Air Bubble-Induced High Intraocular Pressure After Descemet Membrane Endothelial Keratoplasty

Purpose: To investigate the incidence and risk factors of pupillary block caused by an air bubble in the anterior chamber in the early postoperative period after Descemet membrane endothelial keratoplasty (DMEK). Methods: A retrospective review was conducted in 306 eyes that underwent DMEK from September 2009 through October 2014 at the Tubingen Eye Hospital. Intraocular pressure (IOP) elevation was defined as a spike above 30 mm Hg. In the first 190 eyes, an intraoperative peripheral iridectomy was performed at the 12-o'clock position and in the other 116 eyes at the 6-o'clock position. If possible, reasons for IOP elevation were identified. For all eyes, preoperative and postoperative slit-lamp examinations and IOP measurements were performed. Results: Overall, 30 eyes (9.8%) showed a postoperative IOP elevation within the first postoperative day. The incidence of IOP elevation was 13.9% (5/ 36) in the triple DMEK group, and 2 of 5 phakic eyes (40%) developed an air bubble-induced IOP elevation. All eyes presented with a de novo IOP elevation, associated in 25 patients with pupillary block from air anterior to iris and in 5 patients with angle closure from air migration posterior to the iris. All of them had an iridectomy at the 12-o'clock position. Conclusions: A postoperative pupillary block with IOP elevation caused by the residual intraoperative air bubble may be an important complication that could be avoided by close and frequent observations, especially in the first postoperative hours and by an inferior peripheral iridectomy and an air bubble with a volume of <= 80% of the anterior chamber.