Corneal ulcer: Acanthamoeba: 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 · Corneal ulcer: Acanthamoeba

Sample item

A soft contact lens wearer who swims in lens has severe pain out of proportion to signs, a ring infiltrate and radial keratoneuritis. What is the best treatment?

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

The answer and the reasoning

D. Topical polyhexamethylene biguanide or chlorhexidine

Acanthamoeba keratitis is diagnosed by scrapings and culture on non-nutrient agar with E coli overlay. Biguanides such as PHMB or chlorhexidine, with or without diamidines, are used.

Option by option

  • A. Topical natamycin

    Natamycin treats filamentous fungi.

  • B. Topical acyclovir

    Acyclovir does not work against amoeba.

  • C. Topical steroids alone

    Steroids alone would worsen the infection.

  • D. Topical polyhexamethylene biguanide or chlorhexidine (correct)

    Correct. Biguanides are cysticidal and are first-line treatment.

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, Topical polyhexamethylene biguanide or chlorhexidine. Acanthamoeba keratitis is diagnosed by scrapings and culture on non-nutrient agar with E coli overlay.

Why is "Topical natamycin" not the answer?

Natamycin treats filamentous fungi.

Why is "Topical acyclovir" not the answer?

Acyclovir does not work against amoeba.

Why is "Topical steroids alone" not the answer?

Steroids alone would worsen the infection.

What concept does this question test?

It tests Corneal ulcer: Acanthamoeba in Ophthalmology. Biguanides such as PHMB or chlorhexidine, with or without diamidines, are used.

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 Corneal ulcer: Acanthamoeba?

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.