Ultraviolet radiation from the sun can cause cumulative damage to your eyes as you age — but you can protect your vision by wearing sunglasses every day, even in cloudy weather. Here's what you need to know about choosing the best sunglasses, to prevent age-related cataracts and other eye problems over time.
UV Radiation and the Aging Eye: As we get older, our eyes undergo physiological changes that can cause vision problems and eye diseases such as age-related macular degeneration and glaucoma. Ultraviolet light from the sun carries two types of radiation, UVA, and UVB rays (which also cause photoaging and wrinkling of our skin). Since UV light carries more energy than visible light, it can do greater damage to our eyes. As we age, the damage simply has more time to accumulate: a cataract, (cloudiness of the lens) for example, is believed to be caused by many years of exposure to bright sunlight.
How Do Sunglasses Help? Sunglasses designed to block 100% of UVA and UVB rays will protect your eyes against this cumulative damage.
How dark should you go? While very dark lenses might seem to offer greater protection, how dark the lens is only affects visible light, not ultraviolet light.
Natalie Hutchings, Associate Professor in the University of Waterloo's School of Optometry and Vision Science, says dark lenses can actually cause the pupil of your eye to get larger to let in more light, making UV protection even more important.
"Degree of darkness and lens color or tint are not the factors which protect your eyes," she tells me. "It's crucial to choose glasses which block 100% all of the UV light, both UVA and UVB. This protection can be a function of the material the glasses are made of, the thickness of the material, or it may be a coating on the lens — even in lenses without any color or tint at all. It's the 100% UV blockage you should look for on the label, since you can't tell whether they have it, just by looking at the glasses."
- Tips for Choosing the Best Sunglasses: According to the American Academy of Ophthalmology (AAO), the best sunglasses offer:
- 100% UV protection
- High optical quality (lenses are free of manufacturing defects like bubbles or waves that could bother your eyes
- Scratch-resistant lenses
- larger frame that offers more coverage of eye area
In addition, pick sunglasses that are comfortable and fit your face properly, because you'll be more inclined to wear them. Hutchings suggests that older adults may prefer larger, robust frames that are easier to handle with arthritic fingers.
What about polarized lenses? Hutchings says polarized lenses work on visible light (not UV rays), by blocking out polarized light that is reflected off of a horizontal surface like snow, water or a hot road. Consider polarized lenses if you ski, live near water, or find them more comfortable while driving. While these lenses are usually more expensive, you may find you prefer them as you get older.
When Do I Need to Wear Sunglasses? The AAO recommends recommends wearing sunglasses anytime you are outdoors, particularly in the summer, when the level of UV radiation is triple that of other times of the year. In addition, you should take care to wear sunglasses when on the water or in snow, when light rays are reflected.
Older adults may find they need to wear sunglasses more often than they used to, says Natalie Hutchings, because light passing through the cornea and lens is scattered to a greater degree in an aging eye. This scattering effect can be distracting and annoying, but it is alleviated with the use of sunglasses, especially larger ones that block light coming in from the sides.
What if I've had cataract surgery already? During cataract surgery a new intraocular lens (IOL) is inserted to replace the old cloudy lens. Most intraocular lenses now absorb UV light. If you had your cataract surgery some time ago, your lens may not absorb UV light, and you should wear sunglasses that offer that protection. The AOO recommends even people with UV-absorbing lenses after cataract surgery wear protective sunglasses.
- Read more: Can presbyopia be prevented or reversed?
Other Ways to Protect Your Eyes in the Sun: Sunglasses offer just one form of protection for aging eyes. Health Canada and other agencies advise also wearing a visor or wide-brimmed hat when you're outdoors, and avoiding times of brightest and most intense sunlight, such as summer days between the hours of 11am and 4pm (when the UV index is highest).
- Learn how to protect your skin in the sun:
- How high an SPF do I need?
- Which sunscreens are anti-aging?
- How much sunscreen should I use?
Aging and Your Eyes. US National Institute on Aging Public Information Sheet. Accessed June 25, 2013.
Natalie Hutchings. Associate Professor, School of Optometry and Vision Science, University of Waterloo. Interview conducted by phone May 21, 2013.
Sunglasses. Health Canada Public Information Sheet. Accessed June 25, 2013.
Sunglasses: Protection from UV Eye Damage. American Academy of Ophthalmology Public Information Sheet. Accessed June 25, 2013.