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

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 And...