Reality: No, it is not true that using a stronger power than you need makes your eyes come to need that power. You can wear any power reading glasses that you want. You need to choose reading glasses based on the distance at which you work. You may want a stronger power for reading the newspaper than for working on the computer.

Myth: Redness means infection.

Reality: Eye infections are relatively infrequent compared with the cases of red eyes from noninfectious causes. Viral infections (which do not respond to antibiotics) occur somewhat more often but also are relatively uncommon.

Eye redness usually is due to simple irritation of the surface of the eye -- from allergies or from dryness, for example, or from blepharitis, an inflammation of the eyelid, which also can cause dry eyes.

Self-test: The eye will be very red if you have an infection (bacterial or viral). With a bacterial infection, you might notice a thick yellow-white discharge. A viral infection is likely to have a clear, continuous watery discharge. Viral conjunctivitis (commonly called "pink eye") results in a very irritated, very red eye, which often spreads to the other eye in one to three days. Typically, people with pink eye have had a cold recently or have been exposed to someone with pink eye.

Pink eye is very contagious and can quickly spread to family members and coworkers. To reduce the spread of infection, limit your contact with other people and wash hands frequently. Unlike bacterial conjunctivitis, which is treated with antibiotic eyedrops, there is no treatment for viral pink eye except lubricating eyedrops to reduce discomfort.

Myth: Extended-wear contacts are safe to keep in when you sleep.

Reality: The Food and Drug Administration (FDA) has approved extended-wear contact lenses that you can keep in when you sleep, but I see a lot of patients with eye inflammation caused by these lenses.

The cornea, the transparent front of the eye, takes in oxygen all the time. Wearing a contact lens for extended periods reduces oxygen at the eye surface. Silicone hydrogen lenses allow much more oxygen to get to the cornea, but even they can cause irritation and infection when worn too long.

Always follow your doctor's instructions. If your contact lenses are designed to be worn for two or four weeks, then change them at the recommended frequency. If you are wearing your contacts overnight and your eyes become irritated or red, stop wearing them and see your eye doctor. Generally, if you take your contacts out each night, there's less risk for infection and irritation.

Irritation sometimes can be caused by multipurpose or cleaning solutions.