The efficacy of intravitreal injection of conbercept on different types of macular edema induced by branch retinal vein occlusion

Objective

To investigate the clinical efficacy of intravitreal injection of conbercept on different types of macular edema (ME) induced by branch retinal vein occlusion (BRVO).

Methods

A prospective case-control study was designed.Fifty-six eyes of 56 patients diagnosed with ME secondary to BRVO in Weifang Eye Hospital between May 2016 and May 2017 were chosen for this study.According to the morphologies of ME through optical coherence tomography (OCT), patients were divided into 3 groups: 15 cases 15 eyes with serous retinal detachment (SRD), 19 cases 19 eyes with cystoid macular edema (CME), and 22 cases 22 eyes with mixed edema.All of the patients received intravitreal injection of conbercept using “1+ PRN” method and followed up for 6 months.When the change of central macular thickness (CMT) exceed 100 μm, repeat the injection.The best corrected visual acuity (BCVA) and CMT before and after treatment for 1 week, 1 month and 6 months and the average injection times were compared among different groups and time points.This study was approved by the Ethic Committee of Weifang Ophthalmic Hospital.Informed consent was signed from each patient before any treatments were proceeded.

Results

The differences of BCVA (LogMAR vision) at different time points before and after treatment among the 3 groups were statistically significant (F_group=105.834, P=0.000; F_time=68.070, P=0.000). One month after treatment, BCVA in SRD group was the best, the next was CME group, and BCVA in mixed edema group was the poorest, and the difference between SRD group and mixed edema group was statistically significant (P<0.05). Six months after treatment, BCVA in SRD group was the best, the next was CME group, and BCVA in mixed edema group was the poorest, the differences compared with each other were statistically significant (all at P<0.05). The BCVA after treatment were improved than those before treatment in all the three groups, BCVA in 6 months after treatment was improved than that in 1 week and 1 month after treatment in each group, the differences were statistically significant (all at P<0.05). The differences of CMT at different time points among the 3 groups were statistically significant (F_group= 68.640, P=0.000; F_time=29.783, P=0.000). CMT in mixed edema group before treatment was thicker than that in the SRD group and CME group, with significant differences between them (all at P<0.05). The CMT after treatment were thinner than those before treatment in 3 groups, with significant differences between them (all at P<0.05). With the extension of time, CMT was thinner gradually in each group, the differences of CMT in 1 week, 1 month, 6 months after treatment were statistically significant (all at P<0.05). The number of injections in 6 months was statistically different among the three groups (F=12.479, P=0.000). The number of injections in SRD group was less than that in the CME group and mixed edema group, and the differences were statistically significant (P=0.001, 0.000). Among the patients who still need to be injected or laser treatment after 6 months of treatment, 1 patient was SRD type ME (6.7%), 3 patients were CME type ME (15.8%), and 5 patients were mixed type ME (22.7%).

Conclusions

The efficacy of intravitreal injection with conbercept on different types of ME induced by BRVO was definitive, which can effectively improve BCVA and reduce ME; of which, the number of average injection times in SRD group is the least and its prognosis is best, just followed by CME group, while the number of injection times in mixed edema group is the largest and its prognosis is the poorest.