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Journal of Vision Mar 2019The cellular origins of slow ERG changes during light adaptation following a dark-adapted state are still unclear. To study light adaptation, six healthy, normal...
The cellular origins of slow ERG changes during light adaptation following a dark-adapted state are still unclear. To study light adaptation, six healthy, normal trichromats were dark-adapted for 30 min prior to full-field ERG recordings to sinusoidal stimuli that isolate responses of the L- or M-cones or that stimulate luminance and chromatic mechanisms at 12 or 36 Hz. Recordings were performed for 16 min with 2-min intervals after onset of a constant background. Generally, the responses were sine-wave-like, and the first harmonic (fundamental) component dominated the Fourier spectrum except for the 12-Hz luminance stimulus in which two components, a sine-wave-like component and a transient component, determined the response profiles, leading to large second harmonic components. The amplitude of the first harmonic component (F) increased as a function of the light-adaptation time except for the 12-Hz luminance stimulus at which the F component decreased as a function of the light-adaptation period. The phase of the first harmonic component changed only slightly (less than 30°) during the light-adaptation period for all stimuli conditions. The L/M ratio in luminance reflecting ERGs decreased with increasing adaptation time. Our present data suggest that the light-adaptation process mainly reflects changes in the luminance pathway. The responses to 12-Hz luminance stimuli are determined by two different luminance driven pathways with different adaptation characteristics.
Topics: Adaptation, Ocular; Adult; Color; Dark Adaptation; Electroretinography; Female; Healthy Volunteers; Humans; Luminescence; Male; Photic Stimulation; Retinal Cone Photoreceptor Cells
PubMed: 30916727
DOI: 10.1167/19.3.12 -
PloS One 2013Recently, researchers have been trying to unravel the function of consciousness by exploring whether unconscious information is (in)capable of exerting cognitive... (Comparative Study)
Comparative Study
Recently, researchers have been trying to unravel the function of consciousness by exploring whether unconscious information is (in)capable of exerting cognitive control. Theoretically, cognitive control functions, such as conflict adaptation, have often been assumed to require consciousness. However, empirical evidence on conscious versus unconscious conflict adaptation is highly contradictory and hitherto, only one study reliably demonstrated adaptation to unconscious conflict. Therefore, the current study wanted to shed further light on this debated issue. A masked and unmasked version of the priming paradigm were used to create unconscious and conscious conflict trials (i.e., when prime and target trigger opposite responses). In contrast to previous studies, the Stimulus Onset Asynchrony was kept constant in both conditions and neutral trials were added to the design in order to investigate the origin of the adaptation and to investigate the specific adaptation effects. Our results showed robust conflict adaptation effects following conscious and unconscious conflict. Furthermore, our results suggest that the adaptation elicited by the conflict, is mainly an adaptation of interference, not of facilitation. We can conclude that conflict adaptation can occur after unconscious conflict, which indicates that this expression of cognitive control is most likely not an exclusive function of consciousness.
Topics: Adolescent; Adult; Awareness; Cognition; Consciousness; Dark Adaptation; Female; Humans; Male; Reaction Time; Unconsciousness; Visual Perception; Young Adult
PubMed: 23405242
DOI: 10.1371/journal.pone.0055976 -
Acta Ophthalmologica Feb 2021To evaluate association of the van Herick (VH) grades with the ultrasound biomicroscopic (UBM) parameters, appositional irido-trabecular contact (A-ITC) and plateau iris...
Evaluation of anterior chamber angle by van Herick grading and ultrasound biomicroscopy in light and dark conditions for finding appositional angle closure and plateau iris configuration.
PURPOSE
To evaluate association of the van Herick (VH) grades with the ultrasound biomicroscopic (UBM) parameters, appositional irido-trabecular contact (A-ITC) and plateau iris (PI) in a randomly sampled population.
METHODS
A 10% random sample of all residents aged 40 or older of the Kumejima study underwent UBM under dark and light conditions in the four quadrants of right eyes.
RESULTS
Of 301 right eyes with eligible UBM images, 101 (33.6%) and 200 (66.4%) were classified as VH ≤ 2 and VH ≥ 3, respectively. The UBM parameters on angle width and ciliary body configuration were significantly different between VH ≤ 2 and VH ≥ 3 eyes (p < 0.001). A-ITC was found in at least one quadrant in 54.5% and 75.2% of VH ≤ 2 eyes under light and dark conditions, respectively; and 20.5% and 45.5% of VH ≥ 3 eyes. When 'VH ≤ 2' was used to screen eyes with A-ITC in three or more quadrants, the sensitivity and specificity were 74.1% and 75.3%, respectively. A-ITC was significantly associated with shallower anterior chamber (p = 0.018) and higher intraocular pressure (p = 0.044) in VH ≥ 3 eyes. Plateau iris (PI) was found in 15.8% and 6.0% of VH ≤ 2 and VH ≥ 3 eyes, respectively. Plateau iris (PI) was significantly associated with the UBM parameters on angle width and ciliary body configuration. When 'VH ≤ 2' was used to screen eyes with PI, the sensitivity and specificity were 57.1% and 68.9%, respectively.
CONCLUSIONS
The VH grade of ≤2 and ≥3 showed significant association with UBM angle width and ciliary body configuration parameters. The VH ≤ 2 criterion should be useful for screening of A-ITC and PI.
Topics: Aged; Anterior Chamber; Ciliary Body; Dark Adaptation; Female; Follow-Up Studies; Glaucoma, Angle-Closure; Gonioscopy; Humans; Intraocular Pressure; Iris; Male; Microscopy, Acoustic; Middle Aged; Photic Stimulation; Retrospective Studies
PubMed: 32567220
DOI: 10.1111/aos.14502 -
The British Journal of Ophthalmology Jun 1994
Topics: Dark Adaptation; Humans; Kinetics; Macular Degeneration; Retinal Diseases; Retinitis Pigmentosa
PubMed: 8060922
DOI: 10.1136/bjo.78.6.426 -
Graefe's Archive For Clinical and... Jul 2013To characterize the rate of rod-mediated sensitivity decline with age using a PC-driven cathode ray tube (CRT) monitor. To provide data regarding the repeatability of...
PURPOSE
To characterize the rate of rod-mediated sensitivity decline with age using a PC-driven cathode ray tube (CRT) monitor. To provide data regarding the repeatability of the technique.
METHODS
Dark adaptation was monitored for 30 min following a minimum 30 % pigment bleach, using a white 1° stimulus (modulated at 1 Hz), presented 11° below fixation on a CRT monitor. Thirty-three subjects with no ocular pathology and normal fundus photographs were divided into two groups: older (≥45, n = 16) and younger (<45, n = 17).
RESULTS
Rod recovery was assessed using component S2 of dark adaptation. S2 was significantly slower in the older (0.19 ± 0.03 log cd.m(-2).min(-1)) compared with the younger group (0.23 ± 0.03 log cd.m(-2).min(-1), t = -4.05, p < 0.0003), despite no difference in visual acuity and fundus appearance. Faster rates of S2 recovery were correlated with lower threshold at 30 min (T30) (r = -0.49). Correlation coefficients between first and second measurements for S2 and T30 were 0.49 (p < 0.009) and 0.84 (p < 0.0001) respectively. The coefficient of repeatability was 0.07 log cd.m(-2).min(-1) for S2 and 0.35 log cd.m(-2) for T30. The coefficients of variation for S2 and T30 were 15 % and 10 % respectively.
CONCLUSIONS
Dark adaptation is slowed in normal ageing. CRT-based dark adaptometry is easily implemented and highly repeatable. The technique described in this article would be useful for documenting visual changes in future clinical trials assessing retinal health in the older eye with and without ocular pathology.
Topics: Adolescent; Adult; Aged; Aging; Cathode Ray Tube; Dark Adaptation; Diagnostic Techniques, Ophthalmological; Female; Fixation, Ocular; Humans; Male; Microcomputers; Middle Aged; Photic Stimulation; Reproducibility of Results; Retinal Rod Photoreceptor Cells; Visual Acuity; Young Adult
PubMed: 23553287
DOI: 10.1007/s00417-013-2324-5 -
Translational Vision Science &... Jul 2023The purpose of this study was to assess test-retest variability and discriminatory power of measures from macular integrity assessment (S-MAIA) and AdaptDx.
Test-Retest Variability and Discriminatory Power of Measurements From Microperimetry and Dark Adaptation Assessment in People With Intermediate Age-Related Macular Degeneration - A MACUSTAR Study Report.
PURPOSE
The purpose of this study was to assess test-retest variability and discriminatory power of measures from macular integrity assessment (S-MAIA) and AdaptDx.
METHODS
This is a cross-sectional study of 167 people with intermediate age-related macular degeneration (iAMD), no AMD (controls; n = 54), early AMD (n = 28), and late AMD (n = 41), recruited across 18 European ophthalmology centers. Repeat measures of mesopic and scotopic S-MAIA average (mean) threshold (MMAT decibels [dB] and SMAT [dB]) and rod intercept time (RIT [mins]) at 2 visits 14 (±7) days apart were recorded. Repeat measures were assessed by Bland-Altman analysis, intra-class correlation coefficients (ICCs) and variability ratios. Secondary analysis assessed the area under the receiver operating characteristic curves (AUC) to determine the ability to distinguish people as having no AMD, early AMD, or iAMD.
RESULTS
Data were available for 128, 131, and 103 iAMD participants for the mesopic and scotopic S-MAIA and AdaptDx, respectively. MMAT and SMAT demonstrate similar test-retest variability in iAMD (95% confidence interval [CI] ICC of 0.79-0.89 and 0.78-0.89, respectively). ICCs were worse in RIT (95% CI ICC = 0.55-0.77). All tests had equivalent AUCs (approximately 70%) distinguishing between subjects with iAMD and controls, whereas early AMD was indistinguishable from iAMD on all measures (AUC = <55%). A learning effect was not seen in these assessments under the operating procedures used.
CONCLUSIONS
MMAT, SMAT, and RIT have adequate test-retest variability and are all moderately good at separating people with iAMD from controls.
TRANSLATIONAL RELEVANCE
Expected levels of test-retest variability and discriminatory power of the AdaptDx and MAIA devices in a clinical study setting must be considered when designing future trials for people with AMD.
Topics: Humans; Dark Adaptation; Visual Field Tests; Cross-Sectional Studies; Macular Degeneration
PubMed: 37477933
DOI: 10.1167/tvst.12.7.19 -
Retina (Philadelphia, Pa.) Mar 2022To test the hypothesis that Müller cell dysfunction in macular telangiectasia type 2 (MacTel) results in delayed cone adaptation kinetics and to assess absolute cone...
PURPOSE
To test the hypothesis that Müller cell dysfunction in macular telangiectasia type 2 (MacTel) results in delayed cone adaptation kinetics and to assess absolute cone and rod thresholds in this condition.
METHODS
Adaptation after an approximate 63.5% full-field cone photopigment bleach was assessed for Goldmann size V (1.7° diameter) 640 nm (red) and 480 nm (blue) targets presented at a retinal locus corresponding to 2° temporal to fixation. The cone time constant of adaptation and absolute cone and rod thresholds were calculated from exponential functions fitted to the resultant dark adaptation curves.
RESULTS
Eighteen eyes with MacTel (from 11 patients) were compared with 19 control eyes (from 16 normal subjects). Cone adaptation kinetics were significantly impaired in MacTel, as was the absolute cone threshold. Final thresholds for blue targets were also significantly elevated in MacTel, consistent with impaired rod absolute threshold. Losses in sensitivity observed in MacTel were consistent with a so-called d1/2 mechanism (i.e., receptoral) site of sensitivity loss.
CONCLUSION
In addition to previously documented impairments in rod dark adaptation, MacTel results in a significant elevation in cone thresholds because of pathology at the level of the photoreceptors. The delays in cone adaptation that we found in eyes with MacTel may reflect impairment of the Müller cell-mediated cone-specific visual cycle.
Topics: Aged; Aged, 80 and over; Cross-Sectional Studies; Dark Adaptation; Female; Humans; Male; Middle Aged; Prospective Studies; Regeneration; Retinal Cone Photoreceptor Cells; Retinal Pigments; Retinal Telangiectasis; Visual Acuity; Visual Fields
PubMed: 35188495
DOI: 10.1097/IAE.0000000000003328 -
Scientific Reports May 2021To evaluate the effect of aging, intra- and intersession repeatability and regional scotopic sensitivities in healthy and age-related macular degeneration (AMD) eyes.... (Observational Study)
Observational Study
To evaluate the effect of aging, intra- and intersession repeatability and regional scotopic sensitivities in healthy and age-related macular degeneration (AMD) eyes. Intra- and intersession agreement and effect of age was measured in healthy individuals. The mean sensitivity (MS) and pointwise retinal sensitivities (PWS) within the central 24° with 505 nm (cyan) and 625 nm (red) stimuli were evaluated in 50 individuals (11 healthy and 39 AMD eyes). The overall intra- and intersession had excellent reliability (intraclass correlation coefficient, ICC > 0.90) and tests were highly correlated (Spearman r = 0.75-0.86). Eyes with subretinal drusenoid deposit (SDD) had reduced PWS centrally, particularly at inferior and nasal retinal locations compared with controls and intermediate AMD (iAMD) without SDD. There was no difference in MS or PWS at any retinal location between iAMD without SDD and healthy individuals nor between iAMD with SDD and non-foveal atrophic AMD groups. Eyes with SDD have reduced rod function compared to iAMD without SDD and healthy eyes, but similar to eyes with non-foveal atrophy. Our results highlight rod dysfunction is not directly correlated with drusen load and SDD location.
Topics: Adult; Aging; Dark Adaptation; Healthy Volunteers; Humans; Macular Degeneration; Male; Middle Aged; Reproducibility of Results; Retinal Drusen; Retinal Rod Photoreceptor Cells; Visual Field Tests
PubMed: 33990634
DOI: 10.1038/s41598-021-89677-4 -
Clinical & Experimental Optometry Nov 2018The standing potential of the eye exhibits a slow damped oscillation under light and dark conditions that continues for at least 80 minutes. However, our understanding...
BACKGROUND
The standing potential of the eye exhibits a slow damped oscillation under light and dark conditions that continues for at least 80 minutes. However, our understanding of the relationship between the slow dark and light oscillation has not been previously studied. The aim of this study was to explore through regression analysis a model of these oscillations in order to establish if they may have the same underlying cellular generators.
METHODS
Healthy participants undertook recordings of the standing potential using the electro-oculogram for 100 minutes. To explore the light oscillation, participants (n = 8) were dilated and performed an extended electro-oculogram protocol consisting of 15 minutes dark adaptation and 85 minutes of white light adaptation at 100 cd/m . For the dark oscillation, participants (n = 11) undertook the electro-oculogram for 100 minutes in complete darkness. Both sessions began with pre-adaptation to 30 cd/m of white light for five minutes. Non-parametric statistics were used to evaluate all data.
RESULTS
Ratios of the dark and light oscillations showed a significantly greater dampening of the dark oscillation compared to the light oscillation (p < 0.000). Regression analysis using a five-factor damped sine function revealed significant differences in the parameters governing the dampening (p = 0.005) and period (p = 0.009) of the functions (R > 0.874). There were no significant differences in the dark trough amplitude.
CONCLUSION
The results support a different underlying physiological mechanism for the light and dark oscillation of the clinical electro-oculogram. Future work will need to establish how the dark oscillation and dark trough of the clinical electro-oculogram arise.
Topics: Adaptation, Ocular; Adult; Dark Adaptation; Electrooculography; Female; Healthy Volunteers; Humans; Male; Reference Values; Retinal Pigment Epithelium; Young Adult
PubMed: 29781186
DOI: 10.1111/cxo.12799 -
Clinical & Experimental Optometry Nov 2017The aim was to investigate the effect of axial length on full-field electroretinogram (ffERG) and multifocal electroretinogram (mfERG) in young Indian subjects.
PURPOSE
The aim was to investigate the effect of axial length on full-field electroretinogram (ffERG) and multifocal electroretinogram (mfERG) in young Indian subjects.
METHODS
One hundred subjects (44 male) with refractive errors from +0.50 to -18.00 DS and no myopic retinopathy underwent axial length measurement. ffERG was measured, which included scotopic and photopic responses according to International Society for Clinical Electrophysiology of Vision (ISCEV) guidelines. The mfERG was recorded after correcting for refractive error according to ISCEV standards. The dark-adapted and light-adapted parameters of ffERG and N1, P1 parameters of six rings in mfERG were analysed with axial length, controlled for refractive error. The subjects were divided into seven groups based on axial length. The b/a ratio of dark-adapted and light-adapted 3.0 ffERG and P1/N1 ratio of mfERG amplitudes were analysed for seven groups of axial length.
RESULTS
The axial length ranged from 21.79 to 30.55 mm. Significant negative correlations were noted for ffERG and mfERG amplitudes, whereas implicit times showed minimal delay with increase in axial length. In ffERG, the scotopic responses were more decreased compared to photopic responses. In mfERG, P1 and N1 amplitudes were significantly decreased in all the rings in all groups and more reduction was noted in the central ring compared to peripheral rings. The P1 amplitudes were more affected as compared to N1 amplitudes. The light-adapted and dark-adapted 3.0 ERG b/a ratio and P1/N1 ratio for seven axial length groups did not show statistically significant difference. The ERG parameters were not significant with refractive error.
CONCLUSION
This study quantifies the relationship of axial length with ffERG and mfERG parameters in a young Indian population. Although the amplitudes were reduced significantly, the implicit times were not significantly affected. The ERG parameters were more related to axial length than refractive error. Hence, interpretation of ffERG and mfERG parameters needs careful consideration in subjects with increasing axial length.
Topics: Adult; Axial Length, Eye; Color Vision; Dark Adaptation; Electroretinography; Female; Humans; Male; Night Vision; Refractive Errors; Retina; Visual Fields; Young Adult
PubMed: 28266057
DOI: 10.1111/cxo.12529