An assessment of intraocular pressure rise in patients with gas-filled eyes during simulated air flight

Purpose: To investigate the safety of aircraft flight for patients with sma ll volumes of residual postoperative intraocular gas. Design: Nonrandomized comparative trial. Participants: Seventeen eyes (nine gas filled and eight control eyes) of ni ne patients and one eye of one control subject were tested. Methods: Patients with postoperative intraocular gas and the control subjec t were tested in the controlled environment of a hypobaric chamber to simul ate the cabin depressurization associated with a typical commercial aircraf t flight. Before, during, and after a simulated flight, the intraocular pre ssure (IOP) in the gas-containing and contralateral eyes was tested using t he Perkins (Edinburgh, UK) and Tone-Pen XL (Jacksonville, FL) tonometers. Main Outcome Measures: The absolute and percentage change in IOP with varie d cabin pressurization. Results: Of the nine patients with intraocular gas, seven had 10% to 15% ga s volume and two had 20% gas volume. In the 10% to 15% gas volume group, th e IOP rose by an average of 109% from baseline during ascent to an average cabin altitude of 7429 feet above sea level. The IOP dropped to an average of 30% above baseline IOP during the cruise phase and further decreased to an average of 38% below baseline IOP on return to baseline altitude. In the 20% gas volume group, the IOP rose by an average of 84% from baseline duri ng ascent to an average cabin altitude of 3400 feet above sea level. The IO P dropped to an average of 42% below baseline IOP on return to baseline alt itude. The IOP in the contralateral control eyes did not vary with altitude changes. No patient experienced pain or visual loss during the experiments . Conclusions: Our results demonstrate that IOP may rise significantly in gas -filled eyes during simulated air flight, supporting the current conservati ve recommendation against air travel for most patients with intraocular gas bubbles. Further testing is warranted to develop a more objective measure of intraocular gas volume estimation and to define better the tolerability of aircraft flight for patients with intraocular gas. Ophthalmology 2001;10 8:40-44 (C) 2001 by the American Academy of Ophthalmology.