I've the change-to-darker-tint-in-sunlight lenses (misremember what they're called) because of light problems. The lens change didn't fix the problem, but then I also went to a discount eyeglass store and the information the woman who owned the place gave me turned out to be false after I researched it further. Unfortunately I already had the glasses, and can't fix the problem anytime soon. It's probably best to check permanent tint options first, the sunglass-lens option has a few flaws, although it isn't without its uses. The sunglass lenses do take a small bit of time to adjust to changes in lighting if you're going into or out of a building, so be prepared to be temporarily 'blinded' while your glasses adjust themselves. If your color contrast is off it would be better, I think, to fix the problem in the long run with a permanent tint than to have it fixed only in certain lighting conditions where the glass lens will change. Since it doesn't change indoors, you'll be screwed if you're in a bright room with a window, which happened to me a lot last summer. Lighting conditions in some stores aren't very good, either, and sunglass lenses don't help with that. The color red superimposes itself on my vision in bright light in various conditions where it isn't supposed to be, though, so if you've a similar tricky problem be careful about what tints are chosen and make sure to check the tint options in several conditions. Trying the suggested tints for about two weeks or so would be better than wearing them for a few days to make sure you've got a firm grip on how the tints affect you in different conditions.
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It's a nice day to start again.
-'White Wedding', Billy Idol