Comparison of 20% sulfur hexafluoride with air for intraocular tamponade in Descemet membrane endothelial keratoplasty (DMEK)

Purpose: To compare the effect of 20% sulfur hexafluoride (SF₆) with that of air on graft detachment rates for intraocular tamponade in Descemet membrane endothelial keratoplasty (DMEK). Methods: Forty-two eyes of patients who underwent DMEK by a single surgeon (A.S.J.) at Wilmer Eye Institute between January 2012 and 2014 were identified; 21 received air for intraocular tamponade and the next consecutive 21 received SF₆. The main outcome measure was the graft detachment rate; univariate and multivariate analyses were performed. Results: The graft detachment rate was 67% in the air group and 19% in the SF₆ group (p < 0.05). No complete graft detachments occurred, and all partial detachments underwent intervention with injection of intraocular air. The percentages of eyes with 20/25 or better vision were not different between the groups (67% vs. 71%). Univariate analysis showed significantly higher detachment rates with air tamponade (OR, 8.50; p < 0.005) and larger donor graft size (OR, 14.96; p < 0.05). Multivariate analysis with gas but not graft size included showed that gas was an independent statistically significant predictor of outcome (OR, 6.65; p < 0.05). When graft size was included as a covariate, gas was no longer a statistically significant predictor of detachment but maintained OR of 7.81 (p=0.063) similar to the results of univariate and multivariate analyses without graft size. Conclusion: In comparison with air, graft detachment rates for intraocular tamponade in DMEK were significantly reduced by 20% SF₆.