Clinical Study on the Efficacy and Safety of TNTL in the Treatment of Non-proliferative Diabetic Retinopathy

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