To report on visual outcome of patients receiving intravitreal triamcinolone a cetonide for treatment of diffuse diabetic macular edema. Prospective, comparati ve clinical interventional study. setting: Institutional. patient population: Th e study included 25 consecutive patients (50 eyes) with bilateral diabetic macul ar edema. intervention procedure: Unilateral intravitreal injection of about 20 mg triamcinolone acetonide into the eye (study group) more severely affected by diabetic maculopathy. The contralateral eyes served as control group. Mean follo w-up was 7.1 ±.4.1 months. main outcome measure: Visual acuity, intraocular pr essure. In the study group, visual acuity increased significantly (P ≤. 001) by 3.0 ±.2.6 Snellen lines to a peak at two to six months after the injection, an d decreased significantly (P=. 001) towards the end of follow up. At the end of follow-up, visual acuity was higher, not significantly (P=. 18) higher, than at baseline. An increase in visual acuity was found in 23 eyes (92%)-. In the co ntrol group, differences between visual acuity at baseline and at any of the re -examinations during follow-up were not significant (P > . 10). In an intra-i ndividual intereye comparison, gain in visual acuity was significantly (P < . 05 ) higher in the injected eyes, for the measurements obtained up to four months a fter injection. Intravitreal triamcinolone acetonide may temporarily increase vi sual acuity in eyes with diabetic macular edema. To report on visual outcome of patients receiving intravitreal triamcinolone a cetonide for treatment of diffuse diabetic macular edema. Prospective, comparati ve clinical interventional study. Setting: Institutional. Patient population: Th e study included 25 consecutive patients (50 eyes) with bilateral diabetic macul ardema intervention procedure: Unilateral intravitreal injection of about 20 mg triamcinolone acetonide into the eye (study group) more severely affected by diabetic maculopathy. The contralateral eyes served as control group. Mean follo w-up was 7.1 ± .4 .1 months. main Outcome measure: Visual acuity, intraocular pr essure. In the study group, visual acuity increased significantly (P ≤ 001) by 3.0 ± .2 Snellen lines to a peak at two to six months after the injection, an d decreased significantly (P At the end of follow-up, visual acuity was higher, not significantly (P =. 18) higher, than at baseline. An increase in visual acu ity was found in 23 eyes (92%) -. In the co ntrol group, differences between visual acuity at baseline and at any of the re -examinations during follow-up were not significant (P> .10). In an intra- i ndividual intereye comparison, gain in visual acuity was significantly (P <. 05) higher in the injected eyes, for the measurements obtained up to four months a fter injection. Intravitreal triamcinolone acetonide may temporarily increase vi sual acuity in eyes with diabetic macular edema .