Optics: 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 · Optics

Sample item

Refraction of a patient with astigmatism shows that one principal meridian is focused exactly on the retina while the other is focused in front of the retina. Which type of astigmatism is this?

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

The answer and the reasoning

B. Simple myopic astigmatism

Astigmatism types are classified by where the two principal meridians focus. If one meridian is on the retina and the other is in front, it is simple myopic. In compound types both lie on the same side, and in mixed astigmatism they lie on opposite sides.

Option by option

  • A. Compound myopic astigmatism

    In the compound type both meridians focus in front of the retina.

  • B. Simple myopic astigmatism (correct)

    One meridian emmetropic and the other myopic defines simple myopic astigmatism.

  • C. Mixed astigmatism

    In the mixed type one meridian focuses in front of and the other behind the retina.

  • D. Simple hypermetropic astigmatism

    In the simple hypermetropic type one meridian is on the retina and the other is behind it.

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 B, Simple myopic astigmatism. Astigmatism types are classified by where the two principal meridians focus.

Why is "Compound myopic astigmatism" not the answer?

In the compound type both meridians focus in front of the retina.

Why is "Mixed astigmatism" not the answer?

In the mixed type one meridian focuses in front of and the other behind the retina.

Why is "Simple hypermetropic astigmatism" not the answer?

In the simple hypermetropic type one meridian is on the retina and the other is behind it.

What concept does this question test?

It tests Optics in Ophthalmology. If one meridian is on the retina and the other is in front, it is simple myopic. In compound types both lie on the same side, and in mixed astigmatism they lie on opposite sides.

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 Optics?

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.