Always check that your sunglasses or UV lenses have a CE, UV 400 or British Standard Mark. This will ensure they provide adequate protection from both UVA and UVB.
The larger the lens, the more protection they’ll give your eyes as there’s less chance that light will filter in through the sides.
Ensure that your sunglasses fit properly. They shouldn’t be able to slide off.
Adding polarised lenses can decrease the amount of glare, which can dazzle and strain your vision
Invest in photochromic lenses (transition lenses) that instantly adapt to light changes, darkening in bright light. Alternatively, have prescription lenses tinted to minimise the amount of UV rays that reach your eyes.