What is the typical set-up for measuring the steepest K in WTR astigmatism?

In the context of measuring the steepest K in WTR (with-the-rule) astigmatism, it is important to understand the orientation of corneal curvature. WTR astigmatism typically has the steepest curvature oriented along the vertical meridian, which is at 90 degrees.

When you measure the steepest K value, you aim to identify the curvature that is most pronounced, and for WTR astigmatism, this will correspond to the vertical orientation. This measurement is crucial for proper fitting of contact lenses and for determining the appropriate corrective measures. By locating the steepest K at 90 degrees, practitioners can more accurately understand the astigmatic correction needed.

Other orientations, such as 180 degrees, 45 degrees, and 135 degrees, would correspond to different types of astigmatism or misalignments and therefore do not reflect the common setup for measuring the steepest K in WTR astigmatism.