Given the K readings of 45.00 @ 180/42.00 @ 90, what is the optimal GP lens design for correcting this patient's vision?

The provided keratometry readings, 45.00 @ 180 and 42.00 @ 90, indicate that the patient's cornea is significantly astigmatic. The numbers represent the steepest and flattest meridians of the cornea, with the first value being the steepest (45.00) and the second representing the flat meridian (42.00).

When designing a gas permeable (GP) lens for this degree of astigmatism, it's essential to take both the corneal curvature and the measured astigmatism into account. The choice D, containing the format 42.00/45.00-2.00/-5.75, indicates that the lens design accommodates the patient's corneal shape by incorporating the necessary curvature for both principal meridians.

The first part of the answer accurately reflects the steep (45.00) and flat (42.00) keratometric values, allowing the lens to align well with the curvature of the patient's eye. The additional values (-2.00 and -5.75) likely represent some form of spherical correction or additional features that provide a proper fit and adequate vision correction.

Furthermore, this lens design respects the patient's ast