Good Vision is something that we can easily take for granted until a problem develops. Many times it can be too late to rectify that problem once the trouble starts. So, what can we do to insure that the our vision will be able to function at its highest efficiency throughout our lifetime?
Being visually oriented beings from birth and taking in the world through our eyes makes us extremely dependent upon this ability to function at a high level throughout our lifetime. Let’s look at some of the dangers to our eyes which lurk in our environment , as while as, some of the steps we can take to prolong health of our eyes.
Eyes function by taking in the light around us to create the images, objects and colors of things that surround us but this light itself can have a degrading effect upon our eyes over a lifetime of use. While most of us are aware of the dangers of sunlight that can cause sunburn and skin cancers from the ultraviolet (UV) radiation in sunlight, we do not often realize that UV light can be causing the same damage to our eyes. Extended exposure to sunlight has been linked to eye damage such as cataracts, macular degeneration, pingueculae, pteygia and photokeratitis that can cause temporary vision loss. And some of the newest research shows that high-energy visible (HEV) radiation(also called blue light) may increase your long-term risk of macular degeneration.
Let’s take a moment here to explain a bit about Macular Degeneration. It has been reported on more commonly in the health news field in recent years and may be a term you have heard before. It can occur over a lifetime and is usually beginning to be noticeable in people in their 50s to 60s. The macula is a small spot near the center of the retina and the part of the eye needed for sharp, central vision, which lets us see objects that are straight ahead. Damage to this area will not cause vision loss but will degrade our ability to distinguish faces, see objects directly in front of us, drive, read, write or to do close work like cooking or fixing things. It can occur in one or both eyes and the damage is not reversible.
UV light is a band of light that is above visible light, therefore invisible to us but having more energy than visible light. It is divided up into three (3) categories: UVA, UVB and UVC. Each type is distinguished by different wave-lengths.
UVC light has the shortest wave-length and contains the most energy. It has the greatest potential for damage to our eyes and skin. Fortunately, UVC light is blocked almost entirely in the atmosphere by the ozone layer. Unless you live or work near the North and South Poles where the ozone layer is depleted during the summer months, you are safe from the effects of this light.
UVB light has a slightly longer wave-length and is partially filtered out by the ozone layer. But some of it does reaches the ground and in low doses it is able to stimulate the production of the skin pigment Melanin, which causes the skin to darken and gives you that healthy suntanned look. In higher doses it is responsible for sunburn, increased risk of skin cancers, skin discoloration, wrinkles and premature skin aging. Not a lot of UVB energy can get through the cornea of the eye and it is not a problem for most people. Overexposure, however, can aid the development of pingueculae and pterygia which are unsightly growths on the surface of the eyes that are known to cause corneal damage and distort vision. When short-term, high exposure levels of UVB happen, the result can be a painful condition called photokeratitis, more commonly called “Snowblindness” where vision can be totally lost for 24-48 hours.
UVA light is closest to the visible light spectrum and has the longest wave-length of the ultraviolet lights. It has the lowest energy of the UV spectrum but is able do the most permanent damage. It easily passes through the cornea of the eye and can reach the lens and retina inside the eye. Research has linked UVA exposure to certain types of cataracts and it may play a role in the development of macular degeneration.
High energy visible light (HEV) , often called “Blue Light” is part of the visible spectrum of light. It has lower energy than the UV spectrum but can penetrate deeply into the eye. There it plays a role in the development of macular degeneration and can cause retinal damage.
So what can we do to protect our vision, especially at times like vacations when outdoor activities can expose eyes to increased amounts of sunlight? A good start is to realize the factors that increase eye damaging exposure.
TIME OF DAY – The sun is strongest from 10 AM to 2 PM when it is highest in the sky.
LOCATION – The closer a geographic location is to the equator the more sunlight energy it will receive.
MEDICATIONS – Use of Tetracycline, birth-control, sulfa drugs, tranquilizers and diuretics can increase your sensitivity to both UV and HEV radiation.
ALTITUDE – The higher the altitude the greater amount of UV radiation reaching the earth.
SETTING – UV and HEV levels are highest in open settings where little shade is available. Sand, water and snow will reflect most of the light radiation back towards your eyes that would otherwise be absorbed by your surroundings.
While a cloudy day may help with HEV exposure, UV radiation penetrates clouds and is the same as on a clear day.
The damage to the eyes from light radiation is cumulative and can add up over the years. One of the best precautions is to purchase and wear a good quality pair of sunglasses that are rated to block 100% of UVA and UVB radiation. Wraparound glasses offer the greatest protection by blocking light reflected from the top, sides and bottom, around the sunglass lenses.
Color also matters. Bronze, tan, amber, copper and blue blocking lenses will screen the greatest amount of HEV light away from the eyes. They are particularly useful in snow situations in blocking the great amount of light (up to 80%) reflected from snow in winter.
Always wear sunglasses when out in the sun, even in a shady area and while driving. Much of the damaging UV light is reflected towards the eyes off roadways, buildings and other surrounding surfaces. Sunglasses are also necessary even if your contact lens provide protection from UV rays. They can only protect the part of the eye directly beneath them and leave the rest of the eyes exposed to damage.
Some people have heard that people with dark eyes are more protected from light damage to the eyes. This is not true and people with dark eyes are just as susceptible to light damage as those with light eyes and fair skin.
Wearing a hat to minimize the amount of light entering the eyes is a good idea too.
Finally, diet can play a large role in protecting the eyes from damage. Many recent studies have shown that higher levels of vitamin C in the blood plasma and the presence of anti-oxidants have a protective ability to ward off macular degeneration and other forms of damage to the eyes. These nutritional components can be easily obtained by eating a healthy diet including fresh fruits and vegetables and through the intake of dietary supplements.
As your mother may have told you,” You only have two eyes, so take good care of them”. With a little planning and the proper precautions your eyes can easily function at their highest efficiency throughout your lifetime.