Sunglasses help reduce bright visible light, but tint darkness does not tell you how much ultraviolet radiation the lenses block. Look for clear labeling that states the intended UV protection and choose products from a reliable source. Larger lenses or wraparound styles can help reduce light entering around the edges, although fit and comfort matter. If you need vision correction, prescription sunglasses are one option; clip-ons or other solutions may suit some glasses wearers.
Polarized lenses reduce glare reflected from surfaces such as roads or water, which some people find helpful for driving or outdoor activities. Polarization is different from UV protection, so check for both features if both matter to you. Some displays may look unusual through polarized lenses, which is worth considering if you use instruments or screens outdoors. Lens color can change visual contrast, but it does not by itself establish the level of UV protection.
Wear sunglasses in bright outdoor conditions, and consider a brimmed hat for additional coverage. Children also need suitable eye protection, and outdoor workers or athletes may have extra requirements. Ask your eye care professional about options if you have a particular eye condition or take medication that affects light sensitivity. Clean sunglasses with products recommended for their lenses and store them in a protective case. If glare or light sensitivity is new or pronounced, seek an eye care assessment rather than relying on tinted lenses alone.