Visible Light, UV Rays, and Sunglasses
Browsing the Olympic Eyewear website quickly reveals that the online distributor of wholesale eyewear has an extensive selection of sunglasses offering both UV and visible light protection. Their sunglasses come in a variety of shapes, colors, and styles as well, giving retailers plenty of options to choose from when stocking their own stores. The question is, how much do visible light and UV ratings matter?
According to the National Eye Institute, wearing sunglasses whenever you are outdoors is an important part of maintaining good eye health. They recommend a quality pair of sunglasses that offers 90 to 100% protection against both UV-A and UV-B radiation.
The government organization also goes on to say that exposure to harmful rays from the sun can lead to all sorts of problems. They estimate that upwards of 20% of all cases of cataracts are in some way related to sun exposure. And that is just one example.
Sunglasses were originally developed in an era before science knew about ultraviolet radiation. The Arctic’s ancient Inuit people developed the earliest form of sunglasses to protect against snow blindness. During the Roman and Greek empires, sunglasses were more about protecting the eyes against visible light. Not until the modern era did we realize just how important it is to protect the eyes against UV radiation.
UV radiation is solar energy contained in wavelengths not visible to the naked eye. These are wavelengths between 320 and 400 nm for UV-A radiation and 290 to 320 nm for UV-B radiation. When you read the label on a pair of sunglasses, the UV rating simply tells you that the lenses block radiation at that wavelength and lower.
The rule of thumb among manufacturers of sunglasses is a rating of UV 400. Such a rating indicates that the lenses block all ultraviolet wavelengths up to, and including 400. So a UV 400 rating means 100% protection against all UV-A and UV-B radiation.
Visible Light Protection
Visible light may not necessarily be as harmful to the eyes as UV radiation, but it can still cause problems. Studies have shown that extended exposure to bright, visible light can bleach receptors in the eyes. Over the course of time, bleaching can impair both night vision and color perception.
The big challenge with sunglasses is that there is no visible light equivalent to UV ratings. Experts recommend lenses that offer a filter of up to 75%, but sunglasses are not marked with that kind of rating. The only thing consumers can do is go with the darkest lens they can find that are still comfortable to wear.
There are some manufacturers and retailers who push sunglasses that protect against blue light exposure. However, the National Eye Institute offers no official recommendations for blocking blue light. If it is a concern for you, your best bet is to purchase orange or yellow lenses. Blue and purple lenses do very little to block blue light.
It is All in the UV Rating
Now you know that protection against visible light and UV rays is important when choosing sunglasses. If you have to choose between the two, choose UV protection. Ultraviolet radiation is among the most dangerous forms of sun energy we know of to date, at least where the eyes are concerned.
Whether you’re purchasing wholesale sunglasses in bulk from Olympic Eyewear or just a single pair down at the local pharmacy, look at the label. Do not buy a pair with a UV rating less than 400 if you want maximum protection against all UV-A and UV-B radiation. Your eyes will thank you.