A patient with 20/100 distance VA wants to read road signs at 20/20 acuity. What telescope magnification is needed?

Study for the NBEO Physiological Optics Test. Prepare with flashcards and multiple-choice questions, each question has hints and explanations. Ace your exam!

Multiple Choice

A patient with 20/100 distance VA wants to read road signs at 20/20 acuity. What telescope magnification is needed?

Explanation:
The moment you’re using a telescope to restore a distant detail to normal acuity, you need the magnification to match the ratio between the two Snellen denominators. Going from 20/100 to 20/20 means the target detail must appear five times larger in angular size. So the required telescope magnification is fivefold, or 5x. Among common options, that’s the one that gives enough enlargement to let the patient read at 20/20. A smaller magnification wouldn’t achieve 20/20, while a larger one can make viewing more awkward with limited field and more eye strain.

The moment you’re using a telescope to restore a distant detail to normal acuity, you need the magnification to match the ratio between the two Snellen denominators. Going from 20/100 to 20/20 means the target detail must appear five times larger in angular size. So the required telescope magnification is fivefold, or 5x. Among common options, that’s the one that gives enough enlargement to let the patient read at 20/20. A smaller magnification wouldn’t achieve 20/20, while a larger one can make viewing more awkward with limited field and more eye strain.

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