A functional test of foveal fixation based upon differential cone directional sensitivity.
D000328:Adult; D005260:Female; D005403:Fixation, Ocular; D005584:Fovea Centralis / Q000502:physiology*; D006801:Humans; D008266:Macula Lutea / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D010786:Photoreceptor Cells / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology