scholarly journals Spatial contrast sensitivity does not explain random figure discrimination latency

1982 ◽  
Vol 32 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Michael S. Loop ◽  
Trudy J. Frey
Keyword(s):  
Contrast Sensitivity ◽  
Spatial Contrast Sensitivity ◽  
Random Figure

Mechanistic modeling of vertebrate spatial contrast sensitivity and acuity at low luminance

2012 ◽  
Vol 29 (3) ◽  
pp. 169-181 ◽  
Author(s):  
JOHN R. JARVIS ◽  
CHRISTOPHER M. WATHES
Keyword(s):  
Contrast Sensitivity ◽  
Mechanistic Modeling ◽  
Spatial Integration ◽  
Modulation Transfer ◽  
Neural Noise ◽  
Light Levels ◽  
Low Luminance ◽  
Spatial Contrast Sensitivity ◽  
Neural Factors ◽  
Experimental Values

AbstractThe validity of the Barten theoretical model for describing the vertebrate spatial contrast sensitivity function (CSF) and acuity at scotopic light levels has been examined. Although this model (which has its basis in signal modulation transfer theory) can successfully describe vertebrate CSF, and its relation to underlying visual neurophysiology at photopic light levels, significant discrepancies between theory and experimental data have been found at scotopic levels. It is shown that in order to describe scotopic CSF, the theory must be modified to account for important mechanistic changes, which occur as cone vision switches to rod vision. These changes are divided into photon management factors [changes in optical performance (for a dilated pupil), quantum efficiency, receptor sampling] and neural factors (changes in spatial integration area, neural noise, and lateral inhibition in the retina). Predictions of both scotopic CSF and acuity obtained from the modified theory were found to be in good agreement with experimental values obtained from the human, macaque, cat, and owl monkey. The last two species have rod densities particularly suited for scotopic conditions.

Spatial Contrast Sensitivity of Migraine Patients Without Aura

Cephalalgia ◽  
2002 ◽  
Vol 22 (2) ◽  
pp. 142-145 ◽  
Author(s):  
K Benedek ◽  
J Tajti ◽  
M Janáky ◽  
L Vécsei ◽  
G Benedek
Keyword(s):  
Healthy Volunteers ◽  
Contrast Sensitivity ◽  
Migraine Without Aura ◽  
Marked Decrease ◽  
Primary Headache ◽  
Visual Pathway ◽  
Control Subjects ◽  
Spatial Frequencies ◽  
Spatial Contrast Sensitivity ◽  
Visual Disturbances

Visual disturbances are frequent symptoms in migraine. Since there is a possibility of separate damage in the magno- or parvo-cellular visual pathway in migraine patients, we performed a study including the measurement of static and dynamic spatial contrast sensitivity on 15 patients suffering from migraine without aura under photopic and scotopic conditions. Fifteen healthy volunteers without primary headache served as controls. The results revealed a marked decrease in contrast sensitivity at low spatial frequencies in the migraine patients. Spatial contrast sensitivity demonstrated some lateralization, as the sensitivity to low spatial frequencies obtained through separate eyes showed significantly larger side-differences in migraine patients than in control subjects. These findings suggest that the mechanisms responsible for vision at low spatial frequencies are impaired in migraine patients. This might indicate impaired function of the magnocellular pathways in this condition.

scholarly journals Spatial contrast sensitivity: effects of reliability, test–retest repeatability and sample size using the Metropsis software

Eye ◽  
2019 ◽  
Vol 33 (10) ◽  
pp. 1649-1657 ◽  
Author(s):  
Thiago Paiva Fernandes ◽  
Natalia Leandro de Almeida ◽  
Pamela D. Butler ◽  
Natanael Antonio Santos
Keyword(s):  
Sample Size ◽  
Contrast Sensitivity ◽  
Reliability Test ◽  
Spatial Contrast Sensitivity
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