Ophthalmologic abnormalities in high school students with mental retardation in Taiwan

Background and Purpose: Visual and ocular disorders are common in mental retardation (MR), and can influence sensory-motor development and learning. This study investigated visual and ocular abnormalities in a population of high school students with MR. Methods: All students with MR in their first year at a special education high school who underwent ophthalmic examinations in December 2001 were included. Data were collected by retrospective review of hospital records and student health records. Results: A total of 68 students with MR, including 45 males and 23 females, completed ophthalmologic examinations. Abnormal ophthalmologic findings in these 68 students (15-23 years old) included astigmatism (74.4%), myopia (53.7%), amblyopia (29.3%), exodeviation (23.5%), anisometropia (22.0%), blepharoconjunctivitis (20.6%), hyperopia (18.2%), cataract (13.2%) and suspected glaucoma (11.8%). Amblyopia was mainly attributed by refractive errors and strabismus. Myopia was less prevalent than in the general population of the same age in Taiwan, but astigmatism and anisometropia were more prevalent. More than one-third of the exodeviations were large-angle exotropia. The presence and type of cataract were highly associated with Down's syndrome. Conclusion: The prevalence of visual and ocular disorders in teenage and young-adult students with MR is high. Because these disorders can be detrimental to learning, early and regular ophthalmic examinations of children with MR are mandatory, with particular attention to screening for refractive error, amblyopia, strabismus and cataract and treatment of these conditions when identified.