Vitrectomy is required for removal of vitreous hemorrhage or retinal traction tissue in some patients with proliferative diabetic retinopathy. Post-vitrectomy macular edema may occur in these diabetic patients. Intravitreal injections of anti-VEGF agents or corticosteroid are required for treating diabetic macular edema (DME) in vitrectomized eyes. Intraocular levels of various cytokines may alter in the diabetic eyes following vitrectomy. Pharmacokinetics may be different between various intraocular agents in vitrectomized eyes. Herein our study will prospectively randomize to compare the clinical behavior between intravitreal ranibizumab (IVR) and intravitreal dexamethasone implant (IDI) in vitrectomized patients with DME. To our knowledge, it is the first study involving such subject.~Pseudophakic vitrectomized eyes with treatment-naïve center-involved DME will be enrolled with one eye in each patient. They are randomized into one group receiving IDI every 3 to 4 months, and the other group undergoing IVR using 3 monthly plus treat-and-extend injections all with monthly follow-up for 6 months. Switch of intravitreal drugs or deferred macular laser is not allowed. Primary outcome measures include change in central foveal thickness (CFT) in 1 mm by spectral-domain optic coherence tomography, and best corrected visual acuity (BCVA) at Month 6. Primary outcome measures include change in CFT and BCVA at Month 6. Injection number, BCVA, CFT, post-injection complications, and IOP are recorded and compared with Wilcoxon signed rank test within the group and Wilcoxon rank sum test between groups. Fisher's exact test is used for categorical comparison between groups. P value less than 0.05 is considered significant.
Vitrectomy is required for removal of vitreous hemorrhage or retinal traction tissue in some patients with proliferative diabetic retinopathy. Post-vitrectomy macular edema may occur in these diabetic patients. Intravitreal injections of anti-VEGF agents or corticosteroid are required for treating diabetic macular edema (DME) in vitrectomized eyes. Intraocular levels of various cytokines may alter in the diabetic eyes following vitrectomy. Pharmacokinetics may be different between various intraocular agents in vitrectomized eyes. Herein our study will prospectively randomize to compare the clinical behavior between intravitreal ranibizumab (IVR) and intravitreal dexamethasone implant (IDI) in vitrectomized patients with DME. To our knowledge, it is the first study involving such subject.