Ray-tracing Analysis of the Corneal Power From Scheimpflug Data

What is the corneal power? Most clinicians will ask for the “K-reading,” neglecting the fact that the keratometer does not measure the power directly. What the keratometer really does is measure the size of the Purkinje I image reflected from the front surface of the cornea in a paracentral ring of approximately 3 mm and calculate the radius of curvature of the convex mirror constituted by the tear film of the cornea. The next step in the classic K-reading is to regard the cornea as a “thin lens” and calculate the dioptric power “K” as a function of the radius according to the paraxial

Source: Journal of Refractive Surgery - January 10, 2018 Category: Opthalmology Authors: Thomas Olsen, MD Source Type: research