Sunglasses are protective eye wear that prevent damage to the eyes from high energy light or sunlight. Sunlight include the Ultraviolet light spectrum and these rays may cause eye problems if the eyes are exposed to excessive amounts of UV radiation over a period of time.
There are 3 types of Ultraviolet Rays namely; UVA, UVB, and UVC.
UVA- Ultraviolet A
Passes through glasses easily, and has a longer wavelength. Protective eyewear can prevent damage to the eyes from this class of ultraviolet rays.
Medium-wavelength UVB rays do not go through the glasses; they are the most dangerous among the three, so sunscreen and sunglasses are a must when one is going out or at the beach.
The most damaging type of UV radiation. The atmosphere of the earth blocks these Short-wavelength UVC from reaching the earth’s surface.
When do UV Affects the Eyes
As some UV rays are able to easily pass through the clouds, when outside, it is advisable to wear UV-blocking sunglasses and broad-brimmed hats as sun damage to eyes can occur anytime during the year.
Other factors to consider are; reflection and glare, which are likely to occur around sand, snow, water or from the tarmac while driving. As a precaution, remember to put on suitable sunglasses in these environment.
Sunglasses that Protects Your Eyes
When purchasing sunglasses, it is advisable to look for the best quality available, one that will protect your eyes from any kind of damage regardless of the color, price or brand. The American Optometric Association (AOA) advises use of a frame that fit close to your eyes and contour to the shape of the face, to prevents any harmful UV ray from entering or damaging your eyes from all sides, even from behind.
Consider sunglasses labeled UV 400, as it can block rays as small as 400 nanometers. UV 400 covers both UVB and UVA rays.
Points to Consider when Buying Sunglasses
To choose the right sunglasses, consider the following;
- It should be able to block UVB, UVA at 99 to 100%.
- For proper color recognition, consider lenses that are gray in color.
- Always consider the amount of visible light. Proper sunglasses should screen out 75 to 90%.
- Lenses should be free from imperfection and distortions.
- Lenses should have a uniform tint.
- Most polarized lenses offer protection to your eyes.
- Remember, the ability to block UV rays is not determined by the degree of darkness or the color of your sunglasses but the quality.
- Optician or manufacturer can help in assessing and measuring the protection of sunglasses from UV rays.
- Ensures the lenses fit close enough to the face, but not too close to eyelashes to reduce any chances of stray light from reaching the eyes from any side.
UV rays can cause long and short-term problems to the eyes such as pterygium, cataracts, photokeratitis, various eye cancer and snow blindness. Always ensure that before purchasing your sunglasses, to check the label that it is UV 400 capable, so your eyes are protected from UVA and UVB rays.