Objective:To evaluate intravitreal injection of triamcinolone acetonide before laser panretinal photocoagulation(PRP)in the treatment of proliferative diabetic retinopathy.Methods:This interventional case series included 9 patients with bilateral proliferative diabetic retinopathy.One eye received intravitreal triamcinolone before PRP(injected eye)and the other,PRP alone(control eye).The main outcome measures were the change in planimetric area of fluorescein leakage from retinal neovascularization and in central macular thickness on optical coherence tomography at 3,6,9,and 12months.Secondary end points were change in vision,intraocular pressure,and cataract progression.Results:All patients completed 9 months and 5 patients,12 months of follow-up.Initial mean(SD)planimetric area of fluorescein leakage and central macular thickness were 7.22(5.70)mm2 and 372.11(91.88)μ m in injected eyes and 9.08(6.17)mm2 and 355.33(115.23)μ m in control eyes,respectively.At the 9-and 12-month intervals,the planimetric area of fluorescein leakage decreased by 86% and 88% in injected eyes and 33% and 50% in controls,respectively.Central macular thickness significantly decreased in injected eyes and increased in control eyes.Vision slightly improved in injected eyes and worsened in control eyes.Conclusion:Intravitreal injection of triamcinolone before PRP may be useful in improving the effects of PRP in eyes with proliferative diabetic retinopathy by reducing neovascularization and macular thickening. Objective: To evaluate intravitreal injection of triamcinolone acetonide before laser panretinal photocoagulation (PRP) in the treatment of proliferative diabetic retinopathy. Methods: This interventional case series included 9 patients with bilateral proliferative diabetic retinopathy .One eye received intravitreal triamcinolone before PRP (injected eye) and the other, PRP alone (control eye). The main outcome measures were the change in planimetric area of ​​fluorescein leakage from retinal neovascularization and in central macular thickness on optical coherence tomography at 3,6,9, and 12 months. Secondary end points were Changes in vision, intraocular pressure, and cataract progression. Results: All patients completed 9 months and 5 patients, 12 months of follow-up. Initial mean (SD) planimetric area of ​​fluorescein leakage and central macular thickness were 7.22 (5.70) mm2 and 372.11 (91.88) μ m in injected eyes and 9.08 (6.17) mm2 and 355.33 (115.23) μ m in control eyes, respectively. At the 9-and 12-month interv als, the planimetric area of ​​fluorescein leakage decreased by 86% and 88% in injected eyes and 33% and 50% in controls, respectively. Central macular thickness significantly decreased injected injected eyes and increased in control eyes. Vision slightly improved in injected eyes and worsened in control eyes. Objective: Intravitreal injection of triamcinolone before PRP may be useful in improving the effects of PRP in eyes with proliferative diabetic retinopathy by reducing neovascularization and macular thickening.