Optic nerve oedema at high altitude occurs independent of acute mountain sickness

Schatz, Andreas; Guggenberger, Vanessa; Fischer, Manuel; Schommer, Kai; Bartz‐Schmidt, Karl Ulrich; Gekeler, Florian; Willmann, Gabriel

doi:10.1136/bjophthalmol-2018-312224

Cited by 13 publications

(7 citation statements)

References 43 publications

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“…Notably, exposure to naturally high altitude environments has been also shown effects on eyes. The long-term exposure causes a number of eye disorders, such as pterygium (Lu et al, 2010), dry eye (Gupta et al, 2008), and lens opacity (Brilliant et al, 1983), whereas the short-term exposure often causes changes in visual function (Willmann et al, 2010; Gibson and Mckenna, 2011), refractive error (Mader et al, 1996), cornea thickness (Morris et al, 2007), retina vessels (Liu et al, 2013; Yang et al, 2019), optic nerve (Bosch et al, 2008; Schatz et al, 2018), as well as IOP.…”

Section: Introductionmentioning

confidence: 99%

Intraocular Pressure Changes of Healthy Lowlanders at Different Altitude Levels: A Systematic Review and Meta-Analysis

et al. 2019

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Background: High altitude, characterized by hypobaric hypoxia, low temperature, and intensive ultraviolet radiation, is identifiably one of the examples of scientific enquiry into aviation and space analogs. However, little is known about the ocular physiological response, especially intraocular pressure (IOP) changes at high altitude.Objectives: This study aimed to systematically review of high altitude exposure on IOP for healthy lowlanders with unoperated eyes.Methods: A comprehensive systematic literature search was conducted in the electronic databases until September 1st, 2019. A meta-analysis was performed following the preferred reporting items for systematic review and meta-analysis statement (PRISMA). We systematically searched the studies conducted over 2,000 m above sea level (a.s.l) in healthy lowlanders with measurements of IOP. Meta-analyses (random effect model and heterogeneity tests), subgroup analyses (altitude, duration, type, and pattern of exposure), sensitivity analysis, funnel plot, Begger's and Egger's test for publication bias were performed. Quality assessment was conducted using the Newcastle–Ottawa scale. The meta-analysis was registered in the PROSPERO database (CRD42019136865).Results: Of 9595 publications searched, 20 publications (n = 745) qualified for inclusion, with non-significant decrease in overall IOP [standardized mean difference (SMD): 0.14, 95% CI: −0.12–0.40; p = 0.30] with high heterogeneity (p < 0.001, I2 = 82%). However, subgroup analyses revealed significant decrease of IOP at high altitude of 3,000–5,500 m a.s.l (SMD: 0.57, 95% CI: 0.07–1.06; p = 0.03) whereas increase of IOP at extreme altitude of over 5,500 m a.s.l (SMD: −0.34, 95% CI: −0.61–0.06; p = 0.02). And the duration of exposure more than 72 hours (h) was likely to induce a decrease of IOP bordering on statistical significance at the 5% level (SMD: 1.29, 95% CI: 0.02–2.56; p = 0.05). Simultaneously, we also observed significant decrease of IOP for active exposure (e.g., physical activity and hiking, SMD: 0.81, 95% CI: 0.05–1.57; p = 0.04).Conclusion: Our analysis shows exposure to the altitude over 3,500 m a.s.l, duration of exposure more than 72 h and active exposure pattern may have modest, but significant effects on IOP. The higher altitude, the duration of exposure as well as physical activity seem to play crucial roles in the effects of high-altitude exposure on IOP.

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Section: Introductionmentioning

confidence: 99%

Intraocular Pressure Changes of Healthy Lowlanders at Different Altitude Levels: A Systematic Review and Meta-Analysis

et al. 2019

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“… 6 , 7 Few real-world studies of hypoxic environments in the plateau have been conducted. They have been limited to the study of one sublayer of the macula or optic disk, so the patterns of change in different regions and sublayers of the structure in hypoxic environments are inconclusive, 8 , 9 and investigating the correlation between changes in fundus tissues and the development of AMS has yielded little results. 10 , 11 …”

Section: Introductionmentioning

confidence: 99%

Patterns of Structural Changes in the Fundus Measured by Optical Coherence Tomography Angiography as Potential Markers of Acute Mountain Sickness

Zhao,

Zou,

Fan

et al. 2023

Trans. Vis. Sci. Tech.

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Purpose To use optical coherence tomography angiography (OCTA) to assess the pattern of changes in retinal and choroidal blood flow and structure in healthy volunteers who quickly went from sea level to a plateau and to determine the parameters associated with acute mountain sickness (AMS). Methods Forty-five individuals (89 eyes) were examined by OCTA and filled out the AMS questionnaire. One baseline examination was performed on the plain, followed by examinations at days 1, 3, and 5 after entering the plateau. Parameters were self-controlled to explore patterns of change, analyzed for correlation with AMS score, and modeled as a nomogram of AMS risk. Results On the plateau compared to the plain, vascular morphology showed dilated superficial macular retinal vessels and constricted deeper layers with increased vessel length density and fractal dimension; vessel density increased in all retinal strata and decreased in the choroidal macrovascular layer; and thickness increased except for a decrease in mean retinal thickness in the central macular sulcus. The rate of increase in retinal nerve fiber layer (RNFL) thickness in the inner and outer macular rings correlated with AMS score ( r = −0.211). The nomogram showed moderate accuracy (AUC = 0.672) and consistency (C-index = 0.659) in assessing AMS risk. Conclusions In high-altitude hypoxia, retinal vessels dilate and distort, resulting in increased blood flow density and thickness. Increased RNFL thickness in the paracentral macula may be a marker of low AMS risk. Translational Relevance The changes in the retinal structure of the fundus can be used to assess the risk of developing AMS.

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“…Instead, they showed an altitude-related increase in ONSD that seems to be independent of AMS symptoms and disappears after descent to lower altitudes. 16 -19…”

Section: Introductionmentioning

confidence: 99%

“…Instead, they showed an altitude-related increase in ONSD that seems to be independent of AMS symptoms and disappears after descent to lower altitudes. [16][17][18][19] There is limited data available on the use of point-ofcare echocardiography at high altitude. HAPE is a noncardiogenic type of pulmonary edema.…”

Section: Introductionmentioning

confidence: 99%

Point-of-Care Ultrasound Diagnosis of Acute High Altitude Illness: A Case Report

Wipplinger

Holthof

Lienert

et al. 2021

Wilderness & Environmental Medicine

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With the advent of high-quality portable ultrasound machines, point-of-care ultrasound (POCUS) has gained interest as a promising diagnostic tool for patients with high altitude illness. Although POCUS is used successfully in hospital environments to detect interstitial pulmonary edema and increased intracranial pressure, the relationship between specific sonographic criteria and high altitude illness is still unclear. We report the case of a healthy 32-y-old male who developed acute respiratory distress and neurologic impairment at 4321 m while participating in a high altitude medical research expedition. We discuss the potential of POCUS to diagnose acute high altitude illness by lung ultrasound, optic nerve sheath diameter measurement, and echocardiography. Ultrasound in combination with clinical findings helped us to exclude relevant differential diagnoses, start on-site treatment, and organize an evacuation. We used serial clinical and ultrasound examinations to assess the patient over time. Although its role in high altitude medicine needs further investigation, we believe that POCUS can be a valuable tool to aid clinical decision-making in remote, high altitude environments.

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Optic nerve oedema at high altitude occurs independent of acute mountain sickness

Cited by 13 publications

References 43 publications

Intraocular Pressure Changes of Healthy Lowlanders at Different Altitude Levels: A Systematic Review and Meta-Analysis

Intraocular Pressure Changes of Healthy Lowlanders at Different Altitude Levels: A Systematic Review and Meta-Analysis

Patterns of Structural Changes in the Fundus Measured by Optical Coherence Tomography Angiography as Potential Markers of Acute Mountain Sickness

Point-of-Care Ultrasound Diagnosis of Acute High Altitude Illness: A Case Report

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