The vitreous is a clear substance within the eye, which has a gel-like consistency. If you think of the inside of your eye as being hollow, the vitreous may be thought of as occupying approximately two thirds of this hollow space. This vitreous gel is composed of 99% water, and the other 1% consists of special substances known as collagen and hyaluronic acid, which endow the vitreous with its gel-like consistency.
The vitreous has many functions, which include:
- To help maintain the shape of the eye
- To act as a shock absorber
- To allow transmission of light from the external environment to the retina (located immediately behind the vitreous)
- To help keep the retina in contact with the back wall of the eye
Normally, the back surface of the vitreous is in direct contact with the retina and the blood vessels which supply the retina. However, in most eyes the vitreous becomes more liquid and at some point will pull away or separate from the retina and collapse into the central hollow part of the eye. This even constitutes a posterior vitreous separation or detachment (PVD) and is a normal aging process.