Objective: To determine whether an intravitreal injection of triamcinolone acetonide for persistent diabetic macular edema after adequate laser treatment improves visual acuity.
Design: Prospective, double-masked, placebo-controlled, randomized clinical trial.
Participants and controls: Sixty-nine eyes of 43 patients were entered into the study, with 34 eyes randomized to receive active treatment and 35 randomized to receive a placebo injection. Sixty-five of 69 eyes (94%) completed the 3-month study visit.
Intervention: Using a 27-gauge needle, 0.1 ml of triamcinolone acetonide was injected through the pars plana. The procedure was performed in a minor procedures area in the outpatient clinic under sterile conditions and using topical and subconjunctival anesthesia. Eyes randomized to placebo received a subconjunctival saline injection using the identical procedure for preparation.
Main outcome measures: The main outcome measures were improvement of best-corrected logarithm of the minimum angle of resolution visual acuity by 5 or more letters and incidence of moderate or severe adverse events.
Results: Eighteen of 33 eyes (55%) treated with triamcinolone gained 5 or more letters of best-corrected visual acuity compared with 5 of 32 eyes (16%) treated with placebo (P = 0.002). Macular edema was reduced by 1 or more grades as determined by masked semiquantitative contact lens examination in 25 of 33 treated eyes (75%) versus 5 of 32 untreated eyes (16%; P<0.0001). Optical coherence tomography showed a mean reduction of central retinal thickness of 152 mum in the 21 treated eyes that were examined compared with a reduction of 36 mum in 20 placebo-treated eyes. Infectious endophthalmitis developed in 1 triamcinolone-treated eye that was treated adequately without loss of visual acuity.
Conclusions: In the short term, intravitreal triamcinolone is an effective and relatively safe treatment for eyes with diabetic macular edema that have failed laser treatment. Although it will be essential to study longer-term outcomes, the use of intravitreal triamcinolone may be considered in 1 eye of patients who continue to lose vision from diabetic macular edema despite conventional management.