Even if it’s gray outside, wear your sunglasses.
Because UV rays go right through clouds, according to the American Academy of Ophthalmology. And with snow and ice, 80% of those UV rays can be reflected back up at you. By comparison, grass only reflects 10% of UV rays. And all that ultraviolet light can damage your retinas and lead to issues like cataracts. So wear sunglasses, even in winter, and make sure they block 99% of UV radiation.