You probably know that too much exposure to the sun's ultraviolet (UV) rays can cause sunburn and skin cancer. But did you know UV also can harm your eyes?
Extended exposure to the sun's UV rays has been linked to significant eye problems, including cataracts, macular degeneration, pteryguim, skin cancer and corneal sunburn. Over time, the effects of UV rays can cause damage to your eyes. There are three types of UV rays: UV-A, UV-B and UV-C.
UV-A
Can hurt your central vision. It can damage the macula, a part of the retina at the back of your eye.
UV-B
The front part of your eye (the cornea and the lens) absorbs most UV-B rays, but these rays may cause even more damage to your eyes than UV-A rays.
UV-C
These are the highest energy UV rays and potentially could be the most harmful to your eyes and skin. Fortunately, the atmosphere's ozone layer blocks virtually all UVC rays
What eye problems can UV rays cause:
Macular Degeneration
UV rays may lead to macular degeneration, a leading cause of vision loss for older Americans.
Cataract
UV rays, especially UV-B rays, may also cause some kinds of cataracts. A cataract is a clouding of the eye’s natural lens, the part of the eye that focuses the light we see.
Pterygium
Another UV-related problem is a growth called pterygium. This growth begins on the white of the eye and may involve the cornea. Eventually, the growth may block vision. It is more common in people who work outside in the sun and wind.
Skin Cancer
Skin cancer around the eyelids is also linked to prolonged UV exposure.
Corneal Sunburn
Corneal sunburn, called photokeratitis, is the result of high short-term exposure to UV-B rays. Long hours at the beach or skiing without proper eye protection can cause this problem. It can be very painful and may cause temporary vision loss
 
Protecting your eyes from UV
To protect your eyes from harmful solar radiation, you should wear sunglasses that block 100 percent UV whenever you are outdoors in daylight. Your eyes need protection even on cloudy days because the sun's damaging UV rays can penetrate cloud cover.
The month of July is National UV Safety Awareness month.
Reference: https://www.allaboutvision.com/sunglasses/spf.htm