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Retinal changes in Himalayan climbers
Archives of Ophthalmology (Chicago, Ill. : 1960)
|June 1, 1975
Summary
High-altitude mountaineering caused significant eye changes, including enlarged retinal vessels and hemorrhages in American climbers. Sherpas showed fewer changes, suggesting potential acclimatization benefits.
Area of Science:
- Ophthalmology
- Altitude Medicine
- Physiology
Background:
- Mountaineering expeditions to extreme altitudes present unique physiological challenges.
- Understanding the impact of high altitude on ocular structures is crucial for climber safety.
Purpose of the Study:
- To investigate changes in the eye's fundus among mountaineers at extreme altitudes.
- To compare the ocular responses of acclimatized Sherpas and unacclimatized climbers.
Main Methods:
- Retinal photography was performed on 15 expedition members at sea level and high altitude (5,883 meters).
- Ocular changes were assessed after climbers descended from their highest point.
- A control group of Sherpas and an additional climber were also studied.
Main Results:
- Observed vascular engorgement, tortuosity, and significant increases in arterial (24%) and venous (23%) diameters.
- Retinal hemorrhages occurred in 33% of American climbers but were absent in Sherpas.
- The cause of the high incidence of hemorrhages remains undetermined.
Conclusions:
- Hypoxic vasodilation may increase retinal vessel vulnerability to pressure fluctuations at high altitudes.
- Acclimatization may play a protective role against altitude-induced ocular complications.
- Further research is needed to elucidate the exact mechanisms and implications of these findings.