What exactly are UV rays?
Ultraviolet rays are rays located beyond the visible spectrum. UV rays are categorized into three types: UVA, UVB, and UVC.
- UVA: Most common throughout the year. These rays pass through glass so the can be harmful both indoors and outdoors.
- UVB: The most dangerous type of UV rays and the primary cause of skin burning and retina harm. Rays do not pass through glass.
- UVC: Blocked by the Earth's Ozone layer and do not reach the Earth's surface.
Does where I live affect the amount of UV radiation I am exposed to?
Many factors determine how much UV you are exposed to, including:
- Time of year
- Time of day
- Weather conditions
UV rays are strongest in areas close to the equator. Because the sun is directly over the equator, UV rays only travel a short distance through the atmosphere to reach these areas. UV radiation is also the strongest near the equator because ozone in these areas is naturally thinner, so there is less to absorb the UV radiation.
UV exposure is lower in areas further from the equator because the sun is farther away. Exposure is also decreased because UV rays must travel a greater distance through ozone-rich portions of the atmosphere to reach the earth’s surface.
UV exposure is also greater in areas of snow, sand, pavement, and water due to the reflective properties of these surfaces.
Altitude is another contributing factor to the amount of UV. Higher altitudes have greater UV exposure because there is less atmosphere to absorb UV rays.
Time of Year
The sun’s angle in relation to the Earth varies according to season. During the summer months the sun is in a more direct angle, resulting in a greater amount of UV radiation.
Time of Day
UV is most intense at noon when the sun is at its highest point in the sky, and UV rays have the least distance to travel through the atmosphere. Especially in the hot summer months, it is a good idea to remain indoors during the peak sun hours of 10am and 4pm.
Many people believe that you cannot get sunburned on a cloudy day; this is simply not the case. Even under cloud cover it is possible to damage your skin and eyes, and cause long-term damage. It is important that you protect yourself with sunscreen, even in cloudy weather.
Some surfaces, such as snow, sand, grass, or water can reflect much of the UV radiation that reaches them. Sunglasses rated for 100% UV protection, a wide-brim hat, and broad-spectrum sunscreen can help protect your eyes and skin from reflected UV rays.
Can certain medical problems increase my risk for damage from UV rays?
Yes. People with cataracts (and those who have had cataract surgery), macular degeneration or retinal dystrophies should be extra careful. Read more about these conditions in our Eye Problems and Diseases section.
What are my options to prevent UV damage to my eyes?
You must wear sunglasses to prevent damage to your eyes. While some contact lenses provide UV protection, they don't cover your whole eye, so you still need sunglasses.
Look for sunglasses that protect you from 99 to 100 percent of both UVA and UVB light. This includes those labeled as "UV 400," which blocks all light rays with wavelengths up to 400 nanometers. (This covers all of UVA and UVB rays.)
Also, you may want to consider wraparound sunglasses to prevent harmful UV rays from entering around the frame.
What are the different kinds of lenses that are available?
With so many lenses available, it's a good idea to ask a professional optician for help when choosing sunglasses. Different tints can help you see better in certain conditions, and a knowledgeable optician can help you choose sunglass tints that are best suited for your needs.
Blue-blockers block blue light and sometimes feature amber lenses. Some evidence indicates blue light is harmful and could increase risk of eye damage from diseases such as macular degeneration. These lenses are popular among skiers, hunters, boaters and pilots who use them to heighten contrast.
Both polarized lenses and anti-reflective coating cut reflected glare. Polarized lenses in particular are popular with those who play water and snow sports. Anti-reflecting coatings reduce glare caused by light reflecting off the back surface of your sunglass lenses.
Do mirrored lenses offer better UV protection than standard lenses?
No. Mirrored lenses are coated with a metallic coating that is partially reflective. Mirrored lenses are good for sports and driving where glare is an issue.
Gradient lenses are tinted from the top down, so that the top of the lens is darkest. These lenses are good for driving, because they shield your eyes from overhead sunlight and allow more light through the bottom half of the lens so you can see your dashboard clearly.
Double gradient refers to lenses that are also tinted from the bottom up: The top and bottom are darkest and the middle has a lighter tint. Double gradient lenses are a great choice if you want sunglasses that aren't too dark, but shield your eyes well against bright overhead sunlight and light reflecting off sand, water and other reflective surfaces at your feet.
Photochromic lenses adjust their level of darkness based on the amount of UV light they're exposed to. Read more about photochromic lenses.
Multifocal sunglasses. Over age 40 and experiencing presbyopia? Not a problem. Virtually any type of sunglasses can be made with progressive lenses, bifocals or trifocals.
Do I need to worry about infrared rays?
Infrared rays are located just past the red portion of the visible light spectrum. Though infrared radiation produces heat, most experts agree that the sun's infrared rays do not pose a danger to the eyes.
Which lens color is the best?
Lens color is a personal choice and doesn't affect how well sunglass lenses protect your eyes from UV light. Gray and brown are popular because they distort color perception the least.
Athletes often prefer other tints for their contrast-enhancing properties. For example, yellow lenses are popular with skiers and target shooters because they work well in low light, reduce haze and increase contrast for a sharper image.
Do I need to wear sunglasses on a cloudy day?
UV rays still permeate through clouds and can still cause damage to your eyes. It is recommended you wear protective eyewear on both sunny and cloudy days.
Are impact-resistant lenses necessary?
The FDA requires all sunglass lenses to be impact-resistant. If you play sports or wear sunglasses on the job, you might want to consider ultra-impact-resistant polycarbonate lenses for even greater eye safety.
Do darker sunglass lenses provide more UV protection than lighter lens tints?
Darker sunglasses decrease the amount of visible light that passes through the lenses compared with lighter lens tints, but they don't necessarily provide greater protection from UV rays (which are invisible). For adequate protection, have your optician make sure your sunglasses block 100 percent UV, regardless of the color of the lenses.
Children don't need sunglasses, do they?
Children's sunglasses are essential. Children are at particular risk because they're in the sun much more than adults, and their eyes are more sensitive as well. UV damage is cumulative over a person's lifetime, which means you should begin protecting your child's eyes as soon as possible.
Most parents would not allow their children to go outside without shoes, yet many seem unaware of the need to protect their children's eyes.
I wear glasses. What options are available to me?
You can buy prescription sunglasses or glasses with photochromic lenses (which change from clear to dark) from your eye care practitioner. Clip-ons may be a less expensive option, and can be bought at the same time as your regular eyeglasses to perfectly match the frames.
Some eyeglass frames include sun lenses that magnetically attach to the frame. This gives you the convenience of clip-on sunglasses with less risk of scratching your prescription lenses.
Can sunglasses designed for specific sports really make a difference?
Yes. Sports eyewear in general tends to be safer than regular sunglasses because the lenses and frames are made of special materials that are unlikely to shatter if struck and can give you the benefits of both sunglasses and protective eyewear.
Also, certain lens colors in performance sunglasses can enhance your vision for certain sports; brown, for example, is popular with golfers because it provides nice contrast on those very green golf courses.
Make your appointment today
Due to COVID-19 safety protocols, all eyewear services are currently by appointment only. Please call to make an appointment.
At Golden Eye Optometry, we view good vision care as front line protection at every age. A routine eye exam can detect more than poor vision. It can shed early light on glaucoma, macular degeneration, cataracts and diabetes.