Table 1.

Molecules most commonly involved in maintaining cellular and tissue homeostasis.

Ocular Disorders and Site	Proteases and Protease-Inhibitors Mainly Involved in Ocular Diseases
Degenerative Disorder: keratoconus and keratoglobus	α2-macroglobulin↓ α1-proteinase inhinitor (α1-PI)↓	Cathepsin B and G↑ Matrix Metalloproteinase-1,2,3 (MMP-1,2,3)↑	Acid phosphatase↑ Catalase↑
Keratitis: angiogenesis, tumor, inflammation, oxidative stress, and fibrosis activity	Serpins↑: ovalbumin, α1-antitrypsin, plasminogen activator inhibitor, maspin, pigment epithelial derived factor (PEDF), SERPINA3K	Cathepsin↑ MMP-8↑	Calpain inhibitor↑ Catalase↑
Iris and ciliary body	Secretory leukocyte protease inhibitor (SLPI)↑	MMPs↑	Calpain inhibitor↑
Endophthalmitis, keratitis, vitreous and retina disorders	SLPI↑	MMPs↑	Calpain inhibitor↑
Retina: angiogenesis, tumor, inflammation, oxidative stress, and fibrosis activity	SERPINA3K↑	Metalloproteinase inhibitor-3 (TIMP-3)↓ [age-related macular degeneration, aging, Sorsby dystrophy]	Calpain inhibitor↑
Retina/optic nerve: damage to the retinal ganglion cells (RGC) in glaucoma, multiple sclerosis (MS), retinitis pigmentosa, diabetes, etc.	Caspase 3 inhibitor↑ [apoptosis of RGC and damage to optic nerve fibers]	MMPs↑	Calpain inhibitor↑ [apoptosis of RGC, damage to optic nerve fibers and photoreceptors]