Beletalent (Zhuhai) Pharmaceutical Co., Ltd

1. 观察糖宁通络片改善视力、降低视网膜病变程度有效性； 2. 观察糖宁通络片临床使用的安全性。

The goal of this clinical trial is to learn if drug TNTL works to treat non-proliferative diabetic retinopathy in adults. It will also learn about the safety of drug TNTL. The main questions it aims to answer are:
1. Does drug TNTL can improve visual acuity and reduce the degree of retinopathy?
2. What medical problems do participants have when taking drug TNTL? Researchers will compare drug TNTL to a placebo (a look-alike substance that contains no drug) to see if drug TNTL works to treat non-proliferative diabetic retinopathy.
Participants will:
1. Take drug TNTL or a placebo every day for 6 months
2. Visit the clinic once every 4 weeks for checkups and tests
3. Keep a diary of their symptoms and Change from baseline