This week is Sun Awareness Week. Over the last few years the sun has been the subject of some pretty confusing mixed reviews: Sunlight is good for you – No! It’s bad for you. You need to get out in the sunshine – You need to protect yourself from the sun’s rays. So which is the truth? Well, actually both. Sunlight is necessary for good overall health in all living things. It warms the air and helps plants to grow, and it provides a major source of Vitamin D needed for good health in humans. But like many good things, too much of a good thing can have a negative effect. Just as too much sunshine can dry out and kill plant life, overexposure to the sun’s rays can burn and damage our skin, and also our eyes. But how does this happen?
What is Sunlight?
Let’s begin by defining what sunlight is exactly. What we refer to as sunlight can be defined as a broad spectrum of both visible and invisible electromagnetic radiation. Visible light, of course, can be broken down into a number of colours, which can be seen either in a rainbow after a rainstorm, or by looking through a prism. An important part of visible light is known as High Energy Visible (HEV) light or “Blue” light. Blue light provides many benefits to people, but also has some negative effects, particularly due to the many ways that it has been recreated artificially. Invisible radiation can be broken down into infrared, X-rays, gamma rays and Ultraviolet (UV) rays. It is UV radiation that has the most effect on us, both positively and negatively.
What is HEV Light?
Much like UV radiation, HEV light has a short wavelength and therefore high energy output. But unlike UV rays, the likelihood of getting overexposure to blue light from sunlight alone is very slim. The danger of blue light exposure comes from the fact that it is also in virtually every electronic device we own from computers to tablets to smart phones to flat screen TVs. Limiting our exposure to these devices is very important for good eye health, and for good general health. But that is the subject of another discussion.
What is UV Radiation?
UV radiation is a short wavelength, high energy, invisible radiation that is a portion of what we know as sunlight. UV rays provide the energy that warms the air and tans your skin. In fact, it is the same radiation used in tanning beds. But if you have ever been out in the sun too long, you know that too much exposure to UV radiation can cause a nasty sunburn. UV radiation can also damage your eyes as well. Over exposure can cause or accelerate conditions such as Cataracts, Macular Degeneration, Photokeratitis (Snow blindness), Pterygium (Surfer’s Eye) or even skin cancer around your eyelids.
How Can I Protect Myself from UV Radiation?
The bottom line is that, while sunlight is good for you, it is best taken in moderation. Since you don’t want to avoid the sun altogether, the best thing to do is protect yourself when you are out in it. Wearing a hat and sunscreen can protect your skin and a good pair of sunglasses can protect your eyes. Since not all sunglasses are created equal, look for sunglasses that offer 99-100% protection from UV radiation and 75-90% screening of visible light. When in doubt, always check with your optometrist. Never take chances with your vision.