reza a asked:
Hi. i want to buy sunglasses. but i don’t know how i can test the lenses about distortion.
American Express Platinum
Hi. i want to buy sunglasses. but i don’t know how i can test the lenses about distortion.
American Express Platinum

Hold the glasses about 6 or 8 inches from your eyes, and look through them at a solid vertical line, like the corner of a building for instance.
Then move the glasses back and forth horizontally ( sideways) from edge to edge of one lens ( keeping your other eye closed ), and see if the vertical line stays straight, or gets wavy.
If it doesn’t stay straight, then there is some distortion.
If you are looking for a polarized sunglass, what you can do is put on a pair of polarized sunglasses and hold the pair of polarized sunglasses that you are interested in front of you. Turn the pair of sunglasses that are in your hands while looking at the lens. You will be able to see where the frame is squeezing the lens and distorting the image. If the lenses are not polarized, the best way is to try on the sunglasses and walk around for a little while. A lens that is distorted may make you somewhat dizzy.