Lens: accommodation: practice question

A Ophthalmology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Ophthalmology · Lens: accommodation

Sample item

According to Helmholtz's theory, what happens to increase the lens power during accommodation?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Ciliary muscle contracts, zonules relax and the lens becomes more convex

Contraction of the ciliary muscle relaxes zonular tension, and the elastic capsule moulds the lens into a more spherical shape, mainly anteriorly. Accommodation is mediated by parasympathetic fibres through the third nerve.

Option by option

  • A. The lens flattens through zonular traction

    Flattening occurs in distance focus, not accommodation.

  • B. Ciliary muscle relaxes and zonules tighten

    This describes the state for distance viewing.

  • C. Vitreous pressure moulds the lens

    The vitreous plays no role in accommodation.

  • D. Ciliary muscle contracts, zonules relax and the lens becomes more convex (correct)

    Correct. Relaxed zonules let the lens bulge and increase its power.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Ophthalmology question

What is the answer to this Ophthalmology question?

The best answer is D, Ciliary muscle contracts, zonules relax and the lens becomes more convex. Contraction of the ciliary muscle relaxes zonular tension, and the elastic capsule moulds the lens into a more spherical shape, mainly anteriorly.

Why is "The lens flattens through zonular traction" not the answer?

Flattening occurs in distance focus, not accommodation.

Why is "Ciliary muscle relaxes and zonules tighten" not the answer?

This describes the state for distance viewing.

Why is "Vitreous pressure moulds the lens" not the answer?

The vitreous plays no role in accommodation.

What concept does this question test?

It tests Lens: accommodation in Ophthalmology. Accommodation is mediated by parasympathetic fibres through the third nerve.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Lens: accommodation?

Group the red eye by what to examine and what the pupil does. Then use the flashcards and the other Ophthalmology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.