The sun is essential for life, however too much light from the sun can be harmful. The dangers of excessive sun exposure and associated ultraviolet radiation (UVR) are evident with some skin cancers and eye conditions.
What is ultraviolet radiation?
Ultraviolet radiation is part of the light spectrum and consists of UV A, UV B and UV C with a wavelength of 10nm to 400nm. UVC rays are the highest-energy UV rays and potentially could be the most harmful to your eyes and skin. Fortunately, the ozone layer blocks virtually all UVC rays but the depletion of the ozone layer could allow high-energy UVC rays to reach the earth's surface and cause even more serious UV-related health problems, than currently exists from UV A and UV B alone.
The effects of ultraviolet radiation
The effect of ultraviolet radiation (UVR) on the eye can include damage to your retina, leading to blurred or distorted central vision, non-cancerous growths on the surface of the eye, cataract development and even cancer of the eyelids. Most UV-related eye problems occur very gradually after many years of repeated exposure but it's also possible to get painful sunburn of the eyes from just a few hours in bright sunlight.
Sun protective eye-wear for adequate UV protection
It is important to protect our eyes against the adverse effects of ultraviolet radiation (UVR). Sunglasses offer the greatest protection against UV rays, however not all sunglasses are equal. In order to offer the best protection, sunglasses need to have 100% UV protection or a UV 400 coating. Frames ideally should have a close fitting, wraparound design to limit the amount of light entering the eye from above and the side of the lenses. This together with larger lenses for coverage of the delicate skin around the eyes, offer the ideal sun protection. Wide brim hats are also an excellent supplement for adequate UV protection.
When to wear sun protective eye-wear
While UVR is predominantly found outdoors, they can also be emitted from artificial sources. Protective eyewear is therefore necessary indoors when engaging in activities that involve welding machines, tanning beds and lasers to name a few. The eye protection necessary is similar to that of sunglasses however the lenses do not have to be tinted. Contact lens wearers can enjoy an added measure of protection. Contact lenses with a UV-blocking feature are available. These contact lenses should not replace your sunglasses, but they do provide excellent added protection by blocking much of the UVR that can seep in from around your sunglasses, as well as offering additional protection indoors.
In addition to the protective measures mentioned above the following factors are important to consider; the time of day you choose to spend outside is important. The high-risk periods in the UV Index are between 10 a.m. and 4 p.m. It is estimated that at midday, UVR can be 10 times higher than three hours earlier or later. Protective eyewear should always be worn when outdoors even on a cloudy day as UVR can still be emitted. Opt to find a shaded area but note that while a shaded area is preferable to direct sunlight, UVR can still reach you as it can be reflected of surfaces such as sand, concrete and buildings.
You may also want to read this article on myths about vision to learn to differentiate between fact and fiction concerning eye-care.
