Posterior sub-tenon's capsule triamcinolone injection combined with focal laser photocoagulation for diabetic macular edema

Purpose: To investigate the efficacy of posterior sub-Tenon's capsule triamcinolone injection (PSTI) combined with focal laser (FL) photocoagulation in treatment of diffuse clinically significant diabetic macular edema (CSME). Design: Prospective randomized clinical study. Participants: Sixty patients with diffuse CSME. Methods: We randomized the patients who had CSME into 2 treatment groups. A total of 30 eyes received macular focal and grid laser photocoagulation (MP), and the second group of 30 eyes received FL photocoagulation combined with PSTI (FL + PSTI). Clinical and visual evaluations were performed at baseline and 12 and 18 weeks after treatment, and the results were compared by statistical methods. Mean Outcome Measures: Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity (VA) scores and clinical changes in macular edema. Results: Before treatment, mean ETDRS VA scores were 45.9 +/- 12.7 (mean +/- standard deviation [SD]; range, 24-66) in MP (focal + grid laser) and 44.5 +/- 12.6 (range, 22-66) in the FL + PSTI group. Early Treatment Diabetic Retinopathy Study scores at 18 weeks were 46.4 +/- 14.2 (range, 20-70) after MP and 52.5 +/- 17.5 (range, 22-82) after FL + PSTI. Early Treatment Diabetic Retinopathy Study scores significantly improved in eyes that received FL + PSTI (P = 0.0001, paired t test). The FL + PSTI group had an increase of 12.4 +/- 7.1 (range, 5-26) ETDRS letters, and the MP group had an increase of 7.8 +/- 3.1 (range, 5-15) letters (P = 0.04, unpaired t test). Twelve of 30 (40%) cases in the MP group and 24 of 30 (80%) cases in the FL + PSTI group showed clinical improvement in macular edema according to the stereoscopic evaluation of fundus and fluorescein angiography (P = 0.003). Conclusion: Posterior sub-Tenon's capsule application of triamcinolone may improve early visual outcome in diffuse diabetic macular edema when combined with FL photocoagulation.