ObjectiveTo observe and preliminarily discuss the distribution characteristics of the non-perfusion area (NP) of the retina in different stages of diabetic retinopathy (DR) and its changes with the progression of DR. MethodsA retrospective clinical study. From October 2018 to December 2020, 118 cases of 175 eyes of DR patients diagnosed in Eye Center of Renmin Hospital of Wuhan University were included in the study. Among them, there were 64 males with 93 eyes and 54 females with 82 eyes; the average age was 56.61±8.99 years old. There were 95 eyes of non-proliferative DR (NPDR), of which 25, 47, and 23 eyes were mild, moderate, and severe; 80 eyes were proliferative DR (PDR). Ultra-wide-angle fluorescein fundus angiography was performed with the British Optos 200Tx imaging system, and the fundus image was divided into posterior, middle, and distal parts with Image J software, and the ischemic index (ISI) was calculated. The difference of the retina in different DR staging groups and the difference of ISI were compared in the same area. The Kruskal-Wallis test was used to compare the ISI between the different DR staging groups and the Kruskal-Wallis one-way analysis of variance was used for the pairwise comparison between the groups. ResultsThe ISI of the posterior pole of the eyes in the moderate NPDR group, severe NPDR group, and PDR group were significantly greater than that in the distal periphery, and the difference was statistically significant (χ2=6.551, 3.540, 6.614; P=0.000, 0.002, 0.000). In severe NPDR group and PDR group, the ISI of the middle and peripheral parts of the eyes was significantly greater than that of the distal parts, and the difference was statistically significant (χ2=3.027, 3.429; P=0.015, 0.004). In the moderate NPDR group, there was no significant difference in ISI between the peripheral and distal parts of the eye (χ2=2.597, P=0.057). The ISI of the posterior pole of the eyes in the moderate NPDR group and the PDR group was significantly greater than that in the middle periphery, and the difference was statistically significant (χ2=3.955, 3.184; P=0.000, 0.009). In the severe NPDR group, there was no significant difference in ISI between the posterior pole and the middle periphery of the eye (χ2=0.514, P=1.000). Compared with the mild NPDR group and the moderate NPDR group, the ISI of the whole retina, posterior pole, middle and distal parts of the PDR group was larger, and the difference was statistically significant (χ2=－7.064, －6.349,－6.999, －5.869, －6.695, －6.723, －3.459, －4.098; P=0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.003, 0.000). ConclusionThe NP of the eyes with different DR stages is mainly distributed in the posterior pole and the middle periphery. The higher the severity of DR, the greater the NP in the posterior and middle periphery.
