[abstract] TEAR FILM BUBBLE FORMATION AS AN INDICATOR OF DECOMPRESSION.

Abstract

BACKGROUND: Decompression disorders can occur following a reduction in environmental pressure due to dissolved gases forming bubbles in affected tissues. The objective of this study was to evaluate the utility of tear film bubble formation as an indicator of decompression. METHODS: Formation of bubbles in tear film was monitored following decompression to a simulated altitude of 18,000 feet and following decompression from a simulated dive to 100 fsw for 15 minutes. Both experiments were conducted in a hypo/hyperbaric chamber. Seven subjects particpated in the former and eleven in the latter study. Tear film bubble formation was observed with a zoom photo-slit lamp microscope upon eye lid opening after a 5 second period of lid closure. RESULTS: Following decompression to altitude all subjects had bubbles present in their tear film after 9000 feet. The number and size of the bubbles increased with altitude and similarly decreased with descent. In addition, the content of the meibomian glands was expressed with the rapid climb to altitude resulting in substantial tear debris. Similarly, following decompression from the simulated dive to 100 fsw bubbles were observed in all subjects. The bubbles were randomly distributed in the exposed tear film and a large range was observed in their size. CONCLUSION: It is speculated that these tear film bubbles originate from the vascular supply of the lids and globe. They do not affect visual functioning and may provide an alternative method for monitoring decompression status.