ELEVATED INTRAOCULAR PRESSURE FOLLOWING PARS PLANA VITRECTOMY DUE TO TRAPPED GAS IN THE POSTERIOR CHAMBERChin, Eric K. MD; Almeida, David R. P. MD, MBA, PhD; Strohbehn, Austin L. MD; Mahajan, Vinit B. MD, PhD; Russell, Stephen R. MD; Folk, James C. MDRetinal Cases and Brief Reports: October 2016 - Volume 10 - Issue 4 - p 334–337 doi: 10.1097/ICB.0000000000000256 Case Report Abstract In Brief Author Information Purpose: Elevated intraocular pressure is relatively common following pars plana vitrectomy and intraocular gas tamponade. We discuss a series of patients who experienced elevated intraocular pressure from pupillary block and angle closure secondary to trapped gas in the posterior chamber. Methods: Case series. Results: Case 1 is a patient who underwent pars plana vitrectomy for retinal detachment repair. The intraocular pressure was elevated on postoperative Day 3 because of trapped gas in the posterior chamber, and it did not lower with prone positioning, maximal medical therapy, and laser peripheral iridotomies. Aspiration of the trapped gas was done with the patient sitting upright using a 27-gauge needle at the limbus, which was curative. Case 2 provides anterior-segment optical coherence tomography images that confirmed the location of the trapped gas resulting in angle closure. Case 3 demonstrates the unfortunate sequelae of a central retinal artery occlusion following delayed recognition of this entity. Case 4 highlights the challenges encountered when migratory gas is also seen elsewhere in the eye. Conclusion: Clinicians should be aware of elevated intraocular pressure secondary to trapped gas in the posterior chamber, which may be recalcitrant to medical therapy. Aspiration of the trapped gas can alleviate both pupillary block and angle closure without compromising the gas tamponade. Elevated intraocular pressure following pars plana vitrectomy with intravitreal gas can occur because of migration of gas to the posterior chamber (i.e., between the intraocular lens and iris). Correctly identifying the trapped gas can allow for definitive management to avoid permanent visually-disabling complications. Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa. Reprint requests: Eric K. Chin, MD, Department of Ophthalmology and Visual Sciences, The University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242; e-mail: email@example.com None of the authors have any conflicting interests to disclose. © 2016 by Ophthalmic Communications Society, Inc.