Hypobaric Hypoxia: Effects on Contrast Sensitivity in High Altitude Environments

Pescosolido, Nicola; Barbato, Alfonso; D, Di Blasio

doi:10.3357/amhp.3938.2015

Cited by 14 publications

(13 citation statements)

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“…The higher contrast sensitivity, which was 1.5 ~ 3 Cpd, was decreased signi cantly when the level was raised to 4500 m. This indicated that the small cell channel dealing with the lower spatial frequency was more sensitive to hypoxia. Our results was somewhat in accordance with that of Pescosolido N et al, who found that Hypobaric hypoxia conditions in pilots reduced contrast sensitivity (1.95 log to 1.05 log) in a statistically signi cant result [12] . Besides, et al also argued that the contrast sensitivity signi cantly increased after 5, 10 and 15 min of hypoxic exposure in their study [13] .…”

Section: Discussionsupporting

confidence: 94%

Impacts of Mild and Moderate Acute Hypoxia on Visual Contrast Sensitivity

Yan

Zhao

Long

et al. 2021

Preprint

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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.

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Section: Discussionsupporting

confidence: 94%

Impacts of Mild and Moderate Acute Hypoxia on Visual Contrast Sensitivity

Yan

Zhao

Long

et al. 2021

Preprint

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“…The recorded levels of SaO 2 were lower at PH when compared to both PV and CM, in accordance with literature. [22] The decrease in SaO 2 is explained by the fall of partial pressure of oxygen in the breathing air at high altitudes. Although the percentage of oxygen in inhaled air is constant at different altitudes, the fall in atmospheric pressure at higher altitudes decreases the partial pressure of inhaled oxygen and hence the driving pressure for gas exchange in the lungs.…”

Section: Correlation Between Iop and Systemic Parametersmentioning

confidence: 99%

The Mont Blanc Study: The effect of altitude on intra ocular pressure and central corneal thickness

et al. 2020

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The aim of the Mont Blanc Study was to investigate the relationship between intraocular pressure (IOP), central corneal thickness (CCT), and altitude in healthy subjects. Thirtythree eyes of 33 healthy volunteers (mean age: 24.8 years, 17 females) had their IOP measured with Perkins and I-Care tonometers and their CCT using ultrasound pachymetry at three locations in Italy with different altitudes: Pavia, (PV), 77 meters above sea level (a.s.l); Courmayeur (CM), 1300 meters a.s.l; Pointe Helbronner (PH), 3466 meters a.s.l.). The measurements were performed at 9 am, 11 am, 1 pm and 3 pm (±30') in indoor settings (mean temperature of 19˚C) in PV and PH. At 9 am, CCT and IOP were measured outdoor (mean temperature of-1.4˚C) at PH. The mean values of the IOP curve decreased from PV to PH with the Perkins (p = 0.02) and I-Care tonometers (p = 0.001). Instead, CCT increased upon ascension from PV to PH (p = 0.01), and from CM to PH (p = 0.002). When exposed to sub-zero temperature, the IOP increased (p<0.001), while the CCT did not change (p = 0.30). The results suggest that IOP significantly decreased and CCT significantly increased upon ascension from the sea level to higher altitudes.

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“…Exposure to hypoxia can have a significant effect on human vision, manifesting as changes in colour discrimination (Connolly et al, 2008), reduction in dark adaptation (Kobrick and Appleton, 1971), and loss of contrast sensitivity (Pescosolido et al, 2015), with the changes being more evident in low light environments (Connolly et al, 2008). In contrast, high altitude has no effect on visual acuity (Bosch et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

Retinal blood vessel diameters in children and adults exposed to a simulated altitude of 3,000 m

Mlinar

Debevec²,

Kapus³

et al. 2023

Front. Physiol.

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Introduction: Technological advances have made high-altitude ski slopes easily accessible to skiers of all ages. However, research on the effects of hypoxia experienced during excursions to such altitudes on physiological systems, including the ocular system, in children is scarce. Retinal vessels are embryologically of the same origin as vessels in the brain, and have similar anatomical and physiological characteristics. Thus, any hypoxia-related changes in the morphology of the former may reflect the status of the latter.Objective: To compare the effect of one-day hypoxic exposure, equivalent to the elevation of high-altitude ski resorts in North America and Europe (∼3,000 m), on retinal vessel diameter between adults and children.Methods: 11 adults (age: 40.1 ± 4.1 years) and 8 children (age: 9.3 ± 1.3 years) took part in the study. They spent 3 days at the Olympic Sports Centre Planica (Slovenia; altitude: 940 m). During days 1 and 2 they were exposed to normoxia (FiO2 = 0.209), and day 3 to normobaric hypoxia (FiO2 = 0.162 ± 0.03). Digital high-resolution retinal fundus photographs were obtained in normoxia (Day 2) and hypoxia (Day 3). Central retinal arteriolar equivalent (CRAE) and venular equivalents (CRVE) were determined using an Automated Retinal Image Analyser.Results: Central retinal arteriolar and venular equivalents increased with hypoxia in children (central retinal arteriolar equivalent: 105.32 ± 7.72 µm, hypoxia: 110.13 ± 7.16 µm, central retinal venular equivalent: normoxia: 123.39 ± 8.34 µm, hypoxia: 130.11 ± 8.54 µm) and adults (central retinal arteriolar equivalent: normoxia: 105.35 ± 10.67 µm, hypoxia: 110.77 ± 8.36 µm; central retinal venular equivalent: normoxia: 126.89 ± 7.24 µm, hypoxia: 132.03 ± 9.72 µm), with no main effect of group or group*condition interaction. A main effect of condition on central retinal arteriolar and venular equivalents was observed (central retinal arteriolar equivalent:normoxia: 105.34 ± 9.30 µm, hypoxia: 110.50 ± 7.67 µm, p < 0.001; central retinal venular equivalent: normoxia: 125.41 ± 7.70 µm, hypoxia: 131.22 ± 9.05 µm, p < 0.001).Conclusion: A 20-hour hypoxic exposure significantly increased central retinal arteriolar and venular equivalents in adults and children. These hypoxia-induced increases were not significantly different between the age groups, confirming that vasomotor sensitivity of the retinal vessels to acute hypoxia is comparable between adults and prepubertal children.

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Hypobaric Hypoxia: Effects on Contrast Sensitivity in High Altitude Environments

Abstract: The study demonstrated that hypoxia and variations of atmospheric pressure may produce corneal edema, including changes of CCT and, correlatively, CS reduction.

Cited by 14 publications

References 0 publications

Impacts of Mild and Moderate Acute Hypoxia on Visual Contrast Sensitivity

Impacts of Mild and Moderate Acute Hypoxia on Visual Contrast Sensitivity

The Mont Blanc Study: The effect of altitude on intra ocular pressure and central corneal thickness

Retinal blood vessel diameters in children and adults exposed to a simulated altitude of 3,000 m

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