Fashion aside, sunglasses serve an important purpose: protecting eyes from the harmful rays produced by the sun. You’re probably well aware of the need to protect your skin from the sun, but it’s equally important to protect your eyes.
About UV rays?
Ultraviolet (UV) radiation consists of invisible rays from the sun. The three bands of UV light are: UVA, UVB and UVC. UVC rays are of little concern as they are absorbed by the upper atmosphere and do not reach the earth’s surface.
UVB rays are the ones that burn the skin and can damage the eyes. Combined with cold wind and snow, UVB has the potential to cause snow blindness (photokeratitis), a temporary (lasting 12 to 48 hours) but painful problem in the cornea of the eye.
Although not all scientists agree, there is some research that suggests that daily exposure to UVB in very bright sunlight over a period of many years may cause cataracts, a gradual clouding of the lens of the eye.
Experts also suspect that the primary cause of eye growths such as pingueculae or pterygia is exposure to UVB rays.
People with cataracts (or who’ve had cataract or lens replacement surgery), macular degeneration, and retinal dystrophies should be extra careful.
Does colour matter in sunglasses?
Sunglass lens colors are really a personal preference -some change your perceptions of color, brightness and contrast, and some don’t. A neutral density gray will darken the world but not change your color perceptions. Certain lens colors can enhance your vision for certain sports; brown, for example, is popular with golfers because it provides nice contrast on those very green golf courses.
What is the most important feature to look for in a sunglasses?
The most important feature to look for in a sunglass lens is how much UV radiation it absorbs — you want 100% for maximum protection. Look for sunglasses that protect you from 99% to 100% of both UVA and UVB light. This includes those labeled as “UV 400,” which blocks all light rays with wavelengths up to 400 nanometers. (This covers all of UVA and UVB rays.)
Inferior sunglasses can be more damaging to your eyes than wearing no sunglasses at all. When one wears sunglasses the pupil widens; if the sunglasses have poor UV protection, then the eyes are damaged more by the sun’s rays.
It is also important to get lenses that are ground rather than punched, to minimize distortion. You may want to consider wraparound sunglasses to prevent harmful UV rays from entering around the frame. Polarized lenses are great for those who spend time on water, drive a lot, etc. The polarization actually cuts out the light coming from the horizontal meridian while allowing in the light coming in from the vertical meridian. In other words, it blocks the light that reflects in from water or the highway, reducing glare.
Is standing in the shade as good as wearing sunglasses?
Sunglasses reduce the UV more than if you were to stand in the shade, since the shade more or less evenly attenuates all wavelengths, visible and UV, while sunglasses preferentially attenuate shorter wavelengths (i.e., UV wavelengths).Thus, sunglasses provide more protection than shade alone.
Is it necessary to wear sunglasses in the winter?
While the sun’s rays feel less intense during wintertime, they are still strong enough to worry about eye damage, including the snow blindness mentioned above. New snow can reflect up to 80% of ultraviolet rays, according to the World Health Organization.
Should children wear sunglasses?
Children are at particular risk because they’re in the sun much more than adults, and their eyes are more sensitive as well. UV damage is cumulative over a person’s lifetime, which means you should begin protecting your child’s eyes as soon as possible.
Most parents would not allow their children to go outside without shoes, yet many seem unaware of the need to protect their children’s eyes.
When is sunlight most ar risk?
Most people think that they’re only at risk when they’re outside on a sunny day, but UV light can go right through clouds, so it doesn’t matter if the sky is overcast. The sun’s rays are strongest between 10 am and 2 pm.
Glare and reflections can give you trouble, so have your sunglasses ready if you’ll be around snow, water or sand, or if you’ll be driving (windshields are a big glare source).
The following put you at additional risk: sunlamps, tanning beds and parlors, photosensitizing drugs, and living at high altitudes or near the equator.