Which of the following is true about with-the-rule astigmatism?

With-the-rule astigmatism is characterized by the steepest curvature of the cornea aligned with the vertical meridian. This means that when someone has with-the-rule astigmatism, they typically have a more pronounced degree of curvature in the vertical meridian compared to the horizontal meridian, which is flatter. This type of astigmatism is often described in terms of the orientation of the keratometric readings, where the vertical curvature (0 to 180 degrees) is steeper than that of the horizontal curvature (90 degrees).

Understanding the curvature of the eye is essential in creating effective corrective lenses. In this case, a prescription that indicates the steepest curve is at the vertical meridian would indicate with-the-rule astigmatism, making it the correct identification.

In contrast, other options may describe different characteristics or types of astigmatism, leading to confusion. Specifically, a steeper curve at the horizontal meridian would describe against-the-rule astigmatism. The prevalence of astigmatism types can vary with age, but the assertion regarding age does not directly pertain to the definition of with-the-rule astigmatism. Finally, while a specific prescription example might illustrate astigmatic corrections,