It's a curse of middle age: You can't focus on type less than two feet from your face, so you need reading glasses. To avoid half-glasses or bifocals, you can wear regular specs, but then you have to take them off and put them on to see clearly both near and far.
The condition is called presbyopia (Greek for "old vision"). It starts at fortysomething and worsens for the next 20 years, as the lenses harden or enlarge and lose the flexibility to focus at close range. One alternative is progressive specs--with lenses that increase in magnification, so you don't have to take them off. But several surgical remedies hold hope for improvement, if not a cure.
-- Conductive keratoplasty (CK): You can treat presbyopia by wearing a near-vision contact lens in one eye and a distance lens in the other. The brain adjusts for the conflicting signals by providing continuous near and far vision. If this treatment, called monovision, works for you with contacts, you can make it permanent through CK. CK uses heat to shrink the cornea in one eye so it can see at close range. Since the other eye can see distance, you get the monovision effect.
-- Surgical reversal of presbyopia (SRP): This procedure, now entering phase II clinical trials, operates on the idea that lenses, like nails and hair, continue to grow. At about age 40, a lens is large enough to crowd the muscles around it, so that they can no longer pull it into shape for near vision. SRP surgically implants tiny pieces of contact-lens material into the whites of the eyes that stretch the lens compartment, restoring the tension between the muscles and the lens so the eye can focus naturally. "The procedure turns back the clock 25 years," says Dr. Robert Marmer, director of the Marmer Medical Vision Center in Atlanta. If SRP makes it through the Food & Drug Administration trials, it should be available in the U.S. in two to four years.
-- Refractive lens exchange: Now approved for cataract patients, this operation replaces the natural lens with a multifocal lens or a hinged lens that can move forward or backward. Multifocal lenses have near and far foci etched in two concentric circles. The idea is that the eye sees far and near, but the brain adjusts to the desired signal. "The trade-off is that the contrast perception is not as good," says Dr. Robert Maloney of the Maloney Vision Institute in Los Angeles. He says the best hope lies in hinged lenses, which have had promising results in phase III trials. Such solutions may let you take off your reading glasses for good.
By Pam Black
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-- Surgical reversal of presbyopia (SRP): This procedure, now entering phase II clinical trials, operates on the idea that lenses, like nails and hair, continue to grow. At about age 40, a lens is large enough to crowd the muscles around it, so that they can no longer pull it into shape for near vision. SRP surgically implants tiny pieces of contact-lens material into the whites of the eyes that stretch the lens compartment, restoring the tension between the muscles and the lens so the eye can focus naturally. "The procedure turns back the clock 25 years," says Dr. Robert Marmer, director of the Marmer Medical Vision Center in Atlanta. If SRP makes it through the Food & Drug Administration trials, it should be available in the U.S. in two to four years.
