BMJ  2006;333:942 (4 November), doi:10.1136/bmj.38971.395301.7C (published 5 October 2006)

Research

Effect of beta radiation on success of glaucoma drainage surgery in South Africa: randomised controlled trial

James F Kirwan, research fellow1, Simon Cousens, professor of epidemiology and medical statistics2, Lynette Venter, consultant3, Colin Cook, consultant4, Andries Stulting, professor3, Paul Roux, professor5, Ian Murdoch, senior lecturer1

1 Department of Epidemiology and International Eye Health, Institute of Ophthalmology, University College London, London EC1V 9EL, 2 Infectious Diseases Epidemiology Unit, London School of Hygiene and Tropical Medicine, 3 Ophthalmology Department, National Hospital, Bloemfontein, Republic of South Africa, 4 Ophthalmology Department, Groote Schuur Hospital, Cape Town, Republic of South Africa, 5 Ophthalmology Department, Pretoria Academic Hospital, Pretoria, Republic of South Africa

Correspondence to: I Murdoch i.murdoch{at}ucl.ac.uk

Abstract

Objective To evaluate whether beta radiation may offer a practical method of improving surgical success for glaucoma drainage surgery in South Africa.

Design Double blind, randomised controlled trial.

Setting Three public hospitals in South Africa.

Participants 450 black Africans with primary glaucoma.

Interventions Trabeculectomy with 1000 cGy beta radiation or standard trabeculectomy without beta radiation (placebo).

Main outcome measures Primary outcome measure was surgical failure within 12 months (intraocular pressure > 21 mm Hg while receiving no treatment for ocular hypotension). Secondary outcomes were visual acuity, surgical reintervention for cataract, and intraoperative and postoperative complications.

Results 320 people were recruited. beta radiation was given to 164; 20 (6%) were not seen again after surgery. One year after surgery the estimated risk of surgical failure was 30% (95% confidence interval 22% to 38%) in the placebo arm compared with 5% (2% to 10%) in the radiation arm. The radiation group experienced a higher incidence of operable cataract (18 participants) than the placebo group (five participants; P = 0.01). At two years the estimated risks with placebo and beta radiation were, respectively, 2.8% (0.9% to 8.3%) and 16.7% (10.0% to 27.3%).

Conclusion beta radiation substantially reduced the risk of surgical failure after glaucoma surgery. Some evidence was, however, found of an increased risk for cataract surgery (a known complication of trabeculectomy) in the beta radiation arm during the two years after surgery.

Trial registration ISRCTN62430622 [controlled-trials.com] .


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