Individual Differences in the Post-Illumination Pupil Response to Blue Light: Assessment without Mydriatics.
Melanopsin-containing retinal ganglion cells play an important role in the non-image forming effects of light, through their direct projections on brain circuits involved in circadian rhythms, mood and alertness. Individual differences in the functionality of the melanopsin-signaling circuitry can be reliably quantified using the maximum post-illumination pupil response (PIPR) after blue light. Previous protocols for acquiring PIPR relied on the use of mydriatics to dilate the light-exposed eye. However, pharmacological pupil dilation is uncomfortable for the participants and requires ophthalmological expertise. Hence, we here investigated whether an individual's maximum PIPR can be validly obtained in a protocol that does not use mydriatics but rather increases the intensity of the light stimulus. In 18 participants (5 males, mean age ± SD: 34.6 ± 13.6 years) we evaluated the PIPR after exposure to intensified blue light (550 µW/cm²) provided to an undilated dynamic pupil. The test-retest reliability of the primary PIPR outcome parameter was very high, both between day-to-day assessments (Intraclass Correlation Coefficient (ICC) = 0.85), as well as between winter and summer assessments (ICC = 0.83). Compared to the PIPR obtained with the use of mydriatics and 160 µW/cm² blue light exposure, the method with intensified light without mydriatics showed almost zero bias according to Bland-Altman plots and had moderate to strong reliability (ICC = 0.67). In conclusion, for PIPR assessments, increasing the light intensity is a feasible and reliable alternative to pupil dilation to relieve the participant's burden and to allow for performance outside the ophthalmological clinic.
Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam 1105 BA, The Netherlands. jessica_bruyel@hotmail.com.
Jessica
J
Bruijel
Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam 1105 BA, The Netherlands. w.van.der.meijden@nin.knaw.nl.|Sleep Disorders Center, CHU and FMTS, CNRS-UPR 3212, Institute of Cellular and Integrative Neurosciences, University of Strasbourg, Strasbourg 67084, France. w.van.der.meijden@nin.knaw.nl.|Center for Chronobiology, Psychiatric Hospital of the University of Basel, Basel CH-4012, Switzerland. w.van.der.meijden@nin.knaw.nl.
Wisse P
WP
van der Meijden
PsyQ Psycho-Medical Programs, Expertise Center Adult ADHD, The Hague 2593 HR, The Netherlands. D.Bijlenga@psyq.nl.
Denise
D
Bijlenga
PsyQ Psycho-Medical Programs, Expertise Center Adult ADHD, The Hague 2593 HR, The Netherlands. F.Dorani@psyq.nl.
Farangis
F
Dorani
Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam 1105 BA, The Netherlands. j.coppens@nin.knaw.nl.
Joris E
JE
Coppens
Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam 1105 BA, The Netherlands. b.te.lindert@nin.knaw.nl.
Bart H W
BH
Te Lindert
PsyQ Psycho-Medical Programs, Expertise Center Adult ADHD, The Hague 2593 HR, The Netherlands. s.kooij@psyq.nl.
J J Sandra
JJ
Kooij
Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam 1105 BA, The Netherlands. e.van.someren@nin.knaw.nl.|Departments of Integrative Neurophysiology and Psychiatry GGZ InGeest, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University and Medical Center, Amsterdam 1081 HV, The Netherlands. e.van.someren@nin.knaw.nl.
Eus J W
EJ
Van Someren
intrinsically photosensitive retinal ganglion cells; light; melanopsin; post-illumination pupil response; pupil; pupil dilation