Light Sensitivity

WHEN TO SEE YOUR DOCTOR

* Your eyes suddenly become sensitive to bright light and the discomfort lasts more than an hour.

* You also have pain or pressure in your eyes or see colored halos around lights.

* Your eyes are becoming increasingly sensitive or the sensitivity is interfering with daily activities.

What Your Symptom Is Telling You

It's normal to experience momentary discomfort as your eyes adjust to light. When you emerge from a darkened theater into the afternoon sun, for example, that sudden glare is sure to make you squint. But what if ordinary daylight makes you wince and shield your eyes like a criminal caught in a prison yard's floodlights?

In most cases, sensitivity is no cause for alarm. A cold, a sinus infection, even a speck of dirt can stimulate the nerves leading from the eyes to your brain, sending eye-pain messages that make you wince in ordinary daylight.

Certain antibiotics, antihistamines and other medications can also make your eyes temporarily more sensitive to light. So can an eye infection.

If bright, sunny days, or harshly lit rooms always make you squint, it may simply mean that you have sun-sensitive eyes, just as some people have sun-sensitive skin, according to Jason Slakter, M.D., attending surgeon in the Department of Ophthalmology at the Manhattan Eye, Ear and Throat Hospital. Or, if you've adopted the prudent habit of wearing sunglasses to shield your eyes from damaging ultraviolet rays, the downside is that now your eyes may be less tolerant to bright light. "This sort of sensitivity isn't harmful," says Dr. Slakter.

Bright light intolerance can also be a by-product of the aging process, adds Dr. Slakter. By age 40, he says, it's common for people to become more sensitive to glare from light bouncing off a car's polished hood, for example, or from light reflected off of a lake or snowy bank. This glare sensitivity occurs as the eyes' aging lenses become thicker or more opaque, thus scattering and magnifying light.

Another, less common disorder, called macular degeneration, damages the light sensor cells that normally help the eye adapt to bright light. The most common form of the disease is more prevalent among older people. A sensitivity to light can also be one of the early warning signs of glaucoma, although you most likely will also experience trouble with your vision and have pain.

Symptom Relief

Any problem that comes on suddenly should be brought to the attention of your doctor as soon as possible. If it turns out to be glaucoma, the sooner you can begin treatment, the better your chances are for saving your eyes. (To find out more about glaucoma, see Eye Pain on page 162.) If you're having a problem adjusting quickly from bright light to dim light while driving, for example, it could be an early warning sign of macular degeneration. Unfortunately, few treatments exist for the most common form of this disease, which may lead to tunnel vision in reverse—or the inability to see straight ahead.

If your problem is nothing more than oversensitive eyes, here's what you can do to help cut the glare.

Buy the best sunblockers. If you have sun-sensitive eyes, you need sunglasses with three main features, says Dr. Slakter. For starters, the tag on your sunglasses should indicate that the lenses screen out at least 90 percent or more of harmful ultraviolet-alpha and beta (UVA and UVB) radiation. Besides helping you see comfortably in harsh light, they may also ward off cataract formation and macular degeneration down the road, adds Mitchell H. Friedlaender, M.D., director of corneal services in the Division of Ophthalmology at the Scripps Clinic and Research Foundation in La Jolla, California, and coauthor of 20/20: A Total Guide to Improving Your Vision and Preventing Eye Disease.

The lenses should also be polarized to eliminate the glare from reflected sunlight. "You'd be surprised what a difference polarized lenses make when you're fishing on a sun-dappled lake or skiing down a sunlit snow slope," says Bruce Rosenthal, O.D., chief of low vision services at the State University of New York, College of Optometry in Manhattan.

The third feature—a metallic, mirrored coating—further reduces the amount of light that reaches the eyes by reflecting it away. (To those around you, the lenses look like mirrors)," says Dr. Friedlaender.

Shield your eyes when you're on medication. Light sensitivity can be a temporary side effect of a number of common medications such as antihistamines, antibiotics or blood pressure medication, according to Dr. Friedlaender. If you're taking one of these medicines and notice that you're squinting in bright light more than usual, make sure you wear sunglasses outdoors. You may also need a second pair of glasses with a lighter, tinted lens to wear in harsh, indoor light, he adds.

See also Eye Pain