Show why one cannot see so well in glaring light an observant chauffeur passing an automobile with glaring li headlights noted that objects at the side of the road which had been distinctively visible dropped out of sight when the bright lights were thrown upon them since one can see better in a little light than in no light he wondered qed why can one not see better in bright light than in moderate light the answer Is paradoxically that the less light there Is the better one sees for the brighter the object the less efficient Is the eyesight if after we have been in darkness we suddenly turn on a bright light and look at our eyes in the mirror we can see i the pupil of the eye rapidly growing browin g smaller it if we reduce the light the pupil dilates again what happens Is the same as in the camera when we adjust the shutter to the intensity of the aig light ht the colored iris of the eye corresponds to the shutter it con coni ats t chiefly of a muscle which as aa the light increases Is stimulated to contract thus drawing the curtain and shutting out some of tile the superfluous light it usually takes a few seconds for this adjustment to take place thus when wo we emerge from darkness into light we are blinded until the iris can shut out some of the light from the eyes |