Fig. 27 Regardless of the type of gas employed (room air, sulfur hexafluoride [SF6], perfluoropropane [C3F8]), the main consideration for safe air flight is the percent volume of the vitreous cavity occupied by the air bubble at the time of air flight. During air flight takeoffs, a rapid climb in altitude produces expansion of the air bubble. Even a 20% air bubble may expand sufficiently to cause elevation of intraocular pressure. (Reprinted from Diekert J, O'Connor P, Schaklett D, et al: Air travel and intraocular gas. Ophthalmology 93:642, 1986)