Neuro-ophthalmology and pupils: nutritional optic neuropathy: 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: nutritional optic neuropathy

Sample item

A 55-year-old chronic tobacco smoker and heavy drinker has gradual, painless, symmetrical loss of central vision with dyschromatopsia and bilateral centrocaecal scotomas. Discs are normal. What is the probable cause?

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

The answer and the reasoning

B. Nutritional deficiency, notably of vitamin B12

Tobacco-alcohol amblyopia is a nutritional optic neuropathy, with deficiency of vitamin B12 and other B vitamins, and cyanide toxicity from tobacco. Bilateral centrocaecal scotomas with gradual loss of central acuity are typical. Stopping tobacco and alcohol with B12 supplements helps.

Option by option

  • A. Raised intracranial pressure

    Raised intracranial pressure causes disc swelling and enlarged blind spots.

  • B. Nutritional deficiency, notably of vitamin B12 (correct)

    Correct. Nutritional deficiency affects the papillomacular bundle and gives centrocaecal scotomas.

  • C. Optic neuritis from multiple sclerosis

    Optic neuritis is typically unilateral and painful in a younger person.

  • D. Pituitary tumour

    A pituitary tumour causes bitemporal field loss.

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, Nutritional deficiency, notably of vitamin B12. Tobacco-alcohol amblyopia is a nutritional optic neuropathy, with deficiency of vitamin B12 and other B vitamins, and cyanide toxicity from tobacco.

Why is "Raised intracranial pressure" not the answer?

Raised intracranial pressure causes disc swelling and enlarged blind spots.

Why is "Optic neuritis from multiple sclerosis" not the answer?

Optic neuritis is typically unilateral and painful in a younger person.

Why is "Pituitary tumour" not the answer?

A pituitary tumour causes bitemporal field loss.

What concept does this question test?

It tests Neuro-ophthalmology and pupils: nutritional optic neuropathy in Ophthalmology. Bilateral centrocaecal scotomas with gradual loss of central acuity are typical. Stopping tobacco and alcohol with B12 supplements helps.

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 Neuro-ophthalmology and pupils: nutritional optic neuropathy?

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.