Astigmatic axis independent spatial frequency and contrast sensitivity target and method

Abstract

A set of visual targets and a method for using these targets to evaluate the spatial frequency response and contrast sensitivity of the human visual system. The invention includes four choice test, six choice test, sinusoidal bulls eye and fundamental sinusoidal letters or optotype targets. The four and six choice targets feature sinusoidal gratings oriented vertically, horizontally and at angles thereto. The sinusoidal bull's eye target features concentric circular light and dark areas with brightness varying in a radial sinusoidal fashion. The fundamental sinusoidal optotype target features an optotype, such as a letter, that is made up of strokes, each of which have a width that is equal to ½ of a single sinusoidal period.

Dependencies are inferred from the claim text.