Tangningtongluo Tablet in the Treatment of Non-proliferative Diabetic Retinopathy

Inclusion Criteria: * 1\. Patients with the diagnosis of type 2 diabetes. * 2\. Patients with the diagnosis of non-proliferative diabetic retinopathy and the classified as mild and moderate. * 3\. Target eye best corrected vision acuity (BCVA) ≥ 34 points (ETDRS vision chart, vision equivalent of score 20 / 200, decimal 0.1). * 4\. Patients who meet the syndrome differentiation standards of yin asthenia generating intrinsic heat and eye collateral stasis in traditional Chinese medicine. * 5\. HbA1C ≤ 9%. * 6\. Age between 18 and 75 years old * 7\. Informed consent, voluntary subject. The process of obtaining informed consent form complies with Good Clinical Practice(GCP). Exclusion Criteria: * 1\. Patient with the diagnosis of diabetic retinopathy is combined with severe vitreous blood effusion, or required total retinal laser treatment or vitrectomy. * 2\. Patient who has been treated with full retinal laser photocoagulation. * 3\. Patient with difficulty in evaluating fundus images with refractive medium turbidity. * 4\. Patient was diagnosed of acute metabolic disorders such as diabetic ketoacidosis or combined with severe acute infection in the past 1 month. * 5\. Patient with other serious diabetes complications, such as diabetes gangrene. * 6\. Patient was allergic to Tangningtongluo tablets, or Calcium dobesilate, or its composition. * 7\. Female patient with pregnancy, or prepare for pregnancy, or lactating. * 8\. Patient with serious cardiovascular, liver, kidney or hematopoietic system disease, and mental diseases. * 9\. Liver and renal function (Alanine aminotransferase (ALT) or Aspartate aminotransferase (AST) above 2 x Upper limit of normal (ULN)and Cr\> above 1 x Upper limit of normal (ULN)). The diabetic nephropathy stage was 4 and above. * 10\. Patient with eye diseases such as glaucoma, uveitis, optic neuropathy, and severe cataract. * 11\. Patient participated in other clinical researches within a month.