Cornea: 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

Sample item

A soft contact lens wearer who swims with the lenses in has had severe, disproportionate eye pain for ten days. The slit lamp shows a ring-shaped stromal infiltrate and radial perineural infiltrates, and bacterial cultures are negative. Which organism and treatment are appropriate?

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

The answer and the reasoning

A. Acanthamoeba, treated with topical biguanides such as polyhexamethylene biguanide or chlorhexidine

Acanthamoeba keratitis occurs in contact lens wearers exposed to contaminated water. Severe pain out of proportion to the signs, a ring infiltrate and radial keratoneuritis are typical. Cysts resist most agents, so treatment uses topical biguanides (PHMB or chlorhexidine), often with diamidines.

Option by option

  • A. Acanthamoeba, treated with topical biguanides such as polyhexamethylene biguanide or chlorhexidine (correct)

    Correct. A protozoan with a cyst stage needs biguanide therapy.

  • B. Herpes simplex virus, treated with oral acyclovir alone

    HSV gives dendritic ulcers and does not cause a ring infiltrate and radial neuritis.

  • C. Pseudomonas aeruginosa, treated with fortified gentamicin

    Pseudomonas is the commonest contact-lens bacterial pathogen, but cultures here are negative and the pain is disproportionate.

  • D. Fusarium, treated with natamycin

    Fusarium usually follows vegetable trauma and has satellite lesions with feathery edges.

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.

More Ophthalmology questions

Questions about this Ophthalmology question

What is the answer to this Ophthalmology question?

The best answer is A, Acanthamoeba, treated with topical biguanides such as polyhexamethylene biguanide or chlorhexidine. Acanthamoeba keratitis occurs in contact lens wearers exposed to contaminated water.

Why is "Herpes simplex virus, treated with oral acyclovir alone" not the answer?

HSV gives dendritic ulcers and does not cause a ring infiltrate and radial neuritis.

Why is "Pseudomonas aeruginosa, treated with fortified gentamicin" not the answer?

Pseudomonas is the commonest contact-lens bacterial pathogen, but cultures here are negative and the pain is disproportionate.

Why is "Fusarium, treated with natamycin" not the answer?

Fusarium usually follows vegetable trauma and has satellite lesions with feathery edges.

What concept does this question test?

It tests Cornea in Ophthalmology. Severe pain out of proportion to the signs, a ring infiltrate and radial keratoneuritis are typical. Cysts resist most agents, so treatment uses topical biguanides (PHMB or chlorhexidine), often with diamidines.

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 Cornea?

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.