The three key proteins lysyl oxidase (LOX), transglutaminase-2 (TGM-2), and advanced glycation end products (AGEs) are responsible for more collagen crosslinking, which causes an excessive increase in ECM stiffness and causes ocular stiffness in glaucoma, reflecting the significant role ECM plays in the mechanical homeostasis of the eye [31, 35, 36]. Here, TGM2 is linked to glaucoma.