. In this review, we discuss keratoconus cellular changes evaluated by IVCM before and after CXL. Cellular changes before CXL include decreased keratocyte and nerve densities, disorganized subbasal nerves with thickening, increased nerve tortuosity and shortened nerve fibre length. Repopulation of keratocytes occurs up to 1 year post procedure. IVCM also correlates corneal nerve status to functional corneal sensitivity. Immediately after CXL, there is reduced nerve density and keratocyte absence due to mechanical removal of the epithelium and CXL effect. Nerve regeneration begins after 1 month, with nerve fibre densities recovering to pre-operative levels between 6 months to 1 year and remains stable up to 5 years. Nerves remain tortuous and nerve densities are reduced. Corneal sensitivity is reduced immediately postoperatively but recovers with nerve regeneration. Our article provides comprehensive review on the use of IVCM imaging in keratoconus patients.
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Affiliation(s)
- Alvin Wei Jun Teo
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore;
| | - Hassan Mansoor
- Al Shifa Trust Eye Hospital, Jhelum Road, Rawalpindi 46000, Pakistan;
| | - Nigel Sim
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 168751, Singapore;
| | - Molly Tzu-Yu Lin
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore;
| | - Yu-Chi Liu
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore;
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore;
- Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore 169856, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
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Chen S, Li XY, Jin JJ, Shen RJ, Mao JY, Cheng FF, Chen ZJ, Linardaki E, Voulgaraki S, Aslanides IM, Jin ZB. Genetic Screening Revealed Latent Keratoconus in Asymptomatic Individuals. Front Cell Dev Biol 2021; 9:650344. [PMID: 34136477 PMCID: PMC8202288 DOI: 10.3389/fcell.2021.650344] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose To adopt molecular screening in asymptomatic individuals at high risk of developing keratoconus as a combinative approach to prevent subclinical patients from post-refractive surgery progressive corneal ectasia. Methods In this study, 79 Chinese and nine Greek families with keratoconus were recruited, including 91 patients with clinically diagnosed keratoconus as well as their asymptomatic but assumptive high-risk first-degree relatives based on underlying genetic factor. Mutational screening of VSX1, TGFBI, and ZEB1 genes and full clinical assessment including Pentacam Scheimpflug tomography were carried out in these individuals. Results Five variants in VSX1 and TGFBI genes were identified in three Chinese families and one Greek family, and four of them were novel ones. Surprisingly, ultra-early corneal changes in Belin/Ambrosio Enhanced Ectasia Display of Pentacam corneal topography together with co-segregated variants were revealed in the relatives who had no self-reported symptoms. Conclusions Variants of VSX1 and TGFBI genes identified in both the clinically diagnosed and subclinical patients may cause the keratoconus through an autosomal dominant inheritance pattern, with different variable expressivity. Combining genetic with Belin/AmbrosioEnhanced Ectasia Display can be used to identify patients with latent keratoconus. This study indicates that genetic testing may play an important supplementary role in re-classifying the disease manifestation and evaluating the preoperative examination of refractive surgery.
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Affiliation(s)
- Shihao Chen
- Center for Refractive Surgery, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xing-Yong Li
- Center for Refractive Surgery, The Eye Hospital, Wenzhou Medical University, Wenzhou, China.,Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | - Jia-Jia Jin
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | - Ren-Juan Shen
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China.,Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China
| | - Jian-Yang Mao
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | - Fei-Fei Cheng
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | - Zhen-Ji Chen
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China
| | | | | | - Ioannis M Aslanides
- Center for Refractive Surgery, The Eye Hospital, Wenzhou Medical University, Wenzhou, China.,Emmetropia Mediterranean Eye Institute, Heraklion, Greece
| | - Zi-Bing Jin
- Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, National Center for International Research in Regenerative Medicine and Neurogenetics, Wenzhou, China.,Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing Tongren Hospital, Beijing, China
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Sot M, Gan G, François J, Chaussard D, Da Costa M, Luc MS, Goetz C, Dinot V, Lhuillier L, Perone JM. Risk factors for keratoconus progression after treatment by accelerated cross-linking (A-CXL): A prospective 24-month study. J Fr Ophtalmol 2021; 44:863-872. [PMID: 34059330 DOI: 10.1016/j.jfo.2020.08.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/15/2020] [Accepted: 08/25/2020] [Indexed: 12/30/2022]
Abstract
PURPOSE Identification of potential predictive factors for keratoconus progression after treatment by accelerated Cross-linking (A-CXL) SECONDARY OBJECTIVES: Evaluation of clinical and topographic outcomes for two years following accelerated cross-linking treatment for progressive keratoconus including: best spectacle corrected visual acuity (BSCVA), thinnest pachymetry, maximum keratometry (Kmax), cylinder. STUDY Prospective, interventional, monocentric study. SITE: Metz-Thionville Regional Medical Center, Lorraine University, Mercy Hospital, Metz, France. PATIENTS AND METHODS We included 82 eyes of 60 patients between March 2014 and June 2016 who underwent accelerated corneal cross-linking (A-CXL) with epithelial debridement for progressive keratoconus, with a minimum follow-up of 2 years. A complete clinical evaluation and corneal topography were performed before cross-linking, and subsequently at 6, 12 and 24 months post-procedure. The following parameters were monitored during follow-up: best spectacle corrected visual acuity (BSCVA), minimal pachymetry, maximum keratometry (Kmax), mean anterior and posterior curvatures, maximum posterior curvature, presence of optical aberrations, subdivided into spherical aberration, coma, astigmatism, higher order optical aberrations and residual optical aberrations. After a 2-year follow-up, two groups, defined as "responders" and "non-responders" to treatment, were separated for analysis, and their initial characteristics were compared. RESULTS Data for 82 eyes of 60 patients with progressive keratoconus with a mean age of 24±7 years were studied. Fourteen eyes (17.1%) showed signs of progression after treatment by A-CXL (non-responders), and 68 eyes (82.9%) showed stabilization of the disease (responders). Characteristics of non-responding eyes after A-CXL included a younger mean age (20±5 vs. 25±7 years) (P=0.04) and a lower initial mean BCVA for non-responders of 0.44±0.16 logMAR vs. 0.29±0.19 logMAR (P=0.03). Non-responders also had a higher mean maximal posterior curvature (AKB) of -10.84±1.72D vs. -9.46± 1.12D (P=0.03). They also showed more higher order optical aberrations (3.84±1.72D vs. 2.4±1.02D; P=0.01), including coma (3.85±1.81D vs. 2.1±1.01D; P=0.03) and more residual aberrations than responders (1.05±0.44D vs. 0.45±0.6D; P=0.005). No significant differences were found between responders and non-responders for the other parameters in our study. CONCLUSION Eyes with progressive keratoconus who did not respond to A-CXL treatment were the most aggressive cases in the youngest patients, with highest maximum corneal curvatures and most pronounced optical aberrations. These patients should be informed in advance of the high risk of non-response to A-CXL treatment, and of the potential need for additional treatment in the future.
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Affiliation(s)
- M Sot
- Ophthalmology Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
| | - G Gan
- Ophthalmology Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
| | - J François
- Ophthalmology Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
| | - D Chaussard
- Ophthalmology Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
| | - M Da Costa
- Ophthalmology Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
| | - M S Luc
- Ophthalmology Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
| | - C Goetz
- Clinical Research Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
| | - V Dinot
- Clinical Research Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
| | - L Lhuillier
- Ophthalmology Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
| | - J M Perone
- Ophthalmology Department, Regional Hospital Center of Metz-Thionville, Mercy Hospital, 1, allee du Chateau CS 45001, 57085 Metz Cedex 03, France.
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9
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Regueiro U, López-López M, Hervella P, Sobrino T, Lema I. Corneal and conjunctival alteration of innate immune expression in first-degree relatives of keratoconus patients. Graefes Arch Clin Exp Ophthalmol 2021; 259:459-467. [PMID: 32949300 DOI: 10.1007/s00417-020-04929-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/01/2020] [Accepted: 09/10/2020] [Indexed: 01/18/2023] Open
Abstract
PURPOSE The innate immune toll-like receptors 2 (TLR2) and 4 (TLR4) may play a key role in the physiopathology of keratoconus (KC). Therefore, the aim of this study was to compare TLR2/TLR4 expression in corneal and conjunctival epithelial cells between healthy first-degree relatives of patients with KC and healthy controls as well as KC patients. METHODS Case-control study in 72 healthy eyes of 36 control subjects, 53 eyes of 27 first-degree relatives, and 109 eyes with KC (60 patients). All participants were subjected to a clinical, topographic, aberrometric, and tomographic examination with extraction of corneal and conjunctival epithelial cells through scraping. TLR2/TLR4 expression was measured by flow cytometry, and was compared among controls, first-degree relatives, and KC patients. The relationship between TLR expression and epidemiological-clinical variables or topographic-aberrometric-tomographic parameters was also analyzed. RESULTS Mean TLR2/TLR4 expression showed a significant gradual increase among groups: controls < first-degree relatives < KC patients. Mean expression of TLR2 in corneal epithelial cells and both TLR2/TLR4 in conjunctival epithelial cells were significantly higher in relatives than in controls (p = 0.026, p < 0.001, and p = 0.031, respectively). Sex, age, allergic disease, eye itching, rubbing, and topographic-aberrometric-tomographic parameters were not associated to TLR2/TLR4 expression in relatives. TLR2 conjunctival expression was independently associated to relatives (OR 1.001; CI 95% 1.000-1.002, p = 0.043) after adjustment by sex, age, and rubbing. CONCLUSION TLR2 and TLR4 are overexpressed in corneal and conjunctival epithelial cells of KC relatives compared with controls. Both biomarkers may monitor early ocular changes in first-degree relatives who not show any abnormal clinical-topographic-aberrometric-tomographic parameters.
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Affiliation(s)
- Uxía Regueiro
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain.,Facultade de Óptica e Optometría, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Maite López-López
- Facultade de Óptica e Optometría, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Pablo Hervella
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - Tomás Sobrino
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain.
| | - Isabel Lema
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain. .,Facultade de Óptica e Optometría, Universidade de Santiago de Compostela, Santiago de Compostela, Spain. .,Instituto Galego de Oftalmoloxía (INGO), Hospital Provincial de Conxo, Santiago de Compostela, Spain.
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The Prevalence and Risk Factors for Keratoconus: A Systematic Review and Meta-Analysis. Cornea 2020; 39:263-270. [PMID: 31498247 DOI: 10.1097/ico.0000000000002150] [Citation(s) in RCA: 238] [Impact Index Per Article: 59.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE This study was conducted to determine the prevalence and risk factors for keratoconus worldwide. METHODS In this meta-analysis, using a structured search strategy from 2 sources, 4 electronic databases (PubMed, Web of Science, Google Scholar, and Scopus) and the reference lists of the selected articles were searched from inception to June 2018 with no restrictions and filters. The outcome of the study was the prevalence of keratoconus and its risk factors, including eye rubbing, family history of keratoconus, atopy, allergy, asthma, eczema, diabetes type I and type II, and sex. RESULTS In this study, 3996 articles were retrieved, of which 29 were analyzed. These 29 articles included 7,158,241 participants from 15 countries. The prevalence of keratoconus in the whole population was 1.38 per 1000 population [95% confidence interval (CI): 1.14-1.62 per 1000]. The prevalence of keratoconus was 20.6 per 1000 (95% CI: 11.68-28.44 per 1000) in men and 18.33 per 1000 (95% CI: 8.66-28.00 per 1000) in women in studies reporting sex. The odds ratio of eye rubbing, family history of keratoconus, allergy, asthma, and eczema was 3.09 (95% CI: 2.17-4.00), 6.42 (95% CI: 2.59-10.24), 1.42 (95% CI: 1.06-1.79), 1.94 (95% CI: 1.30-2.58), and 2.95 (95% CI: 1.30-4.59), respectively. CONCLUSIONS The results of this study, as the most comprehensive meta-analysis of keratoconus prevalence and risk factors, showed that keratoconus had a low prevalence in the world and eye rubbing, family history of keratoconus, allergy, asthma, and eczema were the most important risk factors for keratoconus according to the available evidence.
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Garcia-Ferrer FJ, Akpek EK, Amescua G, Farid M, Lin A, Rhee MK, Varu DM, Musch DC, Mah FS, Dunn SP. Corneal Ectasia Preferred Practice Pattern®. Ophthalmology 2019; 126:P170-P215. [DOI: 10.1016/j.ophtha.2018.10.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 10/09/2018] [Indexed: 02/07/2023] Open
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Lyra D, Ribeiro G, Torquetti L, Ferrara P, Machado A, Lyra JM. Computational Models for Optimization of the Intrastromal Corneal Ring Choice in Patients With Keratoconus Using Corneal Tomography Data. J Refract Surg 2018; 34:547-550. [DOI: 10.3928/1081597x-20180615-01] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 06/08/2018] [Indexed: 11/20/2022]
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Hashemi H, Heydarian S, Yekta A, Ostadimoghaddam H, Aghamirsalim M, Derakhshan A, Khabazkhoob M. High prevalence and familial aggregation of keratoconus in an Iranian rural population: a population-based study. Ophthalmic Physiol Opt 2018; 38:447-455. [DOI: 10.1111/opo.12448] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 02/02/2018] [Indexed: 12/25/2022]
Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology; Noor Eye Hospital; Tehran Iran
| | - Samira Heydarian
- Department of Optometry; School of Paramedical Sciences; Mashhad University of Medical Sciences; Mashhad Iran
| | - Abbasali Yekta
- Refractive Errors Research Center; Mashhad University of Medical Sciences; Mashhad Iran
| | - Hadi Ostadimoghaddam
- Refractive Errors Research Center; Mashhad University of Medical Sciences; Mashhad Iran
| | | | - Akbar Derakhshan
- Khatam-al-Anbia Hospital; Mashhad University of Medical Sciences; Mashhad Iran
| | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing; School of Nursing and Midwifery; Shahid Beheshti University of Medical Sciences; Tehran Iran
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Valgaeren H, Koppen C, Van Camp G. A new perspective on the genetics of keratoconus: why have we not been more successful? Ophthalmic Genet 2017; 39:158-174. [DOI: 10.1080/13816810.2017.1393831] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Hanne Valgaeren
- Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp & Antwerp University Hospital, Antwerp, Belgium
| | - Carina Koppen
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
- Department of Ophthalmology, Visual Optics and Visual Rehabilitation, University of Antwerp, Antwerp, Belgium
| | - Guy Van Camp
- Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp & Antwerp University Hospital, Antwerp, Belgium
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Rong SS, Ma STU, Yu XT, Ma L, Chu WK, Chan TCY, Wang YM, Young AL, Pang CP, Jhanji V, Chen LJ. Genetic associations for keratoconus: a systematic review and meta-analysis. Sci Rep 2017; 7:4620. [PMID: 28676647 PMCID: PMC5496893 DOI: 10.1038/s41598-017-04393-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/15/2017] [Indexed: 12/21/2022] Open
Abstract
Genetic associations for keratoconus could be useful for understanding disease pathogenesis and discovering biomarkers for early detection of the disease. We conducted a systematic review and meta-analysis to summarize all reported genetic associations for the disease. We searched in the MEDLINE, Embase, Web of Science, and HuGENET databases for genetic studies of keratoconus published from 1950 to June 2016. The summary odds ratio and 95% confidence intervals of all polymorphisms were estimated using the random-effect model. Among 639 reports that were retrieved, 24 fulfilled required criteria as eligible studies for meta-analysis, involving a total of 53 polymorphisms in 28 genes/loci. Results of our meta-analysis lead to the prioritization of 8 single-nucleotide polymorphisms (SNPs) in 6 genes/loci for keratoconus in Whites. Of them 5 genes/loci were originally detected in genome-wide association studies, including FOXO1 (rs2721051, P = 5.6 × 10-11), RXRA-COL5A1 (rs1536482, P = 2.5 × 10-9), FNDC3B (rs4894535, P = 1.4 × 10-8), IMMP2L (rs757219, P = 6.1 × 10-7; rs214884, P = 2.3 × 10-5), and BANP-ZNF469 (rs9938149, P = 1.3 × 10-5). The gene COL4A4 (rs2229813, P = 1.3 × 10-12; rs2228557, P = 4.5 × 10-7) was identified in previous candidate gene studies. We also found SNPs in 10 genes/loci that had a summary P value < 0.05. Sensitivity analysis indicated that the results were robust. Replication studies and understanding the roles of these genes in keratoconus are warranted.
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Affiliation(s)
- Shi Song Rong
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear, Boston, Massachusetts, USA
| | - Sarah Tsz Ue Ma
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Xin Ting Yu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- Department of Gastroenterology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Li Ma
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wai Kit Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Tommy Chung Yan Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
- Hong Kong Eye Hospital, Kowloon, Hong Kong, China
| | - Yu Meng Wang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Alvin L Young
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Vishal Jhanji
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China.
- UPMC Eye Centre, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
| | - Li Jia Chen
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China.
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Gordon-Shaag A, Millodot M, Kaiserman I, Sela T, Barnett Itzhaki G, Zerbib Y, Matityahu E, Shkedi S, Miroshnichenko S, Shneor E. Risk factors for keratoconus in Israel: a case-control study. Ophthalmic Physiol Opt 2015; 35:673-81. [DOI: 10.1111/opo.12237] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 07/22/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Ariela Gordon-Shaag
- Department of Optometry and Vision Science; Hadassah Academic College; Jerusalem Israel
| | - Michel Millodot
- School of Optometry and Vision Sciences; Cardiff University; Cardiff Wales
| | | | - Tzahi Sela
- CARE Laser Medical Group; Tel Aviv Israel
| | - Guy Barnett Itzhaki
- Department of Optometry and Vision Science; Hadassah Academic College; Jerusalem Israel
| | - Yaffa Zerbib
- Department of Optometry and Vision Science; Hadassah Academic College; Jerusalem Israel
| | - Efrat Matityahu
- Department of Optometry and Vision Science; Hadassah Academic College; Jerusalem Israel
| | - Shira Shkedi
- Department of Optometry and Vision Science; Hadassah Academic College; Jerusalem Israel
| | | | - Einat Shneor
- Department of Optometry and Vision Science; Hadassah Academic College; Jerusalem Israel
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Abstract
Keratoconus (KC) is the most common ectasia of the cornea and is a common reason for corneal transplant. Therapeutic strategies that can arrest the progression of this disease and modify the underlying pathogenesis are getting more and more popularity among scientists. Cumulating data represent strong evidence of a genetic role in the pathogenesis of KC. Different loci have been identified, and certain mutations have also been mapped for this disease. Moreover, Biophysical properties of the cornea create an appropriate candidate of this tissue for gene therapy. Immune privilege, transparency and ex vivo stability are among these properties. Recent advantage in vectors, besides the ability to modulate the corneal milieu for accepting the target gene for a longer period and fruitful translation, make a big hope for stupendous results reasonable.
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Affiliation(s)
- Mahgol Farjadnia
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Naderan
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehrdad Mohammadpour
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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Distribution of ABO and Rh Blood Groups in Patients With Keratoconus: A Case-Control Study. Eye Contact Lens 2014; 41:214-7. [PMID: 25503910 DOI: 10.1097/icl.0000000000000098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED Association of keratoconus (KC) with genetic predisposition and environmental factors has been well documented. However, no single study has investigated the possible relationship between ABO and Rh blood groups and KC. METHODS A case-control study was designed in a university hospital enrolling 214 patients with KC in the case group and equal number of age- and sex-matched healthy subjects in the control group. Primary characteristics, ABO blood group, and Rh factors were compared between the two groups. Topographic findings of KC eyes and the severity of the diseases were investigated according to the distribution of the blood groups. RESULTS Blood group O and Rh(+) phenotype were most frequent in both groups. There was no significant difference between the two groups in terms of ABO blood groups or Rh factors. Mean keratometery (K), central corneal thickness, thinnest corneal thickness, flat K, steep K, sphere and cylinder, spherical equivalent, and uncorrected visual acuity were all similar between ABO blood groups and Rh(+) and Rh(-) groups. However, the best spectacle-corrected visual acuity (BCVA) had the highest value in AB blood group (0.35 ± 0.22 logMAR, P=0.005). Moreover, the blood group AB revealed the highest frequency for grade 3 KC, followed by grades 1, 2, and 4 (P=0.003). CONCLUSION We observed no significant excess of any particular blood group among KC cases compared with healthy subjects. Except BCVA, none of the keratometric or topographic findings was significantly different between blood groups.
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Abstract
ABSTRACT
Keratoconus is a progressive corneal ectactic condition that can lead to visual loss. Despite being the most common cause for keratoplasty in the developed world the aetiology is unknown. It is thought to be multifactorial, with genetic and environmental factors implicated. The association of eye rubbing and pathogenesis of keratoconus has been well documented. In this review, we collate the existing literature and summarize the current knowledge of the role of eye rubbing in the pathogenesis of keratoconus.
How to cite this article
Hawkes E, Nanavaty MA. Eye Rubbing and Keratoconus: A Literature Review. Int J Kerat Ect Cor Dis 2014;3(3):118-121.
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Ozgurhan EB, Kara N, Yildirim A, Bozkurt E, Uslu H, Demirok A. Evaluation of corneal microstructure in keratoconus: a confocal microscopy study. Am J Ophthalmol 2013; 156:885-893.e2. [PMID: 23932262 DOI: 10.1016/j.ajo.2013.05.043] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/29/2013] [Accepted: 05/31/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE To compare the corneal microstructure in patients with manifest keratoconus (KCN), subclinical KCN, and topographically normal relatives of patients with KCN and in healthy controls. DESIGN Prospective and cross-sectional study. METHODS We enrolled 145 subjects in the study. The participants were divided into 4 groups, based on clinical and topographical evaluation: the manifest KCN group (n = 30), the subclinical KCN group (n = 32), the KCN relatives group (n = 53), and the control group (n = 30). Corneal microstructure was assessed by corneal in vivo confocal microscopy in all of the individuals. Mean outcome measures were basal epithelial cell density, endothelial cell density, anterior keratocyte density, posterior keratocyte density, sub-basal nerve density, sub-basal nerve diameter, and stromal nerve diameter. RESULTS The mean basal epithelial cell density, endothelial cell density, and sub-basal nerve diameter were not significantly different among the 4 groups (P = 0.057, P = 0.592, and P = 0.393, respectively). The mean anterior and posterior stromal keratocyte densities were significantly lower in the manifest group, in the subclinical group, and in the relatives group when compared with the control group (for both parameters; P < 0.001, P < 0.001, and P< 0.001, respectively). The mean stromal nerve diameter in the manifest group, subclinical group, and relatives group was significantly higher than in the control group (P = 0.001, P = 0.049, and P = 0.004, respectively). CONCLUSION The anterior and posterior stromal keratocyte densities were statistically lower and stromal nerve diameter was statistically higher in patients with manifest KCN, subclinical KCN, and topographically normal KCN relatives compared with controls. Confocal microscopy may be useful for the determination of early corneal microstructural changes before manifestation of typical or subtle topographic signs.
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Mehravaran S, Hashemi H, KhabazKhoob M, Fotouhi A. Distribution of radii of curvature of anterior and posterior best fit sphere in a normal population: The Tehran Eye Study. Cont Lens Anterior Eye 2013; 36:186-90. [DOI: 10.1016/j.clae.2013.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 01/22/2013] [Accepted: 02/21/2013] [Indexed: 11/27/2022]
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Biomechanical Evaluation of Cornea in Topographically Normal Relatives of Patients With Keratoconus. Cornea 2013; 32:262-6. [DOI: 10.1097/ico.0b013e3182490924] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
Keratoconus (KTCN) is non-inflammatory thinning and anterior protrusion of the cornea that results in steepening and distortion of the cornea, altered refractive error, and decreased vision. Keratoconus is a complex condition of multifactorial etiology. Both genetic and environmental factors are associated with KTCN. Evidence of genetic etiology includes familial inheritance, discordance between dizygotic twins, and association with other known genetic disorders. Several loci responsible for a familial form of KTCN have been mapped; however, no mutations in any genes have been identified for any of these loci. This article focuses on the genetic aspects. In addition, bioinformatics methods applied in KTCN gene identification process are discussed.
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Affiliation(s)
- Dorota M Nowak
- Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland, Strzeszynska 32, 60-479 Poznan
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Wei RH, Zhao SZ, Lim L, Tan DTH. Incidence and characteristics of unilateral keratoconus classified on corneal topography. J Refract Surg 2011; 27:745-51. [PMID: 21563729 DOI: 10.3928/1081597x-20110426-01] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 04/01/2011] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the characteristics of unilateral keratoconus defined on the basis of corneal topography and analyze videokeratography parameters between fellow eyes and normal controls. METHODS A total of 111 patients with clinical keratoconus were prospectively enrolled. Both eyes were evaluated with Tomey (Tomey Corp) and Orbscan II (Bausch & Lomb) corneal topography systems. The patient was classified as having unilateral keratoconus if one eye had clinical keratoconus and the other eye did not have any topographic signs of keratoconus such as asymmetric videokeratographic pattern, positive result in Tomey keratoconus screening, maximum posterior elevation >40 μm, or corneal thinnest pachymetry <500 μm. Clinical characteristics and 13 Orbscan II quantitative indices between keratoconic and fellow eyes and normal control eyes were evaluated. RESULTS Five (4.5%) of 111 patients with keratoconus had no topographic evidence of keratoconus in the fellow eye. All clinically normal fellow eyes had symmetric bowtie patterns. Statistically significant differences were noted in maximum posterior elevation, corneal irregularity, and corneal thinnest values between keratoconic eyes and fellow eyes, and between keratoconic eyes and control eyes. Only 3-mm irregularity was significantly higher in the fellow eyes compared with control eyes (P<.05). An increased trend for corneal 5-mm irregularity was found in fellow eyes compared to control eyes. CONCLUSIONS The incidence of unilateral keratoconus was 4.5%. A trend of higher irregularity was found in fellow eyes compared with control eyes. This finding indicates that fellow eyes may show a certain low-expressivity morphologic feature of keratoconus.
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Affiliation(s)
- Rui Hua Wei
- Tianjin Medical University Eye Centre, Tianjin, China
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KhabazKhoob M, Hashemi H, Yazdani K, Mehravaran S, Yekta A, Fotouhi A. Keratometry measurements, corneal astigmatism and irregularity in a normal population: the Tehran Eye Study. Ophthalmic Physiol Opt 2010; 30:800-5. [DOI: 10.1111/j.1475-1313.2010.00732.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lam AKC. New applications in the corneal topography system. EXPERT REVIEW OF OPHTHALMOLOGY 2010. [DOI: 10.1586/eop.09.71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Chan CCK, Hodge C, Sutton G. External analysis of the Randleman Ectasia Risk Factor Score System: a review of 36 cases of post LASIK ectasia. Clin Exp Ophthalmol 2010; 38:335-40. [DOI: 10.1111/j.1442-9071.2010.02251.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Besharati MR, Shoja MR, Manaviat MR, Kheirandish M, Rad MZ. Corneal topographic changes in healthy siblings of patients with keratoconus. Int J Ophthalmol 2010; 3:73-5. [PMID: 22553522 DOI: 10.3980/j.issn.2222-3959.2010.01.17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 02/02/2010] [Indexed: 11/02/2022] Open
Abstract
AIM To describe the involvement in relatives of keratoconus (KCN) patients with corneal topography map. METHODS A total of 150 siblings of 300 eyes of 75 KCN patients referred to corneal clinic were studied and experienced complete slit-lamp, refraction examinations and topographic cornea maps provided by videophotoker-atography. ANOVA, Fisher exact and Chi-square tests performed to compare of results. RESULTS Of 150 siblings, 56% were female and 44% were male with average age of 21 (range 15-39) years. KCN and suspect KCN diagnosed in 12.3% and 6.6% respectively. The central keratometry (CK) was 46.5±4.51 dioptr (D) in KCN and 45.66±1.52D in suspect KCN. Inferior-superior value (I-S) was 3.51±2.5D in KCN and 1.56±1.22D in suspect KCN. In KCN condition the oval pattern was 67.6% (n=25) and Round pattern detected 32.4% (n=12). In suspect KCN these patterns detected 90% and 10% respectively. Refractive errors in KCN were -7.5 to +1.25 dioptr (-1.25±1.83), in suspect KCN 0.45 to -4.2 dioptr (-0.68±0.76) and in healthy group 2.75 to -7.5 dioptr (-0.6±1.12). Astigmatism was mild in 22.7%, moderate and sever astigmatism in 18.3% in KCN and suspect KCN CONCLUSION: Increasing KCN condition in healthy siblings of KCN patients shows require to screening plan to early diagnose and cautionly treatment of contact lens in these individuals.
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Dauwe C, Touboul D, Roberts CJ, Mahmoud AM, Kérautret J, Fournier P, Malecaze F, Colin J. Biomechanical and morphological corneal response to placement of intrastromal corneal ring segments for keratoconus. J Cataract Refract Surg 2009; 35:1761-7. [DOI: 10.1016/j.jcrs.2009.05.033] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 04/29/2009] [Accepted: 05/05/2009] [Indexed: 11/24/2022]
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Hardten DR, Gosavi VV. Photorefractive keratectomy in eyes with atypical topography. J Cataract Refract Surg 2009; 35:1437-44. [DOI: 10.1016/j.jcrs.2009.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 04/22/2009] [Accepted: 05/01/2009] [Indexed: 10/20/2022]
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Current world literature. Curr Opin Ophthalmol 2009; 20:333-41. [PMID: 19535964 DOI: 10.1097/icu.0b013e32832e478f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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