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Purpose: To investigate 1-year clinical outcome and complication rates following Descemet membrane endothelial keratoplasty (DMEK) with sulfur hexafluoride 20% (SF 6 20%) anterior chamber tamponade compared with conventionally used 100% air for primary graft attachment during DMEK surgery., Methods: Records of 1112 consecutive DMEKs were reviewed retrospectively and grouped by anterior chamber tamponade used during DMEK surgery (SF 6 20% vs 100% air). Outcome measures included intraocular pressure (IOP), best spectacle-corrected visual acuity (BSCVA), endothelial cell density (ECD) and central corneal thickness (CCT) at 1, 3, 6 and 12 months after DMEK surgery. Complication rates were assessed, including intraoperative and postoperative complications, and graft detachment rate requiring rebubbling., Results: A total of 854 cases were included in this study. In 105 cases (12.3%), DMEK was performed with SF 6 20%, and in 749 cases (87.7%) 100% air was used for anterior chamber tamponade. Outcome results for IOP, BSCVA, ECD and CCT at all follow-up time points were comparable for both anterior chamber tamponade groups without statistical significant differences (p≥0.05), but graft detachment rate requiring rebubbling was significantly lower in the SF 6 20% group (p<0.001)., Conclusion: Whereas SF 6 20% anterior chamber tamponade does not seem to negatively affect the clinical outcome of DMEK surgery within the first postoperative year, use of SF 6 20% significantly reduces the rate of rebubblings., Competing Interests: Competing interests: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Inducible loss of gene function experiments are necessary to uncover mechanisms underlying development, physiology and disease. However, current methods are complex, lack robustness and do not work in multiple cell types. Here we address these limitations by developing single-step optimized inducible gene knockdown or knockout (sOPTiKD or sOPTiKO) platforms. These are based on genetic engineering of human genomic safe harbors combined with an improved tetracycline-inducible system and CRISPR/Cas9 technology. We exemplify the efficacy of these methods in human pluripotent stem cells (hPSCs), and show that generation of sOPTiKD/KO hPSCs is simple, rapid and allows tightly controlled individual or multiplexed gene knockdown or knockout in hPSCs and in a wide variety of differentiated cells. Finally, we illustrate the general applicability of this approach by investigating the function of transcription factors (OCT4 and T), cell cycle regulators (cyclin D family members) and epigenetic modifiers (DPY30). Overall, sOPTiKD and sOPTiKO provide a unique opportunity for functional analyses in multiple cell types relevant for the study of human development., Competing Interests: The authors declare no competing or financial interests., (© 2016. Published by The Company of Biologists Ltd.)