Which eye muscle bends and changes the shape of the lens to focus incoming light on the retina at the back of the eye?

Which eye muscle bends and changes the shape of the lens to focus incoming light on the retina at the back of the eye?

• A. Cornea
• B. Iris
• C. Lens muscles
• D. Pupil

Answer: (C)

Accommodation is the eye’s way of focusing by changing the lens shape. The muscles that control the lens—the ciliary muscles, often referred to here as the lens muscles—adjust the lens curvature to fine-tune focus. When you look at something up close, these muscles contract, reducing tension on the suspensory ligaments and causing the lens to become thicker and more curved. That increased convexity raises the lens’s refractive power so light can be focused on the retina. When looking at something far away, the muscles relax, the lens flattens, and its power decreases, allowing distant objects to be focused correctly. The cornea does most of the initial refraction, while the iris controls how much light enters through the pupil.