TY - JOUR
T1 - Retinal vessel diameters in relation to hematocrit variation during acclimatization of highlanders to sea level altitude
AU - Kofoed, Peter Kristian
AU - Sander, Birgit
AU - Zubieta-Calleja, Gustavo
AU - Kessel, Line
AU - Larsen, Michael
AU - Kofoed, Peter Kristian
AU - Sander, Birgit
AU - Zubieta-Calleja, Gustavo
AU - Kessel, Line
AU - Larsen, Michael
N1 - Keywords: Acclimatization; Adult; Altitude; Blood Pressure; Electroretinography; Female; Hematocrit; Humans; Intraocular Pressure; Male; Oxygen; Retinal Vessels; Visual Acuity
PY - 2009/8/1
Y1 - 2009/8/1
N2 - 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.
AB - 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.
U2 - 10.1167/iovs.08-3217
DO - 10.1167/iovs.08-3217
M3 - Journal article
C2 - 19339736
VL - 50
SP - 3960
EP - 3963
JO - Investigative Ophthalmology & Visual Science
JF - Investigative Ophthalmology & Visual Science
SN - 0146-0404
IS - 8
ER -