A study conducted on insulin-dependent patients with diabetes (n = 86; 58.0 ± 8.0 year) showed that tear flow and tear volume, based on the Schirmer tests, were lower (1.1 ± 0.4 μL/min and 10 ± 3 mm, respectively) compared to those obtained from the control group (60.0 ± 9.0 year; 1.1 ± 0.4 μL/min, and 10.0 ± 3.0 mm, respectively) [29]. Here, INS is linked to diabetes mellitus.