نتایج جستجو برای: contrast sensitivity functions

تعداد نتایج: 1162208  

Journal: :Vision research 2017
Wuli Jia Fangfang Lan Xin Zhao Zhong-Lin Lu Chang-Bing Huang Wuxiao Zhao Min Li

Intensive monocular perceptual learning can improve visual acuity, contrast sensitivity, and vernier acuity in the amblyopic eye in adults with amblyopia. It is however not clear how much monocular training can enhance binocular visual functions. In the current study, we aimed to evaluate effects of monocular training on a variety of binocular functions. Nineteen anisometropic amblyopes (18.5±1...

Journal: :Arquivos brasileiros de oftalmologia 2013
Mirella Telles Salgueiro Barboni Claudia Feitosa-Santana Jackson Barreto Junior Marcos Lago Samir Jacob Bechara Milton Ruiz Alves Dora Fix Ventura

PURPOSE The present study aimed to compare the postoperative contrast sensitivity functions between wavefront-guided LASIK eyes and their contralateral wavefront-guided PRK eyes. METHODS The participants were 11 healthy subjects (mean age=32.4 ± 6.2 years) who had myopic astigmatism. The spatial contrast sensitivity functions were measured before and three times after the surgery. Psycho and ...

2013
M.T.S. Barboni B.D. Gomes G.S. Souza A.R. Rodrigues D.F. Ventura L.C.L. Silveira

The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial fre...

2012
Andrew M. Haun Eli Peli

For the visual system, luminance contrast is a fundamental property of images, and is one of the main inputs of any simulation of visual processing. Many models intended to evaluate visual properties such as image discriminability compute perceived contrast by using contrast sensitivity functions derived from studies of human spatial vision. Such use is of questionable validity even for such ap...

Journal: :Vision Research 2015
Elise W. Dees Stuart J. Gilson Maureen Neitz Rigmor C. Baraas

Chromatic contrast sensitivity may be a more sensitive measure of an individual's visual function than achromatic contrast sensitivity. Here, the first aim was to quantify individual- and age-related variations in chromatic contrast sensitivity to a range of spatial frequencies for stimuli along two complementary directions in color space. The second aim was to examine whether polymorphisms at ...

Journal: :Vision Research 2005
William A. Simpson Sharon M. McFadden

Contrast sensitivity functions differ from observer to observer. We propose that these differences arise because each observer has unique weights for the outputs of the neural channels that underlie the contrast sensitivity function. By applying principal components analysis to individual contrast sensitivity functions of 297 observers, estimates of the channel tuning curves were found. We find...

Journal: :The British journal of ophthalmology 2002
A M Gardiner R A Armstrong M C M Dunne P I Murray

AIM To investigate the correlation between tests of visual function and perceived visual ability recorded with a quality of life questionnaire for patients with uveitis. METHODS 132 patients with various types of uveitis were studied. High (monocular and binocular) and low (binocular) contrast logMAR letter acuities were recorded using a Bailey-Lovie chart. Contrast sensitivity (binocular) wa...

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