scholarly journals Impacts of Mild and Moderate Acute Hypoxia on Visual Contrast Sensitivity

2021 ◽  
Author(s):  
Weiming Yan ◽  
Guanhua Zhao ◽  
Pan Long ◽  
Meizhu Chen ◽  
Zuoming Zhang ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Acute Hypoxia ◽  
Color Contrast ◽  
Blood Oxygen Saturation ◽  
Visual Contrast ◽  
Spatial Frequencies ◽  
Temporal Quadrant ◽  
Student’S T ◽  
Visual Contrast Sensitivity

Abstract Introduction: Acute hypoxia could hamper the visual performance during the aviation. In the study, we aimed to investigate the effects of acute hypoxia on the contrast sensitivity (CS) and the color contrast sensitivity (CCS).Methos: 12 healthy volunteers (aged 20-22 years old) were selected for CS and CCS examination at altitude of 300m, 3000m and 4500m by applying the hypobaric cabin to simulate acute hypoxia (3000m in height = mild hypoxia; 4500m = moderate hypoxia). All data were collected after the heart rate and the blood oxygen saturation became stable, and were analyzed by the paired student’s t-test. Results: The CS at the spatial frequency of 1.5 Cpd was significantly increased at the altitude of 3000m (P<0.05), while CS at the higher spatial frequencies was not significantly affected. The CS of 1.5 and 3.0 Cpd was increased at the altitude of 4500m (P<0.05), while the CS of higher spatial frequency did not change significantly. With the increased degree of hypoxia, the overall CCS was increased with a statistical difference at 4500m (P<0.05). The CCS of the temporal superior and inferior quadrants were significantly affected (P<0.05), while those in other quadrants were significantly changed. Conclusions: Mild and moderate acute hypoxia could affect the CS in the low spatial frequency. With the increased degree of acute hypoxia, CCS deteriorates with the temporal quadrant more vulnerable to be affected.

Visual Contrast Sensitivity Functions Obtained with Colored and Achromatic Gratings

1979 ◽  
Vol 21 (2) ◽  
pp. 225-228 ◽  
Author(s):  
Michael A. Nelson ◽  
Ronald L. Halberg
Keyword(s):  
Contrast Sensitivity ◽  
Spatial Information ◽  
Sensitivity Functions ◽  
Visual Contrast ◽  
Spatial Frequencies ◽  
Sinusoidal Gratings ◽  
Visual Contrast Sensitivity ◽  
Contrast Thresholds

Threshold contrasts for red, green, and achromatic sinusoidal gratings were measured. Spatial frequencies ranged from 0.25 to 15 cycles/deg. No significant differences in contrast thresholds were found among the three grating types. From this finding it was concluded that, under conditions of normal viewing, no significant differences should be expected in the acquisition of spatial information from monochromatic or achromatic displays of equal resolution.

Contrast Sensitivity of Air-Breathing Nonprofessional Scuba Divers at a Depth of 40 Meters

1992 ◽  
Vol 75 (1) ◽  
pp. 275-283
Author(s):  
Nico A. M. Schellart
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Fresh Water ◽  
Test Pattern ◽  
Sine Wave ◽  
Air Breathing ◽  
Scuba Divers ◽  
Visual Contrast ◽  
Sine Wave Gratings ◽  
Visual Contrast Sensitivity

Photopic contrast sensitivity of air-breathing scuba divers was measured with a translucent test pattern at depths up to 40 m. The pattern was composed of sine wave gratings with spatial frequency and contrast changing logarithmically. The spatial transfer characteristics were measured at various depths under controlled optical conditions in seawater and in fresh water. Analysis indicates that the visual contrast sensitivity, and therefore probably also acuity, of sport divers is not affected up to depths of 40 m. This holds under ideal as well as poor diving conditions.

Low Spatial Frequency Contrast Sensitivity Deficits in Migraine are not Visual Pathway Selective

Cephalalgia ◽  
2009 ◽  
Vol 29 (5) ◽  
pp. 539-549 ◽  
Author(s):  
AM McKendrick ◽  
GP Sampson
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Parvocellular Pathway ◽  
Functional Deficits ◽  
Visual Contrast ◽  
Sensitivity Loss ◽  
Significant Difference ◽  
Pathway Function ◽  
Migraine Group ◽  
Visual Contrast Sensitivity

Some people who experience migraine demonstrate reduced visual contrast sensitivity that is measurable between migraines. Contrast sensitivity loss to low spatial frequency gratings has been previously attributed to possible impairment of magnocellular pathway function. This study measured contrast sensitivity using low spatial frequency targets (0.25–4 c/deg) where the adaptation aspects of the stimuli were designed to preferentially assess either magnocellular or parvocellular pathway function (steady and pulsed pedestal technique). Twelve people with migraine with measured visual field abnormalities and 17 controls participated. Subjects were tested foveally and at 10° eccentricity. Foveally, there was no significant difference in group mean contrast sensitivity. At 10°, the migraine group demonstrated reduced contrast sensitivity for both the stimuli designed to assess magnocellular and parvocellular function ( P < 0.05). The functional deficits measured in this study infer that abnormalities of the low spatial frequency sensitive channels of both pathways contribute to contrast sensitivity deficits in people with migraine.

scholarly journals Abnormal Adaptation of Visual Contrast Sensitivity In Multiple Sclerosis Patients

1981 ◽  
Vol 8 (3) ◽  
pp. 227-234 ◽  
Author(s):  
J. Raymond ◽  
D. Regan ◽  
T.J. Murray
Keyword(s):  
Multiple Sclerosis ◽  
Contrast Sensitivity ◽  
Test Procedure ◽  
Acute Stage ◽  
Visual Contrast ◽  
Contrast Adaptation ◽  
Spatial Frequencies ◽  
Permanent Loss ◽  
Multiple Sclerosis Patients ◽  
Visual Contrast Sensitivity

SUMMARY:Some multiple sclerosis patients with 20/20 acuity complain of poor vision. In a previous report we accounted for this in our patient group by showing that multiple sclerosis had caused a depression of contrast sensitivity while sparing visual acuity. In this study we investigated whether some of this measured depression might be due to abnormally rapid or severe adaptation during the test procedure rather than a true permanent loss. Our finding was opposite to this supposition: adaptation was abnormally slight and/ or slow.Depressed contrast sensitivity was not well correlated with abnormal adaptation to contrast. In patients whose contrast sensitivity losses were restricted to a band of spatial frequencies, we found no evidence that abnormalities of contrast adaptation were restricted to this same spatial frequency band. Further evidence of dissociation between abnormal contrast sensitivity and abnormal contrast adaptation is that some patients with normal contrast sensitivity showed abnormally small adaptation.Our finding of abnormally slow or abnormally small contrast adaptation in MS patients seems to conflict with Enoch et al’s (1978) report of abnormally great adaptation after inspecting a bright stimulus. This apparent disagreement may be due to their use of prior dark adaptation, very bright adapting stimuli and patients in the acute stage of retrobulbar neuritis.

Parallel development of contour integration and visual contrast sensitivity at low spatial frequencies

2010 ◽  
Vol 472 (3) ◽  
pp. 175-178 ◽  
Author(s):  
Krisztina Benedek ◽  
Márta Janáky ◽  
Gábor Braunitzer ◽  
Alice Rokszin ◽  
Szabolcs Kéri ◽  
...  
Keyword(s):  
Contrast Sensitivity ◽  
Contour Integration ◽  
Parallel Development ◽  
Visual Contrast ◽  
Spatial Frequencies ◽  
Visual Contrast Sensitivity

Is the development of visual contrast sensitivity impaired in children with migraine? An exploratory study

Cephalalgia ◽  
2010 ◽  
Vol 30 (8) ◽  
pp. 991-995 ◽  
Author(s):  
Gábor Braunitzer ◽  
Alice Rokszin ◽  
Jenő Kóbor ◽  
György Benedek
Keyword(s):  
Visual System ◽  
Contrast Sensitivity ◽  
Exploratory Study ◽  
Migraine Without Aura ◽  
Healthy Children ◽  
Visual Contrast ◽  
Spatial Frequencies ◽  
Visual Contrast Sensitivity ◽  
Age And Sex

Introduction: Impairment of visual contrast sensitivity is a well-known phenomenon in adult migraineurs. Little is known, however, about whether contrast sensitivity deficits are already present in children with migraine. Methods: We conducted an exploratory study with 18 children with migraine without aura, in which we tested our subjects’ visual contrast sensitivity. Eighteen age- and sex-matched healthy children served as controls. Results: Among the youngest subjects (6–10 years) we found no significant differences at any of the spatial frequencies tested, as compared to the controls, whereas from the age of 10 on, migraineurs exhibited significantly poorer contrast sensitivity, especially at the lower spatial frequencies. Conclusion: To our knowledge, we are the first to report on such a deficit in children, and we conclude that our findings might be interpreted as reflecting an increased vulnerability of the visual system to migraine attacks as part of the migrainous endophenotype.

Preliminary Findings Suggesting Cyclic Changes in Visual Contrast Sensitivity during the Menstrual Cycle

1987 ◽  
Vol 64 (2) ◽  
pp. 587-594 ◽  
Author(s):  
Nancy Johnson ◽  
J. Timothy Petersik
Keyword(s):  
Contrast Sensitivity ◽  
Time Series Data ◽  
Series Data ◽  
Control Subjects ◽  
Visual Contrast ◽  
Spatial Frequencies ◽  
Amplitude Spectra ◽  
Cyclic Changes ◽  
Visual Contrast Sensitivity ◽  
Contrast Thresholds

Visual contrast thresholds to both stationary and moving gratings of three spatial frequencies (2, 4, and 16 cyc/deg) were measured over a 32-day period in two women displaying normal menstrual cycles and in two noncycling control subjects. The time-series data of each subject in each condition were Fourier analyzed and the resulting amplitude spectra showed differences between the two sets of subjects. The spectra of the control subjects were relatively flat, whereas those of the experimental subjects showed a number of peaks at several harmonics (periods). Conservative significance tests suggested that the peaks in the spectra of the cycling women were larger than might be expected by chance. The data also suggested that changes in sensitivity were greatest for 4-cyc/deg gratings, those nearest the peak of the normal contrast sensitivity function.

Sign in / Sign up

Export Citation Format

Share Document