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Martinez Sanchez M, Chan WM, MacKinnon SE, Barry B, Hunter DG, Engle EC, Whitman MC. Presence of Copy Number Variants Associated With Esotropia in Patients With Exotropia. JAMA Ophthalmol 2024; 142:243-247. [PMID: 38358749 PMCID: PMC10870223 DOI: 10.1001/jamaophthalmol.2023.6782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/10/2023] [Indexed: 02/16/2024]
Abstract
Importance Strabismus is a common ocular disorder of childhood. There is a clear genetic component to strabismus, but it is not known if esotropia and exotropia share genetic risk factors. Objective To determine whether genetic duplications associated with esotropia are also associated with exotropia. Design, Setting, and Participants This was a cross-sectional study conducted from November 2005 to December 2023. Individuals with constant or intermittent exotropia of any magnitude or a history of surgery for exotropia were recruited from pediatric ophthalmic practices. Data were analyzed from March to December 2023. Exposure Genetic duplication. Main Outcomes and Measures Presence of genetic duplications at 2p11.2, 4p15.2, and 10q11.22 assessed by digital droplet polymerase chain reaction. Orthoptic measurements and history of strabismus surgery were performed. Results A total of 234 individuals (mean [SD] age, 19.5 [19.0] years; 127 female [54.3%]) were included in this study. The chromosome 2 duplication was present in 1.7% of patients with exotropia (4 of 234; P = .40), a similar proportion to the 1.4% of patients with esotropia (23 of 1614) in whom it was previously reported and higher than the 0.1% of controls (4 of 3922) previously reported (difference, 1.6%; 95% CI, 0%-3.3%; P < .001). The chromosome 4 duplication was present in 3.0% of patients with exotropia (7 of 234; P = .10), a similar proportion to the 1.7% of patients with esotropia (27 of 1614) and higher than the 0.2% of controls (6 of 3922) in whom it was previously reported (difference, 2.8%; 95% CI, 0.6%-5.0%; P < .001). The chromosome 10 duplication was present in 6.0% of patients with exotropia (14 of 234; P = .08), a similar proportion to the 4% of patients with esotropia (64 of 1614) and higher than the 0.4% of controls (18 of 3922) in whom it was previously reported (difference, 5.6%; 95% CI, 2.5%-8.6%; P < .001). Individuals with a duplication had higher mean (SD) magnitude of deviation (31 [13] vs 22 [14] prism diopters [PD]; difference, 9 PD; 95% CI, 1-16 PD; P = .03), were more likely to have constant (vs intermittent) exotropia (70% vs 29%; difference, 41%; 95% CI, 20.8%-61.2%; P < .001), and had a higher rate of exotropia surgery than those without a duplication (58% vs 34%; difference, 24%; 95% CI, 3%-44%; P = .02). Conclusions and Relevance In this cross-sectional study, results suggest that the genetic duplications on chromosomes 2, 4, and 10 were risk factors for exotropia as well as esotropia. These findings support the possibility that esotropia and exotropia have shared genetic risk factors. Whether esotropia or exotropia develops in the presence of these duplications may be influenced by other shared or independent genetic variants or by environmental factors.
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Affiliation(s)
- Mayra Martinez Sanchez
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Wai-Man Chan
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Sarah E. MacKinnon
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Brenda Barry
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - David G. Hunter
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Elizabeth C. Engle
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
- Howard Hughes Medical Institute, Chevy Chase, Maryland
| | - Mary C. Whitman
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
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Abstract
Strabismus, or misalignment of the eyes, is the most common ocular disorder in the pediatric population, affecting approximately 2%-4% of children. Strabismus leads to the disruption of binocular vision, amblyopia, social and occupational discrimination, and decreased quality of life. Although it has been recognized since ancient times that strabismus runs in families, its inheritance patterns are complex, and its precise genetic mechanisms have not yet been defined. Family, population, and twin studies all support a role of genetics in the development of strabismus. There are multiple forms of strabismus, and it is not known if they have shared genetic mechanisms or are distinct genetic disorders, which complicates studies of strabismus. Studies assuming that strabismus is a Mendelian disorder have found areas of linkage and candidate genes in particular families, but no definitive causal genes. Genome-wide association studies searching for common variation that contributes to strabismus risk have identified two risk loci and three copy number variants in white populations. Causative genes have been identified in congenital cranial dysinnervation disorders, syndromes in which eye movement is limited or paralyzed. The causative genes lead to either improper differentiation of cranial motor neurons or abnormal axon guidance. This article reviews the evidence for a genetic contribution to strabismus and the recent advances that have been made in the genetics of comitant strabismus, the most common form of strabismus.
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Affiliation(s)
- Mayra Martinez Sanchez
- Department of Ophthalmology, Boston Children’s Hospital, Boston, MA, United States
- Department of Ophthalmology, Harvard Medical School, Boston, MA, United States
| | - Mary C. Whitman
- Department of Ophthalmology, Boston Children’s Hospital, Boston, MA, United States
- Department of Ophthalmology, Harvard Medical School, Boston, MA, United States
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA, United States
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Ma MML, Scheiman M. Divergence excess and basic exotropia types of intermittent exotropia: a major review. Part 1: prevalence, classification, risk factors, natural history and clinical characteristics. Strabismus 2023; 31:97-128. [PMID: 37489263 DOI: 10.1080/09273972.2023.2227681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
INTRODUCTION Intermittent exotropia (IXT) is a common form of strabismus. It is an outward deviation of one eye typically when viewing at distance. Symptoms include, but are not limited to double vision, eyes feeling tired, excessive blinking, and reduced quality of life. Its clinical characteristics are distinctive from other types of strabismus. This paper provides a comprehensive review of prevalence, classification, risk factors, natural history and clinical characteristics of the divergence excess and basic exotropia types of IXT. METHODS Search strategies involving combination of keywords including intermittent exotropia, exotropia, divergences excess, basic exotropia, prevalence, incidence, classification, terminology, risk factor, natural history, observation, angle of deviation, control, control score, symptom, quality of life, suppression, anomalous retinal correspondence, AC/A, accommodative convergence/accommodation, accommodative convergence, convergence, accommodation, vergence, incomitance and vertical were used in Medline. All English articles from 1900/01/01 to 2020/09/01 were reviewed. The reference list of the identified article was also checked for additional relevant article. Studies focused on animal model or strabismus associated with neurologic disorder or injury were excluded. RESULTS The estimated prevalence of IXT in children ranges from 0.1% to 3.7%. Hypoxia at birth and being female are potential risk factors of IXT. Using validated measures of control, multicenter prospective studies showed that the rate of conversion from IXT to constant exotropia is low. The angle of deviation is the most reported outcome measure in studies of IXT. It is often used to represent the severity of the condition and has been suggested as one of the four core outcomes for studies of the surgical management of IXT. Control of exodeviation is one of the four suggested core outcomes for study of surgery of IXT and is considered the main parameter of disease severity. Several validated tools for quality of life score are available to evaluate the subjective severity of IXT. DISCUSSION We reviewed the prevalence, classification, risk factors, natural history and clinical characteristics of the divergence excess and basic exotropia types of IXT. Further research into these areas, especially its clinical characteristics (e.g. suppression, dual retinal correspondence), will increase our understanding of this condition and potentially lead to better management of this common form of strabismus.
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Affiliation(s)
- Martin Ming-Leung Ma
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou
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Identification of Possible Risk Variants of Familial Strabismus Using Exome Sequencing Analysis. Genes (Basel) 2021; 12:genes12010075. [PMID: 33435129 PMCID: PMC7827096 DOI: 10.3390/genes12010075] [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: 11/09/2020] [Revised: 12/31/2020] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To investigate candidate genes associated with familial strabismus and propose a theory of their interaction in familial strabismus associated with early neurodevelopment. METHODS Eighteen families, including 53 patients diagnosed with strabismus and 34 unaffected family members, were analyzed. All patients with strabismus and available unaffected family members were evaluated using whole exome sequencing. The primary outcome was to identify rare occurring variants among affected individuals and investigate the evidence of their genetic heterogeneity. These results were compared with exome sequencing analysis to build a comprehensive genetic profile of the study families. RESULTS We observed 60 variants from 58 genes in 53 patients diagnosed with strabismus. We prioritized the most credible risk variants, which showed clear segregation in family members affected by strabismus. As a result, we found risk variants in four genes (FAT3, KCNH2, CELSR1, and TTYH1) in five families, suggesting their role in development of familial strabismus. In other families, there were several rare genetic variants in affected cases, but we did not find clear segregation pattern across family members. CONCLUSION Genomic sequencing holds great promise in elucidating the genetic causes of strabismus; further research with larger cohorts or other related approaches are warranted.
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Whitman MC, Di Gioia SA, Chan WM, Gelber A, Pratt BM, Bell JL, Collins TE, Knowles JA, Armoskus C, Pato M, Pato C, Shaaban S, Staffieri S, MacKinnon S, Maconachie GDE, Elder JE, Traboulsi EI, Gottlob I, Mackey DA, Hunter DG, Engle EC. Recurrent Rare Copy Number Variants Increase Risk for Esotropia. Invest Ophthalmol Vis Sci 2021; 61:22. [PMID: 32780866 PMCID: PMC7443120 DOI: 10.1167/iovs.61.10.22] [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] [Indexed: 11/24/2022] Open
Abstract
Purpose To determine whether rare copy number variants (CNVs) increase risk for comitant esotropia. Methods CNVs were identified in 1614 Caucasian individuals with comitant esotropia and 3922 Caucasian controls from Illumina SNP genotyping using two Hidden Markov model (HMM) algorithms, PennCNV and QuantiSNP, which call CNVs based on logR ratio and B allele frequency. Deletions and duplications greater than 10 kb were included. Common CNVs were excluded. Association testing was performed with 1 million permutations in PLINK. Significant CNVs were confirmed with digital droplet polymerase chain reaction (ddPCR). Whole genome sequencing was performed to determine insertion location and breakpoints. Results Esotropia patients have similar rates and proportions of CNVs compared with controls but greater total length and average size of both deletions and duplications. Three recurrent rare duplications significantly (P = 1 × 10−6) increase the risk of esotropia: chromosome 2p11.2 (hg19, 2:87428677-87965359), spanning one long noncoding RNA (lncRNA) and two microRNAs (OR 14.16; 95% confidence interval [CI] 5.4–38.1); chromosome 4p15.2 (hg19, 4:25554332-25577184), spanning one lncRNA (OR 11.1; 95% CI 4.6–25.2); chromosome 10q11.22 (hg19, 10:47049547-47703870) spanning seven protein-coding genes, one lncRNA, and four pseudogenes (OR 8.96; 95% CI 5.4–14.9). Overall, 114 cases (7%) and only 28 controls (0.7%) had one of the three rare duplications. No case nor control had more than one of these three duplications. Conclusions Rare CNVs are a source of genetic variation that contribute to the genetic risk for comitant esotropia, which is likely polygenic. Future research into the functional consequences of these recurrent duplications may shed light on the pathophysiology of esotropia.
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Affiliation(s)
- Mary C Whitman
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Silvio Alessandro Di Gioia
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Wai-Man Chan
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Alon Gelber
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Brandon M Pratt
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Jessica L Bell
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Thomas E Collins
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - James A Knowles
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, New York, United States
| | - Christopher Armoskus
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, New York, United States
| | - Michele Pato
- Institute for Genomic Health, SUNY Downstate Medical Center, Brooklyn, New York, United States
| | - Carlos Pato
- Institute for Genomic Health, SUNY Downstate Medical Center, Brooklyn, New York, United States
| | - Sherin Shaaban
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States.,Present address: Department of Pathology and ARUP Laboratories, University of Utah School of Medicine, Salt Lake City, Utah, United States
| | - Sandra Staffieri
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
| | - Sarah MacKinnon
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Gail D E Maconachie
- Department of Neuroscience, Psychology and Behavior, The University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester, United Kingdom
| | - James E Elder
- Department of Ophthalmology, Royal Children's Hospital, University of Melbourne, Parkville, Victoria, Australia.,Department of Pediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - Elias I Traboulsi
- Department of Pediatric Ophthalmology and Strabismus, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Irene Gottlob
- Department of Neuroscience, Psychology and Behavior, The University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester, United Kingdom
| | - David A Mackey
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, Australia.,Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia.,Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia
| | - David G Hunter
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Elizabeth C Engle
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States.,Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
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Lee YP, Choi DG. MMPs, TIMPs and BMP-4 in medial rectus muscle obtained from intermittent exotropia patients and their clinical correlations. Acta Ophthalmol 2020; 98:e107-e112. [PMID: 31421016 DOI: 10.1111/aos.14217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 07/23/2019] [Indexed: 11/26/2022]
Abstract
BACKGROUND To measure the amounts of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2 and bone morphogenetic protein (BMP)-4 in medial rectus muscle (MR) tissue obtained from intermittent exotropia (IXT) patients and to investigate the correlation between each protein amount and the clinical features of IXT including angles of deviation, age at surgery, duration of IXT and postoperative recurrence. METHODS The protein amounts were measured by enzyme-linked immunosorbent assay (ELISA) in MR collected during surgery for 78 IXT patients. RESULTS The mean amount of MMP-2 per mm of resected MR was 0.86 ng, of MMP-9, 2.72 ng, of TIMP-1, 1.99 ng, of TIMP-2, 0.92 ng and of BMP-4, 0.82 pg. MMP-2 showed a positive correlation with angle of deviation at distance and at near, age at surgery and duration of IXT (p = 0.000, p = 0.000, p = 0.000, p = 0.022, respectively, Spearman's rank correlation analysis). MMP-9 showed a positive correlation with angle of deviation at distance and at near (p = 0.001, p = 0.024) and BMP-4 showed a positive correlation with angle of deviation at distance (p = 0.012). TIMP-1 showed a negative correlation with angle of deviation at distance and at near (p = 0.003, p = 0.000). CONCLUSION In IXT patients, MMPs and BMP-4 tended to increase and TIMPs to decrease with increasing angle of deviation, greater age at surgery and longer duration of IXT.
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Affiliation(s)
- Yoon Pyo Lee
- Department of Ophthalmology Kangnam Sacred Heart Hospital Hallym University College of Medicine Seoul Korea
| | - Dong Gyu Choi
- Department of Ophthalmology Kangnam Sacred Heart Hospital Hallym University College of Medicine Seoul Korea
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Shaaban S, MacKinnon S, Andrews C, Staffieri SE, Maconachie GDE, Chan WM, Whitman MC, Morton SU, Yazar S, MacGregor S, Elder JE, Traboulsi EI, Gottlob I, Hewitt AW, Hunter DG, Mackey DA, Engle EC. Genome-Wide Association Study Identifies a Susceptibility Locus for Comitant Esotropia and Suggests a Parent-of-Origin Effect. Invest Ophthalmol Vis Sci 2018; 59:4054-4064. [PMID: 30098192 PMCID: PMC6088800 DOI: 10.1167/iovs.18-24082] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 06/19/2018] [Indexed: 11/24/2022] Open
Abstract
Purpose To identify genetic variants conferring susceptibility to esotropia. Esotropia is the most common form of comitant strabismus, has its highest incidence in European ancestry populations, and is believed to be inherited as a complex trait. Methods White European American discovery cohorts with nonaccommodative (826 cases and 2991 controls) or accommodative (224 cases and 749 controls) esotropia were investigated. White European Australian and United Kingdom cohorts with nonaccommodative (689 cases and 1448 controls) or accommodative (66 cases and 264 controls) esotropia were tested for replication. We performed a genome-wide case-control association study using a mixed linear additive model. Meta-analyses of discovery and replication cohorts were then conducted. Results A significant association with nonaccommodative esotropia was discovered (odds ratio [OR] = 1.41, P = 2.84 × 10-09) and replicated (OR = 1.23, P = 0.01) at rs2244352 [T] located within intron 1 of the WRB (tryptophan rich basic protein) gene on chromosome 21 (meta-analysis OR = 1.33, P = 9.58 × 10-11). This single nucleotide polymorphism (SNP) is differentially methylated, and there is a statistically significant skew toward paternal inheritance in the discovery cohort. Meta-analysis of the accommodative discovery and replication cohorts identified an association with rs912759 [T] (OR = 0.59, P = 1.89 × 10-08), an intergenic SNP on chromosome 1p31.1. Conclusions This is the first genome-wide association study (GWAS) to identify significant associations in esotropia and suggests a parent-of-origin effect. Additional cohorts will permit replication and extension of these findings. Future studies of rs2244352 and WRB should provide insight into pathophysiological mechanisms underlying comitant strabismus.
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Affiliation(s)
- Sherin Shaaban
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States
- Dubai Harvard Foundation for Medical Research, Boston, Massachusetts, United States
| | - Sarah MacKinnon
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Caroline Andrews
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
| | - Sandra E. Staffieri
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Department of Ophthalmology, Royal Children's Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Gail D. E. Maconachie
- Department of Neuroscience, The University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester, United Kingdom
| | - Wai-Man Chan
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
| | - Mary C. Whitman
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Sarah U. Morton
- Division of Newborn Medicine, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Seyhan Yazar
- Medical Research Council (MRC) Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, The University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
| | - Stuart MacGregor
- Stastical Genetics Laboratory, Queensland Institute of Medical Research (QIMR) Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - James E. Elder
- Department of Ophthalmology, Royal Children's Hospital, University of Melbourne, Parkville, Victoria, Australia
- Department of Pediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - Elias I. Traboulsi
- Department of Ophthalmology, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Irene Gottlob
- Department of Neuroscience, The University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester, United Kingdom
| | - Alex W. Hewitt
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
- Department of Ophthalmology, School of Medicine, Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | - Strabismus Genetics Research Consortium
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States
- Dubai Harvard Foundation for Medical Research, Boston, Massachusetts, United States
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Department of Ophthalmology, Royal Children's Hospital, University of Melbourne, Parkville, Victoria, Australia
- Department of Neuroscience, The University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester, United Kingdom
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
- Division of Newborn Medicine, Boston Children's Hospital, Boston, Massachusetts, United States
- Medical Research Council (MRC) Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, The University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
- Stastical Genetics Laboratory, Queensland Institute of Medical Research (QIMR) Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Department of Pediatrics, The University of Melbourne, Parkville, Victoria, Australia
- Department of Ophthalmology, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
- Department of Ophthalmology, School of Medicine, Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
- Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, Massachusetts, United States
| | - David G. Hunter
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - David A. Mackey
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
- Department of Ophthalmology, School of Medicine, Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | - Elizabeth C. Engle
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
- Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, Massachusetts, United States
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Mocanu V, Horhat R. Prevalence and Risk Factors of Amblyopia among Refractive Errors in an Eastern European Population. ACTA ACUST UNITED AC 2018; 54:medicina54010006. [PMID: 30344237 PMCID: PMC6037249 DOI: 10.3390/medicina54010006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 03/09/2018] [Accepted: 03/17/2018] [Indexed: 12/18/2022]
Abstract
Background and objective: Amblyopia is the leading cause of visual impairment in children and adults and is very common during childhood. The aim of this study was to identify the prevalence and the risk factors of amblyopia in a pediatric population with refractive errors from an Eastern European country. Materials and methods: A total of 1231 children aged 5–16 years, who had refractive errors and were examined from January to August 2017, were enrolled in a cross-sectional population-based study. Every child underwent a complete ophthalmological exam. Amblyopia was defined as a visual acuity (VA) of less than 0.63. The study respected the Multi-Ethnic Pediatric Eye Disease Study (MEPEDS) criteria for defining amblyopia (MEPEDS, 2008). Parents participated in a face-to-face interview. The questionnaire contained details about their family history of amblyopia; the child’s maternal nutritional status in the preconception period; their history of maternal smoking or work in a toxic environment; the child’s birth, and the child’s history of congenital naso-lacrimal duct obstruction (CNLDO). Results: Amblyopia was identified in 2.8% of the participants. The ocular conditions hyperopia (p = 0.0079), astigmatism (p = 0.046), anisometropia (p < 0.001), esotropia (p < 0.001), exotropia (p = 0.0195), and CNLDO (p < 0.001), as well as a family history of amblyopia (p < 0.001), were associated with amblyopia. The non-ocular risk factors for amblyopia that were found in the study included low birth weight (p < 0.0009), prematurity (p < 0.001), an Apgar score under 7 (p = 0.0008), maternal age, maternal smoking history or work in toxic environment (p < 0.001), and maternal body mass index in the preconception period (p < 0.003). Conclusions: Some of the risk factors we identified for amblyopia are modifiable factors. This is an important observation as an adequate health education program can provide the relevant information for future mothers that will allow for a better management of the condition. We also wanted to highlight the need for amblyopia screening starting from the age of 3 years in case of significant parental refractive errors, strabismus, prematurity, and maternal risk factors.
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Affiliation(s)
- Valeria Mocanu
- Department of Ophthalmology, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania.
- Clinic of Paediatric Surgery, Emergency Children's Hospital Louis Turcanu, 300011 Timisoara, Romania.
| | - Raluca Horhat
- Clinic of Paediatric Surgery, Emergency Children's Hospital Louis Turcanu, 300011 Timisoara, Romania.
- Department of Biophysics, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania.
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Han KE, Baek SH, Kim SH, Lim KH. Prevalence and risk factors of strabismus in children and adolescents in South Korea: Korea National Health and Nutrition Examination Survey, 2008-2011. PLoS One 2018; 13:e0191857. [PMID: 29444106 PMCID: PMC5812601 DOI: 10.1371/journal.pone.0191857] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 01/05/2018] [Indexed: 11/21/2022] Open
Abstract
Purpose To evaluate the prevalence and risk factors associated with horizontal strabismus in children and adolescents in South Korea. Methods A total of 5,935 children and adolescents 5–18 years of age who participated in the fourth and fifth Korean National Health and Nutrition Examination Survey (KNHANES IV-V) from July 2008 to December 2011 were evaluated and the prevalence of horizontal strabismus was estimated. Univariate and multivariate logistic regression analyses were conducted to determine the association between demographic, socioeconomic and clinical risk factors and clinically significant exodeviation (≥15 prism diopters [PD]) and esodeviation (≥10 PD). Results Among 5,935 eligible subjects, 84 subjects had clinically significant exodeviation and 13 had clinically significant esodeviation. The overall prevalence of clinically significant horizontal strabismus was 1.6% (95% confidence interval [CI], 1.2–2.1): 1.3% (95% CI, 1.0–1.7) for clinically significant exodeviation and 0.3% (95% CI, 0.1–0.6) for clinically significant esodeviation. Clinically significant exodeviation was associated with amblyopia (adjusted odds ratio [aOR], 6.45; 95% CI, 2.14–19.44), family history of strabismus (aOR, 4.91; 95% CI, 1.71–14.08) and astigmatism ≥1.0 D (aOR, 1.84; 95% CI, 1.13–2.98). Clinically significant esodeviation was associated with hyperopia (aOR, 12.16; 95% CI, 1.31–113.04) and amblyopia (aOR, 4.70; 95% CI, 1.12–19.81). Other demographic, socioeconomic, and clinical variables were not associated with strabismus. Conclusion This study provides data on the prevalence and independent risk factors for clinically significant exodeviation and esodeviation in a representative population of children and adolescents in South Korea.
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Affiliation(s)
- Kyung Eun Han
- Department of Ophthalmology, Ewha Womans University College of Medicine, Mok-dong Hospital, Seoul, South Korea
| | - Seung-Hee Baek
- Department of Ophthalmology, Kim's Eye Hospital, Konyang University College of Medicine, Seoul, South Korea
| | - Seung-Hyun Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Key Hwan Lim
- Department of Ophthalmology, Ewha Womans University College of Medicine, Mok-dong Hospital, Seoul, South Korea
- * E-mail:
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Wallace DK, Christiansen SP, Sprunger DT, Melia M, Lee KA, Morse CL, Repka MX. Esotropia and Exotropia Preferred Practice Pattern®. Ophthalmology 2017; 125:P143-P183. [PMID: 29108746 DOI: 10.1016/j.ophtha.2017.10.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 10/03/2017] [Indexed: 11/27/2022] Open
Affiliation(s)
- David K Wallace
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Stephen P Christiansen
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts
| | - Derek T Sprunger
- Indiana University Health Physicians, Midwest Eye Institute, Indianapolis, Indiana
| | | | - Katherine A Lee
- Pediatric Ophthalmology, St. Luke's Health System, Boise, Idaho
| | | | - Michael X Repka
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland
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Zhang J, Matsuo T. MGST2 and WNT2 are candidate genes for comitant strabismus susceptibility in Japanese patients. PeerJ 2017; 5:e3935. [PMID: 29062608 PMCID: PMC5649647 DOI: 10.7717/peerj.3935] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/26/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND/AIM Strabismus is a common condition with misalignment between two eyes that may lead to decrease of visual acuity, lack of binocularity, and diplopia. It is caused by heterogeneous environmental and genetic risk factors. Our previous research has identified new chromosomal susceptibility loci in 4q28.3 and 7q31.2 regions for comitant strabismus in Japanese families. We conducted a verification study by linkage analysis to narrow the chromosomal loci down to a single gene. METHODS From Japanese and U.S. databases, 24 rsSNPs and 233 rsSNPs were chosen from the 4q28.3 and 7q31.2 region, respectively, and were typed in 108 affected subjects and 96 unaffected subjects of 58 families with primary and non-syndromic comitant strabismus. Three major analytical methods were used: transmission disequilibrium test (TDT), TDT allowing for errors (TDTae), and linkage analysis under dominant and recessive inheritance. RESULTS The SNPs with significant P values in TDT and TDTae were located solely at the gene, microsomal glutathione S-transferase 2 (MGST2), on chromosome 4q28.3 locus. In contrast, significant SNPs were dispersed in a few genes, containing wingless-type MMTV integration site family member 2 (WNT2), on chromosome 7q31.2 locus. The distribution of significant SNPs on the 7q31.2 locus showed that only the ST7 to WNT2 region in the same big haplotype block contained significant SNPs for all three methods of linkage analysis. CONCLUSIONS This study suggests that MGST2 and WNT2 are potential candidates for comitant strabismus in Japanese population.
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Affiliation(s)
- Jingjing Zhang
- Department of Ophthalmology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama City, Okayama, Japan
| | - Toshihiko Matsuo
- Department of Ophthalmology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama City, Okayama, Japan
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Chaudhuri Z, John J, Aneja S, Thelma BK. Pedigree Analysis of Familial Primary Concomitant Horizontal Strabismus in Northern India. Strabismus 2017; 25:200-213. [PMID: 28796570 DOI: 10.1080/09273972.2017.1350865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE Familial clustering of common forms of primary strabismus like esotropia (ET) and exotropia (XT) is observed in a proportion of the strabismus cohort. The genetic components of this remain unidentified. Linkage studies have demonstrated susceptibility locus for primary strabismus at the STBMS1 locus on 7p22.1 as well as other loci on 4q28.3 and 7q31.2. Recently next generation sequencing (NGS) technology has emerged as a powerful tool in discovery genomics and a large number of novel disease-causing variants are being reported. In this study, we recruited informative families for subsequent genetic analysis for disease-causing variant identification. METHODS All consecutive families with two or more affected members with primary concomitant horizontal strabismus were prospectively recruited at the ophthalmic outpatients department (OPD) of Lady Hardinge Medical College, New Delhi, from August 2014 to February 2017. Detailed phenotypic evaluation and pedigree documentation was performed. RESULTS Of the 39 recruited families of north Indian origin, 18 families each had affected family members demonstrating either ET or XT. 100% concordance of the phenotype in the affected family members was observed in these families. While vertical transmission was observed in 17/18 families with XT, 7 with ET had affected members across one generation, 2 demonstrated consanguineous pedigree, and 2 comprised identical twin families. In 3 families, a combination of ET and XT was noted. This comprised one family with the ET and XT patients being from 2 separate arms of the family related by marriage, one family where one sibling had XT and the other had ET, and another family where the maternal aunt of the affected proband with ET had XT. CONCLUSIONS Subjects with familial primary concomitant strabismus recruited in this study may provide a valuable resource to unravel the genetic determinants of this condition, which is a common disorder of early childhood with high ophthalmic morbidity.
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Affiliation(s)
- Zia Chaudhuri
- a Lady Hardinge Medical College , University of Delhi , New Delhi , India.,b Department of Genetics , University of Delhi South Campus , New Delhi, India
| | - Jibin John
- b Department of Genetics , University of Delhi South Campus , New Delhi, India
| | - Satinder Aneja
- a Lady Hardinge Medical College , University of Delhi , New Delhi , India
| | - B K Thelma
- b Department of Genetics , University of Delhi South Campus , New Delhi, India
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Agarwal AB, Feng CY, Altick AL, Quilici DR, Wen D, Johnson LA, von Bartheld CS. Altered Protein Composition and Gene Expression in Strabismic Human Extraocular Muscles and Tendons. Invest Ophthalmol Vis Sci 2017; 57:5576-5585. [PMID: 27768799 PMCID: PMC5080916 DOI: 10.1167/iovs.16-20294] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose To determine whether structural protein composition and expression of key regulatory genes are altered in strabismic human extraocular muscles. Methods Samples from strabismic horizontal extraocular muscles were obtained during strabismus surgery and compared with normal muscles from organ donors. We used proteomics, standard and customized PCR arrays, and microarrays to identify changes in major structural proteins and changes in gene expression. We focused on muscle and connective tissue and its control by enzymes, growth factors, and cytokines. Results Strabismic muscles showed downregulation of myosins, tropomyosins, troponins, and titin. Expression of collagens and regulators of collagen synthesis and degradation, the collagenase matrix metalloproteinase (MMP)2 and its inhibitors, tissue inhibitor of metalloproteinase (TIMP)1 and TIMP2, was upregulated, along with tumor necrosis factor (TNF), TNF receptors, and connective tissue growth factor (CTGF), as well as proteoglycans. Growth factors controlling extracellular matrix (ECM) were also upregulated. Among 410 signaling genes examined by PCR arrays, molecules with downregulation in the strabismic phenotype included GDNF, NRG1, and PAX7; CTGF, CXCR4, NPY1R, TNF, NTRK1, and NTRK2 were upregulated. Signaling molecules known to control extraocular muscle plasticity were predominantly expressed in the tendon rather than the muscle component. The two horizontal muscles, medial and lateral rectus, displayed similar changes in protein and gene expression, and no obvious effect of age. Conclusions Quantification of proteins and gene expression showed significant differences in the composition of extraocular muscles of strabismic patients with respect to important motor proteins, elements of the ECM, and connective tissue. Therefore, our study supports the emerging view that the molecular composition of strabismic muscles is substantially altered.
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Affiliation(s)
- Andrea B Agarwal
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States
| | - Cheng-Yuan Feng
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States
| | - Amy L Altick
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States
| | - David R Quilici
- Mick Hitchcock Nevada Proteomics Center, University of Nevada, Reno, Nevada, United States
| | - Dan Wen
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
| | - L Alan Johnson
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States 4Sierra Eye Associates, Reno, Nevada, United States
| | - Christopher S von Bartheld
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States
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Ye XC, Pegado V, Patel MS, Wasserman WW. Strabismus genetics across a spectrum of eye misalignment disorders. Clin Genet 2014; 86:103-11. [PMID: 24579652 PMCID: PMC4233980 DOI: 10.1111/cge.12367] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/20/2014] [Accepted: 02/24/2014] [Indexed: 01/24/2023]
Abstract
Eye misalignment, called strabismus, is amongst the most common phenotypes observed, occurring in up to 5% of individuals in a studied population. While misalignment is frequently observed in rare complex syndromes, the majority of strabismus cases are non-syndromic. Over the past decade, genes and pathways associated with syndromic forms of strabismus have emerged, but the genes contributing to non-syndromic strabismus remain elusive. Genetic testing for strabismus risk may allow for earlier diagnosis and treatment, as well as decreased frequency of surgery. We review human and model organism literature describing non-syndromic strabismus, including family, twin, linkage, and gene expression studies. Recent advances in the genetics of Duane retraction syndrome are considered, as relatives of those impacted show elevated familial rates of non-syndromic strabismus. As whole genome sequencing efforts are advancing for the discovery of the elusive strabismus genes, this overview is intended to support the interpretation of the new findings.
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Affiliation(s)
- X C Ye
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, Vancouver, BC, Canada
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Chia A, Lin X, Dirani M, Gazzard G, Ramamurthy D, Quah BL, Chang B, Ling Y, Leo SW, Wong TY, Saw SM. Risk factors for strabismus and amblyopia in young Singapore Chinese children. Ophthalmic Epidemiol 2013; 20:138-47. [PMID: 23713916 DOI: 10.3109/09286586.2013.767354] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PURPOSE To determine the risk factors for strabismus and amblyopia in young Singapore Chinese children. METHODS A total of 3009 children were recruited for the population-based cross-sectional Strabismus, Amblyopia and Refractive Error in Singaporean Preschoolers Study (STARS). Strabismus was defined as any tropia identified on cover test. Visual acuity was measured in children aged 30-72 months with a logMAR chart where possible and the Sheridan-Gardiner test if not. Amblyopia was defined based on visual acuity and refractive error or presence of strabismus or past/present visual axis obstruction. Parents completed questionnaires on family, prenatal and birth histories. RESULTS Our study showed that 24 children aged 6-72 months (1.2%) had strabismus (20 with exotropia), and 20 children aged 30-72 months (0.8%) were amblyopic. After multivariate analysis, strabismus was associated with astigmatism ≥1.00 diopter (D; p = 0.03), amblyopia (p = 0.003), a sibling with strabismus (p < 0.001), and families with lower parental education (p = 0.04). In addition to strabismus, amblyopia was associated with anisometropia ≥1.00 D (p < 0.001) and astigmatism ≥1.00 D (p < 0.001). No association was noted between either strabismus or amblyopia and prematurity, maternal age or smoking. CONCLUSION This study highlights the importance of family history in strabismus, and the close associations between refractive error and strabismus with amblyopia. These factors play a more important role in young Singapore Chinese children.
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Affiliation(s)
- Audrey Chia
- Singapore National Eye Center, Singapore 168751.
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Abstract
Horizontal strabismus has constant risk factors of ethnicity, family history, genetic conditions and potentially modifiable risk factors of maternal smoking, prematurity, low birth weight, refractive errors and neurodisability.
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Heritability of strabismus: genetic influence is specific to eso-deviation and independent of refractive error. Twin Res Hum Genet 2012; 15:624-30. [PMID: 22877876 DOI: 10.1017/thg.2012.22] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Strabismus represents a complex oculomotor disorder characterized by the deviation of one or both eyes and poor vision. A more sophisticated understanding of the genetic liability of strabismus is required to guide searches for associated molecular variants. In this classical twin study of 1,462 twin pairs, we examined the relative influence of genes and environment in comitant strabismus, and the degree to which these influences can be explained by factors in common with refractive error. Participants were examined for the presence of latent ('phoria') and manifest ('tropia') strabismus using cover-uncover and alternate cover tests. Two phenotypes were distinguished: eso-deviation (esophoria and esotropia) and exo-deviation (exophoria and exotropia). Structural equation modeling was subsequently employed to partition the observed phenotypic variation in the twin data into specific variance components. The prevalence of eso-deviation and exo-deviation was 8.6% and 20.7%, respectively. For eso-deviation, the polychoric correlation was significantly greater in monozygotic (MZ) (r = 0.65) compared to dizygotic (DZ) twin pairs (r = 0.33), suggesting a genetic role (p = .003). There was no significant difference in polychoric correlation between MZ (r = 0.55) and DZ twin pairs (r = 0.53) for exo-deviation (p = .86), implying that genetic factors do not play a significant role in the etiology of exo-deviation. The heritability of an eso-deviation was 0.64 (95% CI 0.50-0.75). The additive genetic correlation for eso-deviation and refractive error was 0.13 and the bivariate heritability (i.e., shared variance) was less than 1%, suggesting negligible shared genetic effect. This study documents a substantial heritability of 64% for eso-deviation, yet no corresponding heritability for exo-deviation, suggesting that the genetic contribution to strabismus may be specific to eso-deviation. Future studies are now needed to identify the genes associated with eso-deviation and unravel their mechanisms of action.
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Cotter SA, Varma R, Tarczy-Hornoch K, McKean-Cowdin R, Lin J, Wen G, Wei J, Borchert M, Azen SP, Torres M, Tielsch JM, Friedman DS, Repka MX, Katz J, Ibironke J, Giordano L. Risk factors associated with childhood strabismus: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies. Ophthalmology 2011; 118:2251-61. [PMID: 21856012 DOI: 10.1016/j.ophtha.2011.06.032] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 06/23/2011] [Accepted: 06/23/2011] [Indexed: 10/17/2022] Open
Abstract
OBJECTIVE To investigate risk factors associated with esotropia or exotropia in infants and young children. DESIGN Population-based cross-sectional prevalence study. PARTICIPANTS Population-based samples of 9970 children 6 to 72 months of age from California and Maryland. METHODS Participants were preschool African-American, Hispanic, and non-Hispanic white children participating in the Multi-Ethnic Pediatric Eye Disease Study and the Baltimore Eye Disease Study. Data were obtained by parental interview and ocular examination. Odd ratios and 95% confidence intervals were calculated to evaluate the association of demographic, behavioral, and clinical risk factors with esotropia and exotropia. MAIN OUTCOME MEASURES Odds ratios (ORs) for various risk factors associated with esotropia or exotropia diagnosis based on cover testing. RESULTS In multivariate logistic regression analysis, esotropia was associated independently with prematurity, maternal smoking during pregnancy, older preschool age (48-72 months), anisometropia, and hyperopia. There was a severity-dependent association of hyperopia with the prevalence of esotropia, with ORs increasing from 6.4 for 2.00 diopters (D) to less than 3.00 D of hyperopia, to 122.0 for 5.00 D or more of hyperopia. Exotropia was associated with prematurity, maternal smoking during pregnancy, family history of strabismus, female sex, astigmatism (OR, 2.5 for 1.50 to <2.50 D of astigmatism, and 5.9 for ≥2.5 D of astigmatism), and anisoastigmatism in the J0 component (OR, ≥2 for J0 anisoastigmatism of ≥0.25 D). CONCLUSIONS Prematurity and maternal smoking during pregnancy are associated with a higher risk of having esotropia and exotropia. Refractive error is associated in a severity-dependent manner to the prevalence of esotropia and exotropia. Because refractive error is correctable, these risk associations should be considered when developing guidelines for the screening and management of refractive error in infants and young children. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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Affiliation(s)
- Susan A Cotter
- Doheny Eye Institute and the Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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Wilmer JB, Backus BT. Genetic and environmental contributions to strabismus and phoria: evidence from twins. Vision Res 2009; 49:2485-93. [PMID: 19679148 PMCID: PMC2757458 DOI: 10.1016/j.visres.2009.08.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 08/04/2009] [Accepted: 08/04/2009] [Indexed: 01/15/2023]
Abstract
The causes of manifest (strabismus) and latent (phoria) misalignment of the visual axes are incompletely understood. We calculated genetic and environmental contributions to strabismus based upon a critical review and quantitative meta-analysis of previous strabismus twin studies (n=3418 twin pairs) and calculated contributions to phoria based upon a new twin study (n=307 twin pairs). Our results suggest that genetic liability is necessary to develop strabismus, whereas environmental factors are sufficient to cause most phorias. The different etiologies implied by this work suggest that strabismus and phoria should be carefully distinguished in epidemiological work.
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Preisser JS, Lu B, Qaqish BF. Finite sample adjustments in estimating equations and covariance estimators for intracluster correlations. Stat Med 2009; 27:5764-85. [PMID: 18680122 DOI: 10.1002/sim.3390] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Bias-corrected covariance estimators are introduced in the context of an estimating equations approach for intracluster correlations among binary outcomes. Simulation study results show that the bias-corrected covariance estimators perform better than uncorrected sandwich estimators in terms of bias and coverage probabilities. Additionally, introduction of a matrix-based bias-correction into the estimating equations considerably improves point and interval estimation for the intracluster correlations. The methods are illustrated using data from a nested cross-sectional cluster trial on reducing underage drinking.
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Affiliation(s)
- John S Preisser
- Department of Biostatistics, CB # 7420, School of Public Health, University of North Carolina, Chapel Hill, NC 27599, U.S.A.
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Major A, Maples WC, Toomey S, DeRosier W, Gahn D. Variables associated with the incidence of infantile esotropia. ACTA ACUST UNITED AC 2007; 78:534-41. [PMID: 17904494 DOI: 10.1016/j.optm.2006.11.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 10/31/2006] [Accepted: 11/09/2006] [Indexed: 11/30/2022]
Abstract
PURPOSE Infantile esotropia (manifesting from birth to 6 months) is a common type of strabismus, accounting for 28% to 54% of all esotropias and with an incidence of 1% of the general population. The purpose of this cohort study was to evaluate risk factors for infantile esotropia. Such information may aid in early intervention to prevent manifestation of infantile esotropia. METHODS A retrospective chart review of 5,347 records (October 1, 1993, to September 30, 2003) of birth mothers and infants at the W.W. Hastings Indian Health Science Hospital in Tahlequah, Oklahoma, was performed to identify children with varying degrees of Native American blood who had infantile esotropia. A nonstrabismic birth cohort control group was also identified. Twenty-three medical records indicating a diagnosis of infantile esotropia that were complete enough to be used in analysis were identified. Normal infants were compared with infants with esotropia. RESULTS Infantile esotropia in this preliminary study was associated with 24 factors including prematurity, family ocular history, cardiovascular disease, systemic disease, pregnancy-associated hypertension and low birth weight (<2,500 g) among others. CONCLUSIONS Prematurity, family history or secondary ocular history, perinatal or gestational complications, systemic disorders, use of supplemental oxygen as a neonate, use of systemic medications, and male sex were found to be significant risk factors for infantile esotropia. Our results provide additional evidence that might help facilitate early detection and intervention in cases in which these risk factors are identified.
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Affiliation(s)
- Archima Major
- Northeastern State University-Oklahoma College of Optometry, Tahlequah, Oklahoma, USA
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Abstract
The field of molecular genetics is evolving to encompass techniques that are directly relevant to the diagnosis and management of eye disease. Therefore, pediatric ophthalmologists must have a knowledge base that includes basic genetic concepts and their application to current clinical care.
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Affiliation(s)
- Kathryn Bollinger
- Department of Pediatric Ophthalmology and Strabismus, Cole Eye Institute, Cleveland, Ohio 44195, USA
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Robaei D, Rose KA, Kifley A, Cosstick M, Ip JM, Mitchell P. Factors Associated with Childhood Strabismus. Ophthalmology 2006; 113:1146-53. [PMID: 16675019 DOI: 10.1016/j.ophtha.2006.02.019] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 02/11/2006] [Accepted: 02/13/2006] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To describe strabismus prevalence and associated factors in a representative sample of 6-year-old Australian children. DESIGN Population-based cross-sectional study. PARTICIPANTS One thousand seven hundred thirty-nine predominantly 6-year-old children resident in Sydney examined in 2003 and 2004. METHODS Cover testing was performed at near and distance fixation, and with spectacles if worn. Logarithm of the minimum angle of resolution visual acuity was measured in both eyes before and after pinhole correction, after correcting any cylindrical refraction >0.50 diopters and with spectacles, if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. Each child's medical and perinatal histories were sought in a detailed parental questionnaire. MAIN OUTCOME MEASURES Strabismus was defined as any heterotropia at near or distance fixation, or both, on cover testing. Microstrabismus was defined as a deviation of fewer than 10 prism diopters. RESULTS Strabismus was diagnosed in 48 children (2.8% of the population), 5 of whom had previously undergone surgical correction; 26 children (54%) had esotropia, 14 (29%) had exotropia, 7 (15%) had microstrabismus, and 1 child had VIth cranial nerve palsy. Prematurity was associated with a 5-fold increase in the risk of esotropia (odds ratio, 5.0; 95% confidence interval, 1.8-14.1). Visual impairment (with presenting correction) was significantly more common in children with (22.9%) than without (1.3%) strabismus (P<0.0001). The presence of strabismus was significantly associated with hyperopia, astigmatism, anisometropia, and amblyopia (P<0.0001). CONCLUSIONS This report documents the prevalence of strabismus and its relation to other ocular signs and visual impairment in a representative sample of Australian school children. Presence of strabismus was significantly associated with prematurity.
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Affiliation(s)
- Dana Robaei
- Department of Ophthalmology, Centre for Vision Research, Westmead Hospital, and Westmead Millennium Institute, Sydney, Australia
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Abstract
The relationship between cigarette smoking by young women and amblyopia in children was investigated in 13 population groups. Two searches were conducted on Medline using the following keywords for the first search: amblyopia, prevalence or incidence, and the names of specific countries. The keywords for the second search were smoking, cigarettes, women and the names of the same specific countries. Relevant articles were reviewed. A positive relationship between the rate of smoking among women and the prevalence of amblyopia in school-aged children and military recruits was found. The Pearson correlation coefficient was 0.73. The occurrence of decreased visual acuity attributed to amblyopia in disparate population groups is directly related to rates of cigarette smoking by young women.
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Abstract
Strabismus (misalignment of the eyes; also known as "squint") comprises a common heterogeneous group of disorders characterised by a constant or intermittent ocular deviation often associated with amblyopia (uniocular failure of normal visual development) and reduced or absent binocular vision. The associated poor cosmetic appearance may also interfere with social and psychological development. Extensive twin and family studies suggest a significant genetic component to the aetiology of strabismus. The complexity of the molecular basis of strabismus is now beginning to be elucidated with the identification of genetic loci and disease causing genes. Currently greater insights have been gained into the incomitant subtype (differing magnitude of ocular misalignment according to direction of gaze), whereas less is known about the pathogenesis of the more common childhood concomitant strabismus. It is hoped that a greater understanding of the molecular genetics of these disorders will lead to improved knowledge of disease mechanisms and ultimately to more effective treatment. The aim of this paper is to review current knowledge of the molecular genetics of both incomitant and concomitant strabismus.
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Affiliation(s)
- M Michaelides
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
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Abstract
Amblyopia has a 1.6-3.6% prevalence, higher in the medically underserved. It is more complex than simply visual acuity loss and the better eye has sub-clinical deficits. Functional limitations appear more extensive and loss of vision in the better eye of amblyopes more prevalent than previously thought. Amblyopia screening and treatment are efficacious, but cost-effectiveness concerns remain. Refractive correction alone may successfully treat anisometropic amblyopia and it, minimal occlusion, and/or catecholamine treatment can provide initial vision improvement that may improve compliance with subsequent long-duration treatment. Atropine penalization appears as effective as occlusion for moderate amblyopia, with limited-day penalization as effective as full-time. Cytidin-5'-diphosphocholine may hold promise as a medical treatment. Interpretation of much of the amblyopia literature is made difficult by: inaccurate visual acuity measurement at initial visit, lack of adequate refractive correction prior to and during treatment, and lack of long-term follow-up results. Successful treatment can be achieved in at most 63-83% of patients. Treatment outcome is a function of initial visual acuity and type of amblyopia, and a reciprocal product of treatment efficacy, duration, and compliance. Age at treatment onset is not predictive of outcome in many studies but detection under versus over 2-3 years of age may be. Multiple screenings prior to that age, and prompt treatment, reduce prevalence. Would a single early cycloplegic photoscreening be as, or more, successful at detection or prediction than the multiple screenings, and more cost-effective? Penalization and occlusion have minimal incidence of reverse amblyopia and/or side-effects, no significant influence on emmetropization, and no consistent effect on sign or size of post-treatment changes in strabismic deviation. There may be a physiologic basis for better age-indifferent outcome than tapped by current treatment methodologies. Infant refractive correction substantially reduces accommodative esotropia and amblyopia incidence without interference with emmetropization. Compensatory prism, alone or post-operatively, and/or minus lens treatment, and/or wide-field fusional amplitude training, may reduce risk of early onset esotropia. Multivariate screening using continuous-scale measurements may be more effective than traditional single-test dichotomous pass/fail measures. Pigmentation may be one parameter because Caucasians are at higher risk for esotropia than non-whites.
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Affiliation(s)
- Kurt Simons
- Pediatric Vision Laboratory, Krieger Children's Eye Center, Wilmer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9028, USA
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Parikh V, Shugart YY, Doheny KF, Zhang J, Li L, Williams J, Hayden D, Craig B, Capo H, Chamblee D, Chen C, Collins M, Dankner S, Fiergang D, Guyton D, Hunter D, Hutcheon M, Keys M, Morrison N, Munoz M, Parks M, Plotsky D, Protzko E, Repka MX, Sarubbi M, Schnall B, Siatkowski RM, Traboulsi E, Waeltermann J, Nathans J. A strabismus susceptibility locus on chromosome 7p. Proc Natl Acad Sci U S A 2003; 100:12283-8. [PMID: 14519848 PMCID: PMC218750 DOI: 10.1073/pnas.2035118100] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Strabismus has been known to have a significant genetic component, but the mode of inheritance and the identity of the relevant genes have been enigmatic. This paper reports linkage analysis of nonsyndromic strabismus. The principal results of this study are: (i) the demonstrated feasibility of identifying and recruiting large families in which multiple members have (or had) strabismus; (ii) the linkage in one large family of a presumptive strabismus susceptibility locus to 7p22.1 with a multipoint logarithm of odds score of 4.51 under a model of recessive inheritance; and (iii) the failure to observe significant linkage to 7p in six other multiplex families, consistent with genetic heterogeneity among families. These findings suggest that it will be possible to localize and ultimately identify strabismus susceptibility genes by linkage analysis and mutation screening of candidate genes.
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Affiliation(s)
- Vaishali Parikh
- Departments of Molecular Biology and Genetics, Neuroscience, and Ophthalmology, and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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The clinical spectrum of early-onset esotropia: experience of the Congenital Esotropia Observational Study. Am J Ophthalmol 2002; 133:102-8. [PMID: 11755845 DOI: 10.1016/s0002-9394(01)01317-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To describe historical and presenting features of infants with the onset of esotropia in early infancy to provide a better understanding of the clinical spectrum of the disorder. DESIGN Prospective multicenter cohort study. METHODS Eligibility criteria included age at enrollment 4 to < 20 weeks and an esotropia at near measuring at least 20 prism diopters (pd). Historical information was elicited from the parent or guardian. The esotropia was measured at near and characterized as constant, variable, or intermittent. RESULTS 175 infants were enrolled. Their average age at enrollment was 97 +/- 26 days. The esotropia was characterized as constant in 56% of the patients, variable in 25%, and intermittent in 19%. Forty-nine percent of the deviations were > or = 40 pd. Most of the larger angle deviations were constant whereas the majority of the smaller angle deviations were intermittent or variable. The majority of patients first seen after 12 weeks of age had constant deviations (65%), whereas the majority seen before 12 weeks of age had intermittent or variable deviations (57%). At enrollment, amblyopia was diagnosed in 19% of patients. CONCLUSION The clinical presentation of esotropia in early infancy shows more variation in the esotropia's size and character than has been previously appreciated. Only a minority of the infants who are diagnosed to have esotropia before 20 weeks of age have the commonly accepted profile for congenital esotropia of a large-angle constant deviation. Amblyopia frequently develops, so an evaluation for amblyopia should be an integral part of the examination of an infant with esotropia.
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Seeley MZ, Paul TO, Crowe S, Dahms G, Lichterman S, Traboulsi EI. Comparison of clinical characteristics of familial and sporadic acquired accommodative esotropia. J AAPOS 2001; 5:18-20. [PMID: 11182667 DOI: 10.1067/mpa.2001.111784] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE To compare the clinical characteristics of patients with familial and nonfamilial acquired accommodative esotropia. METHODS We recruited 48 patients from 33 families with acquired accommodative esotropia (an inward deviation of the eyes of 10 PD or more, a hypermetropia greater than or equal to +1.50 D, and an onset of esotropia at, or later than, 1 year of age). Our control group consisted of 20 patients with no known family history. Spherical error of refraction, stereoacuity, and need for strabismus surgery were determined and the 2 groups were compared. RESULTS No statistically significant difference was found between the spherical equivalent error of refraction in familial cases (mean = +4.50 OD, +4.63 OS; range = +1.50 to +10.30 OD, +2.00 to +9.38 OS) versus those with nonfamilial disease (mean = +4.93 OD, +5.02 OS; range = +2.50 to +11.00 OD, +2.50 to +10.90 OS) (P =.47 OD; P =.47 OS). There also was no difference between the percentage of patients with familial disease who had some degree of stereoacuity (58%) and those without a family history (59%) (P > .99). Patients with familial acquired accommodative esotropia did not require more surgical interventions (26%) than those with nonfamilial acquired accommodative esotropia (30%) (P = .79). CONCLUSIONS The general clinical characteristics of familial and nonfamilial acquired accommodative esotropia are very similar.
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Affiliation(s)
- M Z Seeley
- Cleveland Clinic Eye Institute, Cleveland, Ohio, USA
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Abstract
PURPOSE To assess the anatomy of eyes presumed to be amblyopic and their fellow eyes. PARTICIPANTS Two hundred seventy-five patients diagnosed with amblyopia and 88 healthy or glaucomatous subjects. METHODS All subjects underwent complete examinations, including cycloplegic refraction, slit lamp examination, ophthalmoscopy, and retinal imaging. Axial lengths were determined on 263 amblyopic and 88 healthy and glaucomatous subjects by ultrasonic biometry. MAIN OUTCOME MEASURES Optic disc areas were determined by magnification correction of disc images performed with formulas. Dysversion of the optic disc was determined by simultaneous viewing of disc photographs, digitized images of both eyes, or both. RESULTS The mean disc area of eyes presumed to be amblyopic was 1.72 mm(2) +/- 0. 73 SD and 1.95 mm(2) +/- 0.69 SD for nonamblyopic eyes (P =.0017). The mean disc area for 176 optic discs of glaucomatous and healthy eyes was 2.61 mm(2) +/- 0.95 SD. The mean axial length for eyes in the general population is 23.65 mm +/- 1.35 SD. The healthy and glaucomatous group in this study had a mean axial length of 23.89 mm +/- 1.29 SD. The eyes with poorer vision that were assumed to be amblyopic averaged 22.42 mm +/- 2.01 SD in length, whereas their nonamblyopic fellow eyes averaged 22.83 mm +/- 1.89 SD (P =.022). The differences between eyes in the healthy population and eyes that are presumably amblyopic, as well as the healthy and fellow eyes, are highly significant (P <.0001)(7.0 x 10(-16)). CONCLUSION Vision impairment in presumed amblyopia is associated with optic nerve hypoplasia with relative microphthalmos, which is more notable in those eyes with poorer vision.
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Affiliation(s)
- P Lempert
- Department of Physiology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
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