Lens: 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 · Lens

Sample item

A tall child with intellectual disability and a history of a thromboembolic event is found to have a lens displaced downward. What is the most likely diagnosis?

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

The answer and the reasoning

C. Homocystinuria

Ectopia lentis in homocystinuria is usually downward and nasal, and the disease also causes marfanoid habitus, intellectual impairment and thromboembolism. In Marfan syndrome the lens is usually displaced upward and temporally with normal intelligence and no thrombotic tendency.

Option by option

  • A. Neurofibromatosis type 1

    Neurofibromatosis type 1 causes Lisch nodules and optic glioma, not lens dislocation.

  • B. Marfan syndrome

    Marfan syndrome typically gives upward lens displacement without intellectual disability or thrombosis.

  • C. Homocystinuria (correct)

    Correct. Downward lens dislocation with thrombosis and intellectual disability points to homocystinuria.

  • D. Alport syndrome

    Alport syndrome causes anterior lenticonus with nephritis and deafness, not ectopia lentis with thrombosis.

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 C, Homocystinuria. Ectopia lentis in homocystinuria is usually downward and nasal, and the disease also causes marfanoid habitus, intellectual impairment and thromboembolism.

Why is "Neurofibromatosis type 1" not the answer?

Neurofibromatosis type 1 causes Lisch nodules and optic glioma, not lens dislocation.

Why is "Marfan syndrome" not the answer?

Marfan syndrome typically gives upward lens displacement without intellectual disability or thrombosis.

Why is "Alport syndrome" not the answer?

Alport syndrome causes anterior lenticonus with nephritis and deafness, not ectopia lentis with thrombosis.

What concept does this question test?

It tests Lens in Ophthalmology. In Marfan syndrome the lens is usually displaced upward and temporally with normal intelligence and no thrombotic tendency.

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 Lens?

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.