Q. I've been thinking of replacing my glasses with contact lenses. With so many different types available, I'm not sure which kind to get. I've heard that the extended wear lenses can cause some serious eye problems. How do I decide?

A. With five basic types of contact lenses on the market, it can be a bit perplexing deciding which kind to get. The best way is to discuss the pros and cons of each type with your eye doctor -- optometrist or ophthalmologist -- to see what's best for you.

I'll briefly review some of the advantages and disadvantages of each type and give you some tips on choosing your contacts. Hard lenses. Worn by about 10 percent of contact users, this original type of contact lens is decreasing in popularity.

Pros: Compared with soft lenses, these provide very clear vision, require less cleaning and last the longest of all lenses -- up to 20 years with polishing. For overall cost and maintenance, they are least expensive.

Cons: Hard contacts are more uncomfortable, take longer to get used to and can pop out of the eye more easily. Gas-permeable lenses. Worn by about 15 percent of contact users, these are hard contacts that allow oxygen to get through to the surface of the eye.

Pros: These provide very clear vision with more comfort than regular hard lenses. Along with standard hard lenses, these cause fewer serious eye problems than soft lenses do.

Cons: They require more cleaning and must be replaced after about two years. These are the most expensive lenses but don't require as frequent visits to the eye doctor as soft lenses do. Daily-wear soft lenses. Worn by about 50 percent of contact users, these are the most popular.

Pros: Soft lenses are more comfortable and easier to get used to than hard lenses.

Cons: These lenses don't provide as sharp vision as hard contacts and require careful daily cleaning. Although these lenses are cheapest to buy, frequent visits to the eye doctor make them second to extended wear lenses in overall cost. Eye infections are more common with soft lenses than with hard contacts. Because debris and bacterial deposits eventually build up, daily wear soft lenses need to be replaced every 18 to 24 months. Extended-wear soft lenses. Worn by about 25 percent of contact users, these lenses were thought to be the contact wearer's dream -- lenses that could be left in for weeks at a time. Unfortunately, they haven't quite lived up to earlier expectations.

Pros: Many people can wear these lenses for weeks without problems.

Cons: These contacts are more difficult to clean and must be replaced every six to 12 months. The cost of cleaning and frequent eye doctor visits makes these the most expensive overall. These lenses also have a greater risk of causing a corneal ulcer -- a serious, sight-threatening complication.

A corneal ulcer is a raw, sore spot on the front surface of the eye. Eye infections or minor trauma -- such as wearing improperly cleaned contacts or keeping contacts in too long -- can cause an ulcer to develop.

Recently, acanthamoeba keratitis, a rare and difficult-to-treat eye infection, has been increasingly found in people wearing all types of contacts. Pain in the eye is the main symptom of both these serious complications.

If you wear contacts and develop eye pain, see your eye doctor right away.

Because of the more frequent problems with extended-wear lenses, some eye doctors are recommending that their patients keep their lenses in for shorter periods, even for as little as a day at a time. Extended wear, gas permeable semisoft lenses have been available for several months. It is hoped that these will reduce some of the serious problems associated with the current extended wear lenses.

Q. I've heard that there's a medication that will help with the stage fright some people get when speaking or performing in front of an audience. Does it really work? What are the side effects?

A.You're probably referring to Inderal, a medicine doctors often use to treat high blood pressure, angina and other conditions. Although not a disease in itself, stage fright can incapacitate many people with anxiety, which Inderal and drugs like it can help.

Inderal is one of a class of drugs known as beta-blockers, so called because they reduce, or block, the action of a major part of the nervous system. Among their effects, beta-blockers will lower your blood pressure and slow your heartbeat.

Though not tranquilizers, these drugs help counteract the adrenalin-triggered, heart-pounding dread of stage fright. In fact, one of the advantages of using Inderal is that you'll avoid the drowsiness of tranquilizers, which may hamper your ability to speak or perform at your best.

In one study, doctors gave Inderal to some nervous musicians before an important recital. The judges -- who didn't know the musicians had taken Inderal -- judged their performances superior to times when they hadn't taken Inderal. Moreover, the musicians reported feeling more relaxed and confident in their performance, without bothersome side effects.

The side effects of beta-blockers include lethargy and worsening of heart failure and asthma. Most side effects occur only after regular use. Except for the possible triggering of asthma in people with this condition, a single dose of Inderal -- as you would take for stage fright -- will rarely lead to serious problems.

Although I'm not advocating the casual use of Inderal for everyday challenges, it may be helpful for people with incapacitating stage fright on special occasions.

Jay Siwek, a family physician from Georgetown University, practices at the Fort Lincoln Family Medicine Center and Providence Hospital in Northeast Washington.

Send questions to Consultation, Health Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. Questions cannot be answered individually.