AIM:To investigate the changes of microvascular diameter in non-proliferative diabetic retinopathy(NPDR)at different stages.

METHODS: Prospective case-control study. Patients with type 2 diabetes mellitus complicated with diabetic retinopathy(DR)who were hospitalized in the Endocrine Department of our hospital from September 2020 to March 2021 were selected and divided into diabetic non-retinopathy group(50 cases and 50 eyes), DR stage Ⅰ group(50 cases and 50 eyes), DR stage Ⅱ group(50 cases and 50 eyes), DR stage Ⅲ group(50 cases and 50 eyes)according to the “Clinical Diabetic Retinopathy Disease Severity Scale” formulated by the Chinese Medical Association in 1985. In addition, 50 cases and 50 eyes of a control group with normal physical examination were selected, totally 250 cases and 250 eyes. The fundus color photos were taken and entered into the ARIA1.0 automatic analysis software to record the diameters of arterio-venous and capillary vessels in different ranges, with 4 segments in each range and 200 segments in each group for statistical analysis.

RESULTS: There was no significant difference in the diameter of retinal artery between different stages of NPDR(P>0.05), and there was significant difference in the diameter of retinal vein and diameter of perimacular capillary amorg different stages of NPDR(P<0.05). The multiple comparison of retinal vein diameter and perimacular capillary diameter in different groups was statistically significant(P<0.01). The average score of retinal vein diameter in the range of 0-0.5PD was “stage Ⅲ course > stage Ⅱ course>stage Ⅰ course>normal group>control group”. The average score of retinal vein diameter group in the range of 0.5-1.0PD(including 0.5)was “stage Ⅲ course > stage Ⅱ course > stage Ⅰ course > normal group > control group”, the average score of perimacular capillary diameter group was “stage Ⅲ course > stage Ⅰ course > control group; Stage Ⅲ course > normal group; Stage Ⅱ course > stage Ⅰ course > control group; Stage Ⅱ course > normal group; The diseased normal group > the control group”, while there was no significant difference between the stage Ⅲ course and the stage Ⅱ course, the stage Ⅰ course and the diseased normal group(P>0.05).

CONCLUSION: Retinal artery diameter has no obvious change in NPDR stages. The retinal vein and perimacular capillary in diabetic patients are dilated. In different stages of NPDR, the diameter of the vein and perimacular capillary is gradually widened.