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Abstract

Several factors such as systemic diabetic control, blood pressure, renal function, lipid profile, and hemoglobin A1c may contribute to progression of diabetic macular edema. In our randomized study, there was no significant difference in systemic status, diabetic control, and hemoglobin A1c levels between the treatment groups. Dr Salti et al point out the association of diabetic macular edema with the grade of diabetic retinopathy. In the natural progression of diabetic eye disease, macular edema usually precedes the proliferative retinopathy.1Tong L. Vernon S.A. Kiel W. et al.Association of macular involvement with proliferative retinopathy in type 2 diabetes.Diabet Med. 2001; 18: 388-394Crossref PubMed Scopus (28) Google Scholar It is true that passive vascular permeability is increased in eyes with severe retinopathy, and panretinal photocoagulation itself may destroy the blood–retina barrier and may cause progression of macular edema.2Sander B. Larsen M. Moldow B. Lund-Andersen H. Diabetic macular edema passive and active transport of fluorescein through the blood-retina barrier.Invest Ophthalmol Vis Sci. 2001; 42: 433-438PubMed Google Scholar However, in our article we made clear that we excluded patients who had panretinal photocoagulation within the last 4 months before treatment of macular edema. None of the patients in our study had active proliferative disease at the time of the treatment. In our article’s “Materials and Methods,” we also noted that we excluded patients if the macular edema was due to vitreoretinal interface disease (such as proliferative vitreoretinal traction). I agree with Dr Salti et al that a follow-up period longer than 18 weeks would give a stronger evidence for safety of triamcinolone. Steroids certainly have numerous adverse side effects such as development or progression of cataracts and glaucoma. Previous reports show that these adverse effects are lower with periocular triamcinolone injection (40 mg/ml) than with systemic steroids.3Mueller A.J. Jian G. Banker A.S. et al.The effect of deep posterior subtenon injection of corticosteroids on intraocular pressure.Am J Ophthalmol. 1998; 125: 158-163Abstract Full Text PDF PubMed Scopus (58) Google Scholar In our study, we lowered the dose of triamcinolone to 20 mg per injection instead of 40 mg per injection. We believe that the adverse effects of triamcinolone are lower with the dose of 20 mg per injection.4Tunc M. Onder H.I. Kaya M. Posterior sub–Tenon’s capsule triamcinolone injection combined with focal laser photocoagulation for diabetic macular edema.Ophthalmology. 2005; 112: 1086-1091Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar As we divide the regular 40 mg/ml triamcinolone solution in half, each sub–Tenon’s capsule injection volume is 0.5 ml. This low injection volume may also reduce the rate of possible side effects such as blepharoptosis and orbital fat prolapsus. As we mentioned, we reported our preliminary results, and our long-term study is under way to determine the long-term effects of combined laser and posterior sub–Tenon’s capsule triamcinolone for diffuse diabetic macular edema. Macular Edema TreatmentOphthalmologyVol. 113Issue 5PreviewWe read with great interest the recent article by Tunc et al1 comparing the efficacies of posterior sub–Tenon’s capsule triamcinolone injection (PSTI) combined with focal laser photocoagulation and focal laser combined with grid photocoagulation in treating diffuse clinically significant diabetic macular edema. The Early Treatment Diabetic Retinopathy Study visual acuity score and clinical changes in macular edema were evaluated at 12 and 18 weeks after treatment. The authors found that PSTI may improve the early visual outcome when combined with focal laser photocoagulation. Full-Text PDF