Eye Excercise and Eye Muscles

The protein molecules in the aging lens slowly change in ways that make them bend light less, Dr. Koretz said.

Thus, although it is more spherical, an elderly lens is less and less able to focus the light from nearby objects.

Age related changes also take place in the muscles surrounding the lens. Most scientists agree that these muscles do not become weak with age. It would make no sense for one isolated muscle in the body to slowly give out while all the others continue to work perfectly well.

A recent study using high-resolution magnetic resonance to photograph the eye muscles confirmed that the muscles still contracted powerfully in older people who could not focus up close.

But the geometry of the fibers connecting the muscle to the lens shifts as the lens grows with age, and the fibers themselves appear to harden and become less elastic, a process that also interferes with the ability to focus.

Exercises purporting to "strengthen" the lens muscles are purposeless, Dr. Koretz said, since the muscles are already strong: it is their position and fibrous attachments that may hamper their ability to move.

If not exercise, then, can any measures help the owner of two aging eyes elude reading glasses?

Some people find that a satisfactory solution is the creation of "monovision," in which one eye is manipulated to focus well at reading distances (usually with a contact lens or an intraocular lens placed after cataract surgery), while the other focuses for distance.

People instinctively grow to favor one eye or the other for different tasks.

But while some people are delighted with this solution, Dr. Koretz said, others are plagued by dizziness or nausea, or miss the depth of vision they once had.

Finding a better fix for presbyopia is rapidly becoming the Holy Grail of experimental ophthalmology, especially as researchers and entrepreneurs begin to calculate the profits that might accrue from curing an annoyance affecting every single adult in the population.

But the basic disagreements as to why the process occurs have meant that viable solutions are slow to emerge, and are extremely controversial when they do.

Among the most disputed to date is scleral expansion surgery, a procedure devised by Dr. Ronald Schachar, a Texas ophthalmologist and physicist, in the early 1990's.

A maverick who has argued that much of what scientists think they know about the focusing mechanism of the eye is actually untrue, Dr. Schachar holds that presbyopia develops only because, as the lens of the eye swells with age, the muscles and fibers surrounding it grow lax, and the system can no longer work effectively.

By stretching the system out again, Dr. Schachar says, presbyopia can be easily and permanently reversed.  For many, reading glasses is still the answer.

He claims to restore tension to the muscle and fibers by surgically implanting four small curved pieces of plastic in the white of the eye a few millimeters from the iris, which, he says, re-establish an effective working distance between the lens muscles and the lens.

His technique has evoked howls of protest from physiologists who point out that it ignores decades of solid experimental evidence implicating age-related changes within the lens itself as key causes of presbyopia.

"The scientific community never took scleral expansion surgery seriously," Dr. Glasser said.

But a few hundred patients who have volunteered for the surgery over the last decade in Mexico, Canada and Europe have stymied the procedure's critics with reports that the surgery does indeed seem to restore their ability to see up close.

In March, the Food and Drug Administration approved preliminary trials of the operation at six sites in the United States, including the New York Eye and Ear Infirmary in Manhattan, where Dr. Barrie D. Soloway, co-medical director for vision correction, will head the studies. Dr. Stephan D. Plager, 60, an ophthalmologist in Santa Cruz, Calif., is also among the investigators who are to take part in the evaluation of surgical expansion surgery.

In early May, Dr. Plager himself became a patient, undergoing the procedure in both eyes.

Two days later, he said, he was performing cataract surgery in his office, and 10 days later, vision still a little blurry but "getting clearer every day," he cheerfully read passages from his local newspaper to a reporter over the telephone.

"I can't tell you how excited I am," he said.

"I haven't seen this well since I was 35."

Familiar with all the reasons that his surgery should not work, Dr. Plager said only that while the theory behind the procedure might be flawed, the end result was hard to ignore.

"The proof that it works will ultimately be in the scientific studies," he said, "but the proof as far as I'm concerned is already on the table.

I'm not so courageous, I'm more of a pragmatist than courageous.

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