New surgery advances glaucoma treatment

Canaloplasty avoids infection risk of more established procedure

A long-awaited advance in glaucoma treatment may help patients keep their sight without creating a permanent puncture on the eyeball that has been a drawback to the standard surgery.

Glaucoma, a leading cause of blindness that results when pressure damages the optic nerve, has been difficult to treat, and doctors have had one main surgical option to preserve sight. Patients have a small hole cut in their eye to allow fluid to drain out, relieving internal pressure. The surgery is effective, but patients face a lifetime risk of serious eye infection because of the opening, which forms a tiny blister on the eye.

The chance to try an alternative surgery that does not puncture the eye got Audrey Sheheen, 77, to drive five hours to Duke University Medical Center from her home in Camden, S.C. Duke is the only hospital in North Carolina and one of the few in the Southeast that offer the new procedure, which is called canaloplasty.

"I would have had whatever they said I needed, but I much prefer this," Sheheen said of the canaloplasty she had in February. "I think this is going to save a lot of people from having that other surgery."

Canaloplasty is a sort of ocular version of angioplasty. Instead of clearing an artery, ophthalmologists use an extremely fine catheter to clear the drainage canal that runs around the perimeter of the colored part of the eye. The canal drains off fluid that carries oxygen and nutrients in a healthy eye; in a patient with glaucoma, it is collapsed.

During canaloplasty, a microcatheter is fed into the drainage canal through an incision in the white part of the eye. Then the canal is injected with a special gel to dilate and widen it. Finally, a very fine suture is fed all the way through the canal and tied off to hold it open, allowing internal fluid to drain.

Canaloplasty is not as effective as the more established surgery at reducing eye pressure, but studies show that most patients can be returned to pressure levels that compare with those found in the average healthy person. That's a safe level for many people with glaucoma, said Dr. Leon Herndon, an ocular surgeon at Duke who started doing canaloplasty in June. Patients typically can return to normal activities within a few days.

"It's clear that for many patients this is a good option," Herndon said.

Julie Bryce Munro, 24, who works in marketing for the Raleigh software company Red Hat, was eager to try canaloplasty when Herndon mentioned the surgery to her last summer.

"If you have an open sore on your eye, it changes everything," said Munro, referring to the older surgery. Munro was was diagnosed with glaucoma as a teenager; the disease runs in her family. "I was very desperate to avoid it."

Before Munro had canaloplasty, the pressure in her right eye was near 40, or about twice the maximum pressure doctors consider normal, and Munro was using two prescriptions of drops to reduce it. Immediately after, the pressure fell to 12 and it has stayed within the normal range since then. Munro no longer uses any drops in that eye.

By contrast, she still uses two forms of drops to relieve pressure in her left eye, even after having laser treatment to boost drainage and several other invasive procedures. She wishes canaloplasty had been available when she had that eye treated.

"It's really nice to finally see some innovation in glaucoma," Munro said of canaloplasty. Her health insurer initially balked at covering the surgery, which cost more than $10,000, but paid for it after Herndon intervened. "I was getting kind of frustrated."

Dr. Louis Cantor, an ophthalmologist who runs the glaucoma service at Indiana University School of Medicine, said he has offered canaloplasty for more than a year. He said the surgery, which has approval from the U.S. Food and Drug Administration, is one of many innovations for treating glaucoma. One procedure in testing now involves placing a stentlike device in the eye's drainage system via a cut in the cornea.

"There's a lot of creative thinking in glaucoma surgery right now," Cantor said. "Canaloplasty is just one good option."

Not all patients are candidates. To have canaloplasty, patients must have the most common type of glaucoma and cannot have had previous glaucoma surgeries on the eye. Patients who must have very low eye pressure would still need to get the opening on their eye, called a bleb.

But it's great to finally have an alternative that works for some patients, Cantor said.

"In glaucoma surgery, it's essentially been one-size-fits-all," he said.