As shown in Figures 3A3, 3B3, 3A5, 3B5, 4D, and 4E, the density of RGCs in Ex-4+Ex-9-39-treated DM eyes was similar to saline-treated DM eyes in the peripheral (1148 ± 172.2 cells/mm2 vs. 1292 ± 184.8 cells/mm2, p > 0.05, Tukey’s multiple comparisons test after one-way ANOVA) and middle regions (1755 ± 185.7 cells/mm2 vs. 1877 ± 212.0 cells/mm2, p > 0.05), suggesting the involvement of GLP-1R in the Ex-4 effect. Here, GLP1R is linked to diabetes mellitus.