Melanopsin-mediated visual and non-visual functions are difficult to study in vivo. To isolate melanopsin responses, non-standard light stimulation instruments are required, with at least as many primaries as photoreceptor classes in the eye. In this protocol, we describe the physical light calibrations of the display instrumentation, control of stimulus artefacts, and correction of individual between-eye differences in human observers. The protocol achieves complete photoreceptor silent substitution in psychophysical, pupillometry, and electroretinographic experiments for probing melanopsin, rod, and cone function. For complete details on the use and execution of this protocol, please refer to Uprety et al. (2022)..
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http://dx.doi.org/10.1016/j.xpro.2023.102126 | DOI Listing |
JCEM Case Rep
January 2025
Department of Endocrinology, St. Luke's University Health Network, Bethlehem, PA 18015, USA.
Routine serum studies in a female patient with sustained prediabetic glycated hemoglobin A (HbA) levels, controlled on metformin, yielded an unexpected finding: an elevated HbA value of ≥14.9% (≥139 mmol/mol) (normal reference range, <5.7% to <39 mmol/mol).
View Article and Find Full Text PDFBMC Nurs
December 2024
School of Nursing and School of Public Health, Chitwan Medical College, Bharatpur-5, Kailashnagar, Chitwan, Nepal.
Background: The global nursing shortage has particularly severe consequences in resource-constrained countries like Nepal, where a significant outflow of healthcare professionals exacerbates the crisis. While the impact on patient care, workforce dynamics, and organizational challenges within healthcare settings have been extensively researched, the profound implications of this crisis for nursing education remain underexplored. This qualitative study sheds light on the often-unseen consequences of the nursing shortage on undergraduate nursing students' clinical education.
View Article and Find Full Text PDFSleep
December 2024
Centre for Biological Timing, Division of Neuroscience, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PT, UK.
Study Objectives: Melanopsin-expressing retinal ganglion cells, which provide light information to time sleep and entrain circadian clocks, also influence perceived brightness raising the possibility that psychophysical paradigms could be used to explore the origins and implications of variability in melanopic sensitivity. We aimed to develop accessible psychophysical tests of melanopic vision and relate outcomes with a pupillometric measure of melanopsin function (post-illumination pupil response; PIPR) and prior light exposure.
Methods: Individually calibrated pairs of isoluminant stimuli differing in melanopic radiance from a four primary source were presented sequentially with superimposed random colour offsets in a two alternative forced choice brightness preference paradigm to 41 naïve adult participants with personal light exposure data for the prior 7 days and PIPR measures defined by comparing maintained pupil constriction for luminance matched 'red' vs 'blue' pulses.
Rep Biochem Mol Biol
April 2024
Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
Proc Natl Acad Sci U S A
November 2024
Centre for Vision and Eye Research, Queensland University of Technology, Brisbane, QLD 4059, Australia.
A subpopulation of human retinal ganglion cells contains the melanopsin photopigment, allowing them to act as a fifth photoreceptor class. These ganglion cells project to the visual cortex, but to reveal its intrinsic contribution to conscious vision is technically challenging as it requires melanopsin to be separated from the responses originating in the rods and three cone classes. Using a display engineered to isolate the melanopic visual response, we show that it detects lowpass spatial (≤0.
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