Glaucoma Surgery May Yield Fewer Complications for Patients

For years the gold standard for glaucoma surgery has been a trabeculectomy. This procedure creates a new drain in the eye, lowering the elevated intraocular pressure caused by a build-up of aqueous fluid when the natural drain isn’t working properly.

But a procedure that reopens the natural drainage channel rather than creating a new one could someday become the new standard.

Duke glaucoma specialist Leon Herndon, MD, associate professor of ophthalmology, is one of the few surgeons around the country who has performed the cutting-edge procedure called canaloplasty. In July 2007, at the Eye Center, he performed the first two canaloplasties in North Carolina.

“In patients with open-angle glaucoma, the drainage canal has collapsed," Herndon explains. "The canaloplasty procedure opens the canal just as a stent opens a carotid artery in someone suffering from heart disease.

“Traditional trabeculectomy surgery involves creating a new drain for the eye by creating a ‘bleb’ on the eye,” he continues. “A trabeculectomy is a tiny flap cut into the sclera, the white part of the eye, to allow aqueous fluid to drain from the eye in a new direction. While this type of surgery is effective in lowering intraocular pressure, it also can lead to complications. Since the bleb is elevated, it may cause discomfort or irritation. And since the tissue is very thin, these blebs may leak over time, putting the patient at a risk of infection, which may ultimately cause vision loss.”

Although canaloplasty is a more complicated surgery than trabeculectomy, it is a safer  procedure because it reopens the Schlemm’s canal, the eye’s natural drainage channel. In many glaucoma cases, particularly in primary open angle glaucoma (POAG), the Schlemm’s canal has collapsed, blocking the flow of aqueous fluid out of the eye.

Canaloplasty allows the surgeon to reopen the canal and restore flow by using a tiny specialized catheter to go inside the canal and thread a suture 360 degrees around its walls -- just as a stent holds open a collapsed artery.

Canaloplasty is not right for every glaucoma patient in need of surgery, Herndon notes. For now it is best suited for patients who have open-angle glaucoma, have not had previous glaucoma surgery, and do not require extremely low intraocular pressures. It may also appeal to contact lens wearers since contacts can irritate blebs and cause them to leak or become infected.

Herndon says, “Canaloplasty is a great addition to our arsenal for glaucoma surgery, allowing us to fine-tune the appropriate surgery for each patient. I’m excited about the potential -- the likely decreased risk of significant complications and the ability to give patients a better quality of life.”