In a patient with WTR astigmatism, which meridian is steeper?

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

In a patient with WTR astigmatism, which meridian is steeper?

Explanation:
With-the-rule astigmatism means the cornea is steeper in the vertical meridian than in the horizontal. Steepness here corresponds to greater refractive power, so the vertical meridian is the one that is steeper. Consequently, the cylinder is oriented horizontally (its axis is perpendicular to the meridian with excess power), placing the extra power in the vertical meridian. So the vertical meridian is the steeper one in this condition.

With-the-rule astigmatism means the cornea is steeper in the vertical meridian than in the horizontal. Steepness here corresponds to greater refractive power, so the vertical meridian is the one that is steeper. Consequently, the cylinder is oriented horizontally (its axis is perpendicular to the meridian with excess power), placing the extra power in the vertical meridian. So the vertical meridian is the steeper one in this condition.

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