Intrinsically photosensitive retinal ganglion cells (ipRGC) signal environmental light level to the central circadian clock and contribute pupil reflex. It is unknown if ipRGC activity subject extrinsic (central) or intrinsic (retinal) network-mediated modulation during entrainment phase shifting. Eleven younger persons (18–30 years) with no ophthalmological, medical sleep disorders participated. The of inner outer retina (cone photoreceptors) was assessed hourly using reflex a 24 h period...

To determine whether glaucoma alters intrinsically photosensitive retinal ganglion cell (ipRGC) function.Forty-one patients (25 with and 16 healthy age-matched control participants) were tested. Intrinsically function was directly measured by the sustained, postillumination pupil response (PIPR). Forty-one eyes of 41 participants tested 7°, 10-second, short-wavelength (488 nm; bluish) long-wavelength (610 reddish) stimuli (14.2 log photons · cm(-2) s(-1)) presented to right eye in Maxwellian...

Purpose.: The post-illumination pupil response (PIPR) has been quantified using four metrics, but the spectral sensitivity of only one is known; here we determine other three. To optimize human PIPR measurement, protocol producing largest PIPR, duration and metric(s) with lowest coefficient variation. Methods.: consensual light reflex (PLR) was measured a Maxwellian view pupillometer. Experiment 1: Spectral metrics (plateau, 6 seconds, area under curve early late recovery) determined from...

This study investigates the clinical utility of melanopsin-expressing intrinsically photosensitive retinal ganglion cell (ipRGC) controlled post-illumination pupil response (PIPR) as a novel technique for documenting inner function in patients with Type II diabetes without diabetic retinopathy.The PIPR was measured seven diabetes, normal nerve fibre thickness and no retinopathy compared to healthy age-similar controls. A 488- 610-nm, 7.15-diameter stimulus presented Maxwellian view right eye...

Abstract The visual consequences of melanopsin photoreception in humans are not well understood. Here we studied using a technique photoreceptor silent substitution with five calibrated spectral lights after minimising the effects individual differences optical pre-receptoral filtering and desensitising penumbral cones shadow retinal blood vessels. We demonstrate that putative melanopsin-mediated image-forming vision corresponds to an opponent S-OFF L + M-ON response property, average...

We determined the contributions of cone and melanopsin luminance signaling to human brightness perception. The absolute four narrowband primary lights presented in a full-field Ganzfeld was estimated two conditions, either luminance-equated (186.7−1,867.0 cd·m−2) or (31.6−316.3 cd·m−2). show that estimations for each light follow an approximately linear increase with increasing (in log units), but are not equivalent equated luminance. Instead, result from combined interaction between...

BackgroundNew non-pharmacological treatments for improving non-motor symptoms in Parkinson's disease (PD) are urgently needed. Previous light therapies modifying sleep behaviour lacked standardised protocols and were not personalised an individual patient chronotype. We aimed to assess the efficacy of a biologically-directed therapy PD that targets retinal inputs circadian system on sleep, as well other motor functions.MethodsIn this randomised, double-blind, parallel-group,...

Abstract It is difficult to detect visual function deficits in patients at risk for glaucoma (glaucoma suspects) and early disease stages with conventional ophthalmic tests such as perimetry. To this end, we introduce a novel quadrant field measure of the melanopsin retinal ganglion cell mediated pupil light response corresponding typical glaucomatous arcuate defects. The melanopsin-mediated post-illumination (PIPR) was measured 46 different including suspects compared healthy group 21...

Abstract Melanopsin containing intrinsically photosensitive Retinal Ganglion cells (ipRGCs) mediate the pupil light reflex (PLR) during onset and at offset (the post-illumination response, PIPR). Recent evidence shows that PLR PIPR can provide non-invasive, objective markers of age-related retinal optic nerve disease; however there is no consensus on effects healthy ageing or refractive error ipRGC mediated function. Here we isolated melanopsin contributions to control pathway in 59 human...

Abstract Parkinson’s disease (PD) is characterised by non-motor symptoms including sleep and circadian disruption. Melanopsin-expressing intrinsically photosensitive Retinal Ganglion Cells (ipRGC) transmit light signals to brain areas controlling rhythms the pupil reflex. To determine if observed in PD are linked ipRGC dysfunction, we evaluated melanopsin rod/cone contributions response medicated participants with ( n = 17) controls 12). Autonomic tone was measuring pupillary unrest...

Melanopsin expressing intrinsically photosensitive Retinal Ganglion Cells (ipRGCs) entirely control the post-illumination pupil response (PIPR) from 6 s post-stimulus to plateau during redilation after light offset. However, photoreceptor contributions early phase of PIPR (< post-stimulus) have not been reported. Here, we evaluated (0.6 5.0 s) by measuring spectral sensitivity criterion amplitude in 1 pulses at five narrowband stimulus wavelengths (409, 464, 508, 531 and 592 nm). The retinal...

Melanopsin-mediated visual and non-visual functions are difficult to study in vivo. To isolate melanopsin responses, non-standard light stimulation instruments required, with at least as many primaries photoreceptor classes the eye. In this protocol, we describe physical calibrations of display instrumentation, control stimulus artefacts, correction individual between-eye differences human observers. The protocol achieves complete silent substitution psychophysical, pupillometry,...

Purpose: To determine whether melanopsin-expressing intrinsically photosensitive retinal ganglion cell (ipRGC) inputs to the pupil light reflex (PLR) are affected in early age-related macular degeneration (AMD). Methods: The PLR was measured 40 participants (20 AMD and 20 age-matched controls) using a custom-built Maxwellian view pupillometer. Sinusoidal stimuli (0.5 Hz, 11.9 seconds duration, 35.6° diameter) were presented study eye consensual response lights with high melanopsin excitation...

Purpose: Melanopsin expressing intrinsically photosensitive retinal ganglion cells (ipRGC) input to multiple brain regions including those for pupil control, circadian rhythms, sleep and mood regulation. Here we measured ipRGC function its relationship quality depression in patients with advanced AMD. Methods: The melanopsin-mediated post-illumination response (PIPR) was 53 AMD (age 78.8 ± 8.8 years) 20 healthy controls 72.5 3.3 years). Sleep efficiency assessed using the Pittsburgh Quality...

Background: Retinal photoreceptors provide the main stage in mammalian eye for regulating retinal illumination through changes pupil diameter, with a small population of melanopsin-expressing intrinsically photosensitive ganglion cells (ipRGCs) forming primary afferent pathway this response. The purpose study is to determine how melanopsin interacts three cone photoreceptor classes human modulate light-adapted Methods: We investigated independent and combined contributions inner outer inputs...

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....

The gut microbiome is implicated in the development of advanced age-related macular degeneration (AMD), but no study has investigated microbial composition early AMD nor controlled for important modulators such as diet and light. This crucial can change rapidly well affects disease progression. In addition, light signaling photoreceptors are dysfunctional AMD. Here we determined microbiota by conducting 16S DNA metagenomic sequencing 40 fecal samples from 20 participants with without We...

Evidence suggests best-corrected visual acuity is not sensitive to subtle vision losses in early disease stages, indicating the need for other tests. Here, we quantified contrast sensitivity 99 people (20-88 years): 52 with eye diseases (10 AMD, 9 diabetics without retinopathy, 22 glaucoma suspects, 11 high myopes) and 47 age-matched healthy controls using a new spatial chart (0.28-100% Weber contrasts; 3-60 c/° frequencies). In retinal ageing, detected frequency-dependent losses; was...

Abstract This study investigates the time-course and post-receptoral pathway signaling of photoreceptor interactions when rod (R) three cone (L, M, S) classes contribute to mesopic vision. A four-primary photostimulator independently controls activity in human observers. The first experiment defines temporal adaptation response receptoral (L-, S-cone, rod) (LMS, LMSR, +L-M) interactions. Here we show that nonopponent cone-cone (L-cone, LMS, LMSR) have monophasic patterns whereas opponent...