After being informed about the study and potential risks,all patients giving written informed consent will undergo a 1-week screening period to eligibility for study entry.At week 0,patients who meet the eligibility requirements will be randomized into two groups(experimental group and control group)in a 1:1 ratio to Tangningtongluo tablets(4 tablets,tid,po.) or Calcium dobesilate capsules(1 capsule,tid,po.).
This trial is planned to collect relevant clinical data to evaluate the prevention efficacy and safety of Tangningtongluo tablets on the non-proliferation period of diabetic retinopathy.