Vitreous humor

The vitreous humor is a transparent, gel-like extracellular matrix that fills the posterior segment of the eye between the lens and the retina. It is primarily composed of water (98-99%), type II collagen fibers, and glycosaminoglycans like hyaluronic acid, which together maintain the eye's structural integrity and intraocular pressure (StatPearls, 2023). While it is not a specific molecular target such as a receptor or enzyme, it plays a vital role in ocular pharmacology as the primary medium for intravitreal drug delivery. Many therapies for retinal diseases, including anti-vascular endothelial growth factor (VEGF) agents and corticosteroids, are injected directly into the vitreous to reach the underlying retinal tissue (PubMed, PMID: 28933631). Pathological conditions involving the vitreous include vitreous hemorrhage, posterior vitreous detachment, and vitritis, which can significantly impair vision. Understanding its physical and chemical properties is essential for predicting drug diffusion and half-life within the eye. Furthermore, the vitreous can act as a reservoir for inflammatory cytokines and growth factors in diseases like diabetic retinopathy (NIH, 2022).

Other names

Vitreous bodyCorpus vitreumVitreous

The vitreous humor acts as a medium for drug diffusion rather than a molecular target; however, Ocriplasmin works by proteolytically degrading collagen and laminin at the vitreoretinal interface to induce vitreous liquefaction and separation (PubChem, CID 135311643).