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Hartmann EV, Reichert CF, Spitschan M. Effects of caffeine intake on pupillary parameters in humans: a systematic review and meta-analysis. BEHAVIORAL AND BRAIN FUNCTIONS : BBF 2024; 20:19. [PMID: 39103929 DOI: 10.1186/s12993-024-00245-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 07/18/2024] [Indexed: 08/07/2024]
Abstract
Caffeine is a widely used drug that broadly affects human cognition and brain function. Caffeine acts as an antagonist to the adenosine receptors in the brain. Previous anecdotal reports have also linked caffeine intake with changes in pupil diameter. By modifying the retinal irradiance, pupil diameter modulates all ocular light exposure relevant for visual (i.e., perception, detection and discrimination of visual stimuli) and non-visual (i.e., circadian) functions. To date, the extent of the influence of caffeine on pupillary outcomes, including pupil diameter, has not been examined in a systematic review. We implemented a systematic review laid out in a pre-registered protocol following PRISMA-P guidelines. We only included original research articles written in English reporting studies with human participants, in which caffeine was administered, and pupil diameter was measured using objective methods. Using broad search strategies, we consulted various databases (PsycINFO, Medline, Embase, Cochrane Library, bioRxiv and medRxiv) and used the Covidence platform to screen, review and extract data from studies. After importing studies identified through database search (n = 517 imported, n = 46 duplicates), we screened the title and abstracts (n = 471), finding 14 studies meeting our eligibility criteria. After full-text review, we excluded seven studies, leaving only a very modest number of included studies (n = 7). Extraction of information revealed that the existing literature on the effect of caffeine on pupil parameters is very heterogeneous, differing in pupil assessment methods, time of day of caffeine administration, dose, and protocol timing and design. The evidence available in the literature does not provide consistent results but studies rated as valid by quality assessment suggest a small effect of caffeine on pupil parameters. We summarize the numeric results as both differences in absolute pupil diameter and in terms of effect sizes. More studies are needed using modern pupil assessment methods, robust study design, and caffeine dose-response methodology.
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Affiliation(s)
- Elias Vincent Hartmann
- Centre for Chronobiology, University Psychiatric Clinics Basel (UPK), Basel, Switzerland
| | - Carolin Franziska Reichert
- Centre for Chronobiology, University Psychiatric Clinics Basel (UPK), Basel, Switzerland.
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland.
| | - Manuel Spitschan
- Max Planck Institute for Biological Cybernetics, Translational Sensory & Circadian Neuroscience, Tübingen, Germany.
- TUM School of Medicine & Health, Technical University of Munich, Munich, Germany.
- TUM Institute for Advanced Study (TUM-IAS), Technical University of Munich, Garching, Germany.
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Hoseini-Yazdi H, Read SA, Collins MJ, Bahmani H, Ellrich J, Schilling T. Increase in choroidal thickness after blue light stimulation of the blind spot in young adults. Bioelectron Med 2024; 10:13. [PMID: 38825695 PMCID: PMC11145801 DOI: 10.1186/s42234-024-00146-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 05/01/2024] [Indexed: 06/04/2024] Open
Abstract
BACKGROUND Blue light activates melanopsin, a photopigment that is expressed in intrinsically photosensitive retinal ganglion cells (ipRGCs). The axons of ipRGCs converge on the optic disc, which corresponds to the physiological blind spot in the visual field. Thus, a blue light stimulus aligned with the blind spot captures the ipRGCs axons at the optic disc. This study examined the potential changes in choroidal thickness and axial length associated with blue light stimulation of melanopsin-expressing ipRGCs at the blind spot. It was hypothesized that blue light stimulation at the blind spot in adults increases choroidal thickness. METHODS The blind spots of both eyes of 10 emmetropes and 10 myopes, with a mean age of 28 ± 6 years (SD), were stimulated locally for 1-minute with blue flickering light with a 460 nm peak wavelength. Measurements of choroidal thickness and axial length were collected from the left eye before stimulation and over a 60-minute poststimulation period. At a similar time of day, choroidal thickness and axial length were measured under sham control condition in all participants, while a subset of 3 emmetropes and 3 myopes were measured after 1-minute of red flickering light stimulation of the blind spot with a peak wavelength of 620 nm. Linear mixed model analyses were performed to examine the light-induced changes in choroidal thickness and axial length over time and between refractive groups. RESULTS Compared with sham control (2 ± 1 μm, n = 20) and red light (-1 ± 2 μm, n = 6) stimulation, subfoveal choroidal thickness increased within 60 min after blue light stimulation of the blind spot (7 ± 1 μm, n = 20; main effect of light, p < 0.001). Significant choroidal thickening after blue light stimulation occurred in emmetropes (10 ± 2 μm, p < 0.001) but not in myopes (4 ± 2 μm, p > 0.05). Choroidal thickening after blue light stimulation was greater in the fovea, diminishing in the parafoveal and perifoveal regions. There was no significant main effect of light, or light by refractive error interaction on the axial length after blind spot stimulation. CONCLUSIONS These findings demonstrate that stimulating melanopsin-expressing axons of ipRGCs at the blind spot with blue light increases choroidal thickness in young adults. This has potential implications for regulating eye growth.
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Affiliation(s)
- Hosein Hoseini-Yazdi
- Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, Optometry and Vision Science, Queensland University of Technology, Brisbane, 4059, Australia
| | - Scott A Read
- Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, Optometry and Vision Science, Queensland University of Technology, Brisbane, 4059, Australia
| | - Michael J Collins
- Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, Optometry and Vision Science, Queensland University of Technology, Brisbane, 4059, Australia
| | - Hamed Bahmani
- Dopavision GmbH, Krausenstr. 9-10, 10117, Berlin, Germany
| | - Jens Ellrich
- Dopavision GmbH, Krausenstr. 9-10, 10117, Berlin, Germany
- Medical Faculty, Friedrich-Alexander-University Erlangen-Nuremberg, 91054, Erlangen, Germany
| | - Tim Schilling
- Dopavision GmbH, Krausenstr. 9-10, 10117, Berlin, Germany.
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Lazar R, Degen J, Fiechter AS, Monticelli A, Spitschan M. Regulation of pupil size in natural vision across the human lifespan. ROYAL SOCIETY OPEN SCIENCE 2024; 11:191613. [PMID: 39100191 PMCID: PMC11295891 DOI: 10.1098/rsos.191613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/27/2024] [Indexed: 08/06/2024]
Abstract
Vision is mediated by light passing through the pupil, which changes in diameter from approximately 2 to 8 mm between bright and dark illumination. With age, mean pupil size declines. In laboratory experiments, factors affecting pupil size can be experimentally controlled. How the pupil reflects the change in retinal input from the visual environment under natural viewing conditions is unclear. We address this question in a field experiment (N = 83, 43 female, 18-87 years) using a custom-made wearable video-based eye tracker with a spectroradiometer measuring near-corneal spectral irradiance. Participants moved in and between indoor and outdoor environments varying in spectrum and engaged in a range of everyday tasks. Our data confirm that light-adapted pupil size is determined by light level, with a better model fit of melanopic over photopic units, and that it decreased with increasing age, yielding steeper slopes at lower light levels. We found no indication that sex, iris colour or reported caffeine consumption affects pupil size. Our exploratory results point to a role of photoreceptor integration in controlling steady-state pupil size. The data provide evidence for considering age in personalized lighting solutions and against the use of photopic illuminance alone to assess the impact of real-world lighting conditions.
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Affiliation(s)
- Rafael Lazar
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Switzerland
- Research Cluster Molecular and Cognitive Neurosciences, University of Basel, Switzerland
- Department of Biomedicine, University of Basel, Switzerland
| | - Josefine Degen
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Switzerland
| | - Ann-Sophie Fiechter
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Switzerland
| | - Aurora Monticelli
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Switzerland
| | - Manuel Spitschan
- Max Planck Institute for Biological Cybernetics, Translational Sensory & Circadian Neuroscience, Tübingen, Germany
- TUM School of Medicine & Health, Chronobiology & Health, Technical University of Munich, Munich, Germany
- TUM Institute for Advanced Study (TUM-IAS), Technical University of Munich, Garching, Germany
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4
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Schöllhorn I, Stefani O, Lucas RJ, Spitschan M, Epple C, Cajochen C. The Impact of Pupil Constriction on the Relationship Between Melanopic EDI and Melatonin Suppression in Young Adult Males. J Biol Rhythms 2024; 39:282-294. [PMID: 38348477 PMCID: PMC11141089 DOI: 10.1177/07487304241226466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
The pupil modulates the amount of light that reaches the retina. Not only luminance but also the spectral distribution defines the pupil size. Previous research has identified steady-state pupil size and melatonin attenuation to be predominantly driven by melanopsin, which is expressed by a unique subgroup of intrinsically photosensitive retinal ganglion cells (ipRGCs) that are sensitive to short-wavelength light (~480 nm). Here, we aimed to selectively target the melanopsin system during the evening, while measuring steady-state pupil size and melatonin concentrations under commonly experienced evening light levels (<90 lx). Therefore, we used a five-primary display prototype to generate light conditions that were matched in terms of L-, M-, and S-cone-opic irradiances, but with high and low melanopic irradiances (~3-fold difference). Seventy-two healthy, male participants completed a 2-week study protocol. The volunteers were assigned to one of the four groups that differed in luminance levels (27-285 cd/m2). Within the four groups, each volunteer was exposed to a low melanopic (LM) and a high melanopic (HM) condition. The two 17-h study protocols comprised 3.5 h of light exposure starting 4 h before habitual bedtime. Median pupil size was significantly smaller during HM than LM in all four light intensity groups. In addition, we observed a significant correlation between melanopic weighted corneal illuminance (melanopic equivalent daylight illuminance [mEDI]) and pupil size, such that higher mEDI values were associated with smaller pupil size. Using pupil size to estimate retinal irradiance showed a qualitatively similar goodness of fit as mEDI for predicting melatonin suppression. Based on our results here, it remains appropriate to use melanopic irradiance measured at eye level when comparing light-dependent effects on evening melatonin concentrations in healthy young people at rather low light levels.
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Affiliation(s)
- Isabel Schöllhorn
- Centre for Chronobiology, Psychiatric Hospital, University of Basel, Basel, Switzerland
- Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, Basel, Switzerland
| | - Oliver Stefani
- Centre for Chronobiology, Psychiatric Hospital, University of Basel, Basel, Switzerland
- Lucerne University of Applied Sciences and Arts, Lucerne, Switzerland
| | - Robert J Lucas
- Centre for Biological Timing, School of Biology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Manuel Spitschan
- Translational Sensory & Circadian Neuroscience, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Chronobiology & Health, Technical University of Munich, Munich, Germany
- TUM Institute for Advanced Study (TUM-IAS), Technical University of Munich, Munich, Germany
| | - Christian Epple
- Centre for Chronobiology, Psychiatric Hospital, University of Basel, Basel, Switzerland
| | - Christian Cajochen
- Centre for Chronobiology, Psychiatric Hospital, University of Basel, Basel, Switzerland
- Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, Basel, Switzerland
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5
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Barrionuevo PA, Sandoval Salinas ML, Fanchini JM. Are ipRGCs involved in human color vision? Hints from physiology, psychophysics, and natural image statistics. Vision Res 2024; 217:108378. [PMID: 38458004 DOI: 10.1016/j.visres.2024.108378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/09/2024] [Accepted: 02/25/2024] [Indexed: 03/10/2024]
Abstract
Human photoreceptors consist of cones, rods, and melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs). First studied in circadian regulation and pupillary control, ipRGCs project to a variety of brain centers suggesting a broader involvement beyond non-visual functions. IpRGC responses are stable, long-lasting, and with a particular codification of photoreceptor signals. In comparison with the transient and adaptive nature of cone and rod signals, ipRGCs' signaling might provide an ecological advantage to different attributes of color vision. Previous studies have indicated melanopsin's influence on visual responses yet its contribution to color perception in humans remains debated. We summarized evidence and hypotheses (from physiology, psychophysics, and natural image statistics) about direct and indirect involvement of ipRGCs in human color vision, by first briefly assessing the current knowledge about the role of melanopsin and ipRGCs in vision and codification of spectral signals. We then approached the question about melanopsin activation eliciting a color percept, discussing studies using the silent substitution method. Finally, we explore various avenues through which ipRGCs might impact color perception indirectly, such as through involvement in peripheral color matching, post-receptoral pathways, color constancy, long-term chromatic adaptation, and chromatic induction. While there is consensus about the role of ipRGCs in brightness perception, confirming its direct contribution to human color perception requires further investigation. We proposed potential approaches for future research, emphasizing the need for empirical validation and methodological thoroughness to elucidate the exact role of ipRGCs in human color vision.
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Affiliation(s)
- Pablo A Barrionuevo
- Allgemeine Psychologie, Justus-Liebig-Universität Gießen, Germany; Instituto de Investigación en Luz, Ambiente y Visión (ILAV), CONICET - Universidad Nacional de Tucumán, Argentina.
| | - María L Sandoval Salinas
- Instituto de Investigación en Luz, Ambiente y Visión (ILAV), CONICET - Universidad Nacional de Tucumán, Argentina; Instituto de Investigaciones de Biodiversidad Argentina (PIDBA), Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Argentina
| | - José M Fanchini
- Instituto de Investigación en Luz, Ambiente y Visión (ILAV), CONICET - Universidad Nacional de Tucumán, Argentina; Departamento de Luminotecnia, Luz y Visión, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán, Argentina
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Blume C, Cajochen C, Schöllhorn I, Slawik HC, Spitschan M. Effects of calibrated blue-yellow changes in light on the human circadian clock. Nat Hum Behav 2024; 8:590-605. [PMID: 38135734 PMCID: PMC10963261 DOI: 10.1038/s41562-023-01791-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 11/16/2023] [Indexed: 12/24/2023]
Abstract
Evening exposure to short-wavelength light can affect the circadian clock, sleep and alertness. Intrinsically photosensitive retinal ganglion cells expressing melanopsin are thought to be the primary drivers of these effects. Whether colour-sensitive cones also contribute is unclear. Here, using calibrated silent-substitution changes in light colour along the blue-yellow axis, we investigated whether mechanisms of colour vision affect the human circadian system and sleep. In a 32.5-h repeated within-subjects protocol, 16 healthy participants were exposed to three different light scenarios for 1 h starting 30 min after habitual bedtime: baseline control condition (93.5 photopic lux), intermittently flickering (1 Hz, 30 s on-off) yellow-bright light (123.5 photopic lux) and intermittently flickering blue-dim light (67.0 photopic lux), all calibrated to have equal melanopsin excitation. We did not find conclusive evidence for differences between the three lighting conditions regarding circadian melatonin phase delays, melatonin suppression, subjective sleepiness, psychomotor vigilance or sleep.The Stage 1 protocol for this Registered Report was accepted in principle on 9 September 2020. The protocol, as accepted by the journal, can be found at https://doi.org/10.6084/m9.figshare.13050215.v1 .
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Affiliation(s)
- Christine Blume
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland.
- Research Cluster Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland.
- Department of Biomedicine, University of Basel, Basel, Switzerland.
| | - Christian Cajochen
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland
- Research Cluster Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
| | - Isabel Schöllhorn
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland
- Research Cluster Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
| | - Helen C Slawik
- Psychiatric Hospital of the University of Basel, Basel, Switzerland
| | - Manuel Spitschan
- Translational Sensory and Circadian Neuroscience, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
- TUM Department Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich, Munich, Germany.
- TUM Institute for Advanced Study (TUM-IAS), Technical University of Munich, Garching, Germany.
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7
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Taskin HO, Wivel J, Aguirre GD, Beltran WA, Aguirre GK. Cone-Driven, Geniculocortical Responses in Canine Models of Outer Retinal Disease. Transl Vis Sci Technol 2024; 13:18. [PMID: 38241039 PMCID: PMC10807495 DOI: 10.1167/tvst.13.1.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
Purpose Canine models of inherited retinal degeneration are used for proof of concept of emerging gene and cell-based therapies that aim to produce functional restoration of cone-mediated vision. We examined functional magnetic resonance imaging (MRI) measures of the postretinal response to cone-directed stimulation in wild-type (WT) dogs, and in three different retinal disease models. Methods Temporal spectral modulation of a uniform field of light around a photopic background was used to target the canine L/M (hereafter "L") and S cones and rods. Stimuli were designed to separately target the postreceptoral luminance (L+S) and chrominance (L-S) pathways, the rods, and all photoreceptors jointly (light flux). These stimuli were presented to WT, and mutant PDE6B-RCD1, RPGR-XLPRA2, and NPHP5-CRD2 dogs during pupillometry and functional MRI (fMRI). Results Pupil responses in WT dogs to light flux, L+S, and rod-directed stimuli were consistent with responses being driven by cone signals alone. For WT animals, both luminance and chromatic (L-S) stimuli evoked fMRI responses in the lateral geniculate nucleus or visual cortex; RCD1 animals with predominant rod loss had similar responses. Responses to cone-directed stimulation were reduced in XLPRA2 and absent in CRD2. NPHP5 gene augmentation restored the cortical response to luminance stimulation in a CRD2 animal. Conclusions Cone-directed stimulation during fMRI can be used to measure the integrity of luminance and chrominance responses in the dog visual system. The NPHP5-CRD2 model is appealing for studies of recovered cone function. Translational Relevance fMRI assessment of cone-driven cortical response provides a tool to translate cell/gene therapies for vision restoration.
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Affiliation(s)
- Huseyin O. Taskin
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jacqueline Wivel
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Gustavo D. Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - William A. Beltran
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Geoffrey K. Aguirre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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8
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Najjar RP, Prayag AS, Gronfier C. Melatonin suppression by light involves different retinal photoreceptors in young and older adults. J Pineal Res 2024; 76:e12930. [PMID: 38241677 DOI: 10.1111/jpi.12930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 10/31/2023] [Accepted: 11/29/2023] [Indexed: 01/21/2024]
Abstract
Age-related sleep and circadian rhythm disturbances may be due to altered nonvisual photoreception. Here, we investigated the temporal dynamics of light-induced melatonin suppression in young and older individuals. In a within-subject design study, young and older participants were exposed for 60 min (0030-0130 at night) to nine narrow-band lights (range: 420-620 nm). Plasma melatonin suppression was calculated at 15, 30, 45, and 60 min time intervals. Individual spectral sensitivity of melatonin suppression and photoreceptor contribution were predicted for each interval and age group. In young participants, melanopsin solely drove melatonin suppression at all time intervals, with a peak sensitivity at 485.3 nm established only after 15 min of light exposure. Conversely, in older participants, spectral light-driven melatonin suppression was best explained by a more complex model combining melanopsin, S-cone, and M-cone functions, with a stable peak (~500 nm) at 30, 45, and 60 min of light exposure. Aging is associated with a distinct photoreceptor contribution to melatonin suppression by light. While in young adults melanopsin-only photoreception is a reliable predictor of melatonin suppression, in older individuals this process is jointly driven by melanopsin, S-cone, and M-cone functions. These findings offer new prospects for customizing light therapy for older individuals.
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Affiliation(s)
- Raymond P Najjar
- Department of Ophthalmology, Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
- Visual Neurosciences Group, ASPIRE Research Program, Singapore Eye Research Institute, Singapore, Singapore
- Visual Sciences and Ophthalmology Program, Duke-NUS Medical School, Singapore, Singapore
- Center for Innovation & Precision Eye Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Abhishek S Prayag
- Lyon Neuroscience Research Center, Waking Team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Claude Gronfier
- Lyon Neuroscience Research Center, Waking Team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
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9
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Zeng X, Soreze TSC, Ballegaard M, Petersen PM. Integrative Lighting Aimed at Patients with Psychiatric and Neurological Disorders. Clocks Sleep 2023; 5:806-830. [PMID: 38131751 PMCID: PMC10742818 DOI: 10.3390/clockssleep5040052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023] Open
Abstract
The purpose of this paper is to investigate the impact of circadian lighting-induced melatonin suppression on patients with psychiatric and neurological disorders in hospital wards by using an ad-hoc metrology framework and the subsequent metrics formalized by the CIE in 2018. A measurement scheme was conducted in hospital ward rooms in the Department of Neurology, Zealand University Hospital, at Roskilde in Denmark, to evaluate the photometric and colorimetric characteristics of the lighting system, as well as its influence on the circadian rhythm of the occupants. The measurement scheme included point measurements and data logging, using a spectrophotometer mounted on a tripod with adjustable height to assess the newly installed circadian lighting system. The measured spectra were uploaded to the Luox platform to calculate illuminance, CCT, MEDI, etc., in accordance with the CIE S026 standard. Furthermore, the MLIT based on MEDI data logging results was calculated. In addition to CIE S026, we have investigated the usefulness of melatonin suppression models for the assessment of circadian performance regarding measured light. From the results, the lighting conditions in the patient room for both minimal and abundant daylight access were evaluated and compared; we found that access to daylight is essential for both illumination and circadian entrainment. It can be concluded that the measurement scheme, together with the use of the Luox platform and Canva template, is suitable for the accurate and satisfactory measurement of integrative lighting that aligns with CIE requirements and recommendations.
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Affiliation(s)
- Xinxi Zeng
- Department of Electrical and Photonics Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (X.Z.); (P.M.P.)
| | - Thierry Silvio Claude Soreze
- Department of Electrical and Photonics Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (X.Z.); (P.M.P.)
| | - Martin Ballegaard
- Department of Neurology, Copenhagen University Hospital—Zealand University Hospital Roskilde, 4000 Roskilde, Denmark;
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Paul Michael Petersen
- Department of Electrical and Photonics Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (X.Z.); (P.M.P.)
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Taskin HO, Wivel J, Aguirre GD, Beltran WA, Aguirre GK. Cone-driven, geniculo-cortical responses in canine models of outer retinal disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571523. [PMID: 38168165 PMCID: PMC10760074 DOI: 10.1101/2023.12.13.571523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Purpose Canine models of inherited retinal degeneration are used for proof-of-concept of emerging gene and cell-based therapies that aim to produce functional restoration of cone-mediated vision. We examined functional MRI measures of the post-retinal response to cone-directed stimulation in wild type (WT) dogs, and in three different retinal disease models. Methods Temporal spectral modulation of a uniform field of light around a photopic background was used to target the canine L/M (hereafter "L") and S cones and rods. Stimuli were designed to separately target the post-receptoral luminance (L+S) and chrominance (L-S) pathways, the rods, and all photoreceptors jointly (light flux). These stimuli were presented to WT, and mutant PDE6B-RCD1, RPGR-XLPRA2, and NPHP5-CRD2 dogs during pupillometry and fMRI. Results Pupil responses in WT dogs to light flux, L+S, and rod-directed stimuli were consistent with responses being driven by cone signals alone. For WT animals, both luminance and chromatic (L-S) stimuli evoked fMRI responses in the lateral geniculate nucleus (LGN) or visual cortex; RCD1 animals with predominant rod loss had similar responses. Responses to cone-directed stimulation were reduced in XLPRA2 and absent in CRD2. NPHP5 gene augmentation restored the cortical response to luminance stimulation in a CRD2 animal. Conclusions Cone-directed stimulation during fMRI can be used to measure the integrity of luminance and chrominance responses in the dog visual system. The NPHP5-CRD2 model is appealing for studies of recovered cone function. Translational Relevance fMRI assessment of cone driven cortical response provides a tool to translate cell/gene therapies for vision restoration.
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Affiliation(s)
- Huseyin O. Taskin
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Jacqueline Wivel
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Gustavo D. Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - William A. Beltran
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Geoffrey K. Aguirre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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Woelders T, Allen AE, Lucas RJ. Melanopsin enhances image persistence. Curr Biol 2023; 33:5048-5056.e4. [PMID: 37967553 DOI: 10.1016/j.cub.2023.10.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 09/28/2023] [Accepted: 10/20/2023] [Indexed: 11/17/2023]
Abstract
Contributions of the inner retinal photopigment melanopsin to human visual perception are incompletely understood. Here, we use a four-primary display to produce stimuli differing in melanopsin versus cone contrast in psychophysical paradigms in eight subjects with normal color vision. We address two predictions from electrophysiological recordings of the melanopsin system in non-human mammals: melanopsin influences color and/or supports image persistence under visual fixation. We first construct chromatic contrast sensitivity contours for stimuli differing in melanopsin excitation presented as a central annulus (10°) or peripheral (22.5°) spot. We find that although including melanopsin contrast produces modest changes in the average chromatic coordinates in both eccentricities, this occurs equally at low (0.5 Hz) and higher (3.75 Hz) temporal frequencies, arguing that it reflects divergence in cone spectral sensitivity in our participants from that captured in standardized cone fundamentals rather than a melanopsin contribution to color. We continue to ask whether the established ability of melanopsin to sustain firing of visual neurons under extended light exposure has a visual correlate, using the optical illusion of Troxler fading in which blurred spots in periphery disappear during visual fixation. We find that introducing additional melanopsin contrast (+28% Michelson contrast) to either bright or dark spots increases fading latency by 35% ± 8.8% and 41% ± 13.6%, respectively. Our data argue that the primary contribution of melanopsin to perception under these conditions is not to provide a color percept but rather to enhance persistence of low spatial frequency patterns during visual fixation.
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Affiliation(s)
- Tom Woelders
- Division of Neuroscience and Centre for Biological Timing, School of Biology, Faculty of Biology Medicine and Health, University of Manchester, Upper Brook Street, M13 9PT Manchester, UK.
| | - Annette E Allen
- Division of Neuroscience and Centre for Biological Timing, School of Biology, Faculty of Biology Medicine and Health, University of Manchester, Upper Brook Street, M13 9PT Manchester, UK
| | - Robert J Lucas
- Division of Neuroscience and Centre for Biological Timing, School of Biology, Faculty of Biology Medicine and Health, University of Manchester, Upper Brook Street, M13 9PT Manchester, UK.
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Spitschan M, Joyce DS. Human-Centric Lighting Research and Policy in the Melanopsin Age. POLICY INSIGHTS FROM THE BEHAVIORAL AND BRAIN SCIENCES 2023; 10:237-246. [PMID: 38919981 PMCID: PMC7615961 DOI: 10.1177/23727322231196896] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
Beyond visual function, specialized light-sensitive retinal circuits involving the photopigment melanopsin drive critical aspects of human physiology and behavior, including sleep-wake rhythms, hormone production, mood, and cognition. Fundamental discoveries of visual neurobiology dating back to the 1990s have given rise to strong interest from the lighting industry in optimizing lighting to benefit health. Consequently, evidence-based recommendations, regulations, and policies need to translate current knowledge of neurobiology into practice. Here, reviewing recent advances in understanding of NIF circuits in humans leads to proposed strategies to optimize electric lighting. Highlighted knowledge gaps must be addressed urgently, as well as the challenge of developing personalized, adaptive NIF lighting interventions accounting for complex individual differences in physiology, behavior, and environment. Finally, lighting equity issues appear in the context of marginalized groups, who have traditionally been underserved in research on both fundamental visual processes and applied lighting. Biologically optimal light is a fundamental environmental right.
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Affiliation(s)
- Manuel Spitschan
- TUM School of Medicine & Health, Technical University of Munich, Munich, Germany
- TUM Institute for Advanced Study (TUM-IAS), Technical University of Munich, Garching, Germany
- Max Planck Institute for Biological Cybernetics, Max Planck Research Group Translational Sensory & Circadian Neuroscience, Tübingen, Germany
| | - Daniel S. Joyce
- Centre for Health Research, University of Southern Queensland, Ipswich, Queensland, Australia
- School of Psychology and Wellbeing, University of Southern Queensland, Ipswich, Queensland, Australia
- Department of Psychology, University of Nevada, Reno, Reno, Nevada, USA
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13
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Segala FG, Bruno A, Martin JT, Aung MT, Wade AR, Baker DH. Different rules for binocular combination of luminance flicker in cortical and subcortical pathways. eLife 2023; 12:RP87048. [PMID: 37750670 PMCID: PMC10522334 DOI: 10.7554/elife.87048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023] Open
Abstract
How does the human brain combine information across the eyes? It has been known for many years that cortical normalization mechanisms implement 'ocularity invariance': equalizing neural responses to spatial patterns presented either monocularly or binocularly. Here, we used a novel combination of electrophysiology, psychophysics, pupillometry, and computational modeling to ask whether this invariance also holds for flickering luminance stimuli with no spatial contrast. We find dramatic violations of ocularity invariance for these stimuli, both in the cortex and also in the subcortical pathways that govern pupil diameter. Specifically, we find substantial binocular facilitation in both pathways with the effect being strongest in the cortex. Near-linear binocular additivity (instead of ocularity invariance) was also found using a perceptual luminance matching task. Ocularity invariance is, therefore, not a ubiquitous feature of visual processing, and the brain appears to repurpose a generic normalization algorithm for different visual functions by adjusting the amount of interocular suppression.
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Affiliation(s)
| | - Aurelio Bruno
- School of Psychology and Vision Sciences, University of LeicesterLeicesterUnited Kingdom
| | - Joel T Martin
- Department of Psychology, University of YorkYorkUnited Kingdom
| | - Myat T Aung
- Department of Psychology, University of YorkYorkUnited Kingdom
| | - Alex R Wade
- Department of Psychology, University of YorkYorkUnited Kingdom
- York Biomedical Research Institute, University of YorkYorkUnited Kingdom
| | - Daniel H Baker
- Department of Psychology, University of YorkYorkUnited Kingdom
- York Biomedical Research Institute, University of YorkYorkUnited Kingdom
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14
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Sparks S, Pinto J, Hayes G, Spitschan M, Bulte DP. The impact of Alzheimer's disease risk factors on the pupillary light response. Front Neurosci 2023; 17:1248640. [PMID: 37650103 PMCID: PMC10463762 DOI: 10.3389/fnins.2023.1248640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 07/31/2023] [Indexed: 09/01/2023] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia, and its prevalence is increasing and is expected to continue to increase over the next few decades. Because of this, there is an urgent requirement to determine a way to diagnose the disease, and to target interventions to delay and ideally stop the onset of symptoms, specifically those impacting cognition and daily livelihood. The pupillary light response (PLR) is controlled by the sympathetic and parasympathetic branches of the autonomic nervous system, and impairments to the pupillary light response (PLR) have been related to AD. However, most of these studies that assess the PLR occur in patients who have already been diagnosed with AD, rather than those who are at a higher risk for the disease but without a diagnosis. Determining whether the PLR is similarly impaired in subjects before an AD diagnosis is made and before cognitive symptoms of the disease begin, is an important step before using the PLR as a diagnostic tool. Specifically, identifying whether the PLR is impaired in specific at-risk groups, considering both genetic and non-genetic risk factors, is imperative. It is possible that the PLR may be impaired in association with some risk factors but not others, potentially indicating different pathways to neurodegeneration that could be distinguished using PLR. In this work, we review the most common genetic and lifestyle-based risk factors for AD and identify established relationships between these risk factors and the PLR. The evidence here shows that many AD risk factors, including traumatic brain injury, ocular and intracranial hypertension, alcohol consumption, depression, and diabetes, are directly related to changes in the PLR. Other risk factors currently lack sufficient literature to make any conclusions relating directly to the PLR but have shown links to impairments in the parasympathetic nervous system; further research should be conducted in these risk factors and their relation to the PLR.
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Affiliation(s)
- Sierra Sparks
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Joana Pinto
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Genevieve Hayes
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Manuel Spitschan
- TUM Department of Sport and Health Sciences (TUM SG), Chronobiology and Health, Technical University of Munich, Munich, Germany
- TUM Institute for Advanced Study (TUM-IAS), Technical University of Munich, Garching, Germany
- Max Planck Institute for Biological Cybernetics, Translational Sensory and Circadian Neuroscience, Tübingen, Germany
| | - Daniel P. Bulte
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
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15
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Zhao H, Wang H, Zhang M, Weng C, Liu Y, Yin Z. Chromatic pupillometry isolation and evaluation of intrinsically photosensitive retinal ganglion cell-driven pupillary light response in patients with retinitis pigmentosa. Front Hum Neurosci 2023; 17:1212398. [PMID: 37533585 PMCID: PMC10390747 DOI: 10.3389/fnhum.2023.1212398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 07/05/2023] [Indexed: 08/04/2023] Open
Abstract
Purpose The pupil light response (PLR) is driven by rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs). We aimed to isolate ipRGC-driven pupil responses using chromatic pupillometry and to determine the effect of advanced retinitis pigmentosa (RP) on ipRGC function. Methods A total of 100 eyes from 67 patients with advanced RP and 18 healthy controls (HCs) were included. Patients were divided into groups according to severity of visual impairment: no light perception (NLP, 9 eyes), light perception (LP, 19 eyes), faint form perception (FFP, 34 eyes), or form perception (FP, 38 eyes). Pupil responses to rod-weighted (487 nm, -1 log cd/m2, 1 s), cone-weighted (630 nm, 2 log cd/m2, 1 s), and ipRGC-weighted (487 nm, 2 log cd/m2, 1 s) stimuli were recorded. ipRGC function was evaluated by the postillumination pupil response (PIPR) and three metrics of pupil kinetics: maximal contraction velocity (MCV), contraction duration, and maximum dilation velocity (MDV). Results We found a slow, sustained PLR response to the ipRGC-weighted stimulus in most patients with NLP (8/9), but these patients had no detectable rod- or cone-driven PLR. The ipRGC-driven PLR had an MCV of 0.269 ± 0.150%/s and contraction duration of 2.562 ± 0.902 s, both of which were significantly lower than those of the rod and cone responses. The PIPRs of the RP groups did not decrease compared with those of the HCs group and were even enhanced in the LP group. At advanced stages, ipRGC responses gradually became the main component of the PLR. Conclusion Chromatic pupillometry successfully isolated an ipRGC-driven PLR in patients with advanced RP. This PLR remained stable and gradually became the main driver of pupil contraction in more advanced cases of RP. Here, we present baseline data on ipRGC function; we expect these findings to contribute to evaluating and screening candidates for novel therapies.
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Affiliation(s)
- He Zhao
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China
- Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, China
| | - Hao Wang
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China
- Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, China
| | - Minfang Zhang
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China
- Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, China
| | - Chuanhuang Weng
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China
- Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, China
| | - Yong Liu
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China
- Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, China
| | - Zhengqin Yin
- Southwest Hospital/Southwest Eye Hospital, Army Medical University, Chongqing, China
- Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, China
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16
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Martin JT, Boynton GM, Baker DH, Wade AR, Spitschan M. PySilSub: An open-source Python toolbox for implementing the method of silent substitution in vision and nonvisual photoreception research. J Vis 2023; 23:10. [PMID: 37450287 PMCID: PMC10353748 DOI: 10.1167/jov.23.7.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 06/11/2023] [Indexed: 07/18/2023] Open
Abstract
The normal human retina contains several classes of photosensitive cell-rods for low-light vision, three cone classes for daylight vision, and intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing melanopsin for non-image-forming functions, including pupil control, melatonin suppression, and circadian photoentrainment. The spectral sensitivities of the photoreceptors overlap significantly, which means that most lights will stimulate all photoreceptors to varying degrees. The method of silent substitution is a powerful tool for stimulating individual photoreceptor classes selectively and has found much use in research and clinical settings. The main hardware requirement for silent substitution is a spectrally calibrated light stimulation system with at least as many primaries as there are photoreceptors under consideration. Device settings that will produce lights to selectively stimulate the photoreceptor(s) of interest can be found using a variety of analytic and algorithmic approaches. Here we present PySilSub (https://github.com/PySilentSubstitution/pysilsub), a novel Python package for silent substitution featuring flexible support for individual colorimetric observer models (including human and mouse observers), multiprimary stimulation devices, and solving silent substitution problems with linear algebra and constrained numerical optimization. The toolbox is registered with the Python Package Index and includes example data sets from various multiprimary systems. We hope that PySilSub will facilitate the application of silent substitution in research and clinical settings.
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Affiliation(s)
- Joel T Martin
- Department of Psychology, University of York, York, UK
| | | | - Daniel H Baker
- Department of Psychology, University of York, York, UK
- York Biomedical Research Institute, University of York, York, UK
| | - Alex R Wade
- Department of Psychology, University of York, York, UK
- York Biomedical Research Institute, University of York, York, UK
| | - Manuel Spitschan
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- TUM Department of Sport and Health Sciences (TUM SG), Technical University of Munich, Munich, Germany
- TUM Institute for Advanced Study (TUM-IAS), Technical University of Munich, Garching, Germany
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17
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Feord RC, Gomoliszewska A, Pienaar A, Mouland JW, Brown TM. Colour opponency is widespread across the mouse subcortical visual system and differentially targets GABAergic and non-GABAergic neurons. Sci Rep 2023; 13:9313. [PMID: 37291239 PMCID: PMC10250360 DOI: 10.1038/s41598-023-35885-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 05/25/2023] [Indexed: 06/10/2023] Open
Abstract
Colour vision plays many important roles in animal behaviour but the brain pathways processing colour remain surprisingly poorly understood, including in the most commonly used laboratory mammal, mice. Indeed, particular features of mouse retinal organisation present challenges in defining the mechanisms underlying colour vision in mice and have led to suggestions that this may substantially rely on 'non-classical' rod-cone opponency. By contrast, studies using mice with altered cone spectral sensitivity, to facilitate application of photoreceptor-selective stimuli, have revealed widespread cone-opponency across the subcortical visual system. To determine the extent to which such findings are truly reflective of wildtype mouse colour vision, and facilitate neural circuit mapping of colour-processing pathways using intersectional genetic approaches, we here establish and validate stimuli for selectively manipulating excitation of the native mouse S- and M-cone opsin classes. We then use these to confirm the widespread appearance of cone-opponency (> 25% of neurons) across the mouse visual thalamus and pretectum. We further extend these approaches to map the occurrence of colour-opponency across optogenetically identified GABAergic (GAD2-expressing) cells in key non-image forming visual centres (pretectum and intergeniculate leaflet/ventral lateral geniculate; IGL/vLGN). Strikingly, throughout, we find S-ON/M-OFF opponency is specifically enriched in non-GABAergic cells, with identified GABAergic cells in the IGL/VLGN entirely lacking this property. Collectively, therefore, we establish an important new approach for studying cone function in mice, confirming a surprisingly extensive appearance of cone-opponent processing in the mouse visual system and providing new insight into functional specialisation of the pathways processing such signals.
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Affiliation(s)
- R C Feord
- Centre for Biological Timing, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - A Gomoliszewska
- Centre for Biological Timing, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - A Pienaar
- Centre for Biological Timing, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - J W Mouland
- Centre for Biological Timing, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - T M Brown
- Centre for Biological Timing, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
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18
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Yang CC, Tsujimura SI, Yeh SL. Blue-light background impairs visual exogenous attention shift. Sci Rep 2023; 13:3794. [PMID: 36882407 PMCID: PMC9992692 DOI: 10.1038/s41598-022-24862-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 11/22/2022] [Indexed: 03/09/2023] Open
Abstract
Previous research into the effects of blue light on visual-spatial attention has yielded mixed results due to a lack of properly controlling critical factors like S-cone stimulation, ipRGCs stimulation, and color. We adopted the clock paradigm and systematically manipulated these factors to see how blue light impacts the speed of exogenous and endogenous attention shifts. Experiments 1 and 2 revealed that, relative to the control light, exposure to the blue-light background decreased the speed of exogenous (but not endogenous) attention shift to external stimuli. To further clarify the contribution(s) of blue-light sensitive photoreceptors (i.e., S-cone and ipRGCs), we used a multi-primary system that could manipulate the stimulation of a single type of photoreceptor without changing the stimulation of other photoreceptors (i.e., the silent substitution method). Experiments 3 and 4 revealed that stimulation of S-cones and ipRGCs did not contribute to the impairment of exogenous attention shift. Our findings suggest that associations with blue colors, such as the concept of blue light hazard, cause exogenous attention shift impairment. Some of the previously documented blue-light effects on cognitive performances need to be reevaluated and reconsidered in light of our findings.
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Affiliation(s)
- Chien-Chun Yang
- Department of Psychology, National Taiwan University, Taipei, Taiwan
| | - Sei-Ichi Tsujimura
- Faculty of Design and Architecture, Nagoya City University, Nagoya, Japan
| | - Su-Ling Yeh
- Department of Psychology, National Taiwan University, Taipei, Taiwan.
- Graduate Institute of Brain and Mind Sciences, National Taiwan University, Taipei, Taiwan.
- Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan.
- Center for Artificial Intelligence and Advanced Robotics, National Taiwan University, Taipei, Taiwan.
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19
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Wang Y, Belušič G, Pen I, Beukeboom LW, Wertheim B, Stavenga DG, Hut RA. Circadian rhythm entrainment of the jewel wasp, Nasonia vitripennis, by antagonistic interactions of multiple spectral inputs. Proc Biol Sci 2023; 290:20222319. [PMID: 36750184 PMCID: PMC9904953 DOI: 10.1098/rspb.2022.2319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Circadian light entrainment in some insects is regulated by blue-light-sensitive cryptochrome (CRY) protein that is expressed in the clock neurons, but this is not the case in hymenopterans. The hymenopteran clock does contain CRY, but it appears to be light-insensitive. Therefore, we investigated the role of retinal photoreceptors in the photic entrainment of the jewel wasp Nasonia vitripennis. Application of monochromatic light stimuli at different light intensities caused phase shifts in the wasp's circadian activity from which an action spectrum with three distinct peaks was derived. Electrophysiological recordings from the compound eyes and ocelli revealed the presence of three photoreceptor classes, with peak sensitivities at 340 nm (ultraviolet), 450 nm (blue) and 530 nm (green). An additional photoreceptor class in the ocelli with sensitivity maximum at 560-580 nm (red) was found. Whereas a simple sum of photoreceptor spectral sensitivities could not explain the action spectrum of the circadian phase shifts, modelling of the action spectrum indicates antagonistic interactions between pairs of spectral photoreceptors, residing in the compound eyes and the ocelli. Our findings imply that the photic entrainment mechanism in N. vitripennis encompasses the neural pathways for measuring the absolute luminance as well as the circuits mediating colour opponency.
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Affiliation(s)
- Yifan Wang
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9712 CP Groningen, the Netherlands
| | - Gregor Belušič
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Ido Pen
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9712 CP Groningen, the Netherlands
| | - Leo W. Beukeboom
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9712 CP Groningen, the Netherlands
| | - Bregje Wertheim
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9712 CP Groningen, the Netherlands
| | - Doekele G. Stavenga
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9712 CP Groningen, the Netherlands
| | - Roelof A. Hut
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9712 CP Groningen, the Netherlands
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20
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Martin JT, Pinto J, Bulte D, Spitschan M. PyPlr: A versatile, integrated system of hardware and software for researching the human pupillary light reflex. Behav Res Methods 2022; 54:2720-2739. [PMID: 34918229 PMCID: PMC9729317 DOI: 10.3758/s13428-021-01759-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2021] [Indexed: 12/16/2022]
Abstract
We introduce PyPlr-a versatile, integrated system of hardware and software to support a broad spectrum of research applications concerning the human pupillary light reflex (PLR). PyPlr is a custom Python library for integrating a research-grade video-based eye-tracker system with a light source and streamlining stimulus design, optimisation and delivery, device synchronisation, and extraction, cleaning, and analysis of pupil data. We additionally describe how full-field, homogenous stimulation of the retina can be realised with a low-cost integrating sphere that serves as an alternative to a more complex Maxwellian view setup. Users can integrate their own light source, but we provide full native software support for a high-end, commercial research-grade 10-primary light engine that offers advanced control over the temporal and spectral properties of light stimuli as well as spectral calibration utilities. Here, we describe the hardware and software in detail and demonstrate its capabilities with two example applications: (1) pupillometer-style measurement and parametrisation of the PLR to flashes of white light, and (2) comparing the post-illumination pupil response (PIPR) to flashes of long and short-wavelength light. The system holds promise for researchers who would favour a flexible approach to studying the PLR and the ability to employ a wide range of temporally and spectrally varying stimuli, including simple narrowband stimuli.
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Affiliation(s)
- Joel T Martin
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, OX3 7DQ, UK.
| | - Joana Pinto
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, OX3 7DQ, UK
| | - Daniel Bulte
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, OX3 7DQ, UK
| | - Manuel Spitschan
- Department of Experimental Psychology, University of Oxford, Oxford, OX2 6GG, UK
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21
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Esposito T, Houser K. Correlated color temperature is not a suitable proxy for the biological potency of light. Sci Rep 2022; 12:20223. [PMID: 36418869 PMCID: PMC9684473 DOI: 10.1038/s41598-022-21755-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 09/30/2022] [Indexed: 11/25/2022] Open
Abstract
Using a simulation based on a real, five-channel tunable LED lighting system, we show that Correlated Color Temperature (CCT) is not a reasonable predictor of the biological potency of light, whether characterized with CIE melanopic Equivalent Daylight Illuminance (mel-EDI), Equivalent Melanopic Lux (EML) (a scalar multiple of mel-EDI), or Circadian Stimulus (CS). At a photopic corneal illuminance of 300 lx and Rf ≥ 70, spectra can vary in CS from 17 to 41% across CCTs from 2500 to 6000 K, and up to 23% at a single CCT, due to the choice of spectrum alone. The CS range is largest, and notably discontinuous, at a CCT of 3500 K, the location of the inflection point of the CS model. At a photopic corneal illuminance of 300 lx and Rf ≥ 70, mel-EDI can vary from 123 to 354 lx across CCTs from 2500 to 6000 K and can vary by up to 123 lx at a fixed CCT (e.g., 196 to 319 lx at 5000 K). The range of achievable mel-EDI increases as CCT increases and, on average, decreases as color fidelity, characterized with IES TM-30 Rf, increases. These data demonstrate that there is no easy mathematical conversion between CS and mel-EDI when a spectrally diverse spectra set of spectral power distributions is considered.
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Affiliation(s)
- Tony Esposito
- Lighting Research Solutions LLC, Philadelphia, PA, USA.
| | - Kevin Houser
- School of Civil and Construction Engineering, Oregon State University, Corvallis, OR, USA
- Pacific Northwest National Laboratory, Portland, OR, USA
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22
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Blume C, Niedernhuber M, Spitschan M, Slawik HC, Meyer MP, Bekinschtein TA, Cajochen C. Melatonin suppression does not automatically alter sleepiness, vigilance, sensory processing, or sleep. Sleep 2022; 45:zsac199. [PMID: 35998110 PMCID: PMC9644120 DOI: 10.1093/sleep/zsac199] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 08/02/2022] [Indexed: 09/19/2023] Open
Abstract
Presleep exposure to short-wavelength light suppresses melatonin and decreases sleepiness with activating effects extending to sleep. This has mainly been attributed to melanopic effects, but mechanistic insights are missing. Thus, we investigated whether two light conditions only differing in the melanopic effects (123 vs. 59 lx melanopic EDI) differentially affect sleep besides melatonin. Additionally, we studied whether the light differentially modulates sensory processing during wakefulness and sleep. Twenty-nine healthy volunteers (18-30 years, 15 women) were exposed to two metameric light conditions (high- vs. low-melanopic, ≈60 photopic lx) for 1 h ending 50 min prior to habitual bed time. This was followed by an 8-h sleep opportunity with polysomnography. Objective sleep measurements were complemented by self-report. Salivary melatonin, subjective sleepiness, and behavioral vigilance were sampled at regular intervals. Sensory processing was evaluated during light exposure and sleep on the basis of neural responses related to violations of expectations in an oddball paradigm. We observed suppression of melatonin by ≈14% in the high- compared to the low-melanopic condition. However, conditions did not differentially affect sleep, sleep quality, sleepiness, or vigilance. A neural mismatch response was evident during all sleep stages, but not differentially modulated by light. Suppression of melatonin by light targeting the melanopic system does not automatically translate to acutely altered levels of vigilance or sleepiness or to changes in sleep, sleep quality, or basic sensory processing. Given contradicting earlier findings and the retinal anatomy, this may suggest that an interaction between melanopsin and cone-rod signals needs to be considered. Clinical Trial Registry: German Clinical Trials Register, DRKS00023602, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00023602.
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Affiliation(s)
- Christine Blume
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland (institution, where the work was performed)
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
| | - Maria Niedernhuber
- Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Cambridge, UK
| | - Manuel Spitschan
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland (institution, where the work was performed)
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Translational Sensory and Circadian Neuroscience, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- TUM Department of Sport and Health Sciences (TUM SG), Technical University of Munich, Munich, Germany
| | - Helen C Slawik
- Psychiatric Hospital of the University of Basel, Basel, Switzerland
| | - Martin P Meyer
- Psychiatric Hospital of the University of Basel, Basel, Switzerland
| | - Tristan A Bekinschtein
- Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Cambridge, UK
| | - Christian Cajochen
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland (institution, where the work was performed)
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
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Cormenzana Méndez I, Martín A, O'Donell B, Cao D, Barrionuevo PA. Temporal integration of rod signals in luminance and chromatic pathways. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2022; 39:1782-1793. [PMID: 36215550 DOI: 10.1364/josaa.462581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 08/13/2022] [Indexed: 06/16/2023]
Abstract
We assessed how rod excitation (R) affects luminance (L + M + S) and chromatic [L/(L + M)] reaction times (RTs). A four-primary display based on the overlapped images of two spectrally modified monitors, which allowed specific or combined [L + M + S + R, L/(L + M) + R] photoreceptor stimulation, was used to present a C-target stimulus differing from the background only by the selected stimulation. For the luminance pathway, rod input increased RTs, suggesting a suppressive rod-cone interaction. The responses of the chromatic pathway were faster when rods were involved, suggesting a major role of rods in mesopic color perception.
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Tripolone MC, Issolio LA, Agüero C, Lavaque A, Cao D, Barrionuevo PA. Comparing flickering and pulsed chromatic pupil light responses. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2022; 39:1505-1512. [PMID: 36215596 DOI: 10.1364/josaa.455619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 07/12/2022] [Indexed: 06/16/2023]
Abstract
The pupil light reflex (PLR) can serve as a biomarker of the photoreceptor function. Protocols for chromatic PLR consider mostly pulsed stimulation. A more sophisticated and promising technique is based on the PLR to flickering stimulation. Our aim was to compare flickering PLR (fPLR) and pulsed PLR (pPLR) parameters to validate the fPLR paradigm. Two different experiments were carried out in young participants to compare parameters of chromatic pupillary measurements under flickering and pulsed conditions. We found that the fPLR amplitude parameter was significantly associated with the pPLR transient constriction parameter. Also, for some conditions, pulse parameters can be identified directly in the fPLR recordings.
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Giménez MC, Stefani O, Cajochen C, Lang D, Deuring G, Schlangen LJM. Predicting melatonin suppression by light in humans: Unifying photoreceptor-based equivalent daylight illuminances, spectral composition, timing and duration of light exposure. J Pineal Res 2022; 72:e12786. [PMID: 34981572 PMCID: PMC9285453 DOI: 10.1111/jpi.12786] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 12/23/2022]
Abstract
Light-induced melatonin suppression data from 29 peer-reviewed publications was analysed by means of a machine-learning approach to establish which light exposure characteristics (ie photopic illuminance, five α-opic equivalent daylight illuminances [EDIs], duration and timing of the light exposure, and the dichotomous variables pharmacological pupil dilation and narrowband light source) are the main determinants of melatonin suppression. Melatonin suppression in the data set was dominated by four light exposure characteristics: (1) melanopic EDI, (2) light exposure duration, (3) pupil dilation and (4) S-cone-opic EDI. A logistic model was used to evaluate the influence of each of these parameters on the melatonin suppression response. The final logistic model was only based on the first three parameters, since melanopic EDI was the best single (photoreceptor) predictor that was only outperformed by S-cone-opic EDI for (photopic) illuminances below 21 lux. This confirms and extends findings on the importance of the metric melanopic EDI for predicting biological effects of light in integrative (human-centric) lighting applications. The model provides initial and general guidance to lighting practitioners on how to combine spectrum, duration and amount of light exposure when controlling non-visual responses to light, especially melatonin suppression. The model is a starting tool for developing hypotheses on photoreceptors' contributions to light's non-visual responses and helps identifying areas where more data are needed, like on the S-cone contribution at low illuminances.
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Affiliation(s)
- Marina C. Giménez
- Chronobiology UnitGroningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Oliver Stefani
- Centre for Chronobiology and Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN)Psychiatric Hospital of the University of Basel (UPK) and University of BaselBaselSwitzerland
| | - Christian Cajochen
- Centre for Chronobiology and Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN)Psychiatric Hospital of the University of Basel (UPK) and University of BaselBaselSwitzerland
| | | | - Gunnar Deuring
- Forensic DepartmentUniversity Psychiatric Clinics BaselBaselSwitzerland
| | - Luc J. M. Schlangen
- Department of Industrial Engineering and Innovation SciencesHuman‐Technology Interaction Group and Intelligent Lighting InstituteEindhoven University of TechnologyEindhovenThe Netherlands
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Zauner J, Plischke H, Strasburger H. Spectral dependency of the human pupillary light reflex. Influences of pre-adaptation and chronotype. PLoS One 2022; 17:e0253030. [PMID: 35020744 PMCID: PMC8754338 DOI: 10.1371/journal.pone.0253030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 10/30/2021] [Indexed: 11/23/2022] Open
Abstract
Non-visual photoreceptors (ipRGCs) and rods both exert a strong influence on the human pupil, yet pupil models regularly use cone-derived sensitivity as their basis. This inconsistency is further exacerbated by the fact that circadian effects can modulate the wavelength sensitivity. We assessed the pupillary reaction to narrowband light stimuli in the mesopic range. Pupil size for eighty-three healthy participants with normal color vision was measured in nine experimental protocols with varying series of continuous or discontinuous light stimuli under Ganzfeld conditions, presented after 90 seconds of dark adaptation. One hundred and fifty series of stimulation were conducted across three experiments, and were analyzed for wavelength-dependency on the normalized pupillary constriction (nPC), conditional on experimental settings and individual traits. Traits were surveyed by questionnaire; color vision was tested by Ishihara plates or the Lanthony D15 test. Data were analyzed with generalized additive mixed models (GAMM). The normalized pupillary constriction response is consistent with L+M-cone derived sensitivity when the series of light stimuli is continuous, i.e., is not interrupted by periods of darkness, but not otherwise. The results also show that a mesopic illuminance weighing led to an overall best prediction of pupillary constriction compared to other types of illuminance measures. IpRGC influence on nPC is not readily apparent from the results. When we explored the interaction of chronotype and time of day on the wavelength dependency, differences consistent with ipRGC influence became apparent. The models indicate that subjects of differing chronotype show a heightened or lowered sensitivity to short wavelengths, depending on their time of preference. IpRGC influence is also seen in the post-illumination pupil reflex if the prior light-stimulus duration is one second. However, shorter wavelengths than expected become more important if the light-stimulus duration is fifteen or thirty seconds. The influence of sex on nPC was present, but showed no interaction with wavelength. Our results help to define the conditions, under which the different wavelength sensitivities in the literature hold up for narrowband light settings. The chronotype effect might signify a mechanism for strengthening the individual´s chronotype. It could also be the result of the participant’s prior exposure to light (light history). Our explorative findings for this effect demand replication in a controlled study.
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Affiliation(s)
- Johannes Zauner
- Munich University of Applied Sciences, Munich, Germany
- * E-mail:
| | | | - Hans Strasburger
- Institute of Medical Psychology, Ludwig-Maximilians-Universität, Munich, Germany
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Wandell BA, Brainard DH, Cottaris NP. Visual encoding: Principles and software. PROGRESS IN BRAIN RESEARCH 2022; 273:199-229. [DOI: 10.1016/bs.pbr.2022.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Seeing and sensing temporal variations in natural daylight. PROGRESS IN BRAIN RESEARCH 2022; 273:275-301. [DOI: 10.1016/bs.pbr.2022.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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29
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Beyond irradiance: Visual signals influencing mammalian circadian function. PROGRESS IN BRAIN RESEARCH 2022; 273:145-169. [DOI: 10.1016/bs.pbr.2022.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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López de la Fuente C, Sánchez-Cano AI. Photometric and Colorimetric Evaluation of Phototherapy Instruments for Syntonic Treatment of Visual Anomalies. Optom Vis Sci 2021; 98:1355-1365. [PMID: 34743128 DOI: 10.1097/opx.0000000000001813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
SIGNIFICANCE Ocular light exposure therapy has been used in optometric therapies to improve binocular anomalies such as accommodative or vergence dysfunctions, amblyopia therapy or to increase the visual field. Currently, syntonic phototherapy is used worldwide by behavioral optometrists, vision trainers, or occupational therapists, among others, although these treatments are supported by only a few research studies that lack consensus on the efficacy of this approach. PURPOSE In this article, we highlight the optical characteristics of lamps without evaluating the efficacy of their use in optometric procedures. METHODS Our work analyzes four devices often used in clinical practice in terms of spectral power distribution, illuminance levels at the corneal plane, and both theoretical photopic and melanopic contributions to the visual system. RESULTS First, illuminance levels reaching the corneal plane depend on the characteristics of each lamp and their distance from where the eye should be positioned; for example, delta-theta filter photopic illuminance is 13.1, 93.7, 22.7, or 41.6 lux with the four evaluated devices. Second, filters or modes named the same differ in terms of their spectral power distribution. Third, substantial difference in color appearance has been found among the same configurations. CONCLUSIONS The spectral and iluminance characteristics of syntonic systems used for vision therapy vary widely, including variations among filters with the same identifying characteristics. This provides significant sources of variability, which limit the ability to conduct evidence-based medicine clinical trials to assess the true efficacy of syntonic therapy. This study furthers our knowledge of syntonic phototherapy from a technical perspective; however, longitudinal research examining patients' evolution pre-lighting and post-lighting treatments is required to justify and understand the effects of light exposure and its impact on optometric and ocular parameters more clearly.
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Zandi B, Stefani O, Herzog A, Schlangen LJM, Trinh QV, Khanh TQ. Optimising metameric spectra for integrative lighting to modulate the circadian system without affecting visual appearance. Sci Rep 2021; 11:23188. [PMID: 34848762 PMCID: PMC8633386 DOI: 10.1038/s41598-021-02136-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/10/2021] [Indexed: 01/15/2023] Open
Abstract
Smart integrative lighting systems aim to support human health and wellbeing by capitalising on the light-induced effects on circadian rhythms, sleep, and cognitive functions, while optimising the light's visual aspects like colour fidelity, visual comfort, visual preference, and visibility. Metameric spectral tuning could be an instrument to solve potential conflicts between the visual preferences of users with respect to illuminance and chromaticity and the circadian consequences of the light exposure, as metamers can selectively modulate melanopsin-based photoreception without affecting visual properties such as chromaticity or illuminance. This work uses a 6-, 8- and 11-channel LED luminaire with fixed illuminance of 250 lx to systematically investigate the metameric tuning range in melanopic equivalent daylight illuminance (EDI) and melanopic daylight efficacy ratio (melanopic DER) for 561 chromaticity coordinates as optimisation targets (2700 K to 7443 K ± Duv 0 to 0.048), while applying colour fidelity index Rf criteria from the TM-30-20 Annex E recommendations (i.e. Rf [Formula: see text] 85, Rf,h1 [Formula: see text] 85). Our results reveal that the melanopic tuning range increases with rising CCT to a maximum tuning range in melanopic DER of 0.24 (CCT: 6702 K, Duv: 0.003), 0.29 (CCT: 7443 K, Duv: 0) and 0.30 (CCT: 6702, Duv: 0.006), depending on the luminaire's channel number of 6, 8 or 11, respectively. This allows to vary the melanopic EDI from 212.5-227.5 lx up to 275-300 lx without changes in the photopic illuminance (250 lx) or chromaticity ([Formula: see text] [Formula: see text] 0.0014). The highest metameric melanopic Michelson contrast for the 6-, 8- and 11-channel luminaire is 0.16, 0.18 and 0.18, which is accomplished at a CCT of 3017 K (Duv: - 0.018), 3456 K (Duv: 0.009) and 3456 K (Duv: 0.009), respectively. By optimising ~ 490,000 multi-channel LED spectra, we identified chromaticity regions in the CIExy colour space that are of particular interest to control the melanopic efficacy with metameric spectral tuning.
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Affiliation(s)
- Babak Zandi
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, Darmstadt, Germany.
| | - Oliver Stefani
- Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN), Centre for Chronobiology, University of Basel, Basel, Switzerland
| | - Alexander Herzog
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, Darmstadt, Germany
| | - Luc J M Schlangen
- Department Human-Technology, Intelligent Lighting Institute, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Quang Vinh Trinh
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, Darmstadt, Germany
| | - Tran Quoc Khanh
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, Darmstadt, Germany
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Evéquoz G, Truffer F, Geiser M. Maximum possible contrast level for silent substitution: a theoretical model applied to melanopsin stimulation. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2021; 38:1312-1319. [PMID: 34613138 DOI: 10.1364/josaa.420373] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
For any given set of light sources stimulating the photoreceptors of the retina, the theoretical levels of illumination producing the smallest and the largest expression of one photoreceptor with fixed stimulation for the others are analytically computed. The cases of four, five, and more light sources are studied. We show that, for contrast optimization, only as many light sources as photoreceptors do matter and that, in the case of four light sources, the maximum contrast achievable for melanopsin lies at the intersection of the lines joining the sources in the CIE xy chromaticity diagram. This result is used to obtain the optimal position of four Gaussian primaries of equal bandwidth. In addition, we derive a procedure to construct level maps for melanopsin contrast overlying the diagram. In the second part of the paper, the interpersonal variability of the perceived stimulation is shown to be globally reduced if the bandwidth of the light sources is increased and, under some assumptions, if a light source is added.
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Brown TM, Thapan K, Arendt J, Revell VL, Skene DJ. S-cone contribution to the acute melatonin suppression response in humans. J Pineal Res 2021; 71:e12719. [PMID: 33512714 DOI: 10.1111/jpi.12719] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 01/06/2023]
Abstract
Light influences diverse aspects of human physiology and behaviour including neuroendocrine function, the circadian system and sleep. A role for melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) in driving such effects is well established. However, rod and/or cone signals routed through ipRGCs could also influence "non-visual" spectral sensitivity. In humans, this has been most extensively studied for acute, light-dependent, suppression of nocturnal melatonin production. Of the published action spectra for melatonin suppression, one demonstrates a spectral sensitivity consistent with that expected for melanopsin while our own (using briefer 30 minute light exposures) displays very high sensitivity to short wavelength light, suggesting a contribution of S-cones. To clarify that possibility, six healthy young male participants were each exposed to 30 minutes of five irradiances of 415 nm monochromatic light (1-40 µW/cm2 ) across different nights. These data were then combined with the original action spectrum. The aggregated data are incompatible with the involvement of any single-opsin and multi-opsin models based on the original action spectrum (including Circadian Stimulus) fail to predict the responses to 415 nm stimuli. Instead, the extended action spectrum can be most simply approximated by an ~2:1 combination of melanopsin and S-cone signals. Such a model also better describes the magnitude of melatonin suppression observed in other studies using an equivalent 30 minute mono- or polychromatic light paradigm but not those using longer (90 minute) light exposures. In sum, these data provide evidence for an initial S-cone contribution to melatonin suppression that rapidly decays under extended light exposure.
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Affiliation(s)
- Timothy M Brown
- Centre for Biological Timing, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Kavita Thapan
- Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Josephine Arendt
- Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Victoria L Revell
- Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XP, UK
| | - Debra J Skene
- Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
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Spitschan M, Garbazza C, Kohl S, Cajochen C. Sleep and circadian phenotype in people without cone-mediated vision: a case series of five CNGB3 and two CNGA3 patients. Brain Commun 2021; 3:fcab159. [PMID: 34447932 PMCID: PMC8385249 DOI: 10.1093/braincomms/fcab159] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2021] [Indexed: 01/28/2023] Open
Abstract
Light exposure entrains the circadian clock through the intrinsically photosensitive retinal ganglion cells, which sense light in addition to the cone and rod photoreceptors. In congenital achromatopsia (prevalence 1:30-50 000), the cone system is non-functional, resulting in severe light avoidance and photophobia at daytime light levels. How this condition affects circadian and neuroendocrine responses to light is not known. In this case series of genetically confirmed congenital achromatopsia patients (n = 7; age 30-72 years; 6 women, 1 male), we examined survey-assessed sleep/circadian phenotype, self-reported visual function, sensitivity to light and use of spectral filters that modify chronic light exposure. In all but one patient, we measured rest-activity cycles using actigraphy over 3 weeks and measured the melatonin phase angle of entrainment using the dim-light melatonin onset. Owing to their light sensitivity, congenital achromatopsia patients used filters to reduce retinal illumination. Thus, congenital achromatopsia patients experienced severely attenuated light exposure. In aggregate, we found a tendency to a late chronotype. We found regular rest-activity patterns in all patients and normal phase angles of entrainment in participants with a measurable dim-light melatonin onset. Our results reveal that a functional cone system and exposure to daytime light intensities are not necessary for regular behavioural and hormonal entrainment, even when survey-assessed sleep and circadian phenotype indicated a tendency for a late chronotype and sleep problems in our congenital achromatopsia cohort.
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Affiliation(s)
- Manuel Spitschan
- Department of Experimental Psychology, University of Oxford, Oxford, OX2 6GG, UK
- Centre for Chronobiology, Psychiatry Hospital of the University of Basel (UPK), CH-4002 Basel, Switzerland
- Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, CH-4055 Basel, Switzerland
| | - Corrado Garbazza
- Centre for Chronobiology, Psychiatry Hospital of the University of Basel (UPK), CH-4002 Basel, Switzerland
- Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, CH-4055 Basel, Switzerland
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, D-72076 Tübingen, Germany
| | - Christian Cajochen
- Centre for Chronobiology, Psychiatry Hospital of the University of Basel (UPK), CH-4002 Basel, Switzerland
- Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, CH-4055 Basel, Switzerland
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Spitschan M. Time-Varying Light Exposure in Chronobiology and Sleep Research Experiments. Front Neurol 2021; 12:654158. [PMID: 34335437 PMCID: PMC8319561 DOI: 10.3389/fneur.2021.654158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022] Open
Abstract
Light exposure profoundly affects human physiology and behavior through circadian and neuroendocrine photoreception primarily through the melanopsin-containing intrinsically photosensitive retinal ganglion cells. Recent research has explored the possibility of using temporally patterned stimuli to manipulate circadian and neuroendocrine responses to light. This mini-review, geared to chronobiologists, sleep researchers, and scientists in adjacent disciplines, has two objectives: (1) introduce basic concepts in time-varying stimuli and (2) provide a checklist-based set of recommendations for documenting time-varying light exposures based on current best practices and standards.
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Affiliation(s)
- Manuel Spitschan
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.,Centre for Chronobiology, Psychiatric Hospital of the University of Basel (UPK), Basel, Switzerland.,Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
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Uprety S, Zele AJ, Feigl B, Cao D, Adhikari P. Optimizing methods to isolate melanopsin-directed responses. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2021; 38:1051-1064. [PMID: 34263761 DOI: 10.1364/josaa.423343] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/01/2021] [Indexed: 06/13/2023]
Abstract
The intrinsic melanopsin photoresponse may initiate visual signals that differ in spatiotemporal characteristics from the cone-opsin- and rhodopsin-mediated signals. Applying the CIE standard observer functions in silent-substitution methods can require individual differences in photoreceptor spectral sensitivities and pre-receptoral filtering to be corrected; failure to do so can lead to the intrusion of more sensitive cone processes with putative melanopsin-directed stimuli. Here we evaluate heterochromatic flicker photometry (HFP) and photoreceptor-directed temporal white noise as techniques to limit the effect of these individual differences. Individualized luminous efficiency functions (V(λ)) were compared to the CIE standard observer functions. We show that adapting chromaticities used in silent-substitution methods can deviate by up to 54% in luminance when estimated with the individual and standard observer functions. These deviations lead to inadvertent cone intrusions in the visual functions measured with melanopsin-directed stimuli. To eliminate the intrusions, individual HFP corrections are sufficient at low frequencies (∼1Hz) but temporal white noise is also required at higher frequencies to desensitize penumbral cones. We therefore recommend the selective application of individualized observer calibration and/or temporal white noise in silent-substitution paradigms when studying melanopsin-directed photoresponses.
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Ali EN, Carle CF, Lueck CJ, Kolic M, Maddess T. Assessing migraine patients with multifocal pupillographic objective perimetry. BMC Neurol 2021; 21:211. [PMID: 34039302 PMCID: PMC8152334 DOI: 10.1186/s12883-021-02239-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 05/14/2021] [Indexed: 12/22/2022] Open
Abstract
Background To establish the effects of stimulating intrinsically-photosensitive retinal ganglion cells (ipRGCs) on migraine severity, and to determine if migraine produces objectively-measured visual field defects. Methods A randomized, open labelled, crossover study tested migraineurs and normal controls using multifocal pupillographic objective perimetry (mfPOP) with 44 test-regions/eye. A slow blue protocol (BP) stimulated ipRGCs, and a fast yellow protocol (YP) stimulated luminance channels. Migraine diaries assessed migraine severity. Per-region responses were analyzed according to response amplitude and time-to-peak. Results Thirty-eight migraineurs (42.0 ± 16.5 years, 23 females) and 24 normal controls (39.2 ± 15.2 years, 14 females) were tested. The proportion of subjects developing a migraine did not differ after either protocol, either during the 1st day (odds ratio 1.0; 95% confidence interval 0.2–4.4, p = 0.48) or during the first 3 days after testing (odds ratio 0.8; 95% confidence interval 0.3–2.1, p = 0.68). Migraine days/week did not increase following testing with either protocol in comparison to the baseline week (1.4 ± 1.6 pre-testing (mean ± SD), 1.3 ± 1.4 post-BP, and 1.3 ± 1.2 post-YP; p = 0.96), neither did other measures of severity. Migraine occurring up to 2 weeks before testing significantly lowered amplitudes, − 0.64 ± 0.14 dB (mean ± SE), while triptan use increased amplitudes by 0.45 ± 0.10 dB, both at p < 0.001. Conclusions Stimulating ipRGCs did not affect migraine occurrence or severity. Pupillary response characteristics were influenced by the occurrence of a recent migraine attack and a history of triptan use.
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Affiliation(s)
- Eman N Ali
- Eccles Institute of Neuroscience, the John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia.,Department of Neuroscience, King Fahad Specialist Hospital, Dammam, Saudi Arabia
| | - Corinne F Carle
- Eccles Institute of Neuroscience, the John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia
| | - Christian J Lueck
- Australian National University Medical School, Acton, ACT, Australia.,Department of Neurology, The Canberra Hospital, Canberra, ACT, Australia
| | - Maria Kolic
- Eccles Institute of Neuroscience, the John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia
| | - Ted Maddess
- Eccles Institute of Neuroscience, the John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia.
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Mure LS. Intrinsically Photosensitive Retinal Ganglion Cells of the Human Retina. Front Neurol 2021; 12:636330. [PMID: 33841306 PMCID: PMC8027232 DOI: 10.3389/fneur.2021.636330] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 02/15/2021] [Indexed: 12/12/2022] Open
Abstract
Light profoundly affects our mental and physical health. In particular, light, when not delivered at the appropriate time, may have detrimental effects. In mammals, light is perceived not only by rods and cones but also by a subset of retinal ganglion cells that express the photopigment melanopsin that renders them intrinsically photosensitive (ipRGCs). ipRGCs participate in contrast detection and play critical roles in non-image-forming vision, a set of light responses that include circadian entrainment, pupillary light reflex (PLR), and the modulation of sleep/alertness, and mood. ipRGCs are also found in the human retina, and their response to light has been characterized indirectly through the suppression of nocturnal melatonin and PLR. However, until recently, human ipRGCs had rarely been investigated directly. This gap is progressively being filled as, over the last years, an increasing number of studies provided descriptions of their morphology, responses to light, and gene expression. Here, I review the progress in our knowledge of human ipRGCs, in particular, the different morphological and functional subtypes described so far and how they match the murine subtypes. I also highlight questions that remain to be addressed. Investigating ipRGCs is critical as these few cells play a major role in our well-being. Additionally, as ipRGCs display increased vulnerability or resilience to certain disorders compared to conventional RGCs, a deeper knowledge of their function could help identify therapeutic approaches or develop diagnostic tools. Overall, a better understanding of how light is perceived by the human eye will help deliver precise light usage recommendations and implement light-based therapeutic interventions to improve cognitive performance, mood, and life quality.
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Affiliation(s)
- Ludovic S Mure
- Institute of Physiology, University of Bern, Bern, Switzerland.,Department of Neurology, Zentrum für Experimentelle Neurologie, Inselspital University Hospital Bern, Bern, Switzerland
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Hazelhoff EM, Dudink J, Meijer JH, Kervezee L. Beginning to See the Light: Lessons Learned From the Development of the Circadian System for Optimizing Light Conditions in the Neonatal Intensive Care Unit. Front Neurosci 2021; 15:634034. [PMID: 33815040 PMCID: PMC8013699 DOI: 10.3389/fnins.2021.634034] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/19/2021] [Indexed: 11/13/2022] Open
Abstract
The circadian timing system optimizes health by temporally coordinating behavior and physiology. During mammalian gestation, fetal circadian rhythms are synchronized by the daily fluctuations in maternal body temperature, hormones and nutrients. Circadian disruption during pregnancy is associated with negative effects on developmental outcomes in the offspring, highlighting the importance of regular and robust 24-h rhythms over gestation. In the case of preterm birth (before 37 weeks of gestation), maternal cues no longer synchronize the neonate's circadian system, which may adversely affect the neonate. There is increasing evidence that introducing robust light-dark cycles in the Neonatal Intensive Care Unit has beneficial effects on clinical outcomes in preterm infants, such as weight gain and hospitalization time, compared to infants exposed to constant light or constant near-darkness. However, the biological basis for these effects and the relationship with the functional and anatomical development of the circadian system is not fully understood. In this review, we provide a concise overview of the effects of light-dark cycles on clinical outcomes of preterm neonates in the NICU and its alignment with the development of the circadian system.
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Affiliation(s)
- Esther M. Hazelhoff
- Laboratory for Neurophysiology, Department of Cellular and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Jeroen Dudink
- Department of Neonatology, Wilhelmina Children’s Hospital and Brain Centre Rudolf Magnus, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Johanna H. Meijer
- Laboratory for Neurophysiology, Department of Cellular and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Laura Kervezee
- Laboratory for Neurophysiology, Department of Cellular and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
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Comment Concerning the Effects of Light Intensity on Melatonin Suppression in the Review "Light Modulation of Human Clocks, Wake, and Sleep" by A. Prayag et al. Clocks Sleep 2021; 3:181-188. [PMID: 33578834 PMCID: PMC7931082 DOI: 10.3390/clockssleep3010011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/18/2020] [Indexed: 11/17/2022] Open
Abstract
Dose-response curves for circadian phase shift and melatonin suppression in relation to white or monochromatic nighttime illumination can be scaled to melanopic weighed illumination for normally constricted pupils, which makes them easier to interpret and compare. This is helpful for a practical applications.
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Houser KW, Esposito T. Human-Centric Lighting: Foundational Considerations and a Five-Step Design Process. Front Neurol 2021; 12:630553. [PMID: 33584531 PMCID: PMC7873560 DOI: 10.3389/fneur.2021.630553] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/06/2021] [Indexed: 12/22/2022] Open
Abstract
At its best, human-centric lighting considers the visual and non-visual effects of light in support of positive human outcomes. At its worst, it is a marketing phrase used to healthwash lighting products or lighting design solutions. There is no doubt that environmental lighting contributes to human health, but how might one practice human-centric lighting given both the credible potential and the implausible hype? Marketing literature is filled with promises. Technical lighting societies have summarized the science but have not yet offered design guidance. Meanwhile, designers are in the middle, attempting to distinguish credible knowledge from that which is dubious to make design decisions that affect people directly. This article is intended to: (1) empower the reader with fundamental understandings of ways in which light affects health; (2) provide a process for human-centric lighting design that can dovetail with the decision-making process that is already a part of a designer's workflow.
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Affiliation(s)
- Kevin W. Houser
- School of Civil and Construction Engineering, Oregon State University, Corvallis, OR, United States
- Advanced Lighting Team, Pacific Northwest National Laboratory, Portland, OR, United States
| | - Tony Esposito
- Lighting Research Solutions LLC, Cambridge, MA, United States
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Melanopic Limits of Metamer Spectral Optimisation in Multi-Channel Smart Lighting Systems. ENERGIES 2021. [DOI: 10.3390/en14030527] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Modern indoor lighting faces the challenge of finding an appropriate balance between energy consumption, legal requirements, visual performance, and the circadian effectiveness of a spectrum. Multi-channel LED luminaires have the option of keeping image-forming metrics steady while varying the melanopic radiance through metamer spectra for non-visual purposes. Here, we propose the theoretical concept of an automated smart lighting system that is designed to satisfy the user’s visual preference through neural networks while triggering the non-visual pathway via metamers. To quantify the melanopic limits of metamers at a steady chromaticity point, we have used 561 chromaticity coordinates along the Planckian locus (2700 K to 7443 K, ±Duv 0 to 0.048) as optimisation targets and generated the spectra by using a 6-channel, 8-channel, and 11-channel LED combination at three different luminance levels. We have found that in a best-case scenario, the melanopic radiance can be varied up to 65% while keeping the chromaticity coordinates constant (Δu′v′≤7.05×10−5) by using metamer spectra. The highest melanopic metamer contrast can be reached near the Planckian locus between 3292 and 4717 K within a Duv range of −0.009 to 0.006. Additionally, we publish over 1.2 million optimised spectra generated by multichannel LED luminaires as an open-source dataset along with this work.
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Zandi B, Khanh TQ. Deep learning-based pupil model predicts time and spectral dependent light responses. Sci Rep 2021; 11:841. [PMID: 33436693 PMCID: PMC7803766 DOI: 10.1038/s41598-020-79908-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/11/2020] [Indexed: 01/29/2023] Open
Abstract
Although research has made significant findings in the neurophysiological process behind the pupillary light reflex, the temporal prediction of the pupil diameter triggered by polychromatic or chromatic stimulus spectra is still not possible. State of the art pupil models rested in estimating a static diameter at the equilibrium-state for spectra along the Planckian locus. Neither the temporal receptor-weighting nor the spectral-dependent adaptation behaviour of the afferent pupil control path is mapped in such functions. Here we propose a deep learning-driven concept of a pupil model, which reconstructs the pupil's time course either from photometric and colourimetric or receptor-based stimulus quantities. By merging feed-forward neural networks with a biomechanical differential equation, we predict the temporal pupil light response with a mean absolute error below 0.1 mm from polychromatic (2007 [Formula: see text] 1 K, 4983 [Formula: see text] 3 K, 10,138 [Formula: see text] 22 K) and chromatic spectra (450 nm, 530 nm, 610 nm, 660 nm) at 100.01 ± 0.25 cd/m2. This non-parametric and self-learning concept could open the door to a generalized description of the pupil behaviour.
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Affiliation(s)
- Babak Zandi
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, 64289, Darmstadt, Germany.
| | - Tran Quoc Khanh
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, 64289, Darmstadt, Germany
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Abstract
Melanopsin retinal ganglion cells (mRGCs) are the third class of retinal photoreceptors with unique anatomical, electrophysiological, and biological features. There are different mRGC subtypes with differential projections to the brain. These cells contribute to many nonimage-forming functions of the eye, the most relevant being the photoentrainment of circadian rhythms through the projections to the suprachiasmatic nucleus of the hypothalamus. Other relevant biological functions include the regulation of the pupillary light reflex, mood, alertness, and sleep, as well as a possible role in formed vision. The relevance of the mRGC-related pathways in the brain is highlighted by the role that the dysfunction and/or loss of these cells may play in affecting circadian rhythms and sleep in many neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's disease and in aging. Moreover, the occurrence of circadian dysfunction is a known risk factor for dementia. In this chapter, the anatomy, physiology, and functions of these cells as well as their resistance to neurodegeneration in mitochondrial optic neuropathies or their predilection to be lost in other neurodegenerative disorders will be discussed.
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Abstract
One way to study the specific response of the non-visual melanopsin photoreceptors of the human eye is to silence the response of cones and rods. Melanopsin photoreceptors (ipRGC), highlighted in the early 2000s, are intimately linked to the circadian rhythm and therefore to our sleep and wakefulness. Rest and sleep regulation, health and cognitive functions are all linked to ipRGC and play an important role in work and human relationships. Thus, we believe that the study of ipRGC responses is important.We searched and reviewed scientific articles describing instrumentation dedicated to these studies. PubMed lists more than 90,000 articles created since the year 2000 that contain the word circadian but only 252 with silent substitution. In relation to melanopsin, we found 39 relevant articles from which only 11 give a device description for humans, which is incomplete in most cases. We did not find any consensus for light intensity description, melanopsin contrast, sequences of melanopsin light stimulation and optical setup to expose the retina to the light.
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Electrochromic selective filtering of chronodisruptive visible wavelengths. PLoS One 2020; 15:e0241900. [PMID: 33152042 PMCID: PMC7643985 DOI: 10.1371/journal.pone.0241900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 10/22/2020] [Indexed: 01/20/2023] Open
Abstract
We present evidence of pupil response modification, as well as differential theoretical melatonin suppression through selective and dynamic electrochromic filtering of visible light in the 400-500 nm range to minimize chronodisruptive nocturnal blue light exposure. A lower activation of intrinsically photosensitive retinal ganglion cells (ipRGCs), the first step for light to reach a human's internal clock, is related to melatonin secretion therefore avoiding detrimental effects of excessive blue light exposure. Pupillary Light Reflex and Color Naming were experimentally assessed under light filtered by two different coloration states (transmissive and absorptive) of these novel dynamic filters, plus an uncoated test device, in 16 volunteers. Also, different commercial light sources at illuminances ranging from 1 to 1000 lux were differentially filtered and compared in terms of theoretical melatonin suppression. Representative parameters of the pupil responses reflected lower pupil constriction when the electrochromic filters (ECFs) were switched on (absorptive state, blue light is absorbed by the filter) compared to uncoated filters (control sample), but failed to do so under transmissive state (blue light passes through the filter) indicating less activation of ipRGCs under absorptive state (although no significant differences between states was found). Out of eight colors tested, just one showed significant differences in naming between both filter states. Thus, the ECF would have some protecting effect on ipRGC activation with very limited changes in color perception. While there are some limitations of the theoretical model used, the absorptive state yielded significantly lower theoretical melatonin suppression in all those light sources containing blue wavelengths across the illuminance range tested. This would open the way for further research on biological applications of electrochromic devices.
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Mutti DO, Mulvihill SP, Orr DJ, Shorter PD, Hartwick ATE. The Effect of Refractive Error on Melanopsin-Driven Pupillary Responses. Invest Ophthalmol Vis Sci 2020; 61:22. [PMID: 33091116 PMCID: PMC7594593 DOI: 10.1167/iovs.61.12.22] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Human and animal studies suggest that light-mediated dopamine release may underlie the protective effect of time outdoors on myopia development. Melanopsin-containing retinal ganglion cells may be involved in this process by integrating ambient light exposure and regulating retinal dopamine levels. The study evaluates this potential involvement by examining whether melanopsin-driven pupillary responses are associated with adult refractive error. Methods Subjects were 45 young adults (73% female, 24.1 ± 1.8 years) with refractive errors ranging from –6.33 D to +1.70 D. The RAPDx (Konan Medical) pupillometer measured normalized pupillary responses to three forms of square-wave light pulses alternating with darkness at 0.1 Hz: alternating long wavelength (red, peak at 608 nm) and short wavelength (blue, peak at 448 nm), followed by red only and then blue only. Results Non-myopic subjects displayed greater pupillary constriction in the blue-only condition and slower redilation following blue light offset than subjects with myopia (P = 0.011). Pupillary responses were not significantly different between myopic and non-myopic subjects in the red-only condition (P = 0.15). More hyperopic/less myopic refractive error as a continuous variable was linearly related to larger increases in pupillary constriction in response to blue-only stimuli (r = 0.48, P = 0.001). Conclusions Repeated light exposures to blue test stimuli resulted in an adaptation in the pupillary response (more constriction and slower redilation), presumably due to increased melanopsin-mediated input in more hyperopic/less myopic adults. This adaptive property supports a possible role for these ganglion cells in the protective effects of time outdoors on myopia development.
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Affiliation(s)
- Donald O Mutti
- The Ohio State University College of Optometry, Columbus, Ohio, United States
| | | | - Danielle J Orr
- The Ohio State University College of Optometry, Columbus, Ohio, United States
| | - Patrick D Shorter
- Optical Radiation Bioeffects Branch, Tri-Service Research Laboratory, Fort Sam Houston, Texas, United States
| | - Andrew T E Hartwick
- The Ohio State University College of Optometry, Columbus, Ohio, United States
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Mouland JW, Martial F, Watson A, Lucas RJ, Brown TM. Cones Support Alignment to an Inconsistent World by Suppressing Mouse Circadian Responses to the Blue Colors Associated with Twilight. Curr Biol 2020; 29:4260-4267.e4. [PMID: 31846668 PMCID: PMC6926481 DOI: 10.1016/j.cub.2019.10.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/19/2019] [Accepted: 10/16/2019] [Indexed: 01/04/2023]
Abstract
In humans, short-wavelength light evokes larger circadian responses than longer wavelengths [1-3]. This reflects the fact that melanopsin, a key contributor to circadian assessments of light intensity, most efficiently captures photons around 480 nm [4-8] and gives rise to the popular view that "blue" light exerts the strongest effects on the clock. However, in the natural world, there is often no direct correlation between perceived color (as reported by the cone-based visual system) and melanopsin excitation. Accordingly, although the mammalian clock does receive cone-based chromatic signals [9], the influence of color on circadian responses to light remains unclear. Here, we define the nature and functional significance of chromatic influences on the mouse circadian system. Using polychromatic lighting and mice with altered cone spectral sensitivity (Opn1mwR), we generate conditions that differ in color (i.e., ratio of L- to S-cone opsin activation) while providing identical melanopsin and rod activation. When biased toward S-opsin activation (appearing "blue"), these stimuli reliably produce weaker circadian behavioral responses than those favoring L-opsin ("yellow"). This influence of color (which is absent in animals lacking cone phototransduction; Cnga3-/-) aligns with natural changes in spectral composition over twilight, where decreasing solar angle is accompanied by a strong blue shift [9-11]. Accordingly, we find that naturalistic color changes support circadian alignment when environmental conditions render diurnal variations in light intensity weak/ambiguous sources of timing information. Our data thus establish how color contributes to circadian entrainment in mammals and provide important new insight to inform the design of lighting environments that benefit health.
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Affiliation(s)
- Joshua W Mouland
- Centre for Biological Timing, Faculty of Biology, Medicine & Health, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Franck Martial
- Centre for Biological Timing, Faculty of Biology, Medicine & Health, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Alex Watson
- Centre for Biological Timing, Faculty of Biology, Medicine & Health, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Robert J Lucas
- Centre for Biological Timing, Faculty of Biology, Medicine & Health, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Timothy M Brown
- Centre for Biological Timing, Faculty of Biology, Medicine & Health, University of Manchester, Oxford Road, Manchester M13 9PT, UK.
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Brown TM. Melanopic illuminance defines the magnitude of human circadian light responses under a wide range of conditions. J Pineal Res 2020; 69:e12655. [PMID: 32248548 DOI: 10.1111/jpi.12655] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/28/2020] [Accepted: 03/27/2020] [Indexed: 12/18/2022]
Abstract
Ocular light drives a range of nonvisual responses in humans including suppression of melatonin secretion and circadian phase resetting. These responses are driven by intrinsically photosensitive retinal ganglion cells (ipRGCs) which combine intrinsic, melanopsin-based, phototransduction with extrinsic rod/cone-mediated signals. As a result of this arrangement, it has remained unclear how best to quantify light to predict its nonvisual effects. To address this, we analysed data from nineteen different laboratory studies that measured melatonin suppression, circadian phase resetting and/or alerting responses in humans to a wide array of stimulus types, intensities and durations with or without pupil dilation. Using newly established SI-compliant metrics to quantify ipRGC-influenced responses to light, we show that melanopic illuminance consistently provides the best available predictor for responses of the human circadian system. In almost all cases, melanopic illuminance is able to fully account for differences in sensitivity to stimuli of varying spectral composition, acting to drive responses that track variations in illumination characteristic of those encountered over civil twilight (~1-1000 lux melanopic equivalent daylight illuminance). Collectively, our data demonstrate widespread utility of melanopic illuminance as a metric for predicting the circadian impact of environmental illumination. These data therefore provide strong support for the use of melanopic illuminance as the basis for guidelines that seek to regulate light exposure to benefit human health and to inform future lighting design.
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Affiliation(s)
- Timothy M Brown
- Centre for Biological Timing, Faculty of Medicine, Biology and Health, University of Manchester, Manchester, UK
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50
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McAdams H, Kaiser EA, Igdalova A, Haggerty EB, Cucchiara B, Brainard DH, Aguirre GK. Selective amplification of ipRGC signals accounts for interictal photophobia in migraine. Proc Natl Acad Sci U S A 2020; 117:17320-17329. [PMID: 32632006 PMCID: PMC7382295 DOI: 10.1073/pnas.2007402117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Second only to headache, photophobia is the most debilitating symptom reported by people with migraine. While the melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) are thought to play a role, how cone and melanopsin signals are integrated in this pathway to produce visual discomfort is poorly understood. We studied 60 people: 20 without headache and 20 each with interictal photophobia from migraine with or without visual aura. Participants viewed pulses of spectral change that selectively targeted melanopsin, the cones, or both and rated the degree of visual discomfort produced by these stimuli while we recorded pupil responses. We examined the data within a model that describes how cone and melanopsin signals are weighted and combined at the level of the retina and how this combined signal is transformed into a rating of discomfort or pupil response. Our results indicate that people with migraine do not differ from headache-free controls in the manner in which melanopsin and cone signals are combined. Instead, people with migraine demonstrate an enhanced response to integrated ipRGC signals for discomfort. This effect of migraine is selective for ratings of visual discomfort, in that an enhancement of pupil responses was not seen in the migraine group, nor were group differences found in surveys of other behaviors putatively linked to ipRGC function (chronotype, seasonal sensitivity, presence of a photic sneeze reflex). By revealing a dissociation in the amplification of discomfort vs. pupil response, our findings suggest a postretinal alteration in processing of ipRGC signals for photophobia in migraine.
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Affiliation(s)
- Harrison McAdams
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Eric A Kaiser
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Aleksandra Igdalova
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Edda B Haggerty
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Brett Cucchiara
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - David H Brainard
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104
| | - Geoffrey K Aguirre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104;
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