Retinal vessel diameters in relation to hematocrit variation during acclimatization of highlanders to sea level altitude

Peter Kristian Kofoed, Birgit Sander, Gustavo Zubieta-Calleja, Line Kessel, Michael Larsen, Peter Kristian Kofoed, Birgit Sander, Gustavo Zubieta-Calleja, Line Kessel, Michael Larsen

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    6 Citations (Scopus)

    Abstract

    PURPOSE: To examine variations in retinal vessel diameters during acclimatization of native highlanders to normobaric normoxia at sea level. METHODS: Fifteen healthy residents of the greater La Paz region in Bolivia (3600 m above sea level) were examined thrice over a 72-day period, after having traveled by airplane to Copenhagen, Denmark, near sea level. RESULTS: In the study subjects, hematocrit decreased from 49.6% (day 2) to 45.9% (P = 0.0066, day 23) and 41.7% (P <0.0001, day 72); from days 2 to 23, retinal vein diameter increased by 2.68% (P = 0.0079); whereas retinal artery and vein diameters were indistinguishable from baseline after 72 days. No funduscopic signs of retinopathy were observed. Arterial blood pressure remained stable throughout the study. CONCLUSIONS: Although a 16% reduction in hematocrit occurred between days 2 and 72 after arrival at sea level, the only significant excursion observed was that the diameter of the veins was larger at day 23 than at days 2 and 72. Retinal vessel diameters demonstrated a wide homeostatic range during acclimatization-driven hematocrit variation.
    Original languageEnglish
    JournalInvestigative Ophthalmology & Visual Science
    Volume50
    Issue number8
    Pages (from-to)3960-3
    Number of pages4
    ISSN0146-0404
    DOIs
    Publication statusPublished - 1 Aug 2009

    Bibliographical note

    Keywords: Acclimatization; Adult; Altitude; Blood Pressure; Electroretinography; Female; Hematocrit; Humans; Intraocular Pressure; Male; Oxygen; Retinal Vessels; Visual Acuity

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