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

Abstract

To compare clinical outcomes using 20% sulfur hexafluoride (SF6) versus 100% air as a tamponade for graft attachment in Descemet membrane endothelial keratoplasty (DMEK). Retrospective, comparative, interventional case series. 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. 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. Corrected distance visual acuity (CDVA), manifest refraction, pachymetry, central endothelial cell count (cECC), complications, and rebubbling rates. 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. 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.