Effects of rod activity on colour threshold.
D003118:Color Perception / Q000502:physiology*; D003623:Dark Adaptation; D005584:Fovea Centralis / Q000502:physiology; D006801:Humans; D008297:Male; D010786:Photoreceptor Cells / Q000502:physiology*; D013997:Time Factors; D014794:Visual Fields