Standards in Pupillography

Frontiers in Neurology, Год журнала: 2019, Номер 10

Опубликована: Фев. 21, 2019

The number of research groups studying the pupil is increasing, as publications. Consequently, new standards in pupillography are needed to formalize methodology including recording conditions, stimulus characteristics, well suitable parameters evaluation. Since description intrinsically photosensitive retinal ganglion cells (ipRGCs) there has been an increased interest and broader application ophthalmology other fields psychology chronobiology. Colour plays important role not only but also clinical observational therapy studies like gene hereditary degenerations psychopathology. Stimuli can vary size, brightness, duration, wavelength. Stimulus paradigms determine whether rhodopsin-driven rod responses, opsin-driven cone or melanopsin-driven ipRGC responses primarily elicited. Background illumination, adaptation state, instruction for participants will furthermore influence results. This standard recommends a minimum set variables be used specified publication methodologies. Initiated at 32nd International Pupil Colloquium 2017 Morges, Switzerland, aim this manuscript outline based on current knowledge experience experts order achieve greater comparability pupillographic studies. Such particularly facilitate proper by researchers field. First we describe general standards, followed specific suggestions concerning demands different targets research: afferent efferent reflex arc, pharmacology, psychology, sleepiness-related animal

Язык: Английский

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Intrinsically Photosensitive Retinal Ganglion Cells of the Human Retina

Frontiers in Neurology, Год журнала: 2021, Номер 12

Опубликована: Март 25, 2021

Light profoundly affects our mental and physical health. In particular, light, when not delivered at the appropriate time, may have detrimental effects. mammals, light is perceived only by rods cones but also a subset of retinal ganglion cells that express photopigment melanopsin renders them intrinsically photosensitive (ipRGCs). ipRGCs participate in contrast detection play critical roles non-image-forming vision, set responses include circadian entrainment, pupillary reflex (PLR), modulation sleep/alertness, mood. are found human retina, their response to has been characterized indirectly through suppression nocturnal melatonin PLR. However, until recently, had rarely investigated directly. This gap progressively being filled as, over last years, an increasing number studies provided descriptions morphology, gene expression. Here, I review progress knowledge ipRGCs, different morphological functional subtypes described so far how they match murine subtypes. highlight questions remain be addressed. Investigating as these few major role well-being. Additionally, display increased vulnerability or resilience certain disorders compared conventional RGCs, deeper function could help identify therapeutic approaches develop diagnostic tools. Overall, better understanding eye will deliver precise usage recommendations implement light-based interventions improve cognitive performance, mood, life quality.

Язык: Английский

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Light-Induced Pupillary Responses in Alzheimer's Disease

Frontiers in Neurology, Год журнала: 2019, Номер 10

Опубликована: Апрель 12, 2019

The impact of Alzheimer's disease (AD) on the pupillary light response (PLR) is controversial, being dependent stage and experimental pupillometric protocols. main hypothesis driving pupillometry research in AD based concept that AD-related neurodegeneration affects both parasympathetic sympathetic arms PLR (cholinergic noradrenergic theory), combined with additional alterations afferent limb, involving melanopsin expressing retinal ganglion cells (mRGCs), subserving PLR. Only a few studies have evaluated value as potential biomarker AD, providing various results compatible dysfunction, displaying increased latency constriction to light, decreased amplitude, faster redilation after offset, maximum velocity (MCV) acceleration (MCA) compared controls. Decreased MCV MCA appeared be most accurate all parameters allowing differentiation between healthy controls while post-illumination was consistent feature, however, these could not replicated by more recent studies, focusing early pre-clinical stages disease. Whether static or dynamic yields useful biomarkers for screening diagnosis remains unclear. In this review, we synopsize current knowledge features other neurodegenerative diseases, discuss roles detection, monitoring, alone combination biomarkers.

Язык: Английский

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Chromatic Pupillometry Methods for Assessing Photoreceptor Health in Retinal and Optic Nerve Diseases

Frontiers in Neurology, Год журнала: 2019, Номер 10

Опубликована: Фев. 12, 2019

The pupillary light reflex is mediated by melanopsin-containing intrinsically-photosensitive retinal ganglion cells (ipRGCs), which also receive input from rods and cones. Melanopsin-dependent responses are short-wavelength sensitive, have a higher threshold of activation, much slower to activate de-activate compared with rod/cone-mediated responses. Given that rod/cone photoreceptors melanopsin differ in their response properties, stimuli can be designed stimulate preferentially each the different photoreceptor types, providing read-out function. This has given rise chromatic pupillometry methods aim assess health outer ipRGCs measuring blue or red stimuli. Here, we review types protocols been tested patients optic nerve disease, including approaches use short-duration exposures continuous exposure light. Across protocols, disease (e.g., retinitis pigmentosa Leber congenital amaurosis) show reduced absent dim blue-light used rod function, moderately-bright red-light cone By comparison, glaucoma ischemic neuropathy, but not mitochondrial disease) impaired during bright stimuli, post-illumination after offset, These proof-of-concept studies demonstrate damage ipRGCs. In future studies, it will important determine whether for screening early detection diseases. Such may prove useful objectively evaluating degree recovery ipRGC function blind who undergo gene therapy other treatments restore vision.

Язык: Английский

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Photoreceptor contributions to the human pupil light reflex

Journal of Photochemistry and Photobiology, Год журнала: 2023, Номер 15, С. 100178 - 100178

Опубликована: Апрель 2, 2023

The pupil reacts to the amount of light reaching eye. It reduces its size when is high and dilates at low levels allow entrance more photons. This behavior called reflex (PLR). Recent investigations in humans were conducted understand how photoreceptor signals are combined drive reflex. review about physiological processes that govern humans. In particular, cone-opsins, rhodopsin, melanopsin photoreception contribute governing PLR. We also summarize on assessment PLR clinical settings.

Язык: Английский

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Melanopsin Retinal Ganglion Cells and Pupil: Clinical Implications for Neuro-Ophthalmology

Frontiers in Neurology, Год журнала: 2018, Номер 9

Опубликована: Дек. 7, 2018

Melanopsin retinal ganglion cells (mRGCs) are intrinsically photosensitive RGCs that mediate many relevant non-image forming functions of the eye, including pupillary light reflex, through projections to olivary pretectal nucleus. In particular, post-illumination pupil response (PIPR), as evaluated by chromatic pupillometry, can be used a reliable marker mRGC function in vivo. last years, pupillometry has become promising tool assess dysfunction various neurological and neuro-ophthalmological conditions. this review we will present most findings pupillometric studies conditionsincluding hereditary optic neuropathies, glaucoma, ischemic idiopathic intracranial hypertension, multiple sclerosis Parkinson's disease. The use PIPR for is also proposed other neurodegenerative disorders which circadian documented.

Язык: Английский

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Artificial intelligence and deep learning in glaucoma: Current state and future prospects

Progress in brain research, Год журнала: 2020, Номер unknown, С. 37 - 64

Опубликована: Янв. 1, 2020

Язык: Английский

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Pupillary light reflex as a diagnostic aid from computational viewpoint: A systematic literature review

Journal of Biomedical Informatics, Год журнала: 2021, Номер 117, С. 103757 - 103757

Опубликована: Апрель 4, 2021

Язык: Английский

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Melanopsin photoreception differentially modulates rod-mediated and cone-mediated human temporal vision

iScience, Год журнала: 2022, Номер 25(7), С. 104529 - 104529

Опубликована: Июнь 3, 2022

To evaluate the nature of interactions between visual pathways transmitting slower melanopsin and faster rod cone signals, we implement a temporal phase summation paradigm in human observers using photoreceptor-directed stimuli. We show that stimulation interacts with alters both rod-mediated cone-mediated vision regardless whether it is perceptually visible or not. Melanopsin-rod result either inhibitory facilitatory depending on frequency photoreceptor pathway contrast sensitivity. Moreover, by isolating vision, reveal bipartite intensity response property photopic lighting extends its operational range at lower frequencies to beyond classic saturation limits but expense attenuating sensitivity higher frequencies. In comparison, melanopsin-cone always lead facilitation. These can be described linear probability summations potentially involve multiple intraretinal cortical set

Язык: Английский

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Retinal neural dysfunction in diabetes revealed with handheld chromatic pupillometry

Clinical and Experimental Ophthalmology, Год журнала: 2022, Номер 50(7), С. 745 - 756

Опубликована: Май 26, 2022

To evaluate the ability of handheld chromatic pupillometry to reveal and localise retinal neural dysfunction in diabetic patients with without retinopathy (DR).This cross-sectional study included 82 diabetics (DM) 93 controls (60.4 ± 8.4 years, 44.1% males). DM those (n = 25, 64.7 6.3 44.0% males) DR 57, 60.3 8.5 64.9% Changes horizontal pupil radius response blue (469 nm) red (640 light stimuli were assessed monocularly, clinics, using a custom-built pupillometer. Pupillometric parameters (phasic constriction amplitudes [predominantly from outer retina], maximal [from inner retina] post-illumination pupillary responses [PIPRs; predominantly retina]) extracted baseline-adjusted traces compared between controls, DR, DR. Net PIPR was defined as difference PIPRs.Phasic lights decreased (p < 0.001; p 0.001). Maximal 0.02), 0.005). both 0.02; 0.03), suggesting wavelength-dependent (and hence retinal) pupillometric or DR.Handheld can diabetes, even Patients but no displayed primarily dysfunction, while showed dysfunction.

Язык: Английский

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