The vitreous is composed primarily of which two components?

• A. Water and Hyaluronic acid
• B. Collagen and Elastin
• C. Proteoglycans and Lipids
• D. Nucleic acids and Water

Answer: (A)

The vitreous is a hydrated gel, so the most important idea is that water is the dominant component, with a network formed by a glycosaminoglycan that binds water to create the gel-like matrix. Hyaluronic acid is the key molecule that retains water and helps give the vitreous its transparent, viscoelastic properties. Together, these two make up the majority of the vitreous substance.

Collagen is present to provide some structural framework, but elastin is not a main player in the vitreous, and lipids, nucleic acids, or other components do not contribute as the primary two. So the best description is water bound by hyaluronic acid forming the gel that fills the eye’s posterior chamber.