Oliver Bergamin1, Randy H Kardon. 1. Department of Ophthalmology and Visual Sciences and Veterans Administration Hospital, University of Iowa, Iowa City, Iowa 52242, USA.
Abstract
PURPOSE: To investigate the clinical usefulness of the latency of the pupil light reflex by optimizing its measurement, characterizing its variability, and determining the sensitivity of pupil latency as a function of stimulus input in normal subjects. METHODS: Computerized binocular infrared pupillography was performed in 14 eyes of seven healthy subjects. Pupils were recorded simultaneously at 60 and 1000 Hz. Each eye was alternatively stimulated eight times for 50 ms every 2.5 seconds, increasing by 0.5 log units over a 2.0-log-unit range. To determine intersubject and intereye variability, 98 eyes of 49 healthy subjects were recorded at 60 Hz over a 3.0-log-unit range (15 degrees radius stimulation, four repetitions at each intensity). RESULTS: Accuracy and resolution of latency were limited by the number of light reflexes used to estimate the average latency and were significantly affected by sampling rate when the number of reflexes recorded was fewer than four. Binocular recording and interpolation of the 60-Hz recording to 300 Hz added resolution to the latency. Biological variability contributed more to interindividual variability than did measurement variability. The range of intereye afferent asymmetry of latency in normal subjects was only between 8.3 and 35 ms-less with brighter stimulus intensity. CONCLUSIONS: An optimal method for determination of the onset of the pupil light reflex was devised that consisted of filtering, interpolation of pupil recordings, and analysis of the first and second derivative of the pupil movement. Most of the variability in latency as a function of intensity in normal subjects was due to interindividual variation and latency was well matched between the two eyes of the subjects.
PURPOSE: To investigate the clinical usefulness of the latency of the pupil light reflex by optimizing its measurement, characterizing its variability, and determining the sensitivity of pupil latency as a function of stimulus input in normal subjects. METHODS: Computerized binocular infrared pupillography was performed in 14 eyes of seven healthy subjects. Pupils were recorded simultaneously at 60 and 1000 Hz. Each eye was alternatively stimulated eight times for 50 ms every 2.5 seconds, increasing by 0.5 log units over a 2.0-log-unit range. To determine intersubject and intereye variability, 98 eyes of 49 healthy subjects were recorded at 60 Hz over a 3.0-log-unit range (15 degrees radius stimulation, four repetitions at each intensity). RESULTS: Accuracy and resolution of latency were limited by the number of light reflexes used to estimate the average latency and were significantly affected by sampling rate when the number of reflexes recorded was fewer than four. Binocular recording and interpolation of the 60-Hz recording to 300 Hz added resolution to the latency. Biological variability contributed more to interindividual variability than did measurement variability. The range of intereye afferent asymmetry of latency in normal subjects was only between 8.3 and 35 ms-less with brighter stimulus intensity. CONCLUSIONS: An optimal method for determination of the onset of the pupil light reflex was devised that consisted of filtering, interpolation of pupil recordings, and analysis of the first and second derivative of the pupil movement. Most of the variability in latency as a function of intensity in normal subjects was due to interindividual variation and latency was well matched between the two eyes of the subjects.
Authors: Jason C Park; Ana L Moura; Ali S Raza; David W Rhee; Randy H Kardon; Donald C Hood Journal: Invest Ophthalmol Vis Sci Date: 2011-08-22 Impact factor: 4.799
Authors: Albert M Maguire; Francesca Simonelli; Eric A Pierce; Edward N Pugh; Federico Mingozzi; Jeannette Bennicelli; Sandro Banfi; Kathleen A Marshall; Francesco Testa; Enrico M Surace; Settimio Rossi; Arkady Lyubarsky; Valder R Arruda; Barbara Konkle; Edwin Stone; Junwei Sun; Jonathan Jacobs; Lou Dell'Osso; Richard Hertle; Jian-xing Ma; T Michael Redmond; Xiaosong Zhu; Bernd Hauck; Olga Zelenaia; Kenneth S Shindler; Maureen G Maguire; J Fraser Wright; Nicholas J Volpe; Jennifer Wellman McDonnell; Alberto Auricchio; Katherine A High; Jean Bennett Journal: N Engl J Med Date: 2008-04-27 Impact factor: 91.245
Authors: Albert M Maguire; Katherine A High; Alberto Auricchio; J Fraser Wright; Eric A Pierce; Francesco Testa; Federico Mingozzi; Jeannette L Bennicelli; Gui-shuang Ying; Settimio Rossi; Ann Fulton; Kathleen A Marshall; Sandro Banfi; Daniel C Chung; Jessica I W Morgan; Bernd Hauck; Olga Zelenaia; Xiaosong Zhu; Leslie Raffini; Frauke Coppieters; Elfride De Baere; Kenneth S Shindler; Nicholas J Volpe; Enrico M Surace; Carmela Acerra; Arkady Lyubarsky; T Michael Redmond; Edwin Stone; Junwei Sun; Jennifer Wellman McDonnell; Bart P Leroy; Francesca Simonelli; Jean Bennett Journal: Lancet Date: 2009-10-23 Impact factor: 79.321