contact lenses Contact Lens Background and Decisions Imagine wearing your contact lenses for a few hours and then, after you pop them out, still seeing clearly for a portion of the day.  For certain individuals with nearsightedness, that image can be reality. The Reverse Geometry OKŪ Contact Lens for Orthokeratology rigid gas-permeable contact lens, made by ConTEX, Sherman Oaks, Calif., is the first contact lens designed to correct nearsightedness by temporarily reshaping the transparent tissue known as the cornea that covers the iris and pupil. It is just one of many choices for the 28 million Americans who wear contact lenses. These medical devices, sold under more than 350 brand names, offer numerous options, including rigid contact lens handling ease, soft contact lens comfort, bifocal vision, a rainbow of colors, no-fuss disposables, and even protective help against ultraviolet radiation. Shaping Up The idea behind the OK contact lens is not new. Since the early 1960s, some optometrists have used conventional daily-wear rigid contact lenses to help reshape corneas. This procedure is called orthokeratology, or Ortho-K. The United States Food and Drug Agency considers such treatment of an individual patient to be the practice of medicine and therefore not subject to regulation. Selling contact lenses not cleared for Ortho-K to practitioners for that use is illegal. Studies before FDA began regulating contact lenses, in 1976, show that Ortho-K appears to be safe. Ortho-K reshaping involves the use of a series of contact lenses that apply pressure to the cornea.  Once the desired result is achieved, use of daily-wear maintenance contact lenses is critical to retain the reshaping. If you wear the maintenance lenses faithfully, you may only need to wear the lenses for a portion of the day.  Be sure to consult with your own eye doctor however. Ortho-K does not work for everyone. Some people do not experience any significant reduction in nearsightedness.  An individual's response is difficult to predict.  It may take weeks or months to have an effect. Safety Should Be Foremost The most serious safety concern with any contact lens is related to overnight use.  Extended-wear (overnight) contact lenses, be they rigid or soft, increase the risk of corneal ulcers.  Corneal ulcers are infection-caused eruptions on the cornea that can lead to blindness. Symptoms include vision changes, eye redness, eye discomfort or pain, and excessive tearing. The risk of corneal ulcers for people who keep extended-wear lenses in overnight is 10 to 15 times greater than for those who use daily-wear contact lenses only while awake according to the FDA. When the eyes are open tears carry adequate oxygen to the cornea to keep it healthy. But during sleep, the eye produces fewer tears, causing the cornea to swell. Under the binding down of a rigid contact lens during sleep, the flow of tears and oxygen to the cornea is further reduced. This lack of oxygen leaves the eye vulnerable to infection. Extended-wear rigid contact lenses also can cause unexpected, sometimes undesirable, reshaping of the cornea. Soft extended-wear contact lenses also bind down on the closed eye, but they are porous and allow some tears through during sleep. Because they have such little form, their binding has little effect on the shape of the eye. The FDA has approved extended-wear contact lenses for use up to seven days before removal for cleaning. Still, there are risks with use of extended-wear lenses. Daily-wear contact lenses are removed daily for cleaning and are a safer choice, provided they aren't worn during sleep. Another sight-threatening concern is the infection Acanthamoeba keratitis, caused by improper lens care. This difficult-to-treat parasitic infection's symptoms are similar to those of corneal ulcers. The use of homemade saline from salt tablets is one of the biggest contributors to Acanthamoeba keratitis in contact lens wearers.  The FDA no longer condones the use of salt tablets, and neither should a concerned pharmacist. Microorganisms may also be present in distilled water, so always use commercial sterile saline solutions to dissolve enzyme tablets.  Heat disinfection is the only method effective against Acanthamoeba, and it also kills organisms in and on the lens case. Eye Professionals - Who Are They?   Ophthalmologists (M.D. or D.O.) are eye surgeons who study and treat eye diseases and can also perform the duties of optometrists.   Optometrists (O.D.) examine eyes, diagnose and treat vision problems, and prescribe eyeglasses and contact lenses.  In most states, they also can prescribe medicine.   Opticians grind and dispense eyeglasses and in some states dispense contact lenses. Be sure to consult with your own doctor for proper care and maintenance.