As seen from Figure 3A–C (subgroups) patients with advanced DR (PDR, DME) had increased levels of NFL (age-adjusted) compared to DM (FD 2.52 (95%CI: 1.71; 3.72, p < 0.001; adj-p < 0.001 and FD 2.04 (95%CI: 1.33; 3.12, p < 0.001; adj-p < 0.001), respectively) and HC (FD 2.35 (95%CI: 1.67; 3.30, p < 0.001; adj-p < 0.001), and FD 1.89 (95%CI: 1.28; 2.79, p < 0.001; adj-p < 0.001) respectively); In the same patients with no comorbidities a trend increase was found. Here, NEFL is linked to diabetes mellitus.