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Eye (London, England) Feb 2016Under twenty-first-century metropolitan conditions, almost all of our vision is mediated by cones and the photopic system, yet cones make up barely 5% of our retinal... (Review)
Review
Under twenty-first-century metropolitan conditions, almost all of our vision is mediated by cones and the photopic system, yet cones make up barely 5% of our retinal photoreceptors. This paper looks at reasons why we additionally possess rods and a scotopic system, and asks why rods comprise 95% of our retinal photoreceptors. It considers the ability of rods to reliably signal the arrival of individual photons of light, as well as the ability of the retina to process these single-photon signals, and it discusses the advantages that accrue. Drawbacks in the arrangement, including the very slow dark adaptation of scotopic vision, are also considered. Finally, the timing of the evolution of cone and rod photoreceptors, the retina, and the camera-style eye is summarised.
Topics: Animals; Color Vision; Contrast Sensitivity; Dark Adaptation; Humans; Light; Night Vision; Retinal Cone Photoreceptor Cells; Retinal Rod Photoreceptor Cells; Vision, Ocular
PubMed: 26563661
DOI: 10.1038/eye.2015.236 -
Plant Physiology Aug 2021
Topics: Adaptation, Physiological; Biological Transport; Crops, Agricultural; Dark Adaptation; Dehydration; Dendrobium; Flowers; Plant Breeding; Plant Senescence; Plant Stems; Polygalacturonase; Stress, Physiological; Thiamine; Vitis
PubMed: 35237806
DOI: 10.1093/plphys/kiab265 -
Scientific Reports Feb 2022Delayed dark adaptation due to impaired rod photoreceptor homeostasis has been reported as the earliest symptom of eye diseases such as age-related macular degeneration,...
Delayed dark adaptation due to impaired rod photoreceptor homeostasis has been reported as the earliest symptom of eye diseases such as age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa. Objective measurement of dark adaptation can facilitate early diagnosis to enable prompt intervention to prevent vision loss. However, there is a lack of noninvasive methods capable of spatiotemporal monitoring of photoreceptor changes during dark adaptation. Here we demonstrate functional optical coherence tomography (OCT) for in vivo intrinsic signal optoretinography (ORG) of dark adaptation kinetics in the C57BL/6J mouse retina. Functional OCT revealed a shortening of the outer retina, a rearrangement of the cone and rod photoreceptor interdigitation zone, and a reduction in intrinsic signal amplitude at the photoreceptor inner segment ellipsoid (ISe). A strong positive correlation between the outer retinal shortening and ISe intensity reduction was also confirmed. Functional OCT of dark adaptation kinetics promises an objective method for rapid ORG assessment of physiological integrity of retinal photoreceptors.
Topics: Animals; Blindness; Dark Adaptation; Diabetic Retinopathy; Early Diagnosis; Kinetics; Macular Degeneration; Mice, Inbred C57BL; Retinal Rod Photoreceptor Cells; Retinitis Pigmentosa; Tomography, Optical Coherence; Mice
PubMed: 35169239
DOI: 10.1038/s41598-022-06562-4 -
Survey of Ophthalmology 2021Diabetic retinal disease remains a leading cause of vision loss despite currently available screening methods, ocular treatments, and efforts to control metabolic... (Review)
Review
Diabetic retinal disease remains a leading cause of vision loss despite currently available screening methods, ocular treatments, and efforts to control metabolic dysfunction. It is now understood that diabetes damages the entire retina and the cellular components of the neurovascular unit. Multiple studies have demonstrated impairment of various aspects of retinal function across the spectrum of retinopathy severity. Here we review these tests, the principles underlying their use, clinical data from multiple publications, the strengths and limitations of the studies, and prospects for their application to understand the pathophysiology of diabetic retinal disease and monitor its response to therapy. We focus on visual acuity, contrast sensitivity, color vision, visual field, and dark adaptation and their use to understand the pathophysiology of diabetic retinopathy and as potential endpoints for clinical trials.
Topics: Dark Adaptation; Diabetes Mellitus; Diabetic Retinopathy; Humans; Retina; Visual Acuity; Visual Fields
PubMed: 32866468
DOI: 10.1016/j.survophthal.2020.08.003 -
Vision Research Nov 2011This review celebrates the adaptation studies published in Vision Research during the past half a century, and it is thus a complement to the anniversary issues which... (Review)
Review
This review celebrates the adaptation studies published in Vision Research during the past half a century, and it is thus a complement to the anniversary issues which are focusing on more recent work (Vision Research, 51(7 and 8), 2011). Throughout the text, the discussion often starts out from a work presented in Vision Research, but the discussion is not restricted by the journals used for publication. To date, in Vision Research alone, around 500 papers related to light/dark adaptation have been published; this review tries to follow up just a few discussions within the field of vertebrate dark adaptation. The main topics are: (1) the legacies of Wald and Barlow; (2) the Dowling-Rushton relation between regenerated rhodopsin and log threshold; (3) the mechanisms behind fast cone-driven and slow rod-driven dark adaptation; and (4) the role of the decomposition products of photoactivated rhodopsin. This review, and the scientists given leading roles in the story, have been guided by an interest in visual psychophysics, combined with a conviction that we need a thorough understanding of the information processing carried out by the photoreceptors and the neural retina for obtaining a correct understanding of the further analysis performed by the brain.
Topics: Animals; Biomedical Research; Dark Adaptation; History, 20th Century; History, 21st Century; Humans; Periodicals as Topic
PubMed: 21925198
DOI: 10.1016/j.visres.2011.08.021 -
Ophthalmology Jun 2019
Topics: Dark Adaptation; Humans; Longitudinal Studies; Macular Degeneration; Outcome Assessment, Health Care; Retinal Rod Photoreceptor Cells
PubMed: 31122362
DOI: 10.1016/j.ophtha.2018.12.024 -
Vision Research Nov 1999Older adults have serious difficulty seeing under low illumination and at night, even in the absence of ocular disease. Optical changes in the aged eye, such as...
Older adults have serious difficulty seeing under low illumination and at night, even in the absence of ocular disease. Optical changes in the aged eye, such as pupillary miosis and increased lens density, cannot account for the severity of this problem, and little is known about its neural basis. Dark adaptation functions were measured on 94 adults ranging in age from the 20s to the 80s to assess the rate of rod-mediated sensitivity recovery after exposure to a 98% bleach. Fundus photography and a grading scale were used to characterize macular health in subjects over age 49 in order to control for macular disease. Thresholds for each subject were corrected for lens density based on individual estimates, and pupil diameter was controlled. Results indicated that during human aging there is a dramatic slowing in rod-mediated dark adaptation that can be attributed to delayed rhodopsin regeneration. During the second component of the rod-mediated phase of dark adaptation, the rate of sensitivity recovery decreased 0.02 log unit/min per decade, and the time constant of rhodopsin regeneration increased 8.4 s/decade. The amount of time to reach within 0.3 log units of baseline scotopic sensitivity increased 2.76 min/decade. These aging-related changes in rod-mediated dark adaptation may contribute to night vision problems commonly experienced by the elderly.
Topics: Adult; Aged; Aged, 80 and over; Aging; Dark Adaptation; Humans; Middle Aged; Retinal Rod Photoreceptor Cells
PubMed: 10748929
DOI: 10.1016/s0042-6989(99)00092-9 -
The Journal of Physiology Nov 2022
Topics: Retinal Rod Photoreceptor Cells; Retinal Cone Photoreceptor Cells; Electroretinography; Retina; Dark Adaptation
PubMed: 36083438
DOI: 10.1113/JP283652 -
Translational Vision Science &... Jun 2020Functional studies of rods in age-related macular degeneration using the Medmont Dark-Adapted Chromatic Perimeter (DACP) have demonstrated impairments in scotopic...
PURPOSE
Functional studies of rods in age-related macular degeneration using the Medmont Dark-Adapted Chromatic Perimeter (DACP) have demonstrated impairments in scotopic sensitivities and dark adaptation (DA). We investigated the intersession repeatability of scotopic sensitivity and DA parameters including the rod intercept time recorded from the Medmont DACP.
METHODS
Scotopic thresholds (14 test points) and DA using a 30% photobleach (eight test points) were measured on two separate days from participants 50 years of age or older with a range of age-related macular degeneration severity at loci superior and inferior to the fovea. Repeatability coefficients were calculated for prebleach scotopic sensitivity, and for DA parameters including rod intercept time.
RESULTS
Twelve participants (mean age, 79.7 ± 8.1 years) repeated Medmont DACP testing within 50 days. Repeatability coefficients for prebleach scotopic sensitivity to long wavelength (red, 625 nm) and short wavelength (cyan, 505 nm) were 5.9 dB and 7.2 dB, respectively. The DA curve-derived repeatability coefficients for cone threshold was 3.9 dB, final threshold 5.3 dB, with an R value of 0.075 decades/min, rod intercept time 7.6 minutes, and RITslope 0.54 min/degree.
CONCLUSIONS
This study establishes repeatability coefficients for scotopic thresholds and multiple DA parameters obtained with the Medmont DACP in patients with age-related macular degeneration. These repeatability coefficients will serve as the basis for determining clinically meaningful change in rod function in future clinical trials.
TRANSLATIONAL RELEVANCE
Measures of repeatability parameters of scotopic thresholds and DA are essential to the accurate interpretation of results in future studies and trials using these measures.
Topics: Aged; Aged, 80 and over; Dark Adaptation; Fovea Centralis; Humans; Macular Degeneration; Retinal Cone Photoreceptor Cells
PubMed: 32832236
DOI: 10.1167/tvst.9.7.31 -
Current Eye Research May 2023Studies on age-related macular degeneration often use rod-mediated dark adaptation (RMDA) to evaluate macular functional health, studying eyes with cataract and...
PURPOSE
Studies on age-related macular degeneration often use rod-mediated dark adaptation (RMDA) to evaluate macular functional health, studying eyes with cataract and pseudophakic eyes within the same sample. We examine a poorly understood issue-whether rod intercept time (RIT), a measure of RMDA, changes after cataract surgery and intraocular lens (IOL) insertion as compared to RIT before cataract surgery. Cataract may serve as a filter reducing photo-bleach magnitude prior to surgery, biasing RMDA interpretation.
METHODS
A pre-/post-cataract surgery design was used. Persons with nuclear sclerotic and/or cortical cataract per the electronic health record were enrolled. Prior to cataract surgery, visual acuity, RMDA, and the LOCS III classification documenting cataract presence/severity were measured. Thirty days after surgery (mean), visual acuity and RMDA were repeated, followed by fundus photos to document macular health.
RESULTS
Twenty-four participants (mean age 72.7 years, standard deviation 5.6) enrolled. All eyes had nuclear sclerotic and nuclear color cataract; 68% had cortical cataract. All IOLs were monofocal with 21 having blue blocking characteristics and 3 had clear IOLs. Most eyes had higher RIT post-surgery (15.6 min, SD 6.7) as compared to pre-surgery (13.7 min, SD 6.4), = 0.0006, meaning that RMDA was slower post-surgery. Eyes with moderate cataract (<4 on any LOCS III grade) had RIT that increased on average by 0.7 min; those with more advanced cataract (≥4) had RIT that increased by 3.1 min ( = 0.0116). Results were unchanged when clear IOLs were removed from analysis.
CONCLUSION
RMDA was significantly slower (RIT was greater) following cataract surgery, with the greatest impact on RIT in older eyes after surgery for more advanced cataract. These findings suggest that persons with more advanced cataract may bias results when evaluating RMDA using RIT.
Topics: Humans; Aged; Dark Adaptation; Cataract Extraction; Capsule Opacification; Visual Acuity; Cataract
PubMed: 36662498
DOI: 10.1080/02713683.2023.2171438