You ain’t seen nothin’ yet

You don’t have to look very hard to see the shape of the future. It’s already here. It began with a series of elegant procedures designed to correct what ophthalmologists-eye specialists-call refractive errors, such as myopia, or shortsightedness. First there was RK (radial keratotomy, now dubbed "archaic"), then PRK (photorefractive keratectomy, which burst onto the scene with the excimer laser), and finally LASIK (laser-assisted intrastromal keratomileusis), the ultimate in refractive correction.

Each procedure upped the ante, raising costs (until recently, $5,000 for a pair of LASIK’d eyes) and expectations. Even people who bump into furniture without their glasses were regaining 20/20 vision, or close to it.

To say the market is hot is an understatement. Laser eye clinics are springing up faster than taco stands, and prices have begun to tumble. During a pre-Christmas price war in Montreal, for example, you could have both eyes LASIK’d at the best clinic in town for $1,500, a price so low teenage shopgirls were queuing up to have it done.

Prices will probably level off at about twice that, says Dr. Marc Mullie of Montreal’s Clinique Laservue, but the technues-especially LASIK-are here to stay. They’re safe and effective, and eventually, Mullie says, having refractive errors surgically corrected will be as common as braces on your teeth.

Still, only half the population ever needs refractive correction. It’s the next advance in eye surgery that will affect us all-and it too, is already here.

READING GLASSES MAY BE YESTERDAYS NEWS

It began with Dr. Ronald A. Schachar-an M.D./Ph.D. (physics) at the University of Texas. He created a stir by turning a 100-year-old theory about how the eye works right on its head. As a result, he says, “presbyopia is now surgically reversible.” Presboyopia is the loss of the eyes’ ability to focus on nearby objects. It affects virtually everyone. It’s one of those humbling, inevitable changes which occurs in our early 40s to remind us we’re not kids anymore. However, if Schachar’s theory is on the money (and if his theory’s right, we’re talking about a lot of money), all those aging Boomers who’ve been contemplating the morning paper at arm’s length may not need to contemplate an extra pair of specs: Reading glasses may be yesterday’s news.

Schachar disagrees with the age-old popular theory that presbyopia is caused by loss of elasticity in the capsule or hardening of the lens. The problem, he said, is even simpler: Throughout life, the lens grows in diameter at approximately .02 mm/year. Eventually (say, around age 42) the lens is just big enough so that the ciliary muscle can’t develop any real tension when it pulls. It’s like a tug-of-war team that can’t lean back far enough to get all its weight on the rope. The edge of the lens doesn’t flatten; the centre doesn’t steepen; and the magazine you’re trying to read doesn’t come into focus.

OK, you say, but how does that get you any closer to scanning the fine print? A way has to be found to allow the ciliary muscle room to really lean back and haul on the lens again-just like in a younger eye-and fine print would leap into focus. That’s what the Presby Procedure-the surgical application of Schachar’s theory-is designed to do: Four longish incisions, called “belt loops,” are made in the sclera (the white of the eye). A tiny, clear expansion band made of the same material used for intraocular lenses in cataract surgery is inserted into each incision. This four-piece ring lifts the sclera, pulling it outward a few microns (a few thousandths of a millimetre), and the ciliary body-the muscle attached to the sclera on the inside-gets pulled out with it).

Voilà! The muscle has gained a little distance on the lens and can now exert enough force to put things in focus.

PROCEDURES IN CANADA

At the moment, the only Canadian ophthalmologist approved to do the procedure (on a limited, experimental basis) is Dr. Sheldon Herzig, medical director of the Herzig Eye Institute in Toronto. Shachar invited Herzig-who’s president of the Canadian Association of Cataract and Refractive Surgeons-to attend his first course on the procedure in Monterey, Mexico, just over a year ago. Herzig was so impressed with both theory and results that he decided to get involved. He applied for and received permission from Canada’s Health Protection Branch to do 20 procedures. The Branch will then assess the results and decide whether to allow further experimental procedures by other surgeons.

Herzig’s candidates come from his own patient roster. These are people with healthy eyes who’ve lost their reading vision and have reasonably good distance vision without correction. They’re also free of conditions which create healing problems (such as collagen diseases like lupus). They’re also relatively young, because cataracts (a contradication) are more frequent as we approach 70. That said, one of Herzig’s “best” patients was a 65-year-old woman, “so age may not be that critical a factor. I feel more encouraged to do patients in the mid- to late 60s, as long as their eyes are perfectly healthy and there’s no sign of cataract.

“The main thing with this procedure is that it’s safe,” Herzig says. “You’re doing a lot of fiddling, but it’s all on the surface of the eye. The implants are removable if they’re a problem, and you’re not entering the eye, so there’s really no risk to vision. The only risk is time and money”-though complications can occur with any surgery. “You can get a nasty infection that goes beyond where you’d expect things to happen,” Herzig says, “but it’s really unlikely.” Overall, in fact, results aren’t as consistent as they are with laser surgery for myopia, Herzig says: “Some patients have developed a tremendous ability to read the smallest print, while others are just able to read moderate-sized print, so the results are definitely variable.”

PATIENTS EXERCISE THE EYES

The procedure also requires effort on the patients’ part, to get their ciliary muscles back in shape-“just by reading a lot and not reaching for their reading glasses when it gets frustrating,” Herzig says. “Taking small print and holding it close to their eye and watching it zoom in and out, feeling the ache in their eye and not backing off just because it’s uncomfortable.” The result, he says, is that some people improve over the next few months.

Is that enough to conclude that the Presby Procedure really works? That’s certainly the way Schachar and others-including a French ophthalmologist who’s performed the procedure more than 100 times-see it. But success, like beauty, is in the eye of the beholder, and not everyone views the procedure with equal enthusiasm.

Dr. Mullie and his partner, Dr. Gord Balazsi, were among the first in Canada to perform RK, PRK and LASIK. They were also among a handful of international participants who paid $2500 to attend a clinic Herzig presented in Toronto last fall, and they saw the technique performed in Paris. Neither demonstration has convinced Mullie to perform it himself if it’s approved by HPB. “There are still a lot of unresolved issues that need to be looked at,” he says. “I think Schachar may be on to something-his theory to a certain degree may be correct-but I’m not sure this is the right procedure for presbyopia.”

In fact, Mullie argues, the procedure doesn’t even prove Schachar’s theory of accommodation is correct: “He hasn’t really shown that this procedure really does expand the scleral ring. To show that objectively, you’d need to measure the space between the lens and the ciliary body pre- and post-operatively and prove that you’ve actually increased the space between the lens and the ciliary body. And he hasn’t done that.”

Accommodation’s also difficult to measure because it’s subjective. It may be easier to see detail in the morning, for example, when your eyes are rested, than just before bed, and some people can train themselves to overcome a degree of presbyopia-much like Presby patients exercise their ciliary muscles post-operatively to optimize the benefits of surgery.

Mullie also questions the forces the implants exert on the sclera and how they expand the scleral ring-if they do-questions he couldn’t get satisfactory answers for at the seminars he attended. That leaves him wondering if the Presby Procedure “is acting the way [Schachar] thinks it’s acting,” and if “it’s acting completely: If the surgery was really effective and really did as he says it does,” Mullie reasons, “you should be able to take any 70-year-old, do the surgery and get a reversal of presbyopia, but that’s not the case. You get a range of reversals-well, so-called reversals-which go from two diopters [units of measure] to maybe six diopters.” There are some very complicated issues at play, but ultimately the proof is in the pudding-whether people are really regaining some or all of their reading vision, and Herzig is getting results, even if they’re not everything he’d hoped.

“We examined some post-op patients in France when we were at the meeting, and we examined some in Toronto,” Mullie says. “Not 70-year-old patients-patients who were 50 and 55.” They found “some patients seemed to have an effect, while others seemed to have little or no effect, which is very strange.”

So, where does that leave the Presby Procedure? Still experimental, though not without considerable promise; it’s already undergone refinements that have improved the consistency of results. It’s also worth remembering that not many years ago, PRK and LASIK were experimental, too. Now they’re a multimillion-dollar-a-year business, which would suggest there’s plenty of incentive to bring the Presby Procedure up to the same standards of safety and effectiveness. It’s clearly another potential bonanza, since it will likely cost twice as much as LASIK (it’s more labour- and time-intensive), and everyone is a potential customer.

Then again, Presby’s not likely to have the market to itself for long: There’s a lot of work being done these days that may have applications in presbyopia. Take lens refilling, for instance. Experimental work with monkeys suggests that it may be possible to remove an aging lens and refill it with an elastic substitute. As long as the ciliary muscle’s still good, that may be an even better way to reverse presbyopia, and the first experiments in humans may be only two or three years away.

TESTS WITH CATARACT PATIENTS

The initial work will probably be done on cataract patients, Mullie speculates. “We’ll take a 70-year-old patient with a cataract, remove the lens substance, inject the refillable substance, and look at their accommodation.”

Certainly there are distinct advantages to a refilling procedure: In the procedure for cataracts, the cloudy, or opaque, content of the lens is vaporized and sucked out through a tiny incision, and a thin plastic intraocular lens is inserted. The problem with the lenses is they don’t restore the natural anatomy of the eye, leaving it at increased risk of retinal detachment, which happens after about one in a hundred cataract operations. Refilling the capsule to its original thickness would potentially eliminate that risk.

The other big advantage is that that technique could theoretically cure presbyopia and refractive errors, such as myopia, at the same time. Mullie pictures a 50-year-old patient coming to him because she can no longer read without glasses and perhaps has a little myopia-is there anything he can do? “Eventually,” he says, “you may be able to do lens surgery where you have a very precise measurement on how much you’ve refilled the lens capsule, and you adjust the convexity of the lens in the proper amount so you not only solve the refractive errors, but give back your reading vision as well.”

But that, he says, “is probably 10, 15 years down the road.” By which time, refinements to the Presby Procedure may have made it the surgery of choice-at least until the next revolution in eye-popping technology.