Patent ID: 9408535
Filing Date: 2016-08-09
CPC Classification: A61B,G03H

Claim Text:
1. A computer-implemented method of determining refractive error, said method comprising the steps of: receiving a first image and a second image corresponding to an axis-conjugate meridian; removing corneal glints present in pupil regions of said first image and said second image; applying a low-pass filter to each of said pupil regions; rotating said first image and said second image, after applying said low-pass filter to said pupil regions in each of said images, to align a stimulus angle in said axis-conjugate meridian associated with said first image and a stimulus angle in said axis-conjugate meridian associated with said second image with a horizontal meridian; extracting a pixel strip of data from each of said pupil regions centered on a pupil center in said first image and in said second image; computing a ratio of pixel intensity values using said pixel strips of data extracted from said first image and from said second image; generating a refractive error correlate measure based on said ratio of pixel intensity values; and converting said refractive error correlate measure to identify said refractive error.