Certified Ophthalmic Assistant Practice Exam 2025 – Comprehensive Preparation Guide

The correct answer is the ciliary body. The zonular fibers, also known as the zonules of Zinn, are a series of fibrous strands that connect the ciliary body to the lens in the eye. These fibers play a crucial role in the process of accommodation, allowing the lens to change shape for focusing on objects at various distances.

When the ciliary body contracts, it releases tension on the zonular fibers, allowing the lens to become thicker and more rounded for near vision. Conversely, when the ciliary body relaxes, the tension increases, causing the lens to flatten for distance vision. This dynamic adjustment is essential for clear vision at different ranges.

The other options do not have the direct connection to the zonular fibers and lens that the ciliary body does. The iris is involved in regulating light entering the eye, while the medial rectus is a muscle that controls eye movement. Stroma refers to the supportive tissue in various parts of the body but is not specific to the zonular fibers or their function in supporting the lens. Hence, the ciliary body's relationship with zonular fibers is integral to their function in lens stability and accommodation.