Patent ID: 8684946

Claim:
A method for diagnosing a subject with a disease state or condition by determining a sensitivity of cone photoreceptors in the subject, the method comprising the steps of: (a) presenting to a pupil of the subject an adapting field of adjustable intensity to saturate the rod photoreceptors, the adapting field having a single defined wavelength to saturate the rod photoreceptors and an initial intensity selected for the subject such that a target image is either visible or not visible on the adapting field; (b) presenting to the pupil of the subject a target image superimposed on an adapting field, the target image having a wavelength selected to stimulate at least one of the blue, green or red cone photoreceptors and the target image being presented at a plurality of locations within about 0.88Â° of the foveal center of the subject; (c) obtaining at least two endpoint measurements, the endpoint measurements being indicative of the sensitivity of the cone photoreceptors from the subject and being obtained by adjusting the intensity of the adapting field in increments until the target image become invisible if the target image was initial visible or until the target image become visible if the target image was initially not visible; (d) determining if the sensitivity of the cone photoreceptor is impaired or not impaired based on the endpoint measurement; and (e) diagnosing the subject as having a positive disease status if the sensitivity of the cone photoreceptors is impaired or as having a negative disease status if the sensitivity of the cone photoreceptors is not impaired; where at least three endpoint measurements are obtained, wherein one of said endpoint measurements is obtained at a foveal center and the remaining endpoint measurements are selected to span the fovea from the foveal center to about 0.88Â° of the foveal center.