Cornea: chemical injury: 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 · Cornea: chemical injury

Sample item

A worker has splashed lime into his eye. Which statement about alkali burns versus acid burns is correct?

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

The answer and the reasoning

D. Alkalis penetrate deeper because saponification of cell membranes allows spread

Alkalis are lipophilic and cause saponification of fatty acids in cell membranes, allowing deep penetration into the anterior chamber. Acids coagulate proteins and form a barrier that limits penetration. The first step in both is immediate copious irrigation.

Option by option

  • A. Acid burns cause more intraocular damage than alkali

    Alkali usually causes more intraocular damage than acid.

  • B. Acids penetrate deeper than alkalis

    Acid coagulates proteins, limiting its penetration.

  • C. Both act only on the epithelium

    Alkalis penetrate the entire thickness of the cornea.

  • D. Alkalis penetrate deeper because saponification of cell membranes allows spread (correct)

    Correct. Alkali burns penetrate deeper than acid burns.

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 D, Alkalis penetrate deeper because saponification of cell membranes allows spread. Alkalis are lipophilic and cause saponification of fatty acids in cell membranes, allowing deep penetration into the anterior chamber.

Why is "Acid burns cause more intraocular damage than alkali" not the answer?

Alkali usually causes more intraocular damage than acid.

Why is "Acids penetrate deeper than alkalis" not the answer?

Acid coagulates proteins, limiting its penetration.

Why is "Both act only on the epithelium" not the answer?

Alkalis penetrate the entire thickness of the cornea.

What concept does this question test?

It tests Cornea: chemical injury in Ophthalmology. Acids coagulate proteins and form a barrier that limits penetration. The first step in both is immediate copious irrigation.

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 Cornea: chemical injury?

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.