Eye damage (part 3)

Eye damage

picnics.... graduation parties.... cookouts.... direct contact with sunlight for long periods of time....
Maybe we can protect our skin with sun blocks, but what about our eyes....

 First I'm going to give you a little hint about what the eye is all about....
This is a section in the human eye ball showing its different structures...
light travels through the cornea, then through the pupil which is a small hole in the colored iris, through the lens to the retina which is the part of eye which perceives light and translate it into electricity to go through the optic nerve to the brain to be interpreted as visual information.....


What is UV radiation?
Alot of us know about the hazards of UV rays on our skin ( refer to the first article for more information )...
but a few of us realize how dangerous is the UV rays on our eyes, whether natural or artificial, it can cause severe damage to surface eye structures as the cornea and lens....

UV radiation consists of invisible rays from the sun.... There are three types of UV radiation: UVA, UVB and UVC.
UVC rays do not pose any threat, as they are absorbed by the ozone layer.
However, exposure to UVA and UVB rays can have adverse effects on your eyes and vision. Short- and long-term exposure to these dangerous rays can cause significant damage. It is important to note that UV radiation can also be given off by artificial sources like welding machines, tanning beds and lasers.


Short-term effects of UV radiation:

If you are exposed, unprotected, to excessive amounts of UV radiation over a short period of time, you are likely to experience an effect called photokeratitis. Photokeratitis is an inflammation of the cornea caused by a brief exposure to UV radiation, usually when combined with cold wind and snow. Like a "sunburn of the eye", it may be painful and may create symptoms including 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 effects of UV radiation:

Long-term exposure to UV radiation can be more serious. Scientific studies have shown that exposure to small amounts of UV radiation over a period of many years may increase the chance of developing a cataract, which is opacity of the lens, and may cause damage to the retina. This damage to the retina is usually not reversible. Cumulative damage of repeated exposure may contribute to chronic eye disease, as well as increase the risk of developing skin cancer around the eyelids. Long-term exposure to UV light is also a risk factor in the development of pterygium (a growth of conjunctiva that invades the corner of the eyes) and pinguecula (a yellowish, slightly raised lesion that forms on the surface tissue of the white part of your eye, which we Egyptians suffer from it by a considerable percentage).

How can I protect my eye from UV radiation?

It is not yet known how much exposure to UV radiation will cause how much damage, but a good recommendation is to wear quality sunglasses that offer good protection and a wide-brimmed hat when working outdoors, participating in outdoor sports, taking a walk, running errands or doing anything in the sun.

To provide protection for your eyes, your 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.

•Have lenses that are gray for proper color recognition.
 
Finally, even if you are wearing contact lenses that have UV protection, you still need to wear sunglasses. UV rays will likely affect the eye tissue that is not covered by the contacts. Your eyes will be more comfortable, too, with most of the bright light blocked.