Rigid gas permeable contact lenses in hyperbaric environments.

We studied the wearing of hard gas permeable contact lenses during decompression in a hyperbaric environment. Twenty-four exposures of three different lens materials were carried out in a hyperbaric chamber. The dry air dive profiles were: 45.72 m (150 ft) for 30 min and 15 min; 22.86 m (75 ft) for 15 min; and 11.43 m (37.5 ft) for 15 min. Bubbles occurred under all lens types; they were seen at simulated depths as shallow as 1.98 m (6.5 ft) after the least stressful exposure. Due to the tissue offgassing half-time of the eye, it is unlikely that the bubbles are a result of nitrogen from the eye. They probably arise from the tear layer.