Comparison of Sulfur Hexafluoride 20% versus Air Tamponade in Descemet Membrane Endothelial Keratoplasty

Purpose: To compare clinical outcomes using 20% sulfur hexafluoride (SF6) versus 100% air as a tamponade for graft attachment in Descemet membrane endothelial keratoplasty (DMEK). Design: Retrospective, comparative, interventional case series. Participants: Pseudophakic patients with Fuchs' endothelial dystrophy or pseudophakic bullous keratopathy that underwent DMEK using either 20% SF6 (group 1; 42 eyes) or 100% air (group 2; 39 eyes) tamponade between April 2010 and August 2011. Methods: A bimanual infusion technique was used to introduce and position the donor endothelium-Descemet membrane graft tissue. Outcome measures were analyzed at the following time points: before surgery, 3 and 6 months after surgery, and at yearly intervals up to at least 3 years. Main Outcome Measures: Corrected distance visual acuity (CDVA), manifest refraction, pachymetry, central endothelial cell count (cECC), complications, and rebubbling rates. Results: Three years after surgery, mean CDVA improved from 0.48 +/- 0.45 logarithm of the minimum angle of resolution (logMAR) to 0.04 +/- 0.23 in group 1 (P < 0.001) and from 0.67 +/- 0.45 logMAR to 0.09 +/- 0.13 logMAR in group 2 (P < 0.001). The percentage of eyes with CDVA of 20/25 or more was 85.71% (36/42 eyes) in group 1 and 82.05% (32/39 eyes) in group 2 (P = 0.43). Mean preoperative cECCs and at last follow-up were: group 1, 2525 +/- 338 cells/mm(2) and 1758 +/- 398 cells/mm(2) (mean cell loss, 30 +/- 11%; P = 0.008); and group 2, 2492 +/- 204 cells/mm(2) and 1678 +/- 373 cells/mm(2) (mean cell loss, 32 +/- 13%; P = 0.008). Endothelial cell loss was similar in both groups (P = 0.65). Intracameral air reinjection was needed in 1 patient in group 1 (2.38%) and in 5 patients in group 2 (12.8%). The rebubbling rate was significantly higher in group 2 (P = 0.004). No episodes of immunologic graft rejection were documented. Conclusions: Although clinical outcomes and corneal endothelial cell loss were similar in both groups, tamponade with 20% SF6 yielded a significantly lower incidence of graft detachments that may warrant its routine use in DMEK. Longer-term, randomized studies are needed to recommend this approach fully. (C) 2015 by the American Academy of Ophthalmology.