Investigating the Causes of Visual Impairment and Legal Blindness among Patients Coming to a Referral Hospital in Tehran, Iran

Purpose: To examine the causes of vision impairment and blind-ness in a referral medical center in Tehran, Iran. Patients and Methods: The present cross-sectional study was con-ducted on visually impaired and legally blind patients in optometric clinic of Rasoul-e-Akram hospital, Tehran, Iran, in 2015. We used the WHO criteria to evaluate visual impairment. The visual acuity of patients was recorded in a mono-eye fashion (right eye first then the left eye) using a 6-meter Snellen chart. The refractive error was evaluated and the best corrected visual acuity (BCVA) was record-ed. Patients were then referred to ophthalmology department to di-agnose the main cause of reduced vision. Results: This study included 77 legally blind or visually impaired patients. After examining the underlying causes of visual impair-ment, we found that 41.17 % of visual impairment among patients was caused by cataracts and 29.41 % was caused by retinal diseas-es. Corneal pathology, glaucoma and other diseases were the rarer causes of low vision among subjects. The causes of legal blindness were different; retinal diseases were the main causes of legal blind-ness (46.51 %) followed by cataract (30.23 %) and corneal pathol-ogy (13.95 %). Conclusion: Our results from a referral hospital in Tehran indicates that retinal pathology was the most common cause of legal blind-ness among our patients, while the most common cause of visual impairment was cataract. Due to the natural differences of epidemi-ologic findings gathered from a referral center and the community, multicenter studies are recommended to better evaluate the causes of visual impairment in our community.