(MONEY Magazine) – - Okay, what's your excuse? You don't like contact lenses because you refuse to spend half your mornings putting them in? Or half your nights cleaning them? You can't bear to crawl around on all fours when one pops out? Your cousin tried them and got an eye infection? You tried them and they hurt? Or you've heard that contacts can't fix your astigmatism or replace your bifocals? If any (or all) of the above explain why you are among the five out of six blurry-sighted Americans who prefer eyeglasses to contact lenses, then you might want to hitch up your specs and give the subject a fresh look. Spurred by consumer complaints, scientists and manufacturers have been working hard to improve the lenses and their associated paraphernalia. That effort is now paying off in a new generation of contacts that are safer, more comfortable, more convenient, and more versatile than even many current lens users realize. While a few years ago your options were basically hard lenses vs. soft, today you can select from a comprehensive menu (see the table on page 164) of standard and specialty contacts, including: -- Lenses you may wear for weeks at a time; -- Dirt-resistant Teflon-like lenses that are easier to clean; -- Disposable lenses, now being test marketed, that eliminate cleaning altogether -- Hard lenses that are nearly as comfortable as soft ones; -- Color-changing lenses for light- or dark-colored eyes; -- Even lenses that correct for astigmatism and presbyopia (the condition that requires bifocals). The result is that contacts, heretofore favored mainly by young women mindful of Dorothy Parker's warning about girls who wear glasses not getting passes, are attracting a wider clientele. Each year, Americans spend about 10% more on this $2 billion-a-year business. And the number of wearers -- 21 million -- is more than twice what it was only a decade ago. Not that contact lenses are for everyone: they remain a poor choice for people who are sloppy about hygiene or who have unsteady hands or dry eyes. And at $100 to $400 a pair, they are pricier than glasses -- up to twice as expensive, depending on the lens and the wearer's particular needs. Nevertheless, for most people they offer several advantages over glasses: they don't block your peripheral vision for active sports, they don't fog up when you come in from the cold, they don't slide down your nose when the going gets hot and, perhaps most important, they improve the way you see the world without changing the way the world sees you. The name contact lens is a bit of a misnomer; the lens does not actually touch the eye. Rather, it floats on the veil of tears that covers the cornea, the eye's clear outer membrane. This fluid keeps the eye lubricated, clean and protected from harmful microorganisms. Held in place by surface tension, contact lenses get a free ride and a periodic window wash, courtesy of the natural cleansing mechanism of blinking.

HARD LENSES The first commercial contacts, introduced in the early 1950s, were hard lenses made of a Plexiglas-like material called polymethyl methacrylate. Though almost never prescribed anymore, PMMAs remain the classic Model T's of the field: they give crisp, reliable vision, are easy to clean and can last 10 years or more. But they are stiff and uncomfortable and pop out easily. And, since they are impermeable to gases, they block the cornea's oxygen supply (it must get oxygen directly from the air because it doesn't have its own blood supply). ''PMMAs are an excellent corrective device -- but only for those patients who can tolerate them,'' says Dr. Perry Binder of the University of California at San Diego, past head of the Contact Lens Association of Ophthalmologists.

SOFT DAILY-WEAR LENSES Soft lenses, which first appeared in 1971 and now make up some 55% of all lenses, made several improvements over the old PMMAs. Constructed of an absorbent, oxygen-permeable plastic, they drape over the cornea like a floppy, comfortable cap. ''The first thing you notice when you fit one,'' says Dr. Oliver Dabezies, chief of ophthalmology at Southern Baptist Hospital in New Orleans, ''is the smile on the patient's face as he leaves. Once you switch a patient from PMMA lenses to soft, it's impossible to convert him back.'' Their cost: $100 to 300 for the first pair (the figures include exam and fitting, supplies and follow-up care). The drawbacks of soft lenses are the flip side of their virtues. The high water content that makes them pliant also makes them less stable optically: vision is rarely as sharp as it would be with hard lenses. Soft lenses wear out quicker than hard lenses, often needing replacement every six to 18 months. And they are more difficult to keep clean, mainly because their pores serve as lodging spots for natural proteins made by the eye and for bacteria from the environment. People who wear soft lenses must be fastidious about cleaning and disinfecting them. Cautions Dr. James Aquavella, director of the Cornea Research Laboratory at the University of Rochester Medical Center: ''Wearing a poorly cared-for soft lens is like having a cesspool on the surface of your eye.''

SOFT EXTENDED-WEAR LENSES To eliminate the necessity of daily cleaning, manufacturers in 1981 introduced so-called extended-wear soft lenses (initial cost: about $100 to $400). These resemble ordinary soft lenses except that they are often flimsier and are always more oxygen-permeable -- minor modifications that are needed for overnight wear. When the eyelids are closed, the cornea gets only about a third as much oxygen as it does during the day. Ordinary lenses would reduce this even further. But extended-wear lenses let enough air through so that they can be worn nonstop for many days. And, because they are so thin, flexible and water-retentive, most people find them even more comfortable than daily-wear soft lenses. Evidently, they may even be a little too comfortable. ''There are people who wear these like it was some kind of marathon,'' says Aquavella. ''They don't realize that by extending the wear, you extend the risk.'' The wearers are not entirely to blame: the Food and Drug Administration, which regulates contacts, approves keeping them in for up to 30 days. But most practitioners now say that is too long. For one thing, it may allow the proteins and bacteria that collect between cleanings to grow so thick that some people experience an allergic or chafing reaction of the eyelids. For another, doctors found that the number of infections and corneal ulcers -- though small -- began to rise a few years after extended-wear lenses went on sale. ''From what we know so far, there are about 500 to 1,000 reported cases of sight-threatening complications to date,'' says Dr. Kenneth Kenyon, head of cornea services at Massachusetts Eye and Ear Infirmary in Boston, the headquarters of a multicenter study of the phenomenon sponsored by the lens industry. The link to extended-wear lenses is not proved. Nevertheless, though some 3.5 million of the lenses are now in use, some practitioners have stopped prescribing them until the preliminary results of the study are released this spring.

RIGID LENSES Enter -- or, more properly, re-enter -- the hard lens, but this time in a new guise. So-called rigid gas-permeable lenses (RGPs), first sold for daily wear in 1979, are made of hard plastic that contains silicone to enhance its oxygen flow. They improve the cornea's oxygen supply while providing clearer vision, ease of cleaning and enough durability to last for two years or more between replacements. RGPs' main drawback is that, though more comfortable than PMMAs, they remain less so than soft lenses. In a quest to improve them, one manufacturer -- Barnes-Hind -- has created a hybrid lens ($250 to $350 initially) that has a rigid center for clear vision and soft edges for comfort. The trick to wearing RGPs, say the experts, is patience. ''Rigid gas- permeable lenses start out bad -- that is, uncomfortable -- and get better and better, while soft lenses start out good and get worse and worse,'' says Neal Bailey, a clinical optometrist and editor of the journal Contact Lens Spectrum. Adds Aquavella: ''Probably all lens fitters would be happier if their patients wore gas-permeable lenses because they're safer and give better vision.'' Indeed, RGPs, which cost about $150 to $350 initially, already make up three-quarters of the 6 million pairs of hard lenses in service (the rest are PMMAs). The latest wrinkle, introduced a year ago, is extended-wear RGPs, which, their makers say, are less likely to be linked to complications because their harder plastic is easier to clean. Some even resist dirt. The Boston Equalens ($200 to $350), made for daily and extended wear by Polymer Technology of Wilmington, Mass., contains fluorine, raising its oxygen permeability and making it resist deposits much like fluorine-based Teflon does on a frying pan.

DISPOSABLE LENSES An equally novel approach to the cleaning problem is disposable soft contact lenses, which require no cleaning at all. You just wear them for a week and then throw them out. The cost is competitive: about $520 a year, including exam and fitting. The first such, Acuvue lenses by Vistakon (a subsidiary of Johnson & Johnson), are now undergoing market tests in Florida and California. ''Essentially, these are extended-wear soft contacts that can be turned out in an inexpensive and highly repeatable fashion,'' says Robert Kniffin, a Vistakon spokesman. One reservation: disposables may be almost too convenient. ''If, after six days, a patient's vision is clear, will he toss the lenses out -- the way he's supposed to -- or will he keep on wearing them?'' asks Binder of UCSD. ''What's to stop him from ordering a year's supply and extending it into five years just to save money?''

LENSES FOR ASTIGMATISM Manufacturers are also designing lenses for conditions that previously could be handled only by glasses, such as astigmatism. This inborn defect, which leaves the eyeball football shaped, requires different corrections for light entering the eye from different angles. Toric lenses -- so called because of their complex curvature -- can compensate for astigmatism provided the lens does not somehow rotate out of position. One solution to that problem: a lens whose bottom is cut off so that its flat edge rests against the lower eyelid. Another: a round lens that is heavier at the bottom so that gravity holds it in place. Both types are available in soft or RGP form (approximate cost: $250 to $400).

BIFOCAL LENSES Bifocal contacts, quite primitive only a few years ago, are also becoming more sophisticated. The newest high-tech bifocals, so-called holographic lenses, have four to 10 diamond-made cuts radiating out from the center to give two different corrections over the entire field of vision simultaneously. A soft holographic lens made by Allergan/Hydron is in clinical trials and could be available next year. A rigid gas-permeable model, the Pilkington ''Diffrax,'' was just introduced in Britain for about (pounds)250 ($444) and is expected to go into clinical trials in the U.S. this spring. For now, however, the best solution is to put a different power lens in each eye; the brain automatically selects the clearer image.

TINTED LENSES Lenses that change the hue of light-colored eyes have been around for four years. Now there are DuraSoft Color lenses by Wesley-Jessen ($160 to $300), which change brown eyes to blue, sapphire, aqua, hazel or green. In a little over a year since their introduction, more than 750,000 pairs have been sold, a third of them noncorrecting lenses for people who simply wanted a new look. There are even special contacts for many of the people (including some 8% of all men) who are color-blind. The X-Chrom lens ($300 to $400), for example, compensates for red-green color-blindness, the most common form, by putting a clear lens in one eye and a bright red one in the other. You will look odd, but some jobs demand that the worker can distinguish between green and red.

BUYING CONTACTS Almost half of all new lenses are sold through large optical chains at a discount (typically $125 for soft daily-wear lenses, for example). But low % cost is not necessarily a bargain since what you really pay for is service: ideally, regular follow-up visits for at least three months and semi-annual checkups for two to four years. A better course might be to consult an optometrist in private practice (cost: $200 or so for the lenses described above) or an ophthalmologist ($300 or more). ''These programs cost money, but wearing contact lenses isn't like buying a pair of shoes,'' says Bailey of Contact Lens Spectrum. Ask what the fee will be if you turn out to be among the 10% of people who can't tolerate lenses. And if the practitioner claims to be able to fit anyone with contacts, take your business elsewhere. Once you have a prescription, you can usually buy a full range of lenses at the same office or store. Some manufacturers offer a package deal that includes replacement pairs. There is also lens insurance, for about $25 a year, that cuts the cost of replacements by about 40%. Another way to save money is to buy through a discount mail-order firm such as Dial A Contact Lens (800-238-LENS). Prices vary widely, so shop around. Finally, three tips from the experts on how to handle your lenses once you have them: -- There are times not to wear them, such as when your eyes are dried out from the flu or from the arid air on jet planes. -- Don't keep extended-wear lenses in any longer than the practitioner recommends, even if a friend wears his longer. -- Above all, don't engage in lens macho. ''Wearing lenses is not an endurance test,'' says Dr. Michael G. Harris, chief of the contact lens clinic at the University of California at Berkeley. ''If there's trouble, take them out and call your practitioner immediately.''

CHART: TEXT NOT AVAILABLE CREDIT: NO CREDIT CAPTION: Putting the cost of contact lenses into focus This guide to the major types of contacts shows that soft and rigid gas- permeable lenses are about equally costly. Soft lenses are less expensive initially but cost more to maintain. They need more cleaning (making supply expense greater) and require more frequent replacement. DESCRIPTION: Costs, advantages of several types of contact lenses.