"PI-less DMEK": results of Descemet's membrane endothelial keratoplasty (DMEK) without a peripheral iridotomy

Purpose: To assess Descemet's membrane endothelial keratoplasty (DMEK) without performing a peripheral iridotomy (PI) prior to or during surgery ("PI-less DMEK"). Materials and methods: This retrospective study included consecutive patients that underwent PI-less DMEK by a single surgeon (EL) between February 2016 and February 2017 at the Rabin Medical Center, a Tertiary Hospital. Intraoperative and postoperative complications were assessed. Results: Thirty-one patients, mean age 75.9 +/- 7.9 years with 58.1% female were included. Leading indications for surgery were pseudophakic bullous keratopathy (18/31) and Fuchs' endothelial dystrophy (9/31). Preoperative best-corrected distance visual acuity was 1.13 +/- 0.59 1ogMAR (-6/80 Snellen). For 12/31 that had postoperative endothelial cell count measurements, cell loss was 49 +/- 20%. Intraoperative complications included anterior chamber (AC) hyphema during graft insertion requiring reinsertion (n = 1), and minor hyphema from the main corneal incision (n = 1). Partial slit lamp gas evacuation was performed in all patients 1.5 h postoperatively. Postoperative complications included partial graft detachment requiring rebubbling (n = 5), self-resolving minimal peripheral graft detachment (n = 5), uncontrolled intraocular hyper-tension requiring trabeculectomy in a patient with a history of medically controlled glaucoma (n = 1), postoperative cystoid macular edema that resolved medically (n = 1) and graft failure 5 months postoperatively (n = 1). No patients developed pupillary block. Excluding graft failure (n = 1), preoperative amblyopia (n = 2) and premature loss to follow-up (n = 1), final corrected distance visual acuity was 0.18 +/- 0.14 1ogMAR (similar to 20/30 Snellen) with 44.4% reaching 6/7.5 (Snellen) or more. Conclusions: PI-Less DMEK is a safe, technically easy, and effective modification that avoids the time and complications associated with performing a PI before or during surgery.