Background: To determine the cause of monocular and binocular blindness and low vision in an OPD-ophthalmology clinic setting

Materials and Methods: In a prospective OPD-based cross-sectional study, 420 subjects were examined in general ophthalmology clinic in Kashan from June 2003-2004. All patients underwent dilated pupil examination by an ophthalmologist. Low vision and blindness defined as best corrected visual acuity< 20/70 (<3/10) or < 20/200 respectively.

Results: Of 420 patients enrolled in this study186 (44.3%) were males. Three hundreds and two of cases were blind and 18 had low vision. Common causes of low vision and blindness in order of frequency were: cataract 39.8%, diabetic retinopathy 10.9%, myopic fundus 9.5%, amblyopia 9.3% and ARMD 7.9% The most common anatomic site of decreased vision were lens, retina, optic nerve and visual pathway

Conclusion: Cataract, retinal diseases including diabetic retinopathy and myopic degeneration are the leading cause of low vision and blindness. Trauma is a significant cause of sever, unilateral vision loss, especially in the young and in newly presenting subjects. Diabetes was the leading cause of blindness among the working age group population.