Table 1.

Definitions of the Seven Pupillometry Measures

Pupillometer Measure	Definition
Parasympathetic pupillary function
Basal pupil diameter (BPD)	Pupillary diameter at a resting phase
End pupil diameter (EPD)	Smallest pupil diameter recorded in response to the light stimulus
Latency of pupil constriction (Reaction Time)	Time lapse before the pupil actually begins to constrict in response to the light stimulus
Maximum constriction velocity (MCV)	The maximum rate at which the pupil constricts in response to the light stimulus
Average constriction velocity (ACV)	The average rate at which the pupil constricts in response to the light stimulus
Sympathetic pupillary function
Average dilation velocity (ADV)	The average rate at which the pupil dilates after maximum constriction in response to the light stimulus
Recovery time (T75)	Time for the pupil to dilate to 75% of the initial, pre-stimulus, steady-state level (ie 75% of BPD)