Patent ID: 8678592

Claim:
An apparatus for detecting fixation of at least one eye of a subject on a target, comprising: an optical illumination system arranged to scan at least a portion of a retina of an eye of said subject with an illuminating beam of light; an optical detection system arranged to detect at least a portion of said illuminating beam of light after being reflected back from said retina of said subject's eye to provide a detection signal; and a signal processing system adapted to communicate with said optical detection system to receive said detection signal, wherein said illuminating beam of light is polarized light such that reflected portions of said illuminating beam are affected by birefringence of substructures of said retina of said subject's eye, wherein said detection signal has a first frequency signature when said subject's eye is fixed on said target and a second frequency signature when said subject's eye is not fixed on said target, wherein said signal processing system is configured to calculate at least one of a time-frequency distribution or an Auto-Regressive spectral estimation of said detection signal to provide a frequency distribution of said detection signal at a plurality of times for use in determining periods in which said subject's eye is fixed on said target based on said first and second frequency signatures, and wherein a time resolution of said at least one of a time-frequency distribution or an Auto-Regressive spectral estimation is smaller than 0.03 seconds and a frequency resolution of said time-frequency distribution is smaller than 5 Hz.