What happens when the ciliary muscles of the eye contract? The

Analyze the question: It asks about accommodation in the eye, which is how the eye focuses on near or far objects. Specifically, it asks what happens when the ciliary muscles contract.

Concept: The lens is held in place by the suspensory ligaments, which attach to the ciliary body (the ciliary muscles). The lens is elastic, so its shape depends on the tension pulling on it.

Step-by-step solution:

1. Ciliary muscles contract. They are ring-shaped, so contraction makes the ring smaller, like a drawstring tightening.
2. Tension on the suspensory ligaments drops. The ligaments become slack or loose.
3. The lens is no longer pulled flat. Because it is elastic, it bulges and becomes thicker, which means more convex.
4. Focal length becomes shorter. A thicker, more curved lens bends light more strongly. This lets the eye focus on near objects.

Checking the options:

• A. Lens more concave: Wrong. The eye's lens is biconvex and never becomes concave.
• B. Lens becomes more convex: Correct.
• C. Longer focal length: Wrong. A more convex lens has a shorter focal length.
• D. Suspensory ligament becomes tight: Wrong. It becomes slack. Tightening happens when the ciliary muscles relax.

Answer: B

Memory tip: "Contract = Close-up = Convex =カ slack ligaments." Better still, remember this pair:

• Ciliary muscles contract → ligaments loose → fat lens → near vision.
• Ciliary muscles relax → ligaments tight → thin lens → distant vision.

Many students get this wrong because they think "contract" means "tighten" for the ligaments, but the ligament does the opposite of the muscle.