Different Dosages of Intravitreal Triamcinolone Acetonide for Diffuse Diabetic Macular Edema

Abstract

Abstract: : Purpose: To test the effect of different dosages of intravitreal triamcinolone acetonide (TA) as treatment for diffuse diabetic macular edema. Methods: In a prospective, double masked, randomized, clinical interventional study 29 eyes (27 patients) with diffuse diabetic macular edema were randomly divided into 3 study groups. Each group received an intravitreal injection of filtered TA of which 9 eyes obtained 4mg, 11 eyes 8 mg, and 9 eyes 25mg. The applied TA dosage was determined prior to its filtration. Mean follow–up was 6.3 ± 2.5 months (3 to 12 months). The visual acuity was determined by ETDRS and used as main outcome measure. Results: Maximal increase of visual acuity was significantly (p=0.038; r=0.39) correlated with the applied dosage of intravitreal TA: Correspondingly, a maximal gain of visual acuity was significantly (p=0.024) higher in the 25mg study group than in the 4mg group. The peak time of visual increase, defined as the time at which visual acuity started to decrease, was significantly (p=0.031) longer in the 25mg study group than in the 4mg study group. The visual peak time increased significantly with higher intravitreal TA dosages (r=0.45; p=0.014). In the 25 mg study group (at 1 week; p=0.028) the increase of visual acuity occurred significantly earlier than in the 2 groups with a lower dosage of which a tendency towards visual increase was not seen before than after about 1 month post injection. Conclusions: Diffuse diabetic macular edema, treated by an intended (dosage prior to filtration) dosage of 25 mg intravitreal TA, a visual increase will result earlier, be of longer duration and more pronounced than after an intended dosage of 8 mg or 4 mg intravitreal TA.

Keywords: diabetic retinopathy • corticosteroids • injection