Abstract： Diabetic retinopathy (DR),which is a common complication of diabetic and the main cause of blindness,brings not only a heavy economic burden to society,but also seriously threatens to the patients'quality of life.Clinical researches on the therapies of DR are active at present,but how to perform a good clinical research with scientific design should be considered with high priority.The randomized controlled trial (RCT) is considered to be the gold standard for evidence-based medicine,but RCT is not always perfect.Limitations still exist in certain circumstance and the conclusions from RCTs also need to be interpreted by an objective point of view before clinical practice.Real world study (RWS) bridges the gap between RCT and clinical practice,in which the data can be easily collected without much cost,and results might be obtained within a short period.However,RWS is also faced with the challenge of not having standardized data and being susceptible to confounding bias.The standardized single disease database for DR and propensity score matching method can provide a wide range of data sources and avoid of bias for RWS in DR.