Certified Paraoptometric (CPO) Practice Exam 2025

Which substance fills the eye between the lens and the retina?

1. Vitreous Humor

2. Aqueous Humor

3. Lacrimal Fluid

4. Corneal Fluid

The correct answer is: Vitreous Humor

The vitreous humor is the gel-like substance that fills the space between the lens and the retina in the eye. It helps maintain the shape of the eyeball, provides support to the retina, and allows light to pass through to the retina without obstruction. The vitreous humor is crucial for eye health and function, as it plays a role in stabilizing the position of the retina against the back wall of the eye. In contrast, aqueous humor is found in the anterior and posterior chambers of the eye, between the cornea and lens, rather than filling the space between the lens and retina. Lacrimal fluid is related to tear production and lubrication of the eye's surface, while corneal fluid is not a recognized term in ocular anatomy. Thus, the correct answer highlights the role of the vitreous humor specifically in the posterior segment of the eye.