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

Inclusion Criteria:

• symptomatic patients aged 18 years or above with center involved diabetic macular edema in the involved eye and without clinically significant diabetic macular edema in the fellow eye defined on the basis of spectral-domain optical coherence tomography (OCT)
• central macular thickness (CMT) ≥300 μm measured by OCT
• the involved eyes diagnosed as severe non-proliferative diabetic retinopathy (sNPDR) confirmed by two independent experienced ophthalmologists based on the ETDRS standard seven field color fundus photographs

Exclusion Criteria:

• concomitant or previous macular diseases that may hinder visual improvement other than diabetic retinopathy (e.g., retinal vein occlusion, age-associated macular degeneration, uveitis, vitreomacular traction or epiretinal membrane)
• history of glaucoma or optic neuropathy of any kind
• previous vitreoretinal surgery or pan-retinal photocoagulation
• intravitreal injection anti-VEGF drugs within 6 months or intravitreal injection glucocorticoid within 3 months
• macular focal/grid laser photocoagulation within 3 months