May 25, 2013 – Yes, your eyes can get a sunburn – and during any season of the year!
Without protective eyewear your eyes can receive extensive UV exposure that can result in a condition called 'photokeratitis' which feels like particles of sand are trapped inside your eye socket and under your eyelid - scratching and burning your eyes. Reflections from water, sand, snow, concrete and glass can inflame the cornea and conjunctiva within minutes.
The front clear surface of the eye, called the cornea, is composed of epithelial tissue similar to our skin and it is very susceptible to environmental elements like the sun and the wind. It can take up to 72 hours for your eyes to heal, and in this time, you may experience reduced or blurred vision. Photokeratitis is treated with eye drops and rest.
While squinting may protect your eyes, it can lead to headaches and eye strain so the best protection is a pair of sunglasses that will block UVA and UVB rays. Prolonged exposure of UV rays can also be a contributing factor to such conditions as macular degeneration, cataracts, and melanoma.
Here are a few guidelines that will help you choose the right sunglasses for your and your children:
- Make sure the lenses are dark enough for visual eye comfort and that they do not reduce your vision.
- If you have sensitive eyes, wear sunglasses with a darker lense. They will keep out 85% of light. 75% is considered a medium dark lense.
- Wear medium to dark lenses with a grey, or slightly brown or green tint to block 'blue light' if you spend a great deal of time outdoors where there is a lot of glare from sunlight. Blue light is visible light in the blue portion of the colour spectrum. Your eyes cannot focus clearly in blue light. Some scientists believe that routine exposure to blue light over many years may age the retina and increase the risk of blindness in some people over the age of sixty.
- Choosing grey, grey-green or brown sunglass lenses will allow you to see true colour.
- Yellowish lenses block blue light. People who play sports such as golf prefer yellow lenses because they offer ocular precision and sharp object definition.
- Plastic lenses are tougher than glass and less likely to shatter. If you buy plastic lenses, look for a pair with a scratch-resistant coating.
- Check the lenses for distortion. Put the sunglasses on and look at a rectangular pattern in your view, such as floor tiles or boxes on a shelf. If the lines stay straight when you move your head up and down, and side-to-side, then the amount of distortion is acceptable.
Do you know the difference between lenses?
Regular lenses reduce the brightness of everything evenly.
Polarized lenses greatly reduce reflected glare, such as sunlight off water or snow and are especially effective for driving.
Photochromic lenses alter with the intensity of UV rays by turning darker when you are outdoors and lighter when you are indoors. Please note that while they darken quickly, they take several minutes to return to their lightened shade.
"Flash" or mirror lenses reflect all or part of the light instead of absorbing it. They offer no performance advantage and they do not have a scratch-resistant coating. Mirror coating lenses are purely cosmetic.
Gradient sunglasses are usually darker on the top than on the bottom. These sunglasses may prove beneficial for someone with unstable footing or depth perception difficulty.
Just by looking at a pair of sunglasses, you cannot tell how much UV protection they will provide. A label attached to the sunglasses will tell you what type of sunglasses they are and the amount of protection they will provide. Manufacturers follow 'voluntary' industry standards when labelling sunglasses. Sunglasses that comply with industry standards are grouped in three categories:
Cosmetic sunglasses have lightly tinted lenses for use in sunlight that is not harsh. They block 0 to 60% of visible light and UVA rays, and between 87.5 to 95% of UVB rays. These glasses are not recommended for daytime driving.
General-purpose sunglasses block from 62 to 92% of visible light and UVA rays, and between 95 to 99% of UVB rays. General purpose sunglasses are good for driving, and recommended for harsh sunlight that causes you to squint.
Special purpose sunglasses block up to 97% of visible light and up to 98.5% of UVA rays. They also block at least 99% of UVB rays and are suitable for prolonged sun exposure. These sunglasses are not recommended for driving.
Health Canada's web section on Ultraviolet Radiation.
Health Canada's UV Index Sun Awareness Program.
Health Canada's Safe Summer Fun Web section.
Health Canada - Sun Safety section
The Canadian Association of Optometrists Eye Health Library.
Visit Health Canada's Consumer Safety Portal for safety information about food, health and consumer products
Health Canada – Sunglasses and UV Rays