Recent information about UV radiation destroying Covid-19 virus allied with information about possible transmitting virus through your eyes’ conjunctiva, confused many people. As result, people stopped wearing sunglasses. And it is our professional concern.

Among abundant “health” devices there are talks about UVC lamp, that has germicidal properties. The confusion rises from not knowing that sunlight contains three types of UV. When we talk about your sunglasses and UV protection, we talk about UVA and UVB. UVC light is not part of our discussion. That’s because they absorbed by the earth’s atmosphere, making harmful effects of little concern.

UVA is capable of penetrating deep into the skin and is thought to be responsible for up to 80% of skin aging, from wrinkles to age spots.

UVB, which can damage the DNA in our skin, leads to sunburn and eventually skin cancer (recently scientists have discovered that UVA can also do this). 

Both are reasonably well known, and can be blocked out by most good sun creams.

UVC consists of shorter, more energetic wavelength of light. Scientists determined that UVC kills microorganisms and could be emulated by devices. Since the finding in 1878, artificially produced UVC has become a staple method of sterilization – one used in hospitals, airplanes, offices, and factories every day. Crucially, it’s also fundamental to the process of sanitizing drinking water; some parasites are resistant to chemical disinfectants such as chlorine, so it provides a fail-safe.

Even then, in a recent study, which looked at whether UVC could be used to disinfect PPE, showed that while it is possible to kill the virus this way, the amount of ultraviolet required varied widely, depending on factors such as the shape and type of material the virus was on.  

UVC is really nasty stuff – you shouldn’t be exposed to it,” says specialist of UV Light Technology. “It can take hours to get sunburn from UVB, but with UVC it takes seconds. If your eyes are exposed… you know that gritty feeling you get if you look at the sun? It’s like that times 10, just after a few seconds.”    

To use UVC safely, you need specialist equipment and training.

World Health Organization (WHO) has issued a stern warning against people using UV light to sterilize their hands or any other part of their skin.

Can UVA and UVB protect you against virus at all?

Possible. But don’t rely on it. “Two factors are required for UV light to destroy a virus: intensity and time,” says professor of Environmental Health. “But if the light is intense enough to beat apart a virus in a short time, it’s going to be dangerous to people … it will damage tender tissue such as the eyes.”

Please, keep wearing your sunglasses, which is sunscreen for your eyes !