Although sunglasses may not seem like safety equipment, they really are for more than looking cool while you ride. (Although many of the bizarre “cycling” sunglasses I see on rides are anything but cool!)
Blocking glare from your eyes is one obvious benefit of sunglasses. But blocking your eyes from bugs, gravel and other things flying at your face is perhaps the most important benefit! Just today, as a matter of fact, I was hit by seemingly thousands of bugs in my path as I rode immediately after a strong rain. (We get lots of “flying ants” or termites or whatever they’re properly called after rains in Tucson.) If I wouldn’t have had glasses on, I might have swerved and caused an accident!
I always ride with glasses during my morning rides in the dark as well. I have a special set of glasses that have interchangeable lenses and I use clear lenses for this purpose. (I suppose Home Depot safety glasses would work just as well.) Many times I’ve been thankful that I’ve had them on, as a small bug or stone comes hurtling towards my eyes!
Note: I use Tifosi “photo gray” (photochromic) glasses as my normal riding glasses these days. They lighten or darken automatically, according to the brightness outside. They don’t get totally clear enough for dark rides, but they’re very effective otherwise!