نتایج جستجو برای: contrast sensitivity functions

تعداد نتایج: 1162208  

Journal: :Vision Research 2016
Naghmeh Mostofi Marco Boi Michele Rucci

Like all saccades, microsaccades cause both spatial and temporal changes in the input to the retina. In space, recent studies have shown that these small shifts precisely relocate a narrow (smaller than the foveola) high-acuity retinal locus on the stimulus. However, it has long been questioned whether the temporal modulations resulting from microsaccades are also beneficial for vision. To addr...

Journal: :Journal of vision 2007
Zhuping Qiu Pengjing Xu Yifeng Zhou Zhong-Lin Lu

For five anisometropic amblyopes and five normal controls, contrast sensitivities in both grating motion direction discrimination and moving grating detection were measured with the same moving sine-wave stimuli over a wide range of spatial and temporal frequencies. We found that the apparent local motion deficits in anisometropic amblyopia can be almost completely accounted for by deficits in ...

Journal: :The British journal of ophthalmology 1985
S Della Sala G Bertoni L Somazzi F Stubbe A J Wilkins

A simple technique is described for assessing the sensitivity of the human visual system to gratings at threshold contrast. The technique has advantages for clinical use in that it is (1) inexpensive, (2) quick to administer, (3) portable, and (4) relatively free from bias. Forty-two diabetic patients and 84 normal controls have been tested. Fifteen diabetic patients (6/20 with retinopathy and ...

2005
Helen Lew Sueng-Han Han Jong-Bok Lee Eun-Seok Lee

To verify the changes of mesopic and photopic contrast sensitivity function of sound eye whose visual acuity was kept the same after occlusion therapy in the amblyopic children. Fourteen sound eyes of amblyopic children (mean; 7.67 years; S.D., 1.50 years) who kept their visual acuity the same after the occlusion therapy were tested. The children had 6 hours of part-time patch therapy for 3 mon...

Journal: :Progress in brain research 2006
Marisa Carrasco

This chapter focuses on the effect of covert spatial attention on contrast sensitivity, a basic visual dimension where the best mechanistic understanding of attention has been achieved. I discuss how models of contrast sensitivity, as well as the confluence of psychophysical, single-unit recording, and neuroimaging studies, suggest that attention increases contrast sensitivity via contrast gain...

Journal: :Vision Research 1995
Piers Cornelissen Alex Richardson Alexandra Mason Sue Fowler John Stein

Development dyslexics perform differently from controls on a number of low level visual tasks. We carried out three experiments to explore some of these differences. Dyslexics have been found to have reduced luminance contrast sensitivity at mesopic luminance levels. We failed to replicate this finding at photopic luminance levels. We also compared the (photopic) coherent motion detection thres...

Journal: :بینا 0
حسین ضیایی h ziaei تهران- پاسداران- بوستان نهم- بیمارستان لبافی نژاد- مرکز تحقیقات چشم احمدرضا باقی ar baghi تهران- پاسداران- بوستان نهم- بیمارستان لبافی نژاد- مرکز تحقیقات چشم محمدرضا جعفری نسب mr jafarinasab تهران- پاسداران- بوستان نهم- بیمارستان لبافی نژاد- مرکز تحقیقات چشم مهدی یاسری m yaseri تهران- پاسداران- بوستان نهم- بیمارستان لبافی نژاد- مرکز تحقیقات چشم

purpose: to compare acrysof iq and akreos ao aspheric intraocular lenses (iols) in terms of spherical aberration and contrast sensitivity. methods: thirty-seven eyes of 37 patients undergoing phacoemulsification cataract surgery were randomized to implantation of acrysof iq or akreos ao iols. three months postoperatively, best-corrected visual acuity (bcva), spherical aberration (with 4 and 6 m...

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