EFFECTS OF HYPERBARIC EXPOSURE ON EYES WITH INTRAOCULAR GAS-BUBBLES

Background: Air travel is known to be potentially hazardous for patien ts with intraocular gas bubbles, and the external pressure changes ass ociated with hyperbaric oxygen therapy and scuba diving could be simil arly dangerous. Methods: Rabbits with a perfluoropropane/air gas mixtu re filling approximately 60% of the vitreous cavity of the right eye w ere exposed to 3 different hyperbaric pressure profiles to an equivale nt depth of 33 feet. The first group were a control group and were not exposed to hyperbaric pressures. The second group remained at an equi valent depth of 33 feet for 30 minutes, and the third group remained a t 33 feet for 1 minute. Both groups ascended to normal atmospheric pre ssure at a rate of 1 foot per minute. The fourth group remained at 33 feet for 1 minute and then ascended at a rate of 0.2 feet per minute. Results: In all eyes with an intraocular gas bubble, intraocular press ure dropped to zero when the atmospheric pressure was increased, and r ose to more than 50 mmHg when the atmospheric pressure was returned to normal. Pressures in excess of 50 mmHg were sustained for 10 minutes or longer in each rabbit exposed to one of the hyperbaric profiles. No significant intraocular pressure changes were observed in eyes withou t an intraocular gas bubble or eyes not exposed to hyperbaric pressure . Conclusion: Marked elevation in intraocular pressure occurs as a res ult of hyperbaric exposure in eyes with an intraocular gas bubble. Hyp erbaric exposure is therefore not advisable for patients with intraocu lar gas bubbles.