Subcontact Lens Bubble Formation under Low Atmospheric Pressure Conditions

摘要

Concern regarding contact lens wear in aviation has been the fear of subcontact lens bubble formation. Previous reports have documented the occurrence of bubbles with hard PMMA lenses. Reported here are the results of contact lens bubble studies with soft hydrophilic and rigid gas-permeable lenses. Testing was accomplished in simulated aircraft flights in hypobaric chambers and onboard military transport aircraft. Hypobaric chamberflights were of 3 types: high-altitude flights up to 25,000 ft; explosive rapid decompressions from, 8,000 ft to 25,000 ft; and 4-h flights at 10,000 ft. Transport aircraft typically had cabin pressures equivalent to 5,000 ft to 8,000 ft and ranged in duration from 3 to 10 h. For rigid gas-permeable lenses, central bubbles were detected in 2 of 10 eyes and occurred at altitudes greater than f20,000 ft. For soft contact lenses, bubble formation detected in 22 of 92 eyes tested, and occurred at altitudes as low as 6,000 ft. Soft lens bubbles were located only at the limbus and were without sequela to vision or corneal epithelial integrity. Bubbles under the rigid lenses were primarily central, with potential adverse effects on vision and the corneal epithelium. Keywords: Aviation medicine, Altitude depending, cornea.