American Board of Ophthalmology (ABO) Practice Exam

What is the gelatinous material filling the central cavity of the eye called?

1. Aqueous humor

2. Vitreous humor

3. Corneal fluid

4. Lens gel

The correct answer is: Vitreous humor

The gelatinous material filling the central cavity of the eye is known as vitreous humor. This substance plays an important role in maintaining the shape of the eye and providing a clear pathway for light to reach the retina. The vitreous humor is a clear, gel-like fluid that is composed primarily of water, collagen fibers, and hyaluronic acid, contributing to its jelly-like consistency. Vitreous humor serves several functions: it helps to maintain intraocular pressure, supports the retina by keeping it in place, and acts as a shock absorber to protect the inner structures of the eye. Its unique properties also help to ensure that light can pass through to the retina without distortion, which is crucial for proper vision. In contrast, aqueous humor is a different fluid that fills the anterior chamber of the eye, providing nutrients to the avascular structures like the cornea and lens, while corneal fluid and lens gel do not accurately describe any recognized anatomical components of the eye. Thus, the choice of vitreous humor is both anatomically and functionally correct.