Causes of Visual Impairment among Patients Referred to Rehabilitation Clinics of Shahid Beheshti Medical University

To describe causes of low vision and blindness in patients referred for low vision aids to rehabilitation clinics at Shahid Beheshti Medical University during 2005. Visual acuity was classified to five groups based on best-corrected visual acuity (BCVA) in the better eye according to World Health Organization (WHO) criteria and by using standard Snellen chart which included mild, moderate, severe and profound low vision and blindness. The causes of blindness and low vision were determined using the 10th version of International Classification of Diseases (ICD-10) based on the main cause in both eyes. The study was performed on 432 patients including 275 (65%) male and 148 (35%) female subjects with mean age of 43.6±25.5 (range 3-92) years. Mild to moderate and severe low vision and blindness were present in 28.8%, 46.4% and 24.8% of cases, respectively. The main causes of visual impairment were diseases of the retina and choroid (74.5%), optic nerve and optic tract diseases (9.8%), vitreous and globe disorders (3.5%), congenital cataract (3.1%) and glaucoma (2.6%). The pattern of distribution of the causes was almost similar in all age subgroups. Diseases of the retina and choroid are the main cause of visual impairment among patients referred to eye rehabilitation clinics.