Pupillary light reflex.

A wealth of new information has recently come to light concerning the pupillary response to various types of visual input. Much of this information is recent, and has either been published in the last year, is in press, or has just been reported at meetings. This new information is important because it is resulting in reexamination of the pupillary input pathways and the clinical role for using pupillary movements to understand the physiology and pathology of the visual system. This review will focus on this new information and its clinical implication. The review is organized in the following sections: 1) the pupillary response to full-field, global light stimuli; 2) "pupil perimetry" or the pupillary response to focal light stimuli; 3) the pupillary response to isoluminant stimuli, eg, color spatial frequency, motion; 4) receptive field organization in the pupillary light reflex pathway.