Neuro-ophthalmology and pupils: aberrant regeneration: 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 · Neuro-ophthalmology and pupils: aberrant regeneration

Sample item

A man has recovered partially from a third nerve palsy caused by a meningioma. When he looks down, the right upper lid rises, and on adduction the pupil constricts. Which phenomenon explains this?

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

The answer and the reasoning

B. Misdirected regrowth of oculomotor nerve fibres

After chronic compression, axons of the oculomotor nerve can regrow to the wrong muscle. The result is lid retraction on downgaze (pseudo-Graefe sign), pupil constriction on adduction and abnormal eye movements. It indicates a slowly progressive compressive cause rather than ischaemia.

Option by option

  • A. Contracture of the levator after prolonged paralysis

    Levator contracture would give a fixed lid position and not movements linked to gaze.

  • B. Misdirected regrowth of oculomotor nerve fibres (correct)

    Correct. Misdirected regeneration of the oculomotor fibres causes lid and pupil movements with the wrong gaze.

  • C. Supranuclear gaze palsy

    A supranuclear lesion causes gaze limitation without lid and pupil synkinesis.

  • D. Restriction by an orbital mass

    An orbital mass restricts movement but does not rewire nerve branches.

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 B, Misdirected regrowth of oculomotor nerve fibres. After chronic compression, axons of the oculomotor nerve can regrow to the wrong muscle.

Why is "Contracture of the levator after prolonged paralysis" not the answer?

Levator contracture would give a fixed lid position and not movements linked to gaze.

Why is "Supranuclear gaze palsy" not the answer?

A supranuclear lesion causes gaze limitation without lid and pupil synkinesis.

Why is "Restriction by an orbital mass" not the answer?

An orbital mass restricts movement but does not rewire nerve branches.

What concept does this question test?

It tests Neuro-ophthalmology and pupils: aberrant regeneration in Ophthalmology. The result is lid retraction on downgaze (pseudo-Graefe sign), pupil constriction on adduction and abnormal eye movements. It indicates a slowly progressive compressive cause rather than ischaemia.

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 Neuro-ophthalmology and pupils: aberrant regeneration?

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.