Vitreous humor is the eye's transparent jelly-like tissue. It occupies most eyeball, located in the eye's posterior chamber. Its main function is to transmit light rays.
Vitreous humor mainly contains: water (99%), collagen fibrils, peripheral cells, inorganic salts. In the aging process, vitreous humor may change into a liquid, and gradually shrinks or collapses, causing posterior vitreous detachment.
Natural aging may also result in vitreous opacity, due to the opaque cell fragments. Vitreous opacity usually causes floating or flashing vision (e.g. small dots, circles, lines, or cobwebs). Vitreous opacity often affects older people, or nearsighted people. Cataract surgery may also lead to vitreous opacity.