July 2018
Volume 59, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2018
The eye at high altitude.
Author Affiliations & Notes
  • Karel Van Keer
    Research Group Ophthalmology, Neurosciences, KU Leuven, Leuven, Belgium
    Ophthalmology Department, UZ Leuven, Leuven, Belgium
  • Joao Barbosa-Breda
    Research Group Ophthalmology, Neurosciences, KU Leuven, Leuven, Belgium
    Surgery and Physiology (Ophthalmology Unit), Faculdade de Medicina da Universidade do Porto, Porto, Portugal
  • Raf De Jongh
    Department of Anesthesiology, Ziekenhuis Oost Limburg, Genk, Belgium
  • Ivo Nijs
    Ophthalmology Department, Ziekenhuis Oost Limburg, Genk, Belgium
  • Mieke Wirix
    Ophthalmology Department, Ziekenhuis Oost Limburg, Genk, Belgium
  • Luís Abegão Pinto
    Visual Sciences Study Center, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
  • Ingeborg Stalmans
    Research Group Ophthalmology, Neurosciences, KU Leuven, Leuven, Belgium
    Ophthalmology Department, UZ Leuven, Leuven, Belgium
  • Evelien Vandewalle
    Research Group Ophthalmology, Neurosciences, KU Leuven, Leuven, Belgium
    Ophthalmology Department, UZ Leuven, Leuven, Belgium
  • Footnotes
    Commercial Relationships   Karel Van Keer, None; Joao Barbosa-Breda, None; Raf De Jongh, None; Ivo Nijs, None; Mieke Wirix, None; Luís Abegão Pinto, None; Ingeborg Stalmans, None; Evelien Vandewalle, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science July 2018, Vol.59, 3951. doi:
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      Karel Van Keer, Joao Barbosa-Breda, Raf De Jongh, Ivo Nijs, Mieke Wirix, Luís Abegão Pinto, Ingeborg Stalmans, Evelien Vandewalle; The eye at high altitude.. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3951.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : To investigate the physiological response and recovery of retro-bulbar, choroidal and retinal circulations to exposure to simulated high-altitude in healthy individuals.

Methods : Participants were examined with Optical Coherence Tomography (OCT), angio-OCT, retinography and colour Doppler imaging before, during and after a six-hour exposure to a simulated height of 4000m in a normobaric hypoxic chamber. Retinal nerve fiber layer (RNFL) and choroidal (CT) thicknesses were measured on structural OCT-scans. Vessel density in the macular and peripapillary areas were quantified as the mean gray value on angio-OCT images using ImageJ®. Central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were measured on retinographies using iFlexis® software. Repeated measures ANOVA was used to assess the changes within patients over time.

Results : Eighteen eyes of 18 healthy individuals aged 34.5±16.4 years were analyzed. RNFL, CT, peripapillary vessel density and CRVE showed a significant increase after six hours of hypoxia exposure (p = 0.036, p < 0.001, p = 0.040 and p <0.001 respectively) that was accompanied by a decrease in resistive and pulsatility indexes (both p<0.001) and an increase in ophthalmic artery flow velocities (p < 0.001). After one hour of recovery at sea level conditions, all the changes returned to baseline values.

Conclusions : We demonstrated that in healthy individuals a decrease in ambient oxygen saturation is compensated at the retrobulbar, choroidal and retinal micro- and macro-circulatory level. These changes quickly recover back to baseline upon return to normoxic conditions .

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Relative changes in central retinal venular equivalent, choroidal thickness, peripapillary vessel density, retinal nerve fiber layer thickness and ophthalmic artery resistive index at baseline, after a six-hour exposure to a simulated height of 4000m and one hour after removal of the hypoxic stimulus

Relative changes in central retinal venular equivalent, choroidal thickness, peripapillary vessel density, retinal nerve fiber layer thickness and ophthalmic artery resistive index at baseline, after a six-hour exposure to a simulated height of 4000m and one hour after removal of the hypoxic stimulus

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