Randomized trial of peribulbar triamcinolone acetonide with and without focal photocoagulation for mild diabetic macular edema: a pilot study

Abstract

Objective: To provide pilot data on the safety and efficacy of anterior and posterior sub-Tenon injections of triamcinolone either alone or in combination with focal photocoagulation in the treatment of mild diabetic macular edema (DME).

Design: Prospective, phase II, multicenter, randomized clinical trial.

Participants: One hundred nine patients (129 eyes) with mild DME and visual acuity 20/40 or better.

Methods: The participants were assigned randomly to receive either focal photocoagulation (n = 38), a 20-mg anterior sub-Tenon injection of triamcinolone (n = 23), a 20-mg anterior sub-Tenon injection followed by focal photocoagulation after 4 weeks (n = 25), a 40-mg posterior sub-Tenon injection of triamcinolone (n = 21), or a 40-mg posterior sub-Tenon 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 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 mum. Changes in retinal thickening and in visual acuity were not significantly different among the 5 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 less than 250 mum at 17 weeks when the peribulbar triamcinolone was combined with focal photocoagulation. Elevated intraocular pressure and ptosis were adverse effects attributable to the injections.

Conclusions: 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 III trial to evaluate the benefit of these treatments for mild DME is not warranted.

Figure 1. Patient Outcome Visit Follow-Up Flow Chart (for on line)

Flow chart showing visit completion and reasons for study discontinuation in the treatment groups. * Dropped includes deaths, withdrawals, lost to follow up occurring since the last visit

Figure 2. Mean central subfield thickness at baseline and follow-up visits according to treatment group

Mean central subfield thickness at baseline and follow-up according to treatment group.