[islandgal]

http://www.walletpop.com/blog/2010/0...t-bargains-in/:

[Mikeod]

Good advice, as far as it goes. I think they glossed over the part about the quality of the lenses. When buying non-prescription sunglasses, it is advisable to check the lenses for distortion. Hold the sunglasses at arms length and look through each lens at a straight line, column, wall edge about 10 feet or more away. Slowly move the sunglasses side to side watching the image of the straight line through the lens. Then turn the lenses in a clockwise/counterclockwise manner and watch the edge again. It should not move, twist, or otherwise change from the line outside the lens in either test. If so, the lens may create problems with headaches, blurred vision, etc. Check both lenses. If a pair of sunglasses fails this test, don't assume that all of that model are similarly flawed. I have found good and bad throughout a model line. And don't assume the more you pay, the better the lens quality. I have seen junk for more than $100 and good lenses for $20.

We once had a patient suffering from severe headaches for several months and could not determine a reason for the headaches. Turns out he was a long haul truck driver who found a deal on sunglasses at a truck stop and bought a dozen pair. He noted he felt worse while working, but we couldn't find any evidence of sensitivity to anything in his work environment. Finally, we held his sunglasses over the projector at an eye exam and the chart disappeared! There was so much distortion through the lenses his vision was significantly reduced and he was unknowingly squinting in order to see clearly enough to drive. He got a good pair of sunglasses and the headaches disappeared.