Expansion of long-acting gas bubbles for intraocular use. Principles and practice

Expansion of long-acting gas bubbles used in vitreoretinal surgery may lead to increased intraocular pressure and central retinal artery occlusion. To further understand the principles controlling the expansion of long-acting gases, we compared the expansion of perfluoropropane gas bubbles with that of sulfur hexafluoride gas bubbles in an in vitro model, as well as in rabbits. We found that perfluoropropane bubbles expand more rapidly and to a greater extent than do sulfur hexafluoride bubbles in the first 24 hours. The early rate of expansion of a long-acting gas is largely dependent on convection of the surrounding fluid and is independent of the type of long-acting gas. Early postoperative monitoring of intraocular pressure is, therefore, equally important when using any long-acting gas.