Summertime means a few of your favorite outdoor activities are about to come back into full swing. Whether you enjoy hiking, biking, gardening, or some other activity, it’s important to always wear your sunglasses when you plan on being outside for an extended period of time. Sunglasses do an array of good for your eyes, like protecting them from UVA and UVB rays—even in winter. But what exactly are these different rays? And what do they mean for your eye health?
Before getting into specifics, it would be beneficial to understand what UV rays are in the first place. UV rays are a form of ultraviolet light, which is a particular wavelength that is invisible to the human eye. They come through the atmosphere and can damage our skin and eyes. If we are exposed to them in high enough doses, they can cause diseases such as skin cancer.
UVA rays are a subset of the overarching term of UV rays. UVA rays have a specific wavelength within the category of ultraviolet light, ranging about 320-400 nanometers. This is quite small, which is what makes it sit just outside the spectrum of visible light. UVA rays are the most abundant that reach the earth, so they are the most common, and they are the source of many skin-related issues. They are the cause of things like basal and squamous cell skin cancers (deep tissue types). They also cause some more superficial damage, such as skin wrinkling and aging. These are also the rays that cause our skin to tan, which is a leading factor of melanoma after long exposure.
In contrast, UVB rays are far less common than UVA rays and aren’t as harmful in comparison. These are the rays that cause the most superficial damage, such as sunburns and skin rashes. The wavelength on these is about 290-320 nanometers, so they cannot penetrate the skin as deeply as UVA rays.
But what do these rays have to do with your eye health in particular?
Well, since these rays are the root cause of skin irritation and cancers, the same is true for your eyes. Prolonged exposure to these rays can irritate and dry out your eyes, and even lead to more complex conditions over time. They can decrease the quality of your vision and lead to cataracts later in life. It’s best to wear your sunglasses on cloudy or sunny days, as the rays can penetrate through the clouds and reach the earth (and your skin) just the same. So before you leave your house for an outdoor adventure, be sure to stock yourself on sunblock and sunglasses for your own benefit!
For more information on UVA/UVB rays, check out the information at SkinCancer.org.