Deep sclerectomy, trabeculectomy effectively lower IOP

September 1, 2005

Fort Lauderdale, FL—A comparison of penetrating with non-penetrating glaucoma surgery, specifically deep sclerectomy and trabeculectomy, indicated that the latter provided better control of IOP 7 years after the surgery, according to Stefano Gandolfi, MD. When deep sclerectomy was converted to a penetrating procedure, the surgical success rate increased significantly.

Dr. Gandolfi and colleagues conducted a prospective, randomized, masked clinical trial that was carried out at two centers. Patients were included if they were 65 years of age or older and had an open angle and an IOP of 23 mm Hg or more and 30 mm Hg or less. In addition, patients had to be taking two or more antiglaucoma medications, had undergone previous laser trabeculoplasty, used a topical beta blocker in the fellow eye, and had a mean defect of less than 20 dB (24/2 Humphrey full threshold), Dr. Gandolfi explained. He discussed the study at the annual meeting of the Association for Research in Vision and Ophthalmology.

Seventy-nine eyes of 79 patients were included in the trial. Patients were randomly assigned based on pseudoexfoliation and use of pilocarpine to undergo either deep sclerectomy (group A, 41 eyes) or trabeculectomy (group B, 38 eyes), Dr. Gandolfi said. He is professor of ophthalmology and chairman of the University Eye Clinic of Parma, Italy.

IOP after surgery

After surgery, if the IOP remained below 21 mm Hg patients were followed; if the IOP was over 21 mm Hg, patients underwent goniopuncture in the sclerectomy group or medical therapy in the trabeculectomy group. If the IOP was under 21 mm Hg after goniopuncture, and patients were followed without the need for medical treatment, the treatment was considered a qualified success. If the IOP exceeded 21 mm Hg patients received medical therapy and were followed; if they required medical treatment, the treatment was considered a qualified failure, and if they needed surgery it was considered complete failure.

There were no shallow chambers after either surgery. Some sub-Tenon's cysts developed in the trabeculectomy group, hyphema was more prevalent in the trabeculectomy group, and there were no perforations in the eyes treated with sclerectomy. Patients were followed for 7 years.

In the 38 eyes that underwent trabeculectomy, one eye was considered an immediate treatment failure (defined as IOP greater than 21 mm Hg and unresponsive to a needling procedure and application of subconjunctival 5-fluorouracil) within 4 months of the surgery. This eye was treated with trabeculectomy supplemented with mitomycin C.

Thirty patients had well-controlled IOP at the beginning of follow-up; three of these had progression of visual field damage. Seven eyes received medical treatment. One of these underwent phaco and was lost to follow-up, and another eye underwent trabeculectomy combined with mitomycin C; both eyes were considered complete treatment failures, Dr. Gandolfi said.

In eyes that underwent trabeculectomy that initially had well-controlled IOP and did not need additional treatment, 10 required phacoemulsification, and of these two then needed medical therapy. Overall, 26 patients in the trabeculectomy group were classified as having complete treatment success at the end of the 7-year follow-up.

In the deep sclerectomy group, two of the 41 eyes were immediate treatment failures within 4 months of the surgery. These two then underwent trabeculectomy with mitomycin C. Of the remaining 39 eyes, 19 had well-controlled IOP; 17 eyes finished the study; two eyes showed progression of visual field damage. Twenty eyes underwent YAG laser goniopuncture, eight of which were considered qualified treatment successes, and 12 received medical treatment. Of the 12, four were qualified treatment failures, six were complete treatment failures, and two were lost to follow-up, he said.