Vitreous humor is the clear, jelly-like material that fills the posterior chamber (the vitreous body) of the vertebrate eye between the lens and the retina. The vitreous humor, also known simply as the vitreous, consists of collagen and sodium hyaluronate and helps maintain sufficient intraocular pressure to keep the eyeball from collapsing. It includes a meshwork of collagen fibers that hang between the lens and the retina. This meshwork is thicker near the back of the eye, where it is attached to the retina and the optic nerve.