The Prevalence of Refractive Errors and Binocular Anomalies in Students of Deaf Boys Schools in Tehran

The association between deafness and ocular abnormalities is well established; however the nature and prevalence of these problems are diverse across the globe. A team of optometrists and social worker visited one hundred fifty eight deaf boy students at their schools and those who needed more detailed evaluation were referred to the Farabi Eye Hospital''s strabismus clinic. These students in selected schools underwent detailed visual acuity testing, refraction, binocular examination, color vision and fundoscopy. The percentage of ocular abnormalities in the deaf boys included in this study was 52.8%. The frequency of refractive errors in the present study was 39.9%. Astigmatism was the leading refractive anomaly (31%). Hypermetropia was found in 13.2% of the children and myopia was found in 12.6%. Anisometropia was detected in thirty children (19%) and amblyopia was found in 22 children (13.9%). A disturbance of ocular motility was present in 18 cases (11.3%). In 44 (28%) cases stereopsis was reduced, and in six (3.8%) cases it was absent. Majority of the students (89.9%) had congenital hearing loss. 6.3% children had color vision deficiency. Seventy four deaf boys (46.8%) had a normal eye examination, while 84 (53.2%) cases had ocular problems, and 20 (12.65%) of them had more than one problem. The prevalence of refractive error, amblyopia, and strabismus was found to be significantly increased compared to the general population. In addition, the prevalence of ocular abnormalities generally increased with the severity of the hearing loss. We recommended that screening for ocular abnormalities should be made mandatory in hearing-impaired children and parents must be aware of high prevalence of ocular abnormalities in deaf children, as they need appropriate visual sense to compensate their poor auditory sense.