Objective: To report 2-year safety and efficacy outcomes from a trial of intravitreal triamcinolone acetonide (TA) injections (4 mg) in eyes with diabetic macular edema and impaired vision that persisted or recurred after laser treatment.
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 placebo. Two-year data were available for 60 of 69 (87%) eyes of 35 of 41 (85%) patients; 9 eyes of 6 patients were lost to follow-up, of which 6 received a placebo and 3 received intravitreal TA.
Intervention: Triamcinolone acetonide (0.1 ml) was injected through the pars plana using a 27-gauge needle. Eyes randomized to placebo received a subconjunctival injection of saline.
Main outcome measures: Improvement of best-corrected logarithm of the minimum angle of resolution visual acuity (VA) by > or =5 letters after 2 years and incidence of moderate or severe adverse events.
Results: Improvement of > or =5 letters' best-corrected VA was found in 19 of 34 (56%) eyes treated with intravitreal TA, compared with 9 of 35 (26%) eyes treated with the placebo (z(generalized estimating equation) = 2.73, P = 0.006). The mean improvement in VA was 5.7 letters (95% confidence interval, 1.4-9.9) more in the intravitreal TA-treated eyes than in those treated with the placebo. An increase of intraocular pressure (IOP) of > or =5 mmHg was observed in 23 of 34 (68%) treated versus 3 of 30 (10%) untreated eyes (P<0.0001). Glaucoma medication was required in 15 of 34 (44%) treated versus 1 of 30 (3%) untreated eyes (P = 0.0002). Cataract surgery was performed in 15 of 28 (54%) treated versus 0 of 21 (0%) untreated eyes (P<0.0001). Two eyes in the intravitreal TA-treated group required trabeculectomy. There was one case of infectious endophthalmitis in the treatment group.
Conclusion: Intravitreal TA improves vision and reduces macular thickness in eyes with refractory diabetic macular edema. This beneficial effect persists for up to 2 years with repeated treatment. Progression of cataract and elevation of IOP commonly occur but appear manageable. Spontaneous improvement over years can still occur in eyes that are apparently severely affected by diabetic macular edema.