The vitreous body forms about four-fifths of the bulb of the eye. It fills the concavity of the retina, and is hollowed in front, forming a deep concavity, the hyaloid fossa, for the reception of the lens.
It is transparent, of the consistence of thin jelly, and is composed of an albuminous fluid enclosed in a delicate transparent membrane, the hyaloid membrane.
In the center of the vitreous body, running from the entrance of the optic nerve to the posterior surface of the lens, is a canal, the hyaloid canal, filled with lymph and lined by a prolongation of the hyaloid membrane. This canal, in the embryonic vitreous body, conveyed the arteria hyaloidea from the central artery of the retina to the back of the lens.
The fluid from the vitreous body is nearly pure water; it contains, however, some salts, and a little albumin.
No bloodvessels penetrate the vitreous body, so that its nutrition must be carried on by vessels of the retina and ciliary processes, situated upon its exterior.