Want to look like a celebrity? Buy an expensive pair of sunglasses as the first investment. Want to protect your eyes from permanent damage? An inexpensive pair of sunglasses will do the trick.
Sunglasses are more than a fashion statement. The ultraviolet (UV) rays and blue light generated by the sun can cause or speed the progression of eye disease and damage or weaken the tissues that support the structure of your eyes. And every age group of people is affected by these rays; from infants to seniors.
About UV Rays and Blue Light
UV rays carry more energy than visible light rays, so the eye is at greater risk of damage from absorbing UV radiation than from absorbing other kinds of light. There are two types of UV rays that reach the Earth's surface: UVA and UVB. These rays can cause, or speed up the progress of several diseases that affect the eye or its supporting structures. UVB rays have also been linked to skin cancer. Most of the damage caused to eyes by UVB and UVA rays happens over a long period of time and cannot be reversed. Sensitivity to ultraviolet radiation varies from one person to the next.
Blue light is visible light in the blue portion of the color spectrum. For example, the intense glare of light reflecting off water or metal surfaces contains blue light. Your eyes cannot focus clearly in blue light. Some scientists believe that routine exposure to blue light over many years may age the retina and increase the risk of blindness in some people over the age of sixty.
How Light Can Impact Your Eyes
All light is a form of energy. When your eyes absorb light, the process creates heat or chemical reactions in eye tissue. These reactions can cause permanent damage if the eye's natural ability to heal itself is overwhelmed.
Different parts of the eye absorb different kinds of UV radiation and light. For example:
- The surface layers of the outer part of the eyeball (the cornea and the conjunctiva) absorb UVB rays.
- The lens absorbs mainly UVA rays.
- The retina (the light-sensitive lining at the back of the inner eyeball) absorbs visible light.
If eyes are overexposed to ultraviolet radiation, the front portion of the eyes may be damaged. If you stare at visible light that is too bright or intense, even for a moment, the retina can be damaged, causing permanent loss of vision. Examples of bright light include looking directly at the sun or even a welder’s blow torch.
There is some evidence that daily exposure to UV radiation in very bright sunlight over many years may increase the risk of developing cataracts. Cataracts cause a gradual clouding of the natural lens of the eye.
You can also help protect your eyes by wearing a wide-brimmed hat or visor when you are out in bright sunlight, and by avoiding exposure to bright sunlight, especially in the summer between 11:00 a.m. and 4:00 p.m., when the sun's rays are strongest.
