Ultraviolet Rays and Your Eyes
By Erinn Morgan, with updates by Liz Segre
Fashion aside, sunglasses serve an important purpose: protecting eyes from the harmful rays produced by the sun. You're probably well aware of the need to protect your skin from the sun, but it's equally important to protect your eyes.
What to Look for When You're Buying Sunglasses
Sunglass standards for lenses place limits solely on UVB and UVA rays, but bear in mind that both the standards and labeling are voluntary, not mandatory. According to these standards, sunglasses must block at least 70% of UVB and at least 60% of UVA.
To best protect your eyes, look for sunglasses that provide at least 98% protection from both UVA and UVB rays. UVC rays are blocked automatically since they are absorbed in the atmosphere and do not reach the earth. Some of the higher-priced products with polycarbonate, glass or plastic (CR-39) lenses can claim to block 100% of the UV rays.
Protect Your Eyes from the Sun!
Sunglasses help you in two important ways. They filter light and they protect your eyes from damaging ultra-violet (UV) rays. Mounting evidence shows that exposure to UV rays can damage your eyes. Long-term exposure to UV rays can lead to cataracts, macular degeneration, or skin cancer around the eyelids. Sunglasses should be worn when you are outdoors so you can protect your eyes.
UV Rays and Sun Protection
Ultraviolet (UV) radiation is a part of the sun's wavelength spectrum that directly affects the planet Earth, especially its plant and animal life. Scientists tell us the UV rays are divided into three different levels:
UVC - Extremely dangerous for plant and animal life. Fortunately for us, it is completely absorbed by the ozone layer and does not reach the planet's surface.
UVB - 99 percent of these rays are also absorbed by the ozone layer, but the remaining 1 percent that reach through the atmosphere are of concern because they can be responsible for damage at a molecular level to our DNA. Short term effects are reddening of the skin and a loss of the ability to synthesize vitamin D. Long term effects include skin cancer, cataracts and suppression of the immune system.
UVA - These rays penetrate the ozone layer unimpeded. UV-A rays are a necessary component for the synthesis of vitamin D in humans, but like anything else, too much of a good thing can cause harm. Overexposure to UV-A can cause reddening and toughening of the skin, suppression of the immune system and cataracts.
Protect Your Eyes with Sunglasses - Get sunglasses with the highest amount of protection from UVA and UVB rays possible. Keep in mind that industry and labeling standards say that sunglasses must block at least 70 percent of UVB and at least 60 percent of UVA, but those standards are completely voluntary, not mandatory. Look for sunglasses that block at least 98 percent of both UVA and UVB rays, and if possible spring for the more expensive glasses with lenses that will block 100 percent of all UV rays.
Avoid simple tinted lens sunglasses as these can possibly be more dangerous than going without sunglasses. The dark tint will allow the pupil to dilate more fully, allowing more harmful rays to penetrate and potentially increase the occurrence of cataracts.
Protect Your Skin with Sunscreen - If you're in a climate that calls for shorts and short or no-sleeve shirts, then be sure to apply a sunscreen with a Sun Protection Factor (SPF) of 30+ to all exposed portions of skin such as arms, legs, face and neck. Most sunscreens work by using either an organic chemical compound that absorbs ultraviolet light (such as oxybenzone) or an opaque material that blocks or reflects light (such as titanium dioxide or zinc oxide), or a combination of both. Time, absorption and moisture (such as perspiration, precipitation or a dip in a stream or lake) mean that you have to be sure to keep the sunscreen applied as needed to provide the highest level of protection.
