Before purchasing my own prescription sunglasses, I was given the choice between polarized or non-polarized lenses.  I was drawn to the polarized version, which allowed me to see the world with better contrast, and more crisply. However, pilots should resist making a decision just based on comparing lenses in the store. Polarized lenses are not the preferred choice for sunglasses worn by pilots. The coating on windscreens and cockpit instruments doesn’t pair well with them. In fact, instruments could appear completely blacked out when viewed through polarized lenses. Looking through windscreens with polarized lenses can create an optical effect that is rainbow-like and makes it difficult to spot traffic.

Another option you may be offered is tinting the lenses of your new sunglasses. There are many tints available, and for the most part this comes down to personal preference. Keep in mind that some colored tints tend to distort colors, so it’s important to test the options before making a decision. In general, the gray tints tend to distort color the least, so that’s one option to strongly consider for flying.

It may seem like a small detail, but the fit of the frame is important. You’ll regret making a decision just based on the coolness factor if the glasses are ill-fitting, which will especially be an issue on long flights. The frames should not be too heavy, and they should fit comfortably under a headset. The sunglasses aren’t helpful if they’re so uncomfortable that you don't wear them.

Lastly, sunglasses are there to protect your eyes, so you want to ensure that you are getting the ultraviolet light protection you need. Radiation from the sun has an impact on the eyes, and it causes damage over time. According to the FAA, UV radiation exposure increases with altitude (5 percent per 1,000 feet). The American Optometric Association recommends choosing sunglasses with 99 to100 percent UVA and UVB protection to avoid damage to your eyes.