Prophylactic Effect of Conbercept Intravitreal Injection at the Conclusion of Cataract Surgery for Diabetic Macular Edema

Diabetic macular edema (DME) is an important cause of central vision impairment among people with diabetic retinopathy (DR), which can have a significant adverse effect on daily activities and quality of life. Diabetic patients with preexisting DME are at increased risk of worsening edema following cataract surgery. Previous studies also reported progression of DR after cataract surgery. Clinically significant DME is now classified into center-involved DME (CI-DME) and non center-involved DME (non-CI DME). Randomized clinical trials have established intravitreal antivascular endothelial growth factor (VEGF) therapy as first-line treatment for visual impairment from CI-DME and studies have addressed the influence of anti-VEGF therapy among patients with DME undergoing cataract surgery. However, for patients with non-CI DME before cataract surgery, whether anti-VEGF therapy is necessary at the end of surgery to prevent CI-DME is still clinically controversial. In order to evaluate the prophylactic effect of Conbercept (a recombinant fusion protein with high affinity to all VEGF isoforms and PIGF) intravitreal injection at the conclusion of cataract surgery for DME in patients with DR, the investigators will prospectively recruit 40 cataract patients with DR and non-CI DME and randomly assign these subjects into the study group (combined cataract surgery and intravitreal Conbercept injection, 20 cases) and the control group (cataract surgery alone, 20 cases). The primary outcomes include mean changes in central retinal thickness (CRT) and in diabetic retinopathy severity score (DRSS). The secondary outcomes include changes in best corrected visual acuity (BCVA), foveal avascular zone (FAZ), retinal vessel density (VD), the aqueous concentrations of VEGF, PIGF, interleukin- (IL-) 2, IL-5, IL-6, and IL-8.