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Dark Adaptation at High Altitude: An Unexpected Pupillary Response to Chronic Hypoxia in Andean Highlanders

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dc.contributor.author Healy, Katherine
dc.contributor.author Labrique, Alain B.
dc.contributor.author Miranda, J. Jaime
dc.contributor.author Gilman, Robert H.
dc.contributor.author Danz, David
dc.contributor.author Davila-Roman, Victor G.
dc.contributor.author Huicho, Luis
dc.contributor.author Leon-Velarde, Fabiola
dc.contributor.author Checkley, William
dc.date.accessioned 2019-02-06T14:45:35Z
dc.date.available 2019-02-06T14:45:35Z
dc.date.issued 2016
dc.identifier.uri https://hdl.handle.net/20.500.12866/5080
dc.description.abstract Healy, Katherine, Alain B. Labrique, J. Jaime Miranda, Robert H. Gilman, David Danz, Victor G. Davila-Roman, Luis Huicho, Fabiola Leon-Velarde, and William Checkley. Dark adaptation at high altitude: an unexpected pupillary response to chronic hypoxia in Andean highlanders. High Alt Med Biol. 17:208-213, 2016.-Chronic mountain sickness is a maladaptive response to high altitude (>2500 m above sea level) and is characterized by excessive erythrocytosis and hypoxemia resulting from long-term hypobaric hypoxia. There is no known early predictor of chronic mountain sickness and the diagnosis is based on the presence of excessive erythrocytosis and clinical features. Impaired dark adaptation, or an inability to visually adjust from high- to low-light settings, occurs in response to mild hypoxia and may serve as an early predictor of hypoxemia and chronic mountain sickness. We aimed to evaluate the association between pupillary response assessed by dark adaptometry and daytime hypoxemia in resident Andean highlanders aged >/=35 years living in Puno, Peru. Oxyhemoglobin saturation (SpO2) was recorded using a handheld pulse oximeter. Dark adaptation was quantitatively assessed as the magnitude of pupillary contraction to light stimuli of varying intensities (-2.9 to 0.1 log-cd/m(2)) using a portable dark adaptometer. Individual- and stimulus-specific multilevel analyses were conducted using mixed-effect models to elicit the relationship between SpO2 and pupillary responsiveness. Among 93 participants, mean age was 54.9 +/- 11.0 years, 48% were male, 44% were night blind, and mean SpO2 was 89.3% +/- 3.4%. The magnitude of pupillary contraction was greater with lower SpO2 (p < 0.01), and this dose relationship remained significant in multiple variable analyses (p = 0.047). Pupillary responsiveness to light stimuli under dark-adapted conditions was exaggerated with hypoxemia and may serve as an early predictor of chronic mountain sickness. This unexpected association is potentially explained as an excessive and unregulated sympathetic response to hypoxemia at altitude. en_US
dc.language.iso eng
dc.publisher Mary Ann Liebert
dc.relation.ispartof urn:issn:1557-8682
dc.rights info:eu-repo/semantics/restrictedAccess
dc.rights.uri https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
dc.subject chronic mountain sickness en_US
dc.subject hypoxemia en_US
dc.subject impaired dark adaptation en_US
dc.subject oxyhemoglobin saturation en_US
dc.subject portable field dark adaptometer en_US
dc.subject pupillary contraction en_US
dc.title Dark Adaptation at High Altitude: An Unexpected Pupillary Response to Chronic Hypoxia in Andean Highlanders en_US
dc.type info:eu-repo/semantics/article
dc.identifier.doi https://doi.org/10.1089/ham.2016.0041
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#3.02.00 es_PE
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#3.01.08
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#3.03.11
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#3.03.05


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