DYNAMIC PUPILLARY RESPONSE TO POSITIVE DIFFERENTIAL OF LIGHT STIMULUS

<正> Under low background illumination, the pupil responds only to an increase in light in-tensity by a transient constriction when the extent and rate of the increase exceed a certainvalue. We term this response the dynamic pupillary response in order to differentiate it fromthe much more sluggish and much less pronoun ced response moiety that governs the staticpupil size according to the level of light adaptation. The characteristics of the dynamic re-sponse are studied in some detail.This virtually unidirectional rate sensitivity of pupil tolight renders it difficult to be subjected to frequency-response analysis even by small signalapproximation.Analysis of the experimental results suggests that this transient response isa light-precipitated confluence of few consecutive hippus.