Neuro-ophthalmology and pupils: Parks three-step test: 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: Parks three-step test

Sample item

A patient has a right hypertropia that increases on looking to the left and increases when the head is tilted to the right. Which muscle is paretic?

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

The answer and the reasoning

A. Right superior oblique

A right hypertropia implicates the right depressors (superior oblique, inferior rectus) or the left elevators (superior rectus, inferior oblique). Worsening on left gaze leaves right superior oblique or left superior rectus. Worsening on right head tilt, which needs right eye intorsion, leaves the right superior oblique.

Option by option

  • A. Right superior oblique (correct)

    Correct. The three steps converge on the right superior oblique.

  • B. Left inferior oblique

    Left inferior oblique acts best in adduction, so the deviation would worsen on right gaze.

  • C. Right inferior rectus

    Right inferior rectus acts best in abduction, so the deviation would worsen on right gaze.

  • D. Left superior rectus

    Left superior rectus is excluded because it is an intorter of the left eye and would worsen on left tilt.

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 A, Right superior oblique. A right hypertropia implicates the right depressors (superior oblique, inferior rectus) or the left elevators (superior rectus, inferior oblique).

Why is "Left inferior oblique" not the answer?

Left inferior oblique acts best in adduction, so the deviation would worsen on right gaze.

Why is "Right inferior rectus" not the answer?

Right inferior rectus acts best in abduction, so the deviation would worsen on right gaze.

Why is "Left superior rectus" not the answer?

Left superior rectus is excluded because it is an intorter of the left eye and would worsen on left tilt.

What concept does this question test?

It tests Neuro-ophthalmology and pupils: Parks three-step test in Ophthalmology. Worsening on left gaze leaves right superior oblique or left superior rectus. Worsening on right head tilt, which needs right eye intorsion, leaves the right superior oblique.

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: Parks three-step test?

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.