BLOOD-PRESSURE, INTRAOCULAR-PRESSURE, AND RETINAL-VESSELS AFTER HIGH-ALTITUDE MOUNTAIN EXPOSURE

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  • 1 October 1989
    • journal article
    • research article
    • Vol. 60  (10) , 970-976
Abstract
Identical test protocols were used before and after 2 to 7 weeks of high altitude exposure in 23 climbers participating in 3 separate mountain expeditions in the Himalayas. The three groups reached altitudes of 4,000 m, 5,200, and 5,850 m, respectively. High altitude retinal hemorrhages (HARH) were found in three subjects (13%). Two weeks after the mountain exposure, reduced mean values of systolic (p < 0.005) and diastolic (p < 0.05) blood pressure and intraocular pressure (p < 0.005) were found. Retinal veins were dilated 2.6% (p < 0.001), and in both arteries (p < 0.001) and veins (p < 0.005) we observed a tendency for small vessels to dilate and large vessels to constrict. The intensity of reflection of light ("the central light reflex") from arteries was reduced (p = 0.003), indicating hemorrheology changes in the vessels. This study shows that significant changes in blood pressure, intraocular pressure and retinal vascularity follow hypoxic and physical strain of high altitude. The vascular conditioning of altitude acclimatization can be demonstrated in the retinal circulation 2 weeks after the exposure.