Numerous investigations of the effect of a reduction in atmospheric pressure or in the percentage of oxygen have been made on human beings. Studies made both in mountain expeditions and at sea level have shown not only that the entire organism is affected under such conditions but, more specifically, that the greatest effect appears to be on the central nervous system.1 The great interest in visual function under these conditions shown in the literature stems not alone from its practical significance in aviation but from the fact that the eye morphologically and metabolically is an extension of the brain.
During the first World War numerous studies were undertaken to determine the effect of oxygen deprivation on visual function. The results indicated some impairment at relatively high altitudes. The methods, however, were crude and not always well controlled. More recently, Goldmann and Schubert2 found a considerable increase in the