Most of my relatives say that watching television too much is bad for your eyesight. They say it's even worse if you watch television in the dark for too long. Is this true? If it is, please explain how and why it's bad for your eyesight. If I sit in front of the television or computer screen for a long time, my eyes hurt. Why?

Dear Dr. Cory:

Most of my relatives say that watching television too much is bad for your eyesight. They say it's even worse if you watch television in the dark for too long. Is this true? If it please explain how and why it's bad for your eyesight.

Raul Rashid

New York, New York

Dear Dr. Cory:

If I sit in front of the television or computer screen for a long time, my eyes hurt. Why?

Yael Weinstock

Los Angeles, California

Dear Raul and Yael:

Sitting too close or for too long in front of the TV or computer screen may cause eyestrain, but it will not cause damage to your eyes. Eyestrain can cause headaches, blurred vision, and tired eyes, but these things are just temporary. (If you can see the TV clearly only by sitting close to it, you should have your vision checked to see if you need glasses.)

Watching TV or reading in dim light won't affect your vision. It can make focusing difficult, though, making your eyes feel uncomfortable.

You can reduce eyestrain several ways: don't sit too close to the TV screen or computer monitor; take breaks about every half hour; don't watch TV or use the computer in a dark room; and keep the glare from lights or sunlight off the screen. Finally, if your eyes hurt from staring at the TV or computer screen, you're probably spending too much time doing these things!