Surgeons at the Johns Hopkins Wilmer Eye Institute say they have restored functional vision to several patients who were losing their sight to macular degeneration -- so dramatically, in some cases, that people could once again read and drive.
The procedure does not work for everyone and is suitable only for people who have just begun to see their vision fade. Also, it is designed only for patients afflicted with the "wet" form of the disease, a rapidly progressing condition that strikes 200,000 Americans each year.
Despite its limitations, surgeons familiar with the operation say it appears to be the only measure capable of restoring sight to victims of macular degeneration, the most common form of blindness in older Americans.
The most common treatment, which employs a laser beam to destroy rogue blood vessels, is designed to keep vision from getting worse.
"This is the only treatment we have right now that can increase vision or restore more normal vision -- as opposed to other ones which basically stabilize the process," said Dr. Bradley Hinz, who has assisted in the operations.
The lead surgeon is Dr. Eugene de Juan, who has performed the operation -- called macular translocation -- on 43 patients in the past two years. In all cases, the team operated on one eye, though surgeons say some patients could have a second operation later.
Over the same period, surgeons at the Duke University Eye Center have been performing a more invasive procedure that has improved the vision of some patients, though not as much. It could be some time before the techniques can be accurately compared.
Dr. Cynthia Toth, a Duke ophthalmologist, said she accepts patients with more extensive retinal damage than the patients at Hopkins.
"Both of us are obviously at the beginning of a procedure that has not been done on hundreds of people yet," said Toth, who has performed translocation surgery on 13 patients. "Three years from now, we might have something that is an amalgam of both."
In the "wet" form of macular degeneration, abnormal blood vessels suddenly grow into a membrane that underlies the macula, a small portion of the retina that is responsible for central vision. The vessels can break and produce scar tissue, causing an ever-widening hole in the person's sight.
At greatest risk is the fovia, a tiny structure within the macula that accounts for sharp vision. Surgeons protect the fovia by detaching the retina and shifting it slightly. At Hopkins, surgeons move it less than a millimeter. At Duke, doctors move it up to 4 millimeters.
The intent is to slide the fovia to a healthier place. Once that is done, surgeons destroy the abnormal vessels.
De Juan described his first three cases in the May issue of Journal of Ophthalmology. But in an interview, he said he could comment on 24 who had recovered for at least six months -- the minimum time needed to judge the outcome.
In this group, about 25 percent of the patients enjoyed better vision. In one case, a patient improved from 20/200 to 20/25. Before surgery, he was legally blind -- unable to read or recognize faces. After surgery, he could read and drive.
The operation stabilized the vision of another 45 percent, meaning their sight got no worse at a time when rapid decline is expected.
"We had a couple who were 20/60 and they stayed at 20/60," de Juan said. "That's a remarkable result. In Maryland, you need to have 20/70 vision or better to drive."
Thirty percent of the patients, however, got worse after surgery. This was due largely to retinal detachments that occurred during the recovery period. De Juan said he is refining his techniques as he goes along.
De Juan cautioned that the improvements may not last forever. Translocation does not stop the disease process, he said, making it possible that abnormal vessels will someday invade the fovia in its new place.
With 3.5 million people afflicted with macular degeneration, de Juan also cautioned that it is a limited group that can benefit from the surgery.
The "wet" form accounts for 10 percent of all cases, but the vast majority that result in blindness. Even those with the "wet" form must notice their decline early, see an ophthalmologist and get referred for surgery. The idea, says de Juan, is to move the fovia before it has been destroyed.
L Elsewhere, the surgical advance was being viewed cautiously.
"This needs to be watched, it needs to be proven," said Dr. Wayne E. Fung, clinical professor of ophthalmology at the California Pacific Medical Center in San Francisco and a spokesman for the American Academy of Ophthalmology.
He noted that translocation surgery is just one of several approaches investigators around the country are testing. One idea borrowed from the work of cancer researchers is to administer drugs that stop the proliferation of blood vessels. Some researchers are experimenting with thalidomide, a drug that has attracted renewed interest after being cast off in the 1960s after an epidemic of birth defects.
Pub Date: 5/22/98