Luminance, Contrast Function and Visual Acuity in Functional Amblyopia

1966 ◽  
Vol 62 (3) ◽  
pp. 511-520 ◽  
Author(s):  
Ted Lawwill ◽  
Hermann M. Burian
Keyword(s):  
Visual Acuity ◽  
Luminance Contrast ◽  
Contrast Function

Color stimuli perception in presence of light scattering

2006 ◽  
Vol 23 (3-4) ◽  
pp. 597-601 ◽  
Author(s):  
MARIS OZOLINSH ◽  
MICHÉLE COLOMB ◽  
GATIS IKAUNIEKS ◽  
VARIS KARITANS
Keyword(s):  
Visual Acuity ◽  
Light Scattering ◽  
Luminance Contrast ◽  
White Background ◽  
Color Contrast ◽  
Entire Area ◽  
Red Color ◽  
Blue Component ◽  
Different Color ◽  
Landolt C

Perception of different color contrast stimuli was studied in the presence of light scattering: in a fog chamber in Clermont-Ferrand and in laboratory conditions where light scattering of similar levels was obtained, using different light scattering eye occluders. Blue (shortest wavelength) light is scattered in fog to the greatest extent, causing deterioration of vision quality especially for the monochromatic blue stimuli. However, for the color stimuli presented on a white background, visual acuity in fog for blue Landolt-C optotypes was higher than for red and green optotypes on the white background. The luminance of color Landolt-C optotypes presented on a LCD screen was chosen corresponding to the blue, green, and red color contributions in achromatic white stimuli (computer digital R, G, or B values for chromatic stimuli equal to RGB values in the achromatic white background) that results in the greatest luminance contrast for the white–blue stimuli, thus advancing the visual acuity for the white-blue stimuli. Besides such blue stimuli on the white background are displayed with a uniform, spatially unmodulated distribution of the screen blue phosphor emission over the entire area of the screen including the stimulus C optotype area. It follows that scattering, which has the greatest effect on the blue component of screen luminance, has the least effect on the perception of white–blue stimuli.

scholarly journals Visual performance in a flight simulator: multifocal intraocular lenses in pilots

2018 ◽  
Vol 3 (1) ◽  
pp. e000139
Author(s):  
Lee Lenton
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Luminance Contrast ◽  
Intraocular Lenses ◽  
Visual Performance ◽  
Flight Simulator ◽  
Night Time ◽  
Multifocal Intraocular Lenses ◽  
Low Luminance ◽  
Visual Tasks

ObjectiveTo compare the performance of adults with multifocal intraocular lenses (MIOLs) in a realistic flight simulator with age-matched adults with monofocal intraocular lenses (IOLs).Methods and AnalysisTwenty-five adults ≥60 years with either bilateral MIOL or bilateral IOL implantation were enrolled. Visual function tests included visual acuity and contrast sensitivity under photopic and mesopic conditions, defocus curves and low luminance contrast sensitivity tests in the presence and absence of glare (Mesotest II), as well as halo size measurement using an app-based halometer (Aston halometer). Flight simulator performance was assessed in a fixed-based flight simulator (PS4.5). Subjects completed three simulated landing runs in both daytime and night-time conditions in a randomised order, including a series of visual tasks critical for safety.ResultsOf the 25 age-matched enrolled subjects, 13 had bilateral MIOLs and 12 had bilateral IOLs. Photopic and mesopic visual acuity or contrast sensitivity were not significantly different between the groups. Larger halo areas were seen in the MIOL group and Mesotest values were significantly worse in the MIOL group, both with and without glare. The defocus curves showed better uncorrected visual acuity at intermediate and near distances for the MIOL group. There were no significant differences regarding performance of the vision-related flight simulator tasks between both groups.ConclusionsThe performance of visually related flight simulator tasks was not significantly impaired in older adults with MIOLs compared with age-matched adults with monofocal IOLs. These findings suggest that MIOLs do not impair visual performance in a flight simulator.

Low-contrast Acuity Under Strong Luminance Dynamics and Potential Benefits of Divisive Display Augmented Reality

2021 ◽  
Author(s):  
Chou P. Hung ◽  
Chloe Callahan-Flintoft ◽  
Paul D. Fedele ◽  
Kim F. Fluitt ◽  
Barry D. Vaughan ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Augmented Reality ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Luminance Contrast ◽  
Display System ◽  
Single Image ◽  
Low Contrast ◽  
Potential Benefits ◽  
High Dynamic

Understanding and predicting outdoor visual performance in augmented reality (AR) requires characterizing and modeling vision under strong luminance dynamics, including luminance differences of 10000-to-1 in a single image (high dynamic range, HDR). Classic models of vision, based on displays with 100-to-1 luminance contrast, have limited ability to generalize to HDR environments. An important question is whether low-contrast visibility, potentially useful for titrating saliency for AR applications, is resilient to saccade-induced strong luminance dynamics. The authors developed an HDR display system with up to 100,000-to-1 contrast and assessed how strong luminance dynamics affect low-contrast visual acuity. They show that, immediately following flashes of 25× or 100× luminance, visual acuity is unaffected at 90% letter Weber contrast and only minimally affected at lower letter contrasts (up to +0.20 LogMAR for 10% contrast). The resilience of low-contrast acuity across luminance changes opens up research on divisive display AR (ddAR) to effectively titrate salience under naturalistic HDR luminance.

scholarly journals Visual acuity as a function of luminance contrast of Landolt rings and adaptation luminance

1983 ◽  
Vol 7 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Koichi IKEDA ◽  
Koji NODA ◽  
Shoichiro YAMAGUCHI
Keyword(s):  
Visual Acuity ◽  
Luminance Contrast

Perception of Curves

1975 ◽  
Vol 41 (2) ◽  
pp. 495-504 ◽  
Author(s):  
Leonard Zusne
Keyword(s):  
Visual Acuity ◽  
Problem Solving ◽  
Discrimination Problem ◽  
Luminance Contrast ◽  
Perceptual Task ◽  
Two Dimensional ◽  
Random Polygons ◽  
Low Luminance ◽  
Distance Vision

In 4 experiments, in which 66 subjects participated, the perception of 6 types of curved contours in two-dimensional shapes was studied. Random polygons and their curvilinear transformations were presented for detection under low-luminance contrast conditions, oddity-type discrimination problem solving, tachistoscopic identification, and identification involving visual acuity in distance vision. In all experiments curvature affected perception at statistically significant levels, but the extent of this effect was a function of (1) the locus and direction of curvature, (2) the level of compactness-jaggedness of the figure, and (3) the nature of the perceptual task. Shapes with acute corners were more easily perceived than shapes with curved corners. Within these two classes of shapes, those with convex sides were perceived as having greater curvedness than those with concave contours. However, the degree to which curvature affected response was determined primarily by the nature of the perceptual task.

Effects of Luminance, Contrast, and Blur on Visual Acuity

1995 ◽  
Vol 72 (12) ◽  
pp. 864-869 ◽  
Author(s):  
CHRIS A. JOHNSON ◽  
EVANNE J. CASSON
Keyword(s):  
Visual Acuity ◽  
Luminance Contrast

scholarly journals Low-contrast Acuity Under Strong Luminance Dynamics and Potential Benefits of Divisive Display Augmented Reality

2020 ◽  
Author(s):  
Chou P. Hung ◽  
Chloe Callahan-Flintoft ◽  
Paul D. Fedele ◽  
Kim F. Fluitt ◽  
Barry D. Vaughan ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Augmented Reality ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Luminance Contrast ◽  
Display System ◽  
Single Image ◽  
Low Contrast ◽  
Potential Benefits ◽  
High Dynamic

Understanding and predicting outdoor visual performance in augmented reality (AR) requires characterizing and modeling vision under strong luminance dynamics, including luminance differences of 10000-to-1 in a single image (high dynamic range, HDR). Classic models of vision, based on displays with 100-to-1 luminance contrast, have limited ability to generalize to HDR environments. An important question is whether low-contrast visibility, potentially useful for titrating saliency for AR applications, is resilient to saccade-induced strong luminance dynamics. The authors developed an HDR display system with up to 100,000-to-1 contrast and assessed how strong luminance dynamics affect low-contrast visual acuity. They show that, immediately following flashes of 25× or 100× luminance, visual acuity is unaffected at 90% letter Weber contrast and only minimally affected at lower letter contrasts (up to +0.20 LogMAR for 10% contrast). The resilience of low-contrast acuity across luminance changes opens up research on divisive display AR (ddAR) to effectively titrate salience under naturalistic HDR luminance.

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