Photopigment bleaching occurs with saturation of photoreceptor pigment by short-wavelength fundus autofluorescence imaging. This phenomenon is seen as characteristic hyperautofluorescence with subsequent imaging acquisition. Herein, a patient with multiple sclerosis was found to exhibit increased choroidal hyperfluorescence during fluorescein angiography (FA) that corresponded with a circumscribed area of intense blue light exposure during initial scanning laser ophthalmoscopy. To the authors' knowledge, this case is the first description of photobleaching phenomenon during FA and should be recognized as nonpathologic by the clinician. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:590-592.].
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http://dx.doi.org/10.3928/23258160-20190905-09 | DOI Listing |
Mar Pollut Bull
December 2024
Marine Laboratory, University of Guam, Mangilao, Guam.
Coral-dinoflagellate symbiosis underpins coral reef resilience and influences conservation success, given the relationship's role in coral bleaching. Here, we transplanted Guam's dominant staghorn coral, Acropora pulchra, across four coral gardens and monitored their endosymbiotic dinoflagellates (family Symbiodiniaceae) for ∼15 months (May 2021-August 2022). Transplantation and predation resulted in temporary symbiotic destabilization, as signaled by increased cell roughness and decreased cell density.
View Article and Find Full Text PDFJ Exp Bot
July 2024
School of BioSciences, The University of Melbourne, Parkville 3010, Victoria, Australia.
The thermal tolerance of symbiodiniacean photo-endosymbionts largely underpins the thermal bleaching resilience of their cnidarian hosts such as corals and the coral model Exaiptasia diaphana. While variation in thermal tolerance between species is well documented, variation between conspecific strains is understudied. We compared the thermal tolerance of three closely related strains of Breviolum minutum represented by two internal transcribed spacer region 2 profiles (one strain B1-B1o-B1g-B1p and the other two strains B1-B1a-B1b-B1g) and differences in photochemical and non-photochemical quenching, de-epoxidation state of photopigments, and accumulation of reactive oxygen species under rapid short-term cumulative temperature stress (26-40 °C).
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
March 2024
Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
Purpose: The purpose of this study was to investigate rod photopigment bleaching-driven intrinsic optical signals (IOS) in the human outer retina and its measurement repeatability based on a commercial optical coherence tomography (OCT) platform.
Methods: The optical path length of the rod photoreceptor subretinal space (SRS), that is, the distance between signal bands of rod outer segment tips and retinal pigment epithelium, was measured in 15 healthy subjects in ambient light and during a long-duration bleaching white-light exposure.
Results: On 2 identical study days (day 1 and day 2 [D1 and D2]), light stimulation resulted in a significant decrease in rod SRS by 21.
Front Ophthalmol (Lausanne)
April 2023
F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital and Harvard Medical School. Boston, MA, USA.
Melanopsin is a light-activated G protein coupled receptor that is expressed widely across phylogeny. In mammals, melanopsin is found in intrinsically photosensitive retinal ganglion cells (ipRGCs), which are especially important for "non-image" visual functions that include the regulation of circadian rhythms, sleep, and mood. Photochemical and electrophysiological experiments have provided evidence that melanopsin has at least two stable conformations and is thus multistable, unlike the monostable photopigments of the classic rod and cone photoreceptors.
View Article and Find Full Text PDFSci Rep
June 2023
Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, OX3 9DU, UK.
Retinal disease accounts significantly for visual impairment and blindness. An important role in the pathophysiology of retinal disease and aging is attributed to lipofuscin, a complex of fluorescent metabolites. Fundus autofluorescence (AF) imaging allows non-invasive mapping of lipofuscin and is a key technology to diagnose and monitor retinal disease.
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