Randomized Trial of Peribulbar Triamcinolone Acetonide with and without Focal Photocoagulation for Mild Diabetic Macular Edema

Abstract

Objective: To provide pilot data on the safety and efficacy of anterior and posterior subtenon's injections of triamcinolone either alone or in combination with focal photocoagulation in the treatment of mild diabetic macular edema (DME). Design: Prospective phase 2 multi-center randomized clinical trial. Participants: 109 patients (129 eyes) with mild diabetic macular edema and visual acuity 20/40 or better. Methods: The participants were randomly assigned to receive either focal photocoagulation (N = 38), 20 mg anterior subtenon's injection of triamcinolone (N = 23), 20 mg anterior subtenon's injection followed by focal photocoagulation after 4 weeks (N = 25), 40 mg posterior subtenon's injection of triamcinolone (N = 21), or 40 mg posterior subtenon's injection followed by focal photocoagulation after 4 weeks (N = 22). Follow-up visits were performed at 4, 8, 17, and 34 weeks. Main Outcome Measures: Change in visual acuity and retinal thickness measured with the Optical Coherence Tomography (OCT). Results: At baseline, mean visual acuity in the study eyes was 20/25 and mean OCT central subfield thickness was 328 microns. Changes in retinal thickening and in visual acuity were not significantly different among the five groups at 34 weeks (P=0.46 and P=0.94, respectively). There was a suggestion of a greater proportion of eyes having a central subfield thickness < 250 microns at 17 weeks when the peribulbar triamcinolone was combined with focal photocoagulation. Elevated intraocular pressure and ptosis were adverse effects attributable to the injections. Conclusion: In cases of DME with good visual acuity, peribulbar triamcinolone, with or without focal photocoagulation, is unlikely to be of substantial benefit. Based on these results, a phase 3 trial to evaluate the benefit of these treatments for mild DME is not warranted.