Cornea: pachymetry and IOP: 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: pachymetry and IOP

Sample item

A patient with a thin central cornea has an applanation IOP of 17 mmHg. How should this be interpreted?

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

The answer and the reasoning

B. Actual IOP may be higher than measured

A thin cornea is more easily applanated, so Goldmann tonometry underestimates true IOP, while a thick cornea overestimates it. Central corneal thickness is therefore recorded in glaucoma assessment.

Option by option

  • A. Actual IOP is lower than measured

    Overestimation occurs with a thick cornea.

  • B. Actual IOP may be higher than measured (correct)

    Correct. A thin cornea causes underestimation of IOP.

  • C. Measurement is unaffected by thickness

    Corneal thickness clearly affects readings.

  • D. Applanation cannot be used

    Applanation is still the standard method with correction.

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 B, Actual IOP may be higher than measured. A thin cornea is more easily applanated, so Goldmann tonometry underestimates true IOP, while a thick cornea overestimates it.

Why is "Actual IOP is lower than measured" not the answer?

Overestimation occurs with a thick cornea.

Why is "Measurement is unaffected by thickness" not the answer?

Corneal thickness clearly affects readings.

Why is "Applanation cannot be used" not the answer?

Applanation is still the standard method with correction.

What concept does this question test?

It tests Cornea: pachymetry and IOP in Ophthalmology. Central corneal thickness is therefore recorded in glaucoma assessment.

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: pachymetry and IOP?

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.