HOW DO ULTRAVIOLET (UV) RAYS DAMAGE THE EYES?

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 include tanning booths, black lights, germicidal lamps, mercury vapor lamps, halogen lights, high-intensity discharge lamps, fluorescent and incandescent sources, and some types of lasers.

UV is invisible light from the light spectrum and so cannot be seen and exposure occurs even when we are not in the sun. 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:

  1. UV-C: This is absorbed by the ozone layer and does not present any threat.
  2. UV-B: These are partially filtered by the ozone layer, and in low doses stimulates the production of a skin pigment (melanin), which gives you a suntan. In higher doses, UVB will cause the skin to burn, which can increase the chances of skin cancer. UVB radiation can also cause signs of premature aging of the skin, such as wrinkles, as well as skin discolourations. Your eyelids can often be at risk of UVB exposure, especially if sun cream has not been applied and many creams recommend against application around the eyes, putting you at greater risk.
  3. UV-A: These rays are very close to a visible light ray and emits lower energy than both UVB and UVC rays. Though UVA rays are mostly harmless to skin, they can pass through the cornea of your eye and reach the lens and retina causing cataract and macular degeneration (This is an incurable condition that causes blurred vision in the center of the visual field).

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 early onset of cataracts or macular degeneration.

To provide adequate protection for your eyes, sunglasses should:

  • block out 99 to 100 percent of both UV-A and UV-B radiation.
  • have lenses that are perfectly matched in color and free of distortion and imperfection; and
  • have lenses that are gray for proper color recognition.
  • Prescription lenses should have UV protection e.g Transitions or Crizal coatings
  • Ensure you buy contact lenses with UV protection.
  • 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 older citizens, children and teenagers. They typically spend more time in the sun than adults!

 

 

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