Visual pathway: occipital lobe: 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 · Visual pathway: occipital lobe

Sample item

A patient with a posterior cerebral artery occlusion has a left homonymous hemianopia with sparing of the central 10 degrees. Why is the macula spared?

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

The answer and the reasoning

A. Dual blood supply of the occipital pole from the middle cerebral artery

The occipital pole receives collateral supply from the middle cerebral artery, so the macular representation survives a PCA infarct. Occipital lesions give highly congruous defects.

Option by option

  • A. Dual blood supply of the occipital pole from the middle cerebral artery (correct)

    Correct. The pole has a dual blood supply.

  • B. Collateral supply from the ophthalmic artery

    The ophthalmic artery supplies the eye, not the cortex.

  • C. The macula is represented in the parietal lobe

    The macula is represented at the occipital pole.

  • D. Macular fibres do not reach the cortex

    Macular fibres project widely to the occipital pole.

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, Dual blood supply of the occipital pole from the middle cerebral artery. The occipital pole receives collateral supply from the middle cerebral artery, so the macular representation survives a PCA infarct.

Why is "Collateral supply from the ophthalmic artery" not the answer?

The ophthalmic artery supplies the eye, not the cortex.

Why is "The macula is represented in the parietal lobe" not the answer?

The macula is represented at the occipital pole.

Why is "Macular fibres do not reach the cortex" not the answer?

Macular fibres project widely to the occipital pole.

What concept does this question test?

It tests Visual pathway: occipital lobe in Ophthalmology. Occipital lesions give highly congruous defects.

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 Visual pathway: occipital lobe?

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.