Commuting - Dealing with changing light conditions

How do you handle changing light conditions, such as in the morning as it gets brighter, and in the evening when it starts getting dark? Clear or tinted glasses will be too dark in some of these conditions, or too bright in others. Does anyone make glasses with flip up lens, something like I see baseball players wear?

Thanks.

Billy

Rudy project has em. Either that or get photochromatic lenses, specialized is coming out with them next year in bike sunglass form.

I use either my dark or clear lens and let my eye's pupil take over from there to regulate light.

I use the Rudy Project lenses described above.

I have sunglasses from Native Eyewear. They came with four sets of lenses for various lighting conditions. If I know I will be spanning daylight into nighttime, I just carry along the sunglass case in my bag, and swap out the lenses at the appropriate time. It takes only a minute, and gives me a chance to suck down some fluids at the same time.

If I'm only going to be riding from sunset into nighttime, I select the yellow lenses and keep those. The yellow provides amazing "shadow penetration" and doesn't affect my visibility at night all that

If I'm to be riding only at night, I pop in the clear lenses.

There are a set of orange lenses, but I haven't found myself too pleased with those for riding, but I'll try them again if I ever go snow riding.

Thanks for the replies. My current glasses have smoke & amber lenses. I'll just keep both with me if there's a possibility I'll need to switch.

Thanks

Billy