GPT and non-proliferative diabetic retinopathy: In this study, there was no statistically significant difference in age, gender distribution, glycated hemoglobin, fasting blood glucose, alanine aminotransferase, and aspartate aminotransferase among the diabetic retinopathy (DNR), non-proliferative diabetic retinopathy (NPDR), and proliferative diabetic retinopathy (PDR) groups (P>0.05).