Figure 2.

Main components in tear film. The wide variety of components in each layer of the tear film provides function, nutrition, and protection to the ocular surface. However, it is susceptible to change their composition due to oxidative stress and inflammatory processes that involve the eye structures, which makes it an easy access ocular matrix to identify these changes measuring levels of components as biomarkers. SOD1: superoxide dismutase-1, Ser: serine, Thr: Threonine, Pro: Proline, IL: Interleukin, sIgA: surface Immunoglobuline A, MMP-9: matrix metalloproteinase-9, TNF-α: Tumor necrosis factor-α. Image created with BioRender.com.