Sunglasses can help your eyes in two important ways. They help filter light and they protect against the damaging rays of the sun. According to Prevent Blindness America,
sunglasses that that reduce glare and filter 99-100% of ultraviolet (UV) rays are essential. They should be comfortable and protect your eyes without any distortion.

Why do I need sunglasses?

These invisible UV rays can damage your eyes. Some of the damage can happen right away and some can occur over a lifetime of exposure. Constant exposure to bright sunlight can damage the cornea (the clear outer part f the eye that allows light through to the retina), the lens (the part of the eye responsible for focusing), and the retina (the innermost layer of the eye that sends an image to the brain).

How can sunglasses protect my eyes from UV radiation?

All types of eyewear, including prescription and non-prescription glasses, contact lenses and lens implants, should absorb UV-A and UV-B rays. UV protection does not cost a lot of money and does not get in the way of seeing clearly. Shop for sunglasses that block 99% to 100%

How does the sun damage the eyes?

Three types of rays come from the sun:
• Visible: what you see as color.
• Infrared: invisible but felt as heat.
• Ultraviolet (also called UV radiation): invisible but often called “sunburn rays.” UV radiation includes two types of rays that normally reach the earth, UV-A rays and UV-B rays.
UV protection does not cost a lot of money and does not get in the way of seeing clearly.
of both types of ultraviolet rays: UV-A and UV-B. Sunglasses should also eliminate glare and squinting. Be wary of labels that claim a product blocks harmful UV without specifying exactly what percentage of UV rays they block.