Purpose:This study was designed to evaluate the efficacy of combined intravitreal triamcinolone acetonide injection with panretinal photocoagulation in the treatment of proliferative diabetic retinopathy as compared withstandard panretinal photocoagulation.Design:This study is a prospective, comparative, non-randomized study.Setting:Cairo University Hospitals (Kasr El-Aini Teaching Hospital, New Kasr El-Aini Hospitals); Ophthalmic surgical and laser units.Patients and Methods:The study was carried out on 40 eyes with proliferative diabetic retinopathy. They were randomly divided into 2 groups. Group A (20 eyes of 18 patients) were treated with panretinal photocoagulation only. Group B (20 eyes of 14 patients) received intravitreal injection of triamcinolone acetonide followed one week later by panretinal photocoagulation. In group A, laser burns were applied over the entire retina-sparing the central macular area- over 2-3 sessions, 1 week apart. Focal macular photocoagulation (for the microaneurysms) was performed in the first session. In group B, intravitreal triamcinolone acetonide 0.1 ml (4 mg) was injected at the pars plana followed 1 week later by panretinal photocoagulation as in group A.The Main Outcome Measures:These include best corrected visual acuity, fundus examination for the presence of neovessels and fundus fluorescein angiography for the site, size and number of neovessels. The examination was done before the start of treatment. After treatment, patients were first examined after 2 weeks as regards the best corrected visual acuity and fundus examination, and then at 1, 3 and 6 months thereafter. Fundus fluorescein angiography was done before treatment, and then at one month, three months and six months after treatment. The results were statistically analyzed.Results:In group A:At 6 months after treatment, the best corrected visual acuity ranged from counting fingers 1m to 0.6, 3 of the 6 eyes with neovessels at the disc showed recurrence and the other 3 eyes showed complete regression of the neovessels. All the 19 eyes with neovessels elsewhere showed complete regression on fundus fluorescein angiography.In group B:At 6 months after treatment, the best corrected visual acuity ranged from counting fingers 1m to 0.9, 1 of the 8 eyes with neovessels at the disc showed no response to treatment while the other 7 eyes showed complete regression of the neovessels. Only 2 of the 18 eyes with neovessels elsewhere still showed leakage on fundus fluorescein angiography in one area while the other 16 eyes showed complete regression of the neovessels.Conclusion:Intravitreal triamcinolone acetonide is a safe and effective accelerating adjuvant therapy to panretinal photocoagulation in the treatment of proliferative diabetic retinopathy. It speeds the regression of the neovessels through its anti-angiogenic action and speeds the improvement of visual acuity in patients with concomitant diabetic macular edema through its anti-inflammatory action. However, further studies on larger groups for longer follow-up periods are required to support the conclusions.