Evaluation of the pupillary response is an underemphasized aspect of the assessment of visual function. The pupillary light reflex is one of the few objective indicators of afferent input from the retina and optic nerve. Since the pupillary light reflex is processed through the retina, it may be used to assess visual integrity (1). Pupillometry is a reliable technology capable of providing repetitive data on quantitative pupillary function in states of health and disease (2). Amplitude, latency, maximum constriction velocity, mean constriction velocity, and dilation velocity are measured using the Neuroleptics pupillometer. The effects of varying levels of ambient light on these parameters of the pupillary response have not been extensively studied. The purpose of this investigation is to determine the effects of varying luminescent levels on the pupillary response.