Apparatus and method for operating a real time large diopter range sequential wavefront sensor

摘要

An apparatus including a position sensing detector and a processing system, with the processing system configured to determine axis of astigmatism and cylinder and sphere diopter values of a subject eye.

主权项

1. An apparatus comprising:
a position sensing detector configured to output a sequence of position sensing signals, with each position sensing signal indicating deflection of a centroid of a wavefront sample from a reference point on the detector, with the wavefront sample being a sample of an annular ring shaped wavefront portion of an incident wavefront returned from a subject eye; and a processing system coupled to the position sensing detector to receive the sequence of position sensing signals, with the processing system configured to calculate a sequence of deflection coordinates indicating the deflection of each centroid, to calculate a center point of the sequence of centroid deflection coordinates, to associate the sequence of deflection coordinates to an ellipse centered at a center point, with the sequence of centroid deflection coordinates fitted to the ellipse expressed in U, V Cartesian coordinates, with the ellipse having a major axis of amplitude=a and a minor axis of amplitude=b, with the center of the ellipse located at U=0, V=0, and each centroid deflection having coordinates U(t)=a·cos(t), V(t)=b·sin(t) where t=time dependent phase of receipt of a set of sequentially received centroid deflection coordinates and where the ellipse is a circle if the amplitudes of the major and minor axes are equal, to determine the axis of astigmatism based on angular orientation of the major and minor axes and to determine relative magnitude of divergence and convergence based on relative magnitudes of a and b.