What happens to the ciliary muscles when focusing on distant objects?

What happens to the ciliary muscles when focusing on distant objects?

• A. They relax, causing the lens to become flatter
• B. They contract, making the lens thicker
• C. They rotate to adjust focus
• D. They stimulate pupil dilation

Answer: (A)

When focusing on distant objects, the eye reduces its optical power by flattening the lens. This happens because the ciliary muscle relaxes, which tightens the zonular fibers pulling on the lens. A flatter lens has less curvature and lower refractive power, allowing light from distant objects to be focused precisely on the retina. Rotating the lens doesn’t occur to adjust focus; the lens changes shape, not orientation. Pupil dilation is a separate response that affects brightness and depth of field, not the focal length needed for distant vision.

When focusing on distant objects, the eye reduces its optical power by flattening the lens. This happens because the ciliary muscle relaxes, which tightens the zonular fibers pulling on the lens. A flatter lens has less curvature and lower refractive power, allowing light from distant objects to be focused precisely on the retina.

Rotating the lens doesn’t occur to adjust focus; the lens changes shape, not orientation. Pupil dilation is a separate response that affects brightness and depth of field, not the focal length needed for distant vision.