the effect of various colors of sunglasses in visual function

background: adverse effect of sun rays mainly uv ray on the human eye documented and protection of eyes is necessary using different methods such as, sun glasses. sunglasses are designed in different colors. the aim of this study was evaluation of the effect of different colors of sunglasses on the visual acuity, contrast sensitivity, stereopsis and color vision. methods: 81 normal subjects were selected randomly from students of zahedan medical university with average age of 21 years. then we evaluated visual acuity by snellen chart, contrast sensitivity by cambridge low contrast grating chart, stereopsis with tno test and color vision with d15 test in the room ( normal space) with illumination of 991 lux and in the sun with illumination of 54000 lux with and without filters (polaroid  gray, green, brown and gray).                       results: the mean of visual acuity was 10/10 in room and sun. paired t test didn't show significantly difference between contrast sensitivity in room and sun condition (p>0.05). anova analysis showed significantly difference between stereopsis with and without colored filter (p<0.05). there wasn’t significant different between color vision with and without colored filer in sun (p>0.05). conclusion: sunglasses increase contrast sensitivity in the sun and the gray and brown filter increase contrast sensitivity more than the others colors and also these colors had less effect in reduce of stereopsis.