Calculation of the radii of curvature of the crystalline lens surfaces.

A new computing scheme was developed for calculating the radius of curvature of the anterior and posterior surfaces of the crystalline lens from the measured heights of the Purkinje images. The scheme can be applied to objects at any distance from the corneal vertex, for both a stationary object mounted independently of the camera and for a mobile object attached to the camera where the distance of the object to the corneal vertex will change as the camera is refocused from image PI to PIII and PIV. The method can also be used if different objects are employed to form each Purkinje image. The scheme also avoids the need to collimate objects in order to employ the equivalent mirror theorem or to calibrate phakometers with known spherical surfaces where exact relationships are unknown.