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Taiwan J Ophthalmol ; 12(2): 178-183, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35813801


PURPOSE: The purpose of the study was to investigate the relation between the severity of reading disorder and visual functions among children with dyslexia. MATERIALS AND METHODS: The present study included 32 dyslexic children selected from two centers for learning disabilities in Mashhad, Iran. Dyslexics were then classified as mild, moderate, and severe based on an instrument used to determine the severity of their reading disorder. Complete optometric examinations to measure visual acuity, refractive errors, latent and manifest deviations, stereoacuity, and amplitude of accommodation were performed for all participants. The correlation between visual functions among dyslexics and their reading disorder severity was investigated. RESULTS: The mean age of the participants in this study was 8.1 ± 0.8 years. Among participants, 40.6%, 31.3%, and 28.1% presented with severe, moderate, and mild levels of reading difficulties, respectively. Only exophoria significantly correlated with the severity of reading disorders. No significant correlation was found between other visual functions and the severity of reading disorders in dyslexic children. CONCLUSION: We found that higher exophoria at near has a significant correlation with the severity of dyslexia. A complete and detailed eye examination of patients with dyslexia and correcting their visual impairments might be helpful.

J Ophthalmic Vis Res ; 10(2): 130-8, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26425314


PURPOSE: To determine the prevalence of color vision deficiency (CVD) and its correlation with amblyopia and refractive errors among primary school children. METHODS: In this population-based cross-sectional study, 2160 children were selected from 36 primary schools; 60 students were from each school (10 students in each grade), with equal sex distribution. A complete eye examination including refraction using a photorefractometer, determination of visual acuity (VA) and color vision using a Yang vision tester, and evaluation of ocular media opacity using a direct ophthalmoscope was performed. Children who could not answer at least 4 plates of the Ishihara color test were considered as color vision deficient subjects. Amblyopia was determined if pinhole VA was worse than 0.3 LogMAR (equal to 20/40). RESULTS: The prevalence of CVD was 2.2% (95% CI: 1.5% to 3%) which was higher in male subjects (37 [3.5%] boys vs. 11 [1.0%] girls, P < 0.001). Mean VA was lower among students with CVD as compared to normal color vision children (P = 0.035) and amblyopia was observed in 8.3% (95% CI: 0.2% to 16.4%) of patients with CVD versus 2.1% (95% CI: 1.5% to 2.08%) of children with normal color vision perception (P = 0.005). A statistically significant correlation between lower VA and CVD was observed (P = 0.023). CONCLUSION: Although CVD was correlated with lower VA and amblyopia, there was no relationship between CVD and the type of amblyopia, refractive error, anisometropia or strabismus.

J Ophthalmic Vis Res ; 10(3): 221-8, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26730305


PURPOSE: To determine the accuracy of photorefraction and autorefraction as compared to cycloautorefraction and to detect the repeatability of photorefraction. METHODS: This diagnostic study included the right eyes of 86 children aged 7-12 years. Refractive status was measured using photorefraction (PlusoptiX SO4, GmbH, Nürnberg, Germany) and autorefraction (Topcon RM800, USA) with and without cycloplegia. Photorefraction for each eye was performed three times to assess repeatability. RESULTS: The overall agreement between photorefraction and cycloautorefraction was over 81% for all refractive errors. Photorefractometry had acceptable sensitivity and specificity for myopia and astigmatism. There was no statistically significant difference considering myopia and astigmatism in all comparisons, while the difference was significant for hyperopia using both amblyogenic (P = 0.006) and nonamblyogenic criteria (P = 0.001). A myopic shift of 1.21 diopter (D) and 1.58 D occurred with photorefraction in nonamblyogenic and amblyogenic hyperopia, respectively. Using revised cut-off points of + 1.12 D and + 2.6 D instead of + 2.00 D and + 3.50 D improved the sensitivity of photorefractometry to 84.62% and 69.23%, respectively. The repeatability of photorefraction for measurement of myopia, astigmatism and hyperopia was acceptable (intra-cluster correlation [ICC]: 0.98, 0.94 and 0.77, respectively). Autorefraction results were significantly different from cycloautorefraction in hyperopia (P < 0.0001), but comparable in myopia and astigmatism. Also, noncycloglegic autorefraction results were similar to photorefraction in this study. CONCLUSION: Although photorefraction was accurate for measurement of myopia and astigmatism, its sensitivity for hyperopia was low which could be improved by considering revised cut-off points. Considering cut-off points, photorefraction can be used as a screening method.

J Ophthalmic Vis Res ; 10(4): 408-16, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-27051485


PURPOSE: To determine the prevalence of amblyopia and refractive errors among 7 to 12-year-old primary school children in Tehran, Iran. METHODS: This population-based cross-sectional study included 2,410 randomly selected students. Visual acuity was tested using an E-chart on Yang vision tester. Refractive errors were measured by photorefractometry and cycloautorefraction. Strabismus was checked using cover test. Direct ophthalmoscopy was used to assess the anterior segment, lens opacities, red reflex and fundus. Functional amblyopia was defined as best corrected visual acuity ≤20/40 in one or both eyes with no anatomical problems. RESULTS: Amblyopia was present in 2.3% (95% CI: 1.8% to 2.9%) of participants with no difference between the genders. Amblyopic subjects were significantly younger than non-amblyopic children (P=0.004). Overall, 15.9% of hyperopic and 5.9% of myopic cases had amblyopia. The prevalence of hyperopia ≥+2.00D, myopia ≤-0.50D, astigmatism ≥0.75D, and anisometropia (≥1.00D) was 3.5%, 4.9%, 22.6%, and 3.9%, respectively. With increasing age, the prevalence of myopia increased (P<0.001), that of hyperopia decreased (P=0.007), but astigmatism showed no change. Strabismus was found in 2.3% of cases. Strabismus (OR=17.9) and refractive errors, especially anisometropia (OR=12.87) and hyperopia (OR=11.87), were important amblyogenic risk factors. CONCLUSION: The high prevalence of amblyopia in our subjects in comparison to developed countries reveals the necessity of timely and sensitive screening methods. Due to the high prevalence of amblyopia among children with refractive errors, particularly high hyperopia and anisometropia, provision of glasses should be specifically attended by parents and supported by the Ministry of Health and insurance organizations.