Do You Need Sunglasses?

Why Do You Need Sunglasses?

Sunglasses can help your eyes in two important ways. They enhance the normal light-filtering capabilities of your eyes and they protect against the sun’s damaging rays. Good sunglasses will reduce glare, filter out 99 to 100 percent of ultraviolet (UV) rays, provide visual protection, be comfortable and not distort colors.

How does the sun damage the eyes?

The sun emits three types of rays:

  • visible, which is what you see as color
  • infrared, which is invisible but felt as heat
  • ultraviolet, which is invisible but often called the “sunburn rays”

The invisible UV rays can damage your eyes. Some of the damage can be immediate, while some occurs over a life-time of exposure. Chronic exposure to bright sunlight can damage the cornea (the outer transparent part of the eye that transmits light to the retina), the lens (the part of the eye responsible for focusing), and the retina (the innermost layer of the eye that transmits an image to the brain).

How Can Sunglasses Protect Your Eyes From UV Radiation?

Good quality sunglasses help to protect your eyes from harmful UV radiation. When you purchase sunglasses, look for a statement on the amount of UV radiation that is blocked from reaching the eye through the sunglass lens.

The rule of thumb is that the less UV rays that get through, the better. Experts recommend that to protect your eyes from harmful rays, your sunglasses should block 99 to 100 percent of both UV-A and UV-B rays. Since as much as 50 percent of sunlight comes from overhead and gets by many glasses, a brimmed cap or hat should also be worn for maximum sun protection. Eye-wear that wraps around the face also helps minimize the amount of harmful light entering the eyes.

Furthermore, lenses should block at least 70 percent of visible light (that is, they should transmit no more than 30 percent). But even this can vary with the situation. In areas where light is intense, such as at the beach or on snow, as little as 10 to 15 percent transmission is preferred.

As a consumer, it may not be easy for you to identify which sunglasses provide what protection, since manufacturers do not always attach a tag or label stating the amount of UV radiation and visible light they block. However, there are various industry codes, such as those from the American National Standards Institute (ANSI). ANSI’s “Requirements for Non-Prescription Sunglasses and Fashion Eye-wear,” designated by the code Z-80.3, specifies different “type of use” levels for sunglass transmittance.

You should read labels carefully and look for the labels that clearly state that sunglasses block 99 to 100 percent of both UV-A and UV-B rays.

Who is At Risk For Eye Problems Caused By UV Light?

Everyone is at risk: no one is immune to sunlight-related eye problems. People who are at higher risk of developing problems from UV rays include adults who spend long hours in the sun, those who have had cataract surgery, and those who take certain medications, such as tetracycline, sulfa drugs, birth control pills, diuretics and tranquilizers that increase the eye’s sensitivity to light.

Quality and Safety of Lenses

Lenses should be inspected for such flaws as scratches, bubbles and distortions. Poorly made glasses will not damage the structure of your eyes, but flaws and distortion in the lenses may cause your eyes to work harder, and can result in squinting, blinking, tearing and even slight headaches, nausea and dizziness.

The Federal Food and Drug Administration requires that all lenses be impact resistant and made of optical quality glass or plastic–both of which can be purchased with or without a corrective prescription. This does not mean the lenses are shatterproof or unbreakable, but that they can withstand moderate impact.

Glasses for sports with flying balls or physical impact should be made of polycarbonate, which is the most shatter-resistant material widely available today. Polycarbonate is also the best choice for children’s sunglasses.

Selecting the right sunglasses is an important choice to protect your eyes and safeguard your vision. Your eye care professional can provide additional guidance should you have further questions.

Selecting Sunglasses For Children

When selecting sunglasses for children, keep the following suggestions in mind:

  • Check the sunglasses periodically to make sure they fit well and are not damaged. Children often don’t complain about their vision even when there’s a problem, so a periodic check may be necessary.
  • Select sunglasses that suit children’s active lifestyles. The glasses should be impact resistant (made of polycarbonate), lenses should not pop out of the frames, and the frames should be bendable, unbreakable and/or have snap-on temples. Children’s sunglasses should never be made of glass, unless required by their eye doctor.
  • The lenses should be large enough to shield the eyes from most angles (above, below and either side) and to block light that leaks in around the frames. The sunglasses should fit snugly against the bridge of the child’s nose, to reduce the amount of sunlight that enters the eyes.
  • Choose a wide-brimmed hat for your child to maximize protection. Wearing a hat can cut the amount of UV exposure in half.