Science & Technology: SURGERY
A CATARACT BREAKTHROUGH MAY BE ON THE WAY
A new one-step technique could be a bonanza for tiny Optex
Cataract surgery has come a long way from the days when your local practitioner used a finger to push the clouded lens out of the way--a technique used well into this century in the developing world. Surgical methods have improved dramatically, but conventional surgery remains difficult and expensive--big drawbacks for what has become the most frequent operation of any kind for people over 60.
All of the largest makers of ophthalmic equipment have mounted highly secretive internal programs to find new ways to remove the faulty lens. The companies would not discuss their progress, but surgeons report that Alcon Laboratories Inc., in particular, has licensed technology that would use a heated salt solution to melt the lens. Neither the inventor nor Alcon would comment. Some companies are experimenting with lasers, but those efforts have yet to succeed.
Until the big players are willing to talk about what they are doing, the apparent front-runner in this race is a tiny Southern California company, Optex Ophthalmologics Inc. It has developed a technique called Catarex that requires far less surgical skill than conventional methods. Says Dr. Timothy B. Cavanaugh, an eye surgeon at Hunkeler Eye Center in Kansas City, Mo., who has tried it on a pig: "The rapidity and ease with which I could remove the lens was revolutionary."FAST AND CHEAP. In conventional cataract surgery, eye surgeons employ an ultrasonic probe to cut the clouded, hardened lens painstakingly into tiny fragments that can be easily removed by suction. Doctors then implant a rigid, plastic lens that partially restores vision. The problem with this technique--called phacoemulsification, or "phaco"--is that it requires surgeons with a high degree of training and skill. That's why the operation is expensive: Medicare reimburses surgeons about $1,000 per eye.
Optex, based in San Juan Capistrano, Calif., was founded in 1990 specifically to come up with a breakthrough cataract device. It licensed its patents to Atlantic Pharmaceuticals Inc., which is now negotiating with big Japanese and American companies that could take the product through clinical trials and get Food & Drug Administration approval, a process that Optex says should take no more than a year. If the Optex method succeeds, it may even lead to a way to replace lenses for people whose eyesight is weakening as part of the normal aging process, some medical experts speculate.
But even if the technique is used only for cataract surgery, the financial rewards to Optex could be huge. More than 50% of senior citizens will require cataract surgery at some point. And among people who reach 75, the incidence rises to 70%. That translates into 1.5 million cataract removals annually, a number that's growing by 13% a year--and the rate should surge as baby boomers age. Annual Medicare reimbursements for cataract surgery total $3.5 billion, the largest single category in Medicare's budget. "We're looking for cheaper ways to do" cataract surgery, says Ellen Lieberman, director of the lens and cataract program at the National Eye Institute, which is partially funding the Optex research. "This is a one-step process, so it's possibly cheaper and faster."
Researchers don't really know what causes cataracts--the hardening and darkening of the clear center of the lens. They speculate, though, that it is possibly caused by exposure to ultraviolet light over a long period of time. Once the darkening begins, new transparent tissue from the outside edges of the lens moves inward and becomes harder and harder, keeping light from reaching the eye's retina. The job of the eye surgeon is to remove the darkened lens and replace it with something that transmits light.
Breaking up the hard nucleus of the lens is the first step in any cataract surgery. With phaco, the conventional technique, the surgeon must maneuver the vibrating tip of the ultrasonic probe--think of it as a tiny jackhammer--around the nucleus to carve it into tiny pieces. The Catarex technique uses a specially designed spinning blade called an impeller that draws the lens nucleus toward it so that it can chop it up. It's like an old-fashioned milkshake machine that draws solid chunks of ice cream into a vortex and then liquefies them. "We induce a fluid flow within the lens that draws the material to the probe," says John T. Sorensen, the system's inventor.
This new approach allows the surgeon to hold the probe in a stationary position, instead of moving it around within the lens. Using phaco, there's a chance that while maneuvering the instrument the surgeon may rupture the rear wall of the cellophane-like lens capsule that holds the lens--it happens in about 5% of cataract operations. Once the wall is ruptured, surgeons may have trouble stabilizing the implanted plastic lens within the eye. Plus, with phaco, after they break up the lens nucleus, surgeons must insert a second probe into the eye to remove everything that remains. The Catarex system requires just one step--when the pieces of the lens are removed, everything comes with them. And because of the smaller incision, recovery time should be less.SOFT LENSES. There's another bonus with Catarex: It can be done through a tiny hole in the lens capsule. That opens up the possibility of replacing the lens with an injectable, gel-like substance instead of a rigid plastic contact lens--something ophthalmologists have long dreamed about. A soft and pliable lens would more closely mimic the eye's natural function, expanding and contracting quickly to accommodate the different focal lengths needed for near and far vision. That way, cataract patients would no longer need to wear special glasses for reading.
What's more, the same flexible lenses could be implanted into middle-aged people instead of the bifocals they now resort to as their natural lenses start losing their flexibility. "I have the feeling that some kind of material is close to being available," says Dale P. DeVore, chief scientific officer at Collagenesis Inc., a Beverly (Mass.) company that has experimented with collagen lenses in animals. "But everyone's project is on the back burner because, so far, there's no technique for removing the lens and leaving the capsule intact." If the Catarex system reaches the market, though, those research efforts could be stepped up. And aging baby boomers could end up seeing more clearly well before they suffer from cataracts.By Larry Armstrong in Los AngelesReturn to top