Pupil size and spontaneous pupillary waves associated  with alertness, drowsiness, and sleep.
D001143:Arousal; D003624:Darkness; D004106:Dilatation; D004582:Electronics, Medical; D005143:Eyelids; D006801:Humans; D007259:Infrared Rays; D009290:Narcolepsy / Q000503:physiopathology*; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D011680:Pupil / Q000503:physiopathology*; D012890:Sleep; D014851:Wakefulness