Certified Ophthalmic Assistant Practice Exam

If the power of the vertical meridian is greater than the horizontal meridian, which condition does the patient have?

1. With-the-rule astigmatism

2. Against-the-rule astigmatism

3. Hyperopia

4. Myopia

The correct answer is: With-the-rule astigmatism

The condition described—where the power of the vertical meridian is greater than that of the horizontal meridian—indicates with-the-rule astigmatism. In with-the-rule astigmatism, the steepest curvature of the cornea is oriented vertically, resulting in a situation where vertical lines are focused more sharply than horizontal lines. This condition typically occurs when the vertical meridian has a higher refractive power than the horizontal meridian, leading to blurred vision for horizontal objects. In contrast, against-the-rule astigmatism occurs when the horizontal meridian is more powerful than the vertical one. Hyperopia (farsightedness) and myopia (nearsightedness) are refractive errors that do not characterize astigmatism; instead, they refer to the overall focal point relative to the retina, without the specific meridian considerations that define astigmatism. Thus, the correct identification of with-the-rule astigmatism is based on the unique relationship between vertical and horizontal meridians, making it the accurate answer to the question.