Randomized controlled clinical trial of beta irradiation as an adjunct to trabeculectomy in open-angle glaucoma

Abstract

Objective: To assess the effect of a single intraoperative application of 750 cGy of beta irradiation on the outcome of trabeculectomy for uncontrolled open-angle glaucoma.

Design: A prospective, randomized, double-blind, placebo-controlled clinical trial.

Participants: Sixty-one eyes of 61 Caucasian patients at low risk of filtering surgery failure, with poorly controlled primary or secondary open-angle glaucoma undergoing routine trabeculectomy.

Method: Patients were randomly assigned to control or beta irradiation groups. All patients underwent standard trabeculectomy with fornix-based conjunctival incision. Eyes assigned to beta irradiation received 750 cGy of beta irradiation directly over the sclerostomy site on completion of conjunctival suturing. An identical but inactive applicator was applied to control eyes, delivering no radiation. Both operator and patient remained masked to the assignment for the 12-month follow-up period.

Main outcome measures: The main outcome measure was intraocular pressure (IOP) control. Complete success of IOP control was defined as an IOP less than 21 mmHg at 12 months without need for additional medication. Qualified success was defined as an IOP less than 21 mmHg at 12 months where additional medication was required.

Results: Complete success of IOP control was achieved in 19 (86%) control eyes and 35 (90%) irradiated eyes (P = 1.0). Qualified success of IOP control was achieved in 21 (95%) control eyes and 39 (100%) irradiated eyes at 12 months follow-up (P = 1.0)

Conclusions: We experienced a very high success rate of filtration surgery in this select population without adjunctive irradiation. Our sample size was too small to show any improvement in success with use of beta irradiation in this group. Other studies would have to be done to determine whether it may have measurable benefit in cases with a high risk of filtration failure.