Sunglasses offer your eyes protection from the sun’s damaging ultraviolet (UV) rays. Long term exposure UV rays can contribute to cataract formation and damage the cornea, lens and other parts vital to vision. Look for sunglasses that:
• Offer maximum UV protection – Look for sunglasses that block 99 to 100 percent of both UVA and UVB light. Sometimes, labels say that all light below 400 nanometers is blocked. This is the same as 100% UV protection. Since UV coating is colorless, a dark lens doesn’t necessarily mean increased UV protection. In fact, a dark pair of sunglasses that doesn’t block 99 to 100% of UV light may actually increase your UV exposure. Darker glasses reduce the amount of light your eye receives. A natural response is that your pupils dilate to let in more light. As a result, the pupils also let in more UV light.
• Wrap your eyes in protection – The more closely sunglasses fit to your face, the better. Your eyes can be damaged from UV rays that are scattered and reflected into the eye area from beyond the edges of sunglass lenses. Wraparound sunglasses give more complete protection. Regular prescription glasses also can offer UV protection with the addition of chemicals during the manufacturing of the lenses or with the addition of a UV lens coating.