Objective: To evaluate prospectively the efficacy and safety of 1 intravitreal injection of 4 mg of triamcinolone acetonide for refractory diffuse diabetic macular edema.
Design: Interventional case series.
Participants: Fifteen patients with bilateral diabetic macular edema unresponsive to laser photocoagulation. In all patients, one eye received the injection, and the other served as a control.
Intervention: Intravitreal injection of 4 mg of triamcinolone acetonide under subconjunctival anesthesia.
Main outcome measures: The main outcome measure was central macular thickness (CMT) at 1, 3, and 6 months, measured by optical coherence tomography. Secondary outcomes were Early Treatment Diabetic Retinopathy Study (ETDRS) scores, intraocular pressure, and cataract progression.
Results: In this preliminary report, we give the results for 12 patients who had a follow-up of at least 3 months. Seven of them were followed up for 6 months. Before injection, CMT was 509.6+/-143.5 microm (mean +/- standard deviation [SD]) in injected eyes, versus 474.4+/-82.6 microm in control eyes. Four weeks after injection, it was 207.3+/-44.2 microm in injected eyes and 506.7+/-122.4 microm in control eyes (P<0.001, bilateral Wilcoxon test for paired samples), and after 12 weeks, 207+/-96.7 microm and 469.3+/-117.6 microm, respectively (P = 0.005). The difference between the CMTs of injected and control eyes was no longer significant at 24 weeks because of the recurrence of macular edema in 5 of 12 injected eyes. Before triamcinolone injection, the ETDRS score was 47.8+/-13 (mean +/- SD; range, 28-66) in injected eyes, versus 51.9+/-14.6 (range, 31-71) in control eyes. Twelve weeks thereafter, the corresponding values were 52.7+/-10.8 (range, 34-70) and 50.8+/-14.3 (range, 29-69), respectively, and at 24 weeks, 54.7+/-7.6 (range, 47-68) and 50.6+/-18.4 (range, 28-71). At no time was the difference between the ETDRS scores for injected and control eyes significant. In 6 of the 12 injected eyes, intraocular pressure exceeded 25 mmHg, and was controlled by topical medication.
Conclusion: Intravitreal injection of triamcinolone effectively reduces macular thickening due to diffuse diabetic macular edema, at least in the short term. Further studies are required to demonstrate that it provides visual benefit.