Retinal changes in Himalayan climbers
D. Rennie and J. Morrissey
Changes in the fundus of the eye were studied in 15 members of a
mountaineering expedition to Dhaulagiri, Nepal (elevation, 8,167 meters
[26,795 ft]). Retinal photographs were taken at sea level and at 5,883
meters (19,300) after each climber had descended from his highest point.
Five Nepali Sherpas and an additional American climber who came to the base
camp late in the climb were also studied. Vascular engorgement with
tortuosity, a 24% increase in arterial diameter, and a 23% increase in
venous diameter were observed. Retinal hemorrhages were seen in five
American climbers (33%), but in none of the Sherpas. The high incidence is
striking, but the cause is unknown. We suggest that the hypoxic
vasodilatation makes retinal vessels more vulnerable to sudden rises in
intravascular pressure.
