New procedure less invasive than traditional methods, halts vision loss

By Susannah Benady

MONTREAL – An eye surgeon here has introduced a new laser surgery technique that can successfully treat cases of severe glaucoma in patients who have failed to improve with more standard forms of surgery.

The technique, called deep laser sclerotomy, is new in Canada but has been practised in Europe for the past few months, according to Dr. Sam Fanous, assistant professor of ophthalmology at the University of Montreal, who has now performed more than 30 deep sclerotomy procedures.

"The advantage of this procedure is that it is extra-occular, rather than intra-occular so there are far fewer complications," said Dr. Fanous, also head of the Montreal Eye Clinic, a private clinic where he performs all of his surgeries.

"There is no penetration of the eye, so the risk of inflammation or infection is significantly reduced."

Using the laser turns the surgery into a more refined technique than sclerotomy done mechanically and improves the success rate, he has found. "This is very advanced surgery and the cases we have treated so far have been very complicated but the rate of success is over 90%—even in patients whose previous two surgeries have failed."

While all glaucoma patients are candidates for the surgery, it is particularly helpful for those whose previous trabeculectomy has failed, he said. However, the treatment is only available to patients who can afford the fee of $3,900 per eye. Most of that pays for the two hours of operating room time required for the complex procedure.

First, the scleral layer at the corner of the eye is dissected. Next, the sceral layer is lifted and the deep layers are sculpted and thinned with a laser to the point where droplets of aqueous humor begin to drain from the inside the eye. Then, a collagen drain is implanted at the surface of the eye to allow the aqueous humor to flow out, relieving the pressure that causes glaucoma.

"We cut the sclera in the eye with an Excimer laser. The point is to make the sclera membrane very thin so that it allows the aqueous humor liquid inside the eye to flow out." The procedure does not help patients see better but stops the loss of vision that glaucoma causes, he said.

For patients with less advanced glaucoma, a five-minute procedure called selective laser trabeculoplasty can reduce ocular pressure by opening the trabeculum cells without burning, pain or side-effects, said Dr. Fanous, who is the first to offer the technique in Quebec.

"The advantage of selective laser trabeculoplasty is that, unlike conventional Argon laser treatment, it uses a cold laser and is non-invasive so that patients can have the procedure several times, if necessary."

Studies have shown that in 84% of cases, the effects of the surgery remained 12 months after treatment, said Dr. Fanous.