According to a government website, the amount you pay for a pair of sunglasses isn’t as important as the protection they offer. Here are health tips for choosing sunglasses from Health Canada.
Different kinds of light
The kinds of light most likely to injure your eyes are:
• ultraviolet radiation or UV rays, which are invisible
• bright or intense light
• blue light
Because UV rays carry more energy than visible light rays, eyes are at a greater risk of being damaged by absorbing UV rays than from any other kind of light. Most of the damage caused to eyes by UVB and UVA light happens over a long period of time. This type of light can cause or speed up the progress of several diseases that affect the eye or its supporting structures. Sensitivity to ultraviolet light varies from one person to the next.
Blue light is light visible in the blue portion of the color spectrum. Blue light is found in the intense glare of light reflecting off of snow or water. Eyes can’t focus clearly in blue light and some scientists believe that regular exposure to blue light over many years can age the retina and increase the risk of blindness in people over sixty years of age.
How Light Can Damage Eyes
If the eye’s natural ability to heal itself is overwhelmed, your eyes could be permanently damaged. Over-exposure to ultraviolet light could damage the front portion of the eyes. Visible light that is too bright or intense can damage the retina and cause permanent vision loss.
Snow blindness, a temporary but uncomfortable condition, can be caused by UV light combined with wind and dryness of the eyes.
Properly chosen sunglasses protect against the damage caused by all three types of light. When driving a car in bright light, sunglasses reduce glare and improve contrast.
Different kinds of lenses meet different needs:
• Regular lenses reduce the brightness of everything equally.
• Polarized lenses are designed for driving and outdoor activities in the snow or on the water because they cut reflective glare. Medium to dark lenses with a grey, or a slightly brown or green tint, will filter out most blue light.
• UV light turns photochromic lenses darker when outdoors and lighter indoors.
• Mirrored lenses reflect all or part to the light instead of absorbing it however, they scratch easily so choose a pair with a scratch-resistant coating.
Price, color or the darkness of the lenses are not indicators of how much UV protection a pair of sunglasses will provide. Lenses should be dark enough to ensure your eyes’ comfort but not so dark that they reduce your vision.
Most sunglasses are fitted with plastic lenses because they are less likely to shatter. Look for a pair with a scratch-resistant coating and a label that lists the type and amount of protection they give.