Anatomy and physiology of the eye: renewal of photoreceptor discs: 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 · Anatomy and physiology of the eye: renewal of photoreceptor discs

Sample item

Rod outer segment discs are shed from their tips every day and must be removed. Which cells phagocytose them?

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

The answer and the reasoning

A. Retinal pigment epithelial cells

The RPE phagocytoses the shed tips of photoreceptor outer segments. Failure of this process, as in some inherited dystrophies, leads to debris build-up and photoreceptor degeneration.

Option by option

  • A. Retinal pigment epithelial cells (correct)

    Correct. RPE cells engulf and digest the shed discs, recycling retinoids for the visual cycle.

  • B. Choroidal melanocytes

    Choroidal melanocytes are pigmented stromal cells and have no phagocytic role here.

  • C. Muller cells

    Muller cells are supportive glia spanning the retina and do not clear outer segment discs.

  • D. Retinal microglia

    Microglia respond to injury but are not responsible for daily disc turnover.

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 A, Retinal pigment epithelial cells. The RPE phagocytoses the shed tips of photoreceptor outer segments.

Why is "Choroidal melanocytes" not the answer?

Choroidal melanocytes are pigmented stromal cells and have no phagocytic role here.

Why is "Muller cells" not the answer?

Muller cells are supportive glia spanning the retina and do not clear outer segment discs.

Why is "Retinal microglia" not the answer?

Microglia respond to injury but are not responsible for daily disc turnover.

What concept does this question test?

It tests Anatomy and physiology of the eye: renewal of photoreceptor discs in Ophthalmology. Failure of this process, as in some inherited dystrophies, leads to debris build-up and photoreceptor degeneration.

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 Anatomy and physiology of the eye: renewal of photoreceptor discs?

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.