Protecting Your Eyes from Solar Radiation

The sun supports all life on our planet, but its life-giving rays also pose dangers.

The sun’s primary danger is in the form of Ultraviolet (UV) radiation. UV radiation is a component of solar radiation, but it can also be given off by artificial sources like welding machines, tanning beds and lasers.
Most are aware of the harm UV radiation can do to the skin, but many may not realize that exposure to UV radiation can harm the eyes or that other components of solar radiation can also affect vision.
There are three types of UV radiation: UV-C is absorbed by the ozone layer and does not present any threat; UV-A and UV-B radiation can have adverse long- and short-term effects on the eyes and vision.
If your eyes are exposed to excessive amounts of UV radiation over a short period of time, you are likely to experience an effect called photokeratitis.

Like a “sunburn of the eye”, photokeratitis may be painful and include symptoms such as red eyes, a foreign body sensation or gritty feeling in the eyes, extreme sensitivity to light and excessive tearing. Fortunately, this is usually temporary and rarely causes permanent damage to the eyes.
Long-term exposure to UV radiation, however, can be more serious. Scientific studies and research have shown that exposure to small amounts of UV radiation over a period of many years increases the chance of developing a cataract and may cause damage to the retina, a nerve-rich lining of the eye that is used for seeing. Additionally, chronic exposure to shorter wavelength visible light (i.e. blue and violet light) may also be harmful to the retina.
The longer the eyes are exposed to solar radiation, the greater the risk of developing later in life such conditions as cataracts or macular degeneration. Since it is not clear how much exposure to solar radiation will cause damage, the AOA recommends wearing quality sunglasses that offer UV protection and wearing a hat or cap with a wide brim whenever you spend time outdoors. Also, certain contact lenses can provide additional UV protection.
To provide adequate protection for your eyes, sunglasses should:

• block out 99 to 100 percent of both UV-A and UV-B radiation;
• screen out 75 to 90 percent of visible light;
• be perfectly matched in color and free of distortion and imperfection; and
• have lenses that are gray for proper color recognition.

The lenses in sunglasses should be made from polycarbonate or Trivex® material if you participate in potentially eye-hazardous work or sports. These lenses provide the most impact resistance.
If you spend a lot of time outdoors in bright sunlight, wrap around frames can provide additional protection from the harmful solar radiation.
Don’t forget protection for children and teenagers. They typically spend more time in the sun than adults.
Be sure to see your doctor of optometry at least every two years [recommended schedule of examinations] for a comprehensive eye examination. It is a good way to monitor your eye health, maintain good vision and keep track of your solar radiation protection needs as well as new advances in eye protection.


** souce:http://www.aoa.org/patients-and-public/caring-for-your-vision/uv-protection?sso=y