Post-illumination Pupil Response in Subjects without Ocular Disease

• Published in: Investigative ophthalmology & visual science Vol. 51; no. 5; pp. 2764 - 2769
• Main Authors: Kankipati, Laxmikanth, Girkin, Christopher A., Gamlin, Paul D.
• Format: Journal Article
• Language: English
• Published: United States Association for Research in Vision and Ophthalmology, Inc 01.05.2010
• Subjects: Adult; Aged; Aged, 80 and over; Female; Humans; Light; Male; Middle Aged; Photoreceptor Cells, Vertebrate - metabolism; Pupil - physiology; Reflex, Pupillary - radiation effects; Retinal Diseases - diagnosis; Retinal Diseases - metabolism; Retinal Ganglion Cells - metabolism; Rod Opsins - metabolism
• ISSN: 1552-5783; 0146-0404; 1552-5783
• DOI: 10.1167/iovs.09-4717

A sustained pupilloconstriction is often observed after the cessation of a bright visual stimulus. This post-illumination pupil response (PIPR) is produced by the intrinsically photosensitive retinal ganglion cells (ipRGCs). The present study was designed to examine the characteristics of the PIPR in a normal population without ocular disease. Thirty-seven subjects (mean age, 48.6 years) were tested by presenting a 60 degrees, 10-second light stimulus (13 log quanta/cm(2)/s retinal irradiance) and recording pupillary responses for 50 seconds after light cessation. The light stimuli (470 [blue] and 623 [red] nm) were presented by an optical system to one eye after dilation, while the consensual pupil response of the fellow, undilated eye was recorded by infrared pupillometry. A positive PIPR was seen in all subjects tested. The population average of the PIPR for 470-nm light was 1.5 mm (SEM 0.10, P < 0.05) and the net PIPR (blue PIPR minus red PIPR) was 1.4 mm (SEM 0.09, P < 0.0001). The net PIPR correlated positively with baseline pupil diameter (P < 0.05), but not significantly with age, race, or sex (P > 0.05) in the test population. All normal subjects displayed a significant PIPR for a 10-second, 470-nm light stimulus, but not a 623-nm stimulus, which is consistent with the proposed melanopsin-mediated response. In most normal individuals, the amplitude of the PIPR was substantial. This test has the potential to be used as a tool in evaluating subjects with inner retinal dysfunction or melanopsin-related disorders.