Purpose: To determine if intravitreal injection of triamcinolone acetonide is safe and effective in treating diabetic macular edema unresponsive to prior laser photocoagulation.
Design: Prospective, noncomparative, interventional case series.
Participants: Sixteen eyes with clinically significant diabetic macular edema (CSME) that failed to respond to at least two previous sessions of laser photocoagulation.
Methods: Eyes were diagnosed with CSME and treated with at least two sessions of laser photocoagulation according to Early Treatment Diabetic Retinopathy Study guidelines. At least 6 months after initial laser therapy, the response was measured by clinical examination and optical coherence tomography (OCT). Eyes with a residual central macular thickness of more than 300 microm (normal, 200 microm) and visual loss from baseline were offered intravitreal injection of 4 mg triamcinolone acetonide. The visual and anatomic responses were observed as well as complications related to the injection procedure and corticosteroid medication.
Main outcome measures: Visual acuity and quantitative change in OCT macular thickening were assessed. Potential complications were monitored, including intraocular pressure response, cataract progression, retinal detachment, vitreous hemorrhage, and endophthalmitis.
Results: All patients completed 3 months of follow-up, and 8 of 16 patients (50%) completed 6 or more months of follow-up. Mean improvement in visual acuity measured 2.4, 2.4, and 1.3 Snellen lines at the 1-, 3-, and 6-month follow-up intervals, respectively. The central macular thickness as measured by OCT decreased by 55%, 57.5%, and 38%, respectively, over these same intervals from an initial pretreatment mean of 540.3 microm (+/-96.3 microm). Intraocular pressure exceeded 21 mmHg in 5, 3, and 1 eye(s), respectively, during these intervals. One eye exhibited cataract progression at 6 months. No other complications were noted over a mean follow-up of 6.2 months. Reinjection was performed in 3 of 8 eyes after 6 months because of recurrence of macular edema.
Conclusions: Intravitreal triamcinolone is a promising therapeutic method for diabetic macular edema that fails to respond to conventional laser photocoagulation. Complications do not appear to be prohibitive. Further study is warranted to assess the long-term efficacy and safety, and the need for retreatment.