What are we doing to our eyes?
August 22, 1999
Web posted at: 12:00 p.m. EDT (1600 GMT)
From Kathleen Doheny
Special to CNN Interactive
(CNN) -- Most people aren't blessed with perfect vision, or even what they consider good enough vision.
Nearly 60 percent of the population, or about 160 million Americans, wear contact lenses, eyeglasses or both, according to the Vision Council of America.
Now a growing number of Americans, frustrated with broken eyeglasses or the recurring need to buy lens cleaning solutions, have opted for more permanent fixes.
Most popular right now is LASIK (laser assisted in situ
keratomileusis), a refractive surgery in which nearsightedness is corrected by removing a thin layer of corneal tissue.
From 1996 to 1998, about 345,000 people had LASIK, according to the American Society of Cataract and Refractive Surgery. In the same period, another 510,000 have undergone other refractive surgery procedures such as PRK (photorefractive keratectomy), RK (radial keratotomy) and AK (astigmatic keratotomy).
This year, according to the society, about a half-million people are expected to have LASIK surgery.
In addition, about 3,000 persons in the United States have gotten Intacs, tiny rings placed in the periphery of the cornea, according to Keravision, their maker. Intacs were approved for use in April.
With all these surgical options, advocates say, it's only a matter of time before eyeglasses and contact lenses go the way of the manual typewriter.
No way, says Dr. Robert Davis, an Oak Lawn, Illinois, optometrist who chairs the American Optometric Association contact lens section. It's not that he doesn't envision a bright future for alternative remedies such as even better surgery or, someday, a once-a-day prescription eyedrop to fix vision by altering the cornea's shape.
But he adds, "There always will be people who are apprehensive about surgical procedures.'' And eye surgery won't ever be perfect for everyone.
Spectacle and contact lens wearers still vastly outnumber those with surgically altered eyes. Luckily for those who find refractive procedures too scary or too pricey (LASIK's going rate is $2,500 an eye), there are a number of improvements in contact lenses and eyeglasses.
What's new in contacts?
Materials used in contact lenses have improved vastly from the early days when lenses were so rigid they sometimes popped out with a quick turn of the head. Newer materials are softer, more pliable, and allow much more oxygen transmission across the lens into the cornea. Lenses are more comfortable and less irritating.
When describing nearsightedness, farsightedness and astigmatism, doctors talk in diopters (a unit for measuring the refractive power of a lens), while patients want to know in English what it means.
These are rough correlations:
|Mild... ||To -3 diopters|
|Moderate... ||-4 to -7 diopters|
|Severe...||Over -7 diopters|
|Mild... ||+2 diopters|
|Moderate... ||+3 diopters|
|Mild... ||1.5 diopters|
|Moderate... ||2-3 diopters|
Source: Dr. Peter S. Hersh, Director, Cornea & Laser Eye Institute at Hackensack University Medical Center
Made of materials with tongue-twisting names such as balafilcon A, newer lenses also don't dry out nearly as quickly as the hard lenses of yesteryear, due to their high water content.
Soft bifocal contact lenses, which have been available for years but not widely used, have also improved, says Dr. Bob Lee, an assistant professor of optometry at the Southern California College of Optometry, Fullerton, California. They're still not perfect, especially for correcting the
lack of near-focusing ability that accompanies middle age.
They might not work well, he says, if you're trying to read the menu in a restaurant with poor lighting.
Another trend in contact lens wear is "planned replacement,'' with lenses sold in blister packs so wearers can toss the old pair every eight weeks or so. The cost is not much greater than getting a single pair, Lee says, because the bulk of expense is in fitting and follow-up, not in making a few more pairs of the same prescription.
Daily disposable lenses are becoming more common. Now offered by at least two makers, they are meant to eliminate protein deposit problems. The extra expense is offset somewhat if you subtract the costs of soaking solutions and cleaners, Lee says.
The biggest area of disagreement in contact lens wear? The wisdom of extended-wear lenses. Popular in the '80s and worn for a week at a time, the lenses fell out of favor when wearers began to get more eye infections.
At the American Optometric Association meeting in June, Dr. Joseph Shovlin, director of contact lens services at Northeastern Eye Institute in Scranton, Pennsylvania, told colleagues that people can wear them again with confidence, because materials have improved.
It's vital, he stressed, to follow the eye doctor's recommendations about how often to remove them routinely, and, if irritation occurs, to remove the lens immediately and see your eye doctor.
But not everyone votes for a return to extended-wear lenses. In a study published in July in the medical journal Lancet, researchers reported that overnight wearers of soft lenses had an almost 20 times greater risk of eye infection than those who took out their lenses at night.
For the study, they evaluated 92 new cases of infections in lens wearers in 1996.
What's better about eyeglasses?
Improvements in eyeglasses haven't been as fast and furious as advances in contact lenses. For anyone willing to pay the higher price, it's been possible for years to turn even Coke-bottle-thick prescriptions into socially acceptable, light-as-a-feather eyewear.
That's due to the magic of "high-index'' lenses that bend light differently, so that even strong corrections can be thinner, explains optician Joseph L. Bruneni, an assistant professor at the Southern California College of Optometry, Fullerton, California.
Scratch-resistant coatings have gotten tougher recently, he says. And the anti-reflective coatings favored by television anchors, public speakers and others bothered by the bouncing, blinding effect of bright lights
have improved, too.
Eyeglasses with special aspheric lenses -- flatter than conventional lenses -- can help improve the look of eyeglasses for those with strong corrections, says Dr. Gregory Stephens, associate professor at the
University of Houston College of Optometry and a member of the American Optometric Association Commission on Ophthalmic Standards.
These lenses are fitted closer to the face, eliminating the bug-eyed look of some farsighted corrections and the tiny-eyed look of some nearsightedness corrections as well as improving vision.
Computer glasses are becoming increasingly sophisticated. One model, for example, has progressive lenses that allow the wearer to switch easily from reading the computer screen to reading materials on the desk, Stephens says.
What does the future hold?
While there's disagreement on exactly how common refractive surgery
will become, and whether contact lenses and eyeglasses really will be
obsolete, there is consensus on one point. Within the next decade, as
several new techniques under study become available, those with vision
problems will have more options than ever.
The challenge in the new millennium will be to find the right eye
care specialist and -- as a team of two -- decide which solution is best.