Efficacy and Safety of Conbercept for Diabetic Macular Edema Combined With Severe Non-proliferative Diabetic Retinopathy

The goal of this prospective multicenter open label study is to evaluate the efficacy and safety of intravitreal injection Conbercept (IVC) for the treatment of diabetic macular edema (DME) combined with severe nonproliferative diabetes retinopathy (sNPDR). The main questions it aims to answer are: * mean changes in best corrected visual acuity (BCVA) and central macular thickness (CMT) in comparison with baseline at 12 months after initial treatment * proportion of eyes with visual gain ≥15 letters in Early Treatment Diabetic Retinopathy Study (ETDRS) chart and ≥2-step improvement in Diabetic Retinopathy Severity Scale (DRSS) score after 12 months of the treatment * proportion of eyes actually underwent PRP treatment after 3 and 12 months of the treatment * mean changes in BCVA and CMT from baseline to monthly follow-up time point * complications and adverse effects