Specifically, we observed significant decreases in ophthalmological parameters (i.e., MCV, MMT, RNFLT, and GCLT) and increases in tear concentrations of cytokines (i.e., IL-1ra, IL-4, IL-5, IL-6, IL-8, IL-9, IL-13, G-CSF, GM-CSF, IFN-γ, CCL3/MIP-1α, CCL4/MIP-1β, and CCL11/eotaxin-1) in patients with CAD and T2DM, with an inverse correlation among these variables. The gene discussed is IL9; the disease is type 2 diabetes mellitus.