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Sensibilité au contraste
The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate visual acuity and to detect eye disease.
Synonyme(s)
Sensibilité visuelle au contrasteRelation(s)
- voir aussi au terme générique : [Descripteurs (mots clés)] Acuité visuelle
- voir aussi au terme générique : [Descripteurs (mots clés)] Perception de la forme
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Contrast Sensitivity on 1/f Noise Is More Greatly Impacted by Older Age for the Fovea Than Parafovea / Rekha Srinivasan in OVS : Optometry & Vision Science, vol. 98, 04 (Avril 2021)
[article]
in OVS : Optometry & Vision Science > vol. 98, 04 (Avril 2021)
Titre : Contrast Sensitivity on 1/f Noise Is More Greatly Impacted by Older Age for the Fovea Than Parafovea Type de document : article de périodique Auteurs : Rekha Srinivasan ; Andrew Turpin ; Allison M. McKendrick Année de publication : 2021 Langues : Français (fre) Descripteurs (mots clés) : [Thésaurus Mesh]Macula
[Thésaurus Mesh]Rétine
[Thésaurus Mesh]Sensibilité au contraste
[Thésaurus Mesh]Sujet âgéMots-clés : fovea Résumé : SIGNIFICANCE: Contrast sensitivity changes across the visual field with age and is often measured clinically with
various forms of perimetry on plain backgrounds. In daily life, the visual scene is more complicated, and therefore,
the standard clinical measures of contrast sensitivity may not predict a patient's visual experience in more natural
environments.
PURPOSE: This study aims to determine whether contrast thresholds in older adults are different from younger
adults when measured on a 1/f noise background (a nonuniform background whose spatial frequency content is
similar to those present in the natural vision environments).
METHODS: Twenty younger (age range, 20 to 35 years) and 20 older adults (age range, 61 to 79 years) with normal
ocular health were recruited. Contrast thresholds were measured for a Gabor patch of 6 cycles per degree (sine
wave grating masked by a Gaussian envelope of standard deviation 0.17°) presented on 1/f noise background
(root-mean-square contrast, 0.05 and 0.20) that subtended 15° diameter of the central visual field. The stimulus
was presented at four eccentricities (0°, 2°, 4°, and 6°) along the 45° meridian in the noise background, and nine
contrast levels were tested at each eccentricity. The proportion of correct responses for detecting the target at each
eccentricity was obtained, and psychometric functions were fit to estimate the contrast threshold.
RESULTS: Older adults demonstrate increased contrast thresholds compared with younger adults. There was an
eccentricity-dependent interaction with age, with the difference between groups being highest in the fovea compared with other eccentricities. Performance was similar for the two noise backgrounds tested.
CONCLUSIONS: Our results revealed a strong eccentricity dependence in performance between older and younger
adults, highlighting age-related differences in the contrast detection mechanisms between fovea and parafovea for
stimuli presented on nonuniform backgrounds.Note de contenu :
*Permalink : https://bibliotheque.helb-prigogine.be/opac_css/index.php?lvl=notice_display&id= [article]Exemplaires
Cote Support Localisation Section Disponibilité aucun exemplaire Contrast Sensitivity with Center-distance Multifocal Soft Contact Lenses / Augustine N. Nti in OVS : Optometry & Vision Science, vol. 99, 04 (Avril 2022)
[article]
in OVS : Optometry & Vision Science > vol. 99, 04 (Avril 2022)
Titre : Contrast Sensitivity with Center-distance Multifocal Soft Contact Lenses Type de document : article de périodique Auteurs : Augustine N. Nti ; Hannah R. Gregory ; Eric R. Ritchey ; James S. Wolffsohn ; David A. Berntsen Année de publication : 2022 Langues : Français (fre) Descripteurs (mots clés) : [Thésaurus Mesh]Lentilles de contact hydrophiles
[Thésaurus Mesh]Myopie
[Thésaurus Mesh]Sensibilité au contrasteMots-clés : lentilles de contact souples multifocales à distance centrale Résumé : SIGNIFICANCE: The contrast sensitivity (CS) function provides a more detailed assessment of vision than visual
acuity. It was found that center-distance multifocal contact lens designs that are increasingly being prescribed
for myopia control reduce distance photopic and mesopic CS in nonpresbyopic patients across a range of spatial
frequencies.
PURPOSE: This study aimed to determine the effect of center-distance multifocal soft contact lenses (MFCLs) on
CS under photopic and mesopic conditions in nonpresbyopic patients.
METHODS: Twenty-five myopic, nonpresbyopic adults were fitted binocularly with three lenses: Biofinity single vision
contact lens (SVCL), Biofinity Multifocal D +2.50 add, and NaturalVue Multifocal in random order. Contrast sensitivity was measured at distance (4 m) under photopic and mesopic conditions and at near under photopic conditions. Log CS by spatial frequency and area under the log contrast sensitivity function (AULCSF) were analyzed between lenses.
RESULTS: Distance photopic CS at each spatial frequency was higher with the SVCL than the MFCLs ( P < .001),
but there was no difference between the MFCLs ( P = .71). Distance mesopic CS from 1.5 to 12 cycles per degree
(cpd) was higher with the SVCL than the MFCLs (all P < .02); however, at 18 cpd, there was no difference in CS
between NaturalVue and the SVCL (P = .76), possibly because of spurious resolution. Photopic AULCSF for the SVCL
was roughly 10% greater than both MFCLs. Contrast sensitivity at near was generally similar between lenses, only slightly
lower with the NaturalVue at 11 and 15.5 cpd, but AULCSF at near was not different between lenses ( P > .05).
CONCLUSIONS: Multifocal contact lenses reduce distance contrast sensitivity under both photopic and mesopic
conditions. There is no clinically significant difference in near CS among all three lenses. These data show that
MFCLs have effects on vision that are not captured by standard high-contrast visual acuity testing.Permalink : https://bibliotheque.helb-prigogine.be/opac_css/index.php?lvl=notice_display&id= [article]Exemplaires
Cote Support Localisation Section Disponibilité aucun exemplaire Correlation between Contrast Sensitivity and Modulation Transfer Functions / Charles E. Leroux in OVS : Optometry & Vision Science, vol. 98, 11 (Novembre 2021)
[article]
in OVS : Optometry & Vision Science > vol. 98, 11 (Novembre 2021)
Titre : Correlation between Contrast Sensitivity and Modulation Transfer Functions Type de document : article de périodique Auteurs : Charles E. Leroux ; Elise Bouchet ; Pauline Espinasse ; Christophe Fontvieille ; Fabrice Bardin Année de publication : 2021 Langues : Français (fre) Descripteurs (mots clés) : [Thésaurus Mesh]Acuité visuelle
[Thésaurus Mesh]Adolescent
[Thésaurus Mesh]Collecte de données
[Thésaurus Mesh]Enfant
[Thésaurus Mesh]Optométrie
[Thésaurus Mesh]Sensibilité au contrasteMots-clés : corrélation qualité optique Résumé : SIGNIFICANCE
Previous studies found no correlation between visual acuity and optical quality in a population of young subjects with good vision. Using sinusoidal gratings, we systematically investigate the correlation between contrast sensitivity and optical quality as a function of spatial frequency.
PURPOSE
This study describes the correlation between the contrast sensitivity function (CSF) and the modulation transfer function (MTF) in a sample of young and informed subjects. Our results are compared with prior studies on the correlation between visual acuity and metrics of image quality. We also compare our results with previous studies that compare the CSF, the MTF, and the neural contrast sensitivity function (NCSF).
METHODS
The CSF of 28 informed subjects is measured in photopic conditions. The polychromatic MTF is computed from the measurements of monochromatic aberrations. The (CSF, MTF) correlation is estimated as the Pearson correlation coefficient, at each spatial frequency. The NCSF of each subject is estimated as the ratio of CSF to MTF.
RESULTS
We obtain high correlation coefficients (0.8) in the range of spatial frequencies of 3 to 6 cycles per degree, which also corresponds to high NCSF. Correlation decreases with increasing spatial frequency in the range of 6 to 18 cycles per degree (down to 0.0 at 18 cycles per degree). In that range, optical and neural contrast sensitivities are both approximately reduced by factor 4.
CONCLUSIONS
In our sample of young subjects with good vision, the CSF with sinusoidal gratings better differentiates eyes of good optical quality at intermediate spatial frequencies (3 to 6 cycles per degree) than at higher spatial frequencies (12 to 18 cycles per degree). At the highest tested spatial frequency of sinusoidal gratings (18 cycles per degree), there is no significant correlation between optical quality and contrast sensitivity.Permalink : https://bibliotheque.helb-prigogine.be/opac_css/index.php?lvl=notice_display&id= [article]Exemplaires
Cote Support Localisation Section Disponibilité aucun exemplaire Display Characterization for Contrast Sensitivity Testing / Gerard C. de Wit, P in OVS : Optometry & Vision Science, vol. 100, 04 (Avril 2023)
[article]
in OVS : Optometry & Vision Science > vol. 100, 04 (Avril 2023)
Titre : Display Characterization for Contrast Sensitivity Testing Type de document : article de périodique Auteurs : Gerard C. de Wit, P Année de publication : 2023 Langues : Français (fre) Descripteurs (mots clés) : [Thésaurus Mesh]Sensibilité au contraste
[Thésaurus Mesh]Tests de visionMots-clés : écran LCD Résumé : SIGNIFICANCE: Contrast sensitivity measurements using a computer display have been reported to lack accuracy when displaying small contrasts. This report investigates if the characterization/calibration of display luminance may contribute substantively to these kinds of described inaccuracies. PURPOSE: This study aimed to investigate what errors in contrast sensitivity may result from characterizing a display by fitting a gamma curve through physical or psychophysical luminance measurement data. METHODS: The luminance functions of four different in-plane switching liquid crystal displays (IPS LCDs) have been measured for all 256 gray levels (the actual luminance function). This has been compared with a gammafitted luminance curve (the gamma luminance function). Calculated are the errors in displayed contrast that may arise when assuming the gamma luminance function instead of the actual luminance function. RESULTS: The amount of error differs considerably between the displays. In general, for large contrasts (Michelson logCS <1.5), the error may become unacceptably high (>0.15 log unit). CONCLUSIONS: To improve the accuracy of testing contrast sensitivity with an LCD, it is necessary to fully characterize the display, measuring the luminance of each gray level instead of fitting a smooth gamma function through limited luminance data. Permalink : https://bibliotheque.helb-prigogine.be/opac_css/index.php?lvl=notice_display&id= [article]Exemplaires
Cote Support Localisation Section Disponibilité aucun exemplaire Interocular Contrast Balancing Partially Improves Stereoacuity in Keratoconus / Bhagya Lakshmi Marella in OVS : Optometry & Vision Science, vol. 100, 04 (Avril 2023)
[article]
in OVS : Optometry & Vision Science > vol. 100, 04 (Avril 2023)
Titre : Interocular Contrast Balancing Partially Improves Stereoacuity in Keratoconus Type de document : article de périodique Auteurs : Bhagya Lakshmi Marella ; Pravin K. Vaddavalli ; Jagadesh C. Reddy ; Miriam L. Conway ; Catherine M. Suttle ; Shrikant Bharadwaj Année de publication : 2023 Langues : Français (fre) Descripteurs (mots clés) : [Thésaurus Mesh]Kératocône
[Thésaurus Mesh]Sensibilité au contrasteMots-clés : stéréoacuité équilibrage du contraste contraste interoculaire Résumé : SIGNIFICANCE: Partial improvement in stereoacuity may be achieved by balancing the contrast input to the two eyes of patients with bilaterally asymmetric keratoconus. PURPOSE: Interocular differences in image quality, characterized by dissimilar contrast loss and phase shifts, are implicated in stereoacuity loss in keratoconus. This study determined whether contrast balancing improves stereoacuity in this disease condition and, if so, whether it is dependent on the baseline interocular contrast imbalance. METHODS: Interocular contrast imbalance and stereoacuity of 43 subjects (16 to 33 years) with bilaterally asymmetric keratoconus were tested with spectacle correction as baseline using a binocular rivalry paradigm and random-dot stereograms, respectively. Stereoacuity measurements were repeated in a subset of 33 subjects at their contrast balance point (i.e., contrast level in stronger eye allowing balanced rivalry with 100% contrast in weaker eye) and with contrast levels biased in favor of stronger or weaker eye, all conditions in randomized order. RESULTS: Contrast imbalance level was significantly correlated with the subject's stereoacuity at baseline (r = −0.47, P = .002). The median (25th to 75th interquartile range) stereoacuity improved by 34.6% (19.0 to 65.1%) from baseline (748.8 arc sec [261.3 to 1257.3 arc sec]) to the contrast balanced condition (419.0 arc sec [86.6 to 868.9 arc sec]) (P < .001), independent of their baseline stereoacuity or contrast imbalance levels (r < 0.2, P > .26 for both). Contrast bias in favor of the weaker eye (881.3 arc sec [239.6 to 1707.6 arc sec]) worsened stereoacuity more than a bias toward the stronger eye (502.6 arc sec [181.9 to 1161.4 arc sec]), both relative to the contrast balanced condition (P < .002). CONCLUSIONS: Interocular contrast balancing partially improves stereoacuity in bilaterally asymmetric keratoconus, independent of their baseline contrast imbalance level. Cyclopean viewing may be inherently biased toward the input from the stronger eye in keratoconus. Note de contenu :
Permalink : https://bibliotheque.helb-prigogine.be/opac_css/index.php?lvl=notice_display&id= [article]Exemplaires
Cote Support Localisation Section Disponibilité aucun exemplaire Licensure and Driving Status among Visually Impaired Persons / Joshua L. Robinson in OVS : Optometry & Vision Science, vol. 98,12 (Décembre 2021)
PermalinkTechnical Report: Repeatability of Contrast Sensitivity Test in Children / Rosa Hernández-Andrés in OVS : Optometry & Vision Science, vol. 97, 06 (Juin 2020)
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