What is the role of the ciliary muscle in accommodation?

What is the role of the ciliary muscle in accommodation?

• A. Changes lens curvature to focus on objects at different distances
• B. Produces aqueous humor
• C. Regulates iris
• D. Transmits light

Answer: (A)

Accommodation relies on the ciliary muscle changing the lens shape. When the ciliary muscle contracts, it reduces tension on the zonular fibers, allowing the lens to become more curved and increase its refractive power to focus on nearby objects. When the muscle relaxes, tension on the zonules increases, flattening the lens for distant vision. This adjustment is driven by parasympathetic input via the oculomotor nerve. The ciliary muscle doesn’t produce aqueous humor (that’s the ciliary processes), doesn’t regulate the iris (iris muscles handle pupil size), and doesn’t transmit light; those are other structures’ roles.

Accommodation relies on the ciliary muscle changing the lens shape. When the ciliary muscle contracts, it reduces tension on the zonular fibers, allowing the lens to become more curved and increase its refractive power to focus on nearby objects. When the muscle relaxes, tension on the zonules increases, flattening the lens for distant vision. This adjustment is driven by parasympathetic input via the oculomotor nerve. The ciliary muscle doesn’t produce aqueous humor (that’s the ciliary processes), doesn’t regulate the iris (iris muscles handle pupil size), and doesn’t transmit light; those are other structures’ roles.