To compare the efficacy and safety of intravitreal injection of anti-vascular endothelial growth factor drug conbercept and intravitreal dexamethasone implant Ozurdex in the treatment of diabetic macular edema (DME).

A randomized controlled clinical study was performed.Thirty-six DME patients (36 eyes) were enrolled in Weifang Eye Hospital from March 2018 to June 2019.The patients were randomized into Ozurdex group and conbercept group via a random number table, with 18 eyes in each group.Patients received Ozurdex injection once, which was maintained for 6 months, or conbercept injection once a month for 3 times according to grouping.Before and after treatment, the best corrected visual acuity (BCVA) was examined with the International Standard Visual acuity chart and converted to logarithm of minimal angle resolution unit.The intraocular pressure (IOP) was measured using a non-contact tonometer.The central retinal thickness (CRT) was detected by optical coherence tomography (OCT).This study followed the Declaration of Helsinki and was approved by the Ethics Committee of Weifang Eye Hospital.

All patients were followed up for 6 months.In Ozurdex group, the BCVA pre-injection and at 1 month, 3, 4, 6 months after the first injection was 0.59±0.22, 0.53±0.20, 0.41±0.16, 0.38±0.19 and 0.56±0.19, respectively.The BCVA at 1 month, 3 and 4 months after the first injection were better than that before injection, and the differences were statistically significant (all at P<0.05).In conbercept group, the BCVA pre-injection and at 1 month, 3, 4, 6 months after the first injection were 0.60±0.23, 0.51±0.17, 0.29±0.13, 0.56±0.18 and 0.60±0.18, respectively.The BCVA at 1 month and 3 months after the first injection were better than that before injection, showing statistically significant differences (all at P<0.05).The CRT at 1 month, 3 and 4 months after the first injection were significantly lower than that before treatment in both the two groups (all at P<0.05).The CRT pre-injection was (498.61±77.14)μm in Ozurdex group, which was significantly higher than (462.17±48.74)μm at 6 months after the first injection (P<0.05).No significant difference in CRT was found between pre-injection and 6 months after the first injection in conbercept group (P>0.05).The incidence of high IOP in Ozurdex group was 33.3%(6/18), which was higher than 5.56%(1/18) in conbercept group, with a significant difference (χ²=4.433, P=0.035).No adverse effects such as aggravation of cataract, lens injury, endophthalmitis, vitreous hemorrhage and retinal detachment was found during the follow-up.

For DME, both conbercept and Ozurdex can improve BCVA and reduce CRT.Ozurdex shows durable efficacy and needs fewer injections than conbercept, but conbercept has less effect on IOP and is safer than Ozurdex.

Conbercept; Dexamethasone; Drug implants; Diabetic macular edema; Best corrected visual acuity; Cental retinal thickness