Thanks to the great people over at All About Vision we have some useful information about the dangers of UV light. To protect your eyes from harmful solar radiation, sunglasses should block 100 percent of UV rays and also absorb most HEV rays. Frames with a close-fitting wraparound style provide the best protection because they limit how much stray sunlight reaches your eyes from above and beyond the periphery of your sunglass lenses.
While many people refer to ultraviolet radiation as UV light, the term technically is incorrect because you cannot see UV rays.
The three categories of invisible high-energy UV rays are:
UVC rays. 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.
But this also means depletion of the ozone layer potentially could allow high-energy UVC rays to reach the earth’s surface and cause serious UV-related health problems. UVC rays have wavelengths of 100-280 nanometer (nm).
UVB rays. These have slightly longer wavelengths (280-315 nm) and lower energy than UVC rays. These rays are filtered partially by the ozone layer, but some still reach the earth’s surface.
In low doses, UVB radiation stimulates the production of melanin (a skin pigment), causing the skin to darken, creating a suntan.
But in higher doses, UVB rays cause sunburn that increases the risk of skin cancer. UVB rays also cause skin discolorations, wrinkles and other signs of premature aging of the skin.
UVA rays. These are closer to visible light rays and have lower energy than UVB and UVC rays. But UVA rays can pass through the cornea and reach the lens and retina inside the eye.
Overexposure to UVA radiation has been linked to the development of certain types of cataracts, and research suggests UVA rays may play a role in development of macular degeneration.
Various eye problems have been associated with overexposure to UV radiation.
As an example, UVB rays are thought to help cause pingueculae and pterygia. These growths on the eye’s surface can become unsightly and cause corneal problems as well as distorted vision.
In high short-term doses, UVB rays also can cause photokeratitis, a painful inflammation of the cornea. “Snow blindness” is the common term for severe photokeratitis, which causes temporary vision loss usually lasting 24-48 hours.
The risk for snow blindness is greatest at high altitudes, but it can occur anywhere there is snow if you don’t protect your eyes with UV-blocking sunglasses.
Because the cornea appears to absorb 100 percent of UVB rays, this type of UV radiation is unlikely to cause cataracts and macular degeneration, which instead are linked to UVA exposure.
Here at Schmidt’s Optical and Hearing we have plenty of well trained opticians and stylists to help you find the perfect pair of glasses or sunglasses that will protect you from all harmful UV rays. Come visit us today!