Now that the warm weather is starting to end, you might think you can stash those sunglasses for the winter season, but you may need them more than you think. Even in the winter harmful UV-A and UV-B rays can harm your eyes and have long-term and short-term negative consequences on your eyes and overall vision.
Not all of the sun’s rays are harmful. In fact, UV-C is absorbed by the ozone layer and doesn’t pose a threat to our eyes like UV-A and UV-B radiation can.
UV-A rays are the majority of the sun's natural light and are capable of penetrating deep into the skin. UV-B rays are the primary cause of sunburns. These rays are 1000x stronger than UV-A rays. UV-C rays, or short-wave radiation, are those absorbed by the atmospheric filter that is the ozone layer.
Another threat to our eyes is caused by strong UV-A and UV-B rays reflecting off of sand, concrete, and especially off of ice, snow, and water, into the eye(s) called snow blindness. Snow blindness is a form of photokeratitis, or an inflammation of the cornea, which can be likened to a sunburn of the sensitive tissues of the eyeball and eyelid. This inflammation can occur within a few hours of exposure. You might also be at a higher risk if you have lighter coloured eyes.
It is also important to note that the sun’s rays can pass through smog, haze, and thin clouds, which means hats and UV-blocking sunglasses are helpful even on those days when you question whether or not you’re safe. Better safe than sorry!
Knowing the UV Index Scale will also help you monitor your sun exposure. Much like a stop light, the index warns us when it’s time to Stop!, marked in red on the UV index scale below. “Green means go,” and is the low end of the scale when UV rays are a low danger for the average person. When the UV index warning is at 11 or higher this means that there is an extreme risk of harm if you are not protected from the direct sunlight.
Luckily, sunglasses that are capable of blocking most of the UV rays that we are exposed to, and can help to prevent the irritation, pain, and damage that can result from exposure to these rays.
When you’re shopping for sunglasses make sure to look for those that are labeled as “UV 400,” meaning that these will block all rays of light with a wavelength up to 400 nanometers (99-100% of UV-A and UV-B rays). Polarized lenses can cost anywhere from $15 to $180+, depending on the brand that you choose. A reasonable price is anywhere between $30-$75, but for those who work outside, do a lot of recreational activities on the water or in the snow, you should look at investing in frames that have a greater range of coverage around the eyes (and not just in front of them).