Anatomy and physiology of the eye: retrobulbar haemorrhage: 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 · Anatomy and physiology of the eye: retrobulbar haemorrhage

Sample item

After a blow to the lateral orbit, a man has severe pain, tense proptosis, a rock-hard orbit with a tight lid, vision down to counting fingers and a relative afferent pupillary defect. A CT scan will take about an hour. What is the immediate step?

ABedside lateral canthotomy and cantholysisBIntravenous mannitol alone and review in the morningCOral antibiotics with head elevationDWait for the CT before any intervention

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

The answer and the reasoning

A. Bedside lateral canthotomy and cantholysis

Rising pressure within the closed orbit after retrobulbar haemorrhage threatens the optic nerve and retinal circulation, so decompression must not wait for imaging. Lateral canthotomy with inferior cantholysis releases the tension and can be followed by medical lowering of intraocular pressure.

Option by option

A. Bedside lateral canthotomy and cantholysis (correct)
Correct. Immediate canthotomy and cantholysis relieves the orbital compartment pressure and can save vision.
B. Intravenous mannitol alone and review in the morning
Mannitol alone does not decompress the orbit and is inadequate for compressive optic neuropathy.
C. Oral antibiotics with head elevation
Antibiotics and elevation do not relieve a tense haematoma threatening the optic nerve.
D. Wait for the CT before any intervention
Delaying decompression for imaging risks permanent optic nerve and retinal ischaemia.

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.

Questions about this Ophthalmology question

What is the answer to this Ophthalmology question?

The best answer is A, Bedside lateral canthotomy and cantholysis. Rising pressure within the closed orbit after retrobulbar haemorrhage threatens the optic nerve and retinal circulation, so decompression must not wait for imaging.

Why is "Intravenous mannitol alone and review in the morning" not the answer?

Mannitol alone does not decompress the orbit and is inadequate for compressive optic neuropathy.

Why is "Oral antibiotics with head elevation" not the answer?

Antibiotics and elevation do not relieve a tense haematoma threatening the optic nerve.

Why is "Wait for the CT before any intervention" not the answer?

Delaying decompression for imaging risks permanent optic nerve and retinal ischaemia.

What concept does this question test?

It tests Anatomy and physiology of the eye: retrobulbar haemorrhage in Ophthalmology. Lateral canthotomy with inferior cantholysis releases the tension and can be followed by medical lowering of intraocular pressure.

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 Anatomy and physiology of the eye: retrobulbar haemorrhage?

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.