Protecting your children's eyes with sunglasses

Donya Betancourt, Pediatrician, Sanur, Bali, drdonya@hotmail.com

Have you ever wondered if children should wear sunglasses? The sun gives off many different types of radiation. Overexposure to ultraviolet radiation causes skin and eye damage.

UVB is the most damaging and is responsible for sunburn, suntan, skin aging, skin cancer and eye damage. UVA also causes skin and eye damage and increases your risk of developing both common skin cancer and melanoma.

Ultraviolet radiation (UVR) cannot be seen or felt. The amount of UVR varies through the year and through the day. The amount of UVR is greatest when the sun is directly overhead and the distance the sun's rays need to travel to reach the earth is shortest.

The danger period for UV is from 10 a.m. to 3 p.m. or 11 a.m. to 4 p.m. daylight time. Seventy percent of the harmful UVB radiation that is received each day occurs within three hours either side of noon.

Current evidence suggests that childhood sun exposure makes an important contribution to the lifetime risk of skin cancer. The skin of infants is thinner and produces less melanin than at any other time in life.

Excessive exposure to sunlight during early childhood is harmful to the eyes. Eyes, like skin, are susceptible to damage from exposure to UVR. Sometimes tiny, cloudy spots form in the lens. These can spread to turn the entire lens milky white, scattering the incoming light and blocking vision (cataracts). The most important source of this damage is ultraviolet rays, especially while one is young.

Today, retinal diseases are the leading cause of blindness. The hardest-working region of the retina is called the macula. The macula is the part of the retina that lies directly in the path of light rays focused by the lens. The risk for retinal damage from the sun's rays is greatest in children less than 10 years old, although the consequences usually do not become apparent until well after they are adults.

So, teaching your children to wear sunglasses is important. All children should be taught to wear sunglasses, especially between 10 a.m. and 2 p.m., when ultraviolet exposure is the most dangerous.

Parents can set a good example for their children by wearing sunglasses at the appropriate times. The use of wraparound, close-fitting, large sunglasses, helps to reduce reflected UVR and glare that passes around the edge of the sunglasses and reaches the eyes. Up to 40 percent of UVR is reflected off surfaces like water, concrete and glass.

Very small children should not be exposed to UVR from 10 a.m. to 3 p.m. It is important that children always wear a hat, protective clothing and sunglasses when outside in order to reduce their UVR exposure.

Toy sunglasses are just that -- toys -- and may not offer sun protection. Effective sunglasses should block both UVA and UVB radiation. Large lenses that fit close to the eyes are best.

Those that block visible blue light are even safer.

Thankfully, all sunglasses block UVB radiation. A great many sunglasses, however, do not afford UVA protection. Expensive brand names and polarizing lenses are no guarantee.

The sunglasses must be measured to block 99 percent to 100 percent of UVA or UV400. Sunglasses that do not have a UV-rating can make the situation worse because dark lenses cause the pupils to dilate, allowing more of the dangerous UVA radiation to damage the lens and the retina.

Of course, children will break and lose sunglasses with remarkable rapidity. Pick the ones that block blue light and have 100 percent UV400 protection. Some short-term reactions to overexposure include mild irritations such as excessive blinking, swelling or difficulty looking at strong light.

Overexposure causes acute photo keratopathy, which is essentially sunburn of the cornea, like snow blindness or welder's flash burns.

This holiday season, while you are in the sun having fun, make sure to protect yourself and your children's eyes and enjoy a lifetime of sight.