Certified Paraoptometric (CPO) Practice Exam 2025 – All-in-One Study Guide to Ensure Exam Success!

The primary function of aqueous humor is to provide nutrients for the lens and the posterior cornea. This clear fluid fills the anterior and posterior chambers of the eye, which are located between the cornea and lens. Aqueous humor is vital for delivering essential nutrients, such as glucose and amino acids, to these avascular tissues, which lack direct blood supply. Additionally, it plays a significant role in maintaining intraocular pressure, which is crucial for the overall health and functionality of the eye.

While protecting the lens or maintaining eye shape are important aspects of ocular health, they do not capture the primary role of aqueous humor as effectively as its nutrient supply function. Supporting the retina's connection to the cornea is not a direct role of aqueous humor either, as the vitreous humor primarily supports the retina. Therefore, providing nutrients is the most accurate characterization of the main function of aqueous humor.