Objective: To determine the causes of sever visual impairment and blindness in students in school for the blind in Mashad to aid in planning for the prevention and management of avoidable causes is the aim of this study.

Materials & Methods: In this analytical study in 2006, two hundred sixty (260) students attending in four schools for blinds in Mashad, were examined by using the modified WHO/PBL Eye Examination Record, for children with blindness and low vision protocol. The anatomical abnormality and underlying etiology for each eye were recorded. 

Results: The mean age was 14/2±4/2 years. Hundred fifty seven (54/9%) were males and 129 (45/1%) were females. The major anatomical site of visual loss was retina (28/6%), followed by optic nerve atrophy, congenital cataract, corneal opacity, congenital glaucoma, albinism and whole globe problems. The most common type of eye surgery was cataract. The difference between men and women and the distribution of no light Perception (NLP), was statistically significant (P<0.01).

Conclusion: Genetically determined disorders play an important role in the causation of childhood blindness. Genetic consultation, early eye screening of children and public education may help in prevention of blindness.