You can probably think of a lot of reasons to have a good pair of sunglasses. For one thing, not many people have eyes that can stand the brightness of sunlight or the glare of sun on snow or sand without the aid of sunglasses. Sun brightness and glare can not only make you uncomfortable, but it can also make seeing
less efficient. If you wear glasses or contact lenses to correct your vision, it makes sense to also have a pair of
prescription sunglasses.

A good pair of sunglasses is a wise investment in comfortable, efficient vision, but they should be optically perfect. They should also be large enough and in the exact tint and density that is best for you. Cheap and imperfect sunglasses should be avoided. Among many disadvantages, they may cause eye strain, headache, or
fatigue. Also they will not give you the protection you may need from ultra-violet and infra-red rays, both of which can be potentially dangerous to your eyes.