Protecting Your Eyes from Solar Radiation
The sun supports 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. Artificial sources, like welding machines, tanning beds and lasers, can also produce UV radiation.
Most people are aware of how harmful UV radiation is to the skin. However, many may not realize that UV radiation can harm the eyes, and 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. However, UV-A and UV-B radiation can have long- and short-term negative effects on the eyes and vision.
If your eyes are exposed to excessive amounts of UV radiation over a short period of time, you will likely experience photokeratitis. Like a "sunburn of the eye," photokeratitis can be painful. Its symptoms include red eyes, a foreign body sensation or gritty feeling in the eyes, extreme sensitivity to light and excessive tearing. Fortunately, these symptoms are usually temporary and rarely cause permanent damage to the eyes.
The longer the eyes are exposed to solar radiation, the greater the risk of developing cataracts or macular degeneration later in life. It is not clear how much exposure to solar radiation will cause damage. Therefore, whenever you spend time outdoors, wear quality sunglasses that offer UV protection and a hat or cap with a wide brim. 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;
- have lenses that are perfectly matched in color and free of distortion and imperfection; and
- have lenses that are gray for proper color recognition.
If you participate in potentially eye-hazardous outdoor work or sports, your sunglass lenses should be made from polycarbonate or Trivex® material. These lenses provide the most impact resistance.
If you spend a lot of time outdoors in bright sunlight, consider wearing wraparound frames for 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.
Sunglasses Shopping Guide
Protecting Your Eyes from Shorter-Wavelength Visible Light
Chronic exposure to shorter-wavelength visible light (blue and violet light) may also be harmful to the retina. Many digital devices emit this shorter-wavelength visible light.
Blue light is part of the visible light spectrum. The sun emits blue light, as do artificial light sources, such as LEDs, computers and smartphones. Some types of blue light can be beneficial, helping us regulate our bodies' internal biological clocks.
However, blue-violet light can be harmful to the eyes, specifically the retina. It is a risk factor for the onset of age-related macular degeneration, a deterioration of the part of the retina responsible for sharp, central vision.
A recent study found that Americans spend almost 2 ½ hours on their tablets and smartphones every day. In addition, most offices and stores use fluorescent light bulbs, and LED lights are becoming increasingly popular.
Lenses that absorb harmful blue light but allow beneficial blue light through your lenses are entering the marketplace. You could also apply a special clear coating to traditional lenses to enhance their ability to block these harmful rays while you use computers and smartphones.
UV Radiation Checklist
If you can answer "yes" to one or more of the following questions, you could be at higher risk for harm to the eyes from UV radiation:
- Do you spend a great deal of time outdoors?
- Do you spend time skiing, mountain climbing or at the beach?
- Do you use a sunlamp or tanning bed?
- Do you live in the mountains or the U.S. Sunbelt?
- Are you a welder, medical technologist or do you work in the graphic arts or in the manufacture of electronic circuit boards?
- Do you take prescription or over-the-counter drugs that can increase your sensitivity to UV radiation? (If you are unsure, check with your optometrist, pharmacist or physician.)
- Have you had cataract surgery in one or both eyes?
See your optometrist every year 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 advances in eye protection.