Treatment response to Conbercept of different types of diabetic macular edema classified based on optical coherence tomography

Abstract

To compare different types of diabetic macular edema (DME) classified based on optical coherence tomography (OCT) for their responses to Conbercept injection and analyze the factors that affect the treatment responses. We retrospectively analyzed the clinical data of 65 patients (76 eyes) with DME diagnosed and treated with intravitreal injection of Conbercept (1+PRN) in our hospital from February, 2019 to February, 2021. According to OCT findings, DME in these patients was classified into cystic macular edema (CME; 28 eyes), serous retinal detachment (SRD; 33 eyes), and diffuse retinal thickening (DRT; 15 eyes). The best corrected visual acuity (BCVA) and central retinal thickness (CRT) were measured before and at 3 months after the first treatment. The baseline OCT characteristics of different types of DME were compared, and the correlation of these OCT characteristics with the treatment response to Conbercept was analyzed. All the patients showed significant improvement of the BCVA 3 months after the treatment (P < 0.05). For all the 3 types of DME, the CRT at 3 months after the first treatment was significantly reduced as compared to the baseline (P < 0.05). The number of hyperreflective foci (HF) in the outer retina and the proportion of ellipsoid zone (EZ) interruption were the greatest in SRD group (P < 0.05). The baseline outer retinal HF was significantly correlated with the baseline CRT, CRT changes and CRT after treatment (all P < 0.05). The patients with baseline outer limiting membrane (ELM)/ EZ disruption had poorer baseline BCVA, greater baseline CRT, greater variation of CRT and poorer BCVA at 3 months after treatment (all P < 0.05). For all the 3 types of DME, treatment with intravitreal injection of Conbercept can significantly improve the BCVA and CRT of the patients. DME of the SRD type has the best morphological response to Conbercept, while the DRT type has a relatively poor response. A greater number of HF at baseline may indicate a better morphological response to Conbercept treatment, and baseline ELM/EZ disruption may suggest a poor visual prognosis at 3 months after treatment.