Refraction and lens: 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 · Refraction and lens

Sample item

A 65-year-old who needed reading glasses for years now reads small print without them, but distance vision has become blurred, and the lens nucleus looks brownish. What explains this change?

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

The answer and the reasoning

B. Increased refractive index of the sclerosed nucleus causing lenticular myopia

In nuclear sclerosis the lens nucleus becomes denser and its refractive index rises, shifting the eye toward myopia. In a previously hypermetropic or emmetropic presbyope this improves near vision, called second sight, while distance vision worsens. It is an early sign of nuclear cataract.

Option by option

  • A. Lengthening of the axial length

    Axial lengthening does not occur in a mature adult over this timescale.

  • B. Increased refractive index of the sclerosed nucleus causing lenticular myopia (correct)

    Correct. A denser nucleus increases refractive power and produces a myopic shift.

  • C. Steepening of the cornea

    Corneal steepening occurs in keratoconus and would not be linked with a brown nucleus.

  • D. Spasm of the ciliary muscle

    Ciliary spasm is an accommodative disorder of the young and is not related to nuclear colour change.

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.

More Ophthalmology questions

Questions about this Ophthalmology question

What is the answer to this Ophthalmology question?

The best answer is B, Increased refractive index of the sclerosed nucleus causing lenticular myopia. In nuclear sclerosis the lens nucleus becomes denser and its refractive index rises, shifting the eye toward myopia.

Why is "Lengthening of the axial length" not the answer?

Axial lengthening does not occur in a mature adult over this timescale.

Why is "Steepening of the cornea" not the answer?

Corneal steepening occurs in keratoconus and would not be linked with a brown nucleus.

Why is "Spasm of the ciliary muscle" not the answer?

Ciliary spasm is an accommodative disorder of the young and is not related to nuclear colour change.

What concept does this question test?

It tests Refraction and lens in Ophthalmology. In a previously hypermetropic or emmetropic presbyope this improves near vision, called second sight, while distance vision worsens. It is an early sign of nuclear cataract.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Refraction and lens?

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.