The effectiveness of vitrectomy co-adjuvant intravitreal dexamethasone implant on visual outcome in patients with proliferative diabetic retinopathy: study protocol for a prospective randomized controlled trial.

Abstract

Background: Proliferative diabetic retinopathy (PDR) often leads to tractional retinal detachment and vitreous hemorrhage, requiring vitrectomy. Poor visual outcomes are commonly caused by macular edema and proliferative vitreous retinopathy after vitrectomy. Intravitreal dexamethasone implant has shown promise in improving visual function after vitrectomy for diabetic macular edema, but its role in vitrectomy for PDR treatment remains unexplored. This study aims to assess the effectiveness of vitrectomy combined with an intravitreal dexamethasone implant for PDR patients.

Methods: We will design a single-mask, randomized controlled trial with 100 participants diagnosed with PDR requiring vitrectomy. Participants will be randomly assigned to either the Ozurdex (0.7 mg dexamethasone intravitreal implant) group or the control group. The dexamethasone implant group will undergo vitrectomy combined with 0.7 mg dexamethasone intravitreal implant, while the control group will undergo vitrectomy alone. A single surgeon will perform all the vitrectomy surgeries, and the choice of intravitreal dexamethasone implant treatment will be disclosed before the closure of scleral wounds. Primary and secondary outcomes will be assessed at baseline and at 4, 8, 12, and 24 weeks post-vitrectomy.

Statistical analysis: Statistical analysis will be conducted using R software. A p value 0.05 will be considered statistically significant. The analysis methods will include the following: visual acuity and OCT measurements will be analyzed using repeated measures analysis of variance (ANOVA) with two-tailed tests; rates of visual improvement, visual decline, postoperative vitreous hemorrhage, elevated intraocular pressure, and postoperative retinal detachment will be analyzed using chi-square tests with two-tailed tests. Logistic regression analysis will be used to analyze risk factors for poor visual prognosis, neovascular glaucoma development, and postoperative vitreous hemorrhage occurrence.

Discussion: This protocol aims to enhance our understanding of the effects of combining an intravitreal Ozurdex 0.7 mg dexamethasone implant with vitrectomy on visual outcomes and macular morphology changes in treating late complications of PDR.

Trial registration: The trial was registered at the Chinese Clinical Trial Registry on May 11, 2022, with registration number ChiCTR2200059760.