Topic
Contrast (vision)
About: Contrast (vision) is a research topic. Over the lifetime, 10379 publications have been published within this topic receiving 221480 citations.
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TL;DR: It is indicated that after‐cataract impairs resolution and contrast sensitivity without necessarily causing a marked increase in light scatter as measured at a large angle.
Abstract: The benefits of Nd:YAG laser capsulotomy on visual performance were evaluated in 13 patients with after-cataract following extracapsular cataract extraction. Besides clinical evaluation we measured: visual acuity, letter contrast sensitivity with and without the presence of a circular glare source (glare angle: 8 degrees). Finally, the patients were asked to evaluate their subjective glare problems. In all patients, visual acuity had decreased markedly compared to measurements 2 months after cataract surgery. Before capsulotomy we observed impaired letter contrast sensitivity and increased intraocular light scatter compared to normals. Following capsulotomy, VA and contrast sensitivity both improved by a factor of 2. The subjective glare problems diminished, although most patients showed minor decreases in intraocular light scatter. The limited glare induced loss of letter contrast sensitivity, present before capsulotomy, remained after treatment. Our study indicates that after-cataract impairs resolution and contrast sensitivity without necessarily causing a marked increase in light scatter as measured at a large angle.
55 citations
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TL;DR: CA occurring during extended periods of defocus is a possible candidate for a retinal error signal for myopia development and both atropine and reserpine increase contrast sensitivity to a level where no further CA could be induced by frosted goggles.
55 citations
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TL;DR: Current motion models which incorporate Reichardt-type/energy mechanisms and certain types of auxiliary signal transformations which precede those mechanisms do not adequately explain the effects of IFI intensity on the perceived motion of a sinusoidal grating or the effect of I FI duration on the perception of a contrast-modulated grating.
55 citations
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TL;DR: The results suggest that contrast effects occur at or before the extraction of depth and have implications for the response properties of disparity-selective mechanisms.
55 citations
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TL;DR: This study clearly demonstrates that diffuse luminance flicker increases optic nerve head blood flow and increased neural activity in the retina has no effect on choroidal blood flow, which appears to be largely independent of alterations in retinal metabolism.
Abstract: Purpose. In the retina there is general agreement that blood flow adapts in response to different conditions of light and darkness including diffuse luminance flicker. By contrast, regulation of choroidal blood flow in response to different light conditions is still a matter of controversy. Thus, we investigated the effect of diffuse luminance flicker on choroidal and optic nerve head blood flow. Methods. In a group of 14 healthy volunteers, choroidal blood flow and ocular fundus pulsation amplitude were assessed with laser Doppler flowmetry and laser interferometry, respectively. Measurements were done before, during and after stimulation with diffuse luminance flicker. Furthermore, the response of optic nerve head blood flow (ONHBF) to flicker stimulation was measured. Flicker stimuli were generated by a Grass® PS2 photostimulator, stimulating at a frequency of 8 Hz. Flicker light consisted of light flashes at a wavelength below 550nm and produced a retinal irradiance of 140 µW/cm 2. Blood pressure and ...
55 citations