Pupil: RAPD: 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.

Try it

Ophthalmology · Pupil: RAPD

Sample item

On the swinging flashlight test, both pupils dilate when light is moved to the right eye. What does this indicate?

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

The answer and the reasoning

C. A relative afferent pupillary defect in the right eye

When light moves from the normal to the defective eye, pupils paradoxically dilate because the afferent signal is weaker. RAPD occurs in optic neuropathy and extensive retinal disease but not in media opacity.

Option by option

  • A. Normal reaction

    Normal eyes constrict on the swing.

  • B. A left Horner syndrome

    Horner syndrome causes miosis with normal reaction.

  • C. A relative afferent pupillary defect in the right eye (correct)

    Correct. Dilation on light stimulation indicates an afferent defect.

  • D. A right third nerve palsy

    Third nerve palsy causes an efferent defect.

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 C, A relative afferent pupillary defect in the right eye. When light moves from the normal to the defective eye, pupils paradoxically dilate because the afferent signal is weaker.

Why is "Normal reaction" not the answer?

Normal eyes constrict on the swing.

Why is "A left Horner syndrome" not the answer?

Horner syndrome causes miosis with normal reaction.

Why is "A right third nerve palsy" not the answer?

Third nerve palsy causes an efferent defect.

What concept does this question test?

It tests Pupil: RAPD in Ophthalmology. RAPD occurs in optic neuropathy and extensive retinal disease but not in media opacity.

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 Pupil: RAPD?

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.