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TitreThe eye at high altitude
Abstract Nr.2077
ButTo investigate the response and recovery of retro-bulbar, choroidal and retinal circulations to exposure to normobaric hypoxia in healthy individuals.
MéthodesParticipants 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 high-altitude chamber. Retinal nerve fiber layer (RNFL) and choroidal thickness (CT) were measure and vessel density was quantified as the mean gray value on angio-OCT images. Central retinal arteriolar (CRAE) and venular (CRVE) equivalent were measured on retinographies. Repeated measures ANOVA was used to assess the changes within patients over time.
Résultats18 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, all these changes returned to baseline values.
ConclusionTo the best of our knowledge, this study stands as one of the most exhaustive studies on changes in ocular blood flow in response to prolonged hypoxia. We demonstrate that in healthy individuals the decrease in ambient oxygen saturation at high altitudes is compensated at the retrobulbar, choroidal and retinal micro- and macrocirculatory levels and that these changes quickly recover back to baseline.
Conflit d'intérêtNon
Auteur 1
NomVAN KEER
InitialesK
InstitutUZ Leuven
VilleLeuven
Auteur 2
NomBarbosa Breda
InitialesJ
InstitutUZ Leuven
VilleLeuven
Auteur 3
NomDe Jongh
InitialesR
InstitutZOL
VilleGenk
Auteur 4
NomNijs
InitialesI
InstitutZOL
VilleGenk
Auteur 5
NomWirix
InitialesM
InstitutZOL
VilleGenk
Auteur 6
NomAbegão Pinto
InitialesL
InstitutCentro Hospitalar Lisboa Norte
VilleLisbon
Auteur 7
NomStalmans
InitialesI
InstitutUZ Leuven
VilleLeuven
Auteur 8
NomVandewalle
InitialesE
InstitutUZ Leuven
VilleLeuven
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