Now Read This

Sooner or later we all discover that our arms just aren't long enough to read anymore. You know the problem. You can't focus on the small type in books and magazines and on aspirin bottles at your normal reading distance, and so you start moving the print farther and farther away. If you haven't already experienced this trombone effect, don't worry, you will. Starting around age 40, the lenses in most people's eyes start to weaken. You begin to lose the ability to focus on things close up and have to resort to bifocals or reading glasses to make out the fine print. (The moderately nearsighted can often make do until age 50 by taking off their corrective lenses.)

Since a pair of prescription glasses in stylish frames can cost $100 or more, you may have considered picking up a pair of drugstore reading glasses. These are essentially magnifying glasses of varying strengths that often cost $15 to $20. For once, this is a shortcut that won't shortchange you. Optometrists and ophthalmologists agree that, under the right circumstances, drugstore glasses can be just as effective as prescription reading glasses.

There are, however, several things you need to keep in mind. Reading glasses are not the same as the glasses used to correct nearsightedness (the ability to see nearby objects better than those that are far away), farsightedness (the ability to see objects that are farther away somewhat better than those that are nearby) or astigmatism (a kind of warping of the outer layers of the eye). Because of the more complicated optics involved, you need prescription lenses or contacts to compensate for any of the three conditions. Drugstore reading glasses, which contain two lenses of identical magnification, won't help if one eye is significantly weaker than the other. Nor will they help you drive better or see a movie screen.

For other uses, if the cheap glasses work for you, go ahead and use them. "I have some over-the-counter reading glasses myself," says Dr. Donald Schwartz, associate clinical professor of ophthalmology at the University of California at Irvine. "They can be very convenient."

So what, besides attractive frames and a comfortable fit, should you look for? Mostly it's a process of trial and error. Bring some of your typical reading material to the store to see which magnification you need. (If you do a lot of computer work, you may want a separate, slightly weaker pair of glasses, since most computer screens aren't placed within normal reading range.) Probably the trickiest part of selecting the right pair of reading glasses is making sure the lenses are correctly centered over the eyes. Misalignment can cause headaches and eyestrain. Any qualified eye-care provider can check this for you. Many will even tell you which magnification to look for.

And it never hurts to use a little common sense. If you can't find a pair of drugstore glasses that work for your eyes, you probably need to give up and pay for a prescription pair. Even if you find a pair of glasses that you can read with, don't use that as an excuse to skip regular eye exams. There are other conditions--such as glaucoma --for which you should be checked. Consider the money you save on drugstore glasses as partial payment for your next trip to the eye doctor.

E-mail Christine at gorman@time.com