Soft Contact Lenses Worn at a Simulated Altitude of 18 000 Feet

Five subjects wearing soft contact lenses were placed in a low pressure chamber where the atmospheric pressure was reduced to 50%. Subjective and objective criteria were used to determine corneal distress. After four hours at 1/2 atmosphere all 10 eyes showed objective changes and four out of five subjects claimed subjective changes indicating corneal distress. None of the subjects showed subjective or objective signs of similar changes, when the study was repeated at normal atmospheric pressure.