If the patient's "K" readings are 41.50@75/43.75@165 and a vertex distance is 12.0mm, what should the power be if the lens base curve is ordered at 42.25?

In this scenario, the question involves understanding how to calculate the power of a contact lens based on the patient's corneal curvature readings and the vertex distance. The "K" readings indicate the steep and flat meridian keratometry measurements of the patient's cornea, which are necessary for determining the appropriate contact lens power.

Given that the lens base curve is ordered at 42.25D, we can use the concepts of vertex distance and the relationship between the cornea's curvature and the lens design to calculate the required power. The formula for adjusting the power of a lens based on vertex distance is as follows:

Adjusted Power = Lens Power + (Vertex Distance in mm x Lens Power²)/1000

However, in this case, since the ordered base curve (42.25D) is known, the required adjustment can be derived from how far the base curve differs from the K readings.

First, it is important to understand that the K readings suggest that the patient's cornea has a slightly steeper curvature than the ordered base curve. This difference indicates that a slightly higher power will be required to achieve adequate alignment and vision correction.

Starting from the average K reading, which can be derived from the given values (41.50D and 43