UVB light can cause the greatest eye damage. Overexposure to intense UVB light can damage the cornea, producing a painful condition known as photokeratitis. While recovery occurs over several days, the eye often must be bandaged. Many scientists think there is a link between prolonged exposure to UVB light and the formation of lens cataracts. Because UVA light can reach the retina, researchers are studying whether long-term exposure may be related to loss of vision in old age.
Sunglasses offer the best eye protection from UV light, better than visor hats or parasols.
In addition, the agreement encourages manufacturers to list the actual amount of UVA and UVB the product blocks. If this information doesn't appear on the label, consumers might want to check with the manufacturers to find out how much UVA and UVB light is screened out by these lenses. Sunglasses should not be worn when it's dark because they compromise night vision. That also goes for tinted contact lenses. Protective sunglasses, however, are not sufficient for people exposed to UV lamps, such as those found in tanning booths.