I picked up some new prescription glasses this week since it’s been a few years since I purchased new glasses. I’m cheap about some things but I don’t mind paying extra for good quality lenses, since I use my eyes all the time. I also checked that these fancy lenses come with UV protection, which they have.

I have worn glasses and contact lenses for most of my life and one advantage to this is that I get a bit of added protection from the sun’s rays. Even if you buy inexpensive lenses, it’s always a good idea to pay a few extra dollars to get the UV coating added to protect you from the sun. So, what is sunlight anyway?

The 19th century British artist J.M.W. Turner’s last words are supposedly “the sun is god” and if that’s true, he had a good point. All energy on earth originates from sunlight, even our fossil fuels are just the remains of prehistoric plants and animals. You can think of light as a thing (called a particle, known as a photon) or as a disturbance that moves or radiates (called a wave). It can be both. If you figure how the two go together, you will literally get a Nobel prize and go down in history.

Sunlight energy comes in three flavours: light (this is visible radiation, which has low energy and generally can’t hurt us); heat (this is infrared radiation, which has enough energy to burn things); and UV light (ultraviolet radiation, which has the so much energy that it can change your DNA and cause cancer).

The best analogy that I’ve heard for how the sun’s light affects us is to think of light particles (photons) as many balls that the sun throws at us. Visible light is like getting hit by many ping pong balls, but UV light is like getting hit by a smaller number of hardballs. Luckily for us, only three per cent of the sunlight that hits us is UV light.

Ultraviolet light comes in three strengths: UV-A called soft UV, which has the least energy (this is what is produced by blacklight bulbs); UV-B which is medium wavelength and is mostly absorbed by the earth’s ozone layer; and UV-C, called hard UV;, which is also an ionizing radiation, just like nuclear radiation or cosmic radiation. Thankfully, UV-C is almost completely absorbed by the ozone layer before reaching the earth’s surface, and us. If you live in the north, you can actually see ionizing radiation as it hits the upper atmosphere and makes it glow, called the Northern lights.

Actually, a little UV-B is good for us; it has a sterilizing effect which helps treat wounds and skin conditions, it is important for plant growth and five to 15 minutes of casual sun exposure of hands, face and arms two to three times a week during the summer months is sufficient to keep your vitamin D levels high.

However, eye exposure to the sun’s UV-B can damage the lenses, causing cataracts which cloud your vision, or cause growths on clear part of the eye (the cornea), such as Pinguecula or Pterygiums, or damage to the sensors on the back of the eye (the retina) such as macular degeneration.

I’ll try to put a positive spin on this by saying that our short northern summers reduce the risk of eye damage due to intense sunlight. While it’s here, let’s enjoy the sun by wearing sunglasses with 100 per cent UV protection (or prescription glasses that have a UV coating) wear a hat that shades your eyes, and know that the UV light gets through to you even on cloudy days.

James Golemiec is a Canadian Registered Safety Professional with over eleven years’ experience coordinating and managing complex safety systems at manufacturing facilities and performing inspections on project job sites across Canada.