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Aim: To describe the changes in corneal graft thickness following ultrathin Descemet's Stripping Automated Endothelial Keratoplasty (UT-DSAEK) comparing pre- and postoperative values over a 24-month period., Methods: In this retrospective single-center case series, patients who received eye bank-prepared tissues for UT-DSAEK surgery were included. Preoperative and postoperative graft thickness measurements were determined in the eye bank and in clinic using anterior segment optical coherence tomography (AS-OCT) images. Graft thickness measurements and their percentage change between preoperative values and values at 1 day, 1 week and 1, 6, 12, 24 months were calculated., Results: In total, 47 eyes of 47 patients with a mean age of 69 ± 11 years (29 males) were included. Twnty-three patients had Fuchs' endothelial dystrophy (49%) and the remaining 24 had pseudophakic bullous keratopathy (51%). In total, 29/47 eyes underwent UT-DSAEK alone (62%) and 18/47 received combined cataract surgery as a triple procedure (38%). Preoperative donor graft thickness was 92 ± 28 μm. Compared to preoperative values, where graft thickness increased to 194 ± 101.3 μm at 1 day, 151.1 ± 71.4 μm at 1 week, and 108.4 ± 52.5 μm at 1 month. Graft thickness continued to gradually decrease over time until 6 months (91.7 ± 33.6 μm), and then plateaued at 12 months (83.9 ± 25.0 μm), showing minimal changes at 2 years (101.4 ± 37.5 μm)., Conclusion: Preoperative DSAEK graft thickness measurements as reported by the eye bank are a valid approximation of DSAEK graft thickness at 6 months after surgery and these measurements tend to stabilize over time up to 2 years after surgery., (© 2022. The Author(s), under exclusive licence to The Royal College of Ophthalmologists.)

Aim: To investigate the difference in adhesion and rebubbling rate between eye bank and surgeon prepared Descemet membrane endothelial keratoplasty (DMEK) tissues., Methods: Laboratory and clinical retrospective comparative interventional case series. Research corneal tissues were obtained for laboratory investigation. The clinical study involved patients with endothelial dysfunction who underwent DMEK surgery and tamponade with air. Tissues were stripped using a standard DMEK stripping technique (SCUBA) and shipped as prestripped or loaded in a 2.2 intra-ocular lens cartridge with endothelium facing inwards (preloaded) before transporting from the eye bank to the surgeon. For surgeon prepared tissues, all the grafts were stripped in the theatre and transplanted or stripped in the laboratory and tested immediately. Adhesion force and elastic modulus were measured in the centre and mid-periphery in a laboratory ex vivo investigation using atomic force microscopy, while rebubbling rates were recorded in the clinical study., Results: There was no difference in endothelial cell viability between surgeon or eye bank prepared tissue. Surgeon-stripped DMEK grafts in the laboratory investigation showed significantly higher elastic modulus and adhesion force compared to prestripped and preloaded tissues (p<0.0001). In the clinical data, rebubbling rates of 48%, 40% and 15% were observed in preloaded, prestripped and surgeon-stripped DMEK grafts, respectively. Rebubbling rates were significantly associated with combined cataract surgery (p=0.009) and with time from harvesting the graft to the surgery (p=0.02)., Conclusions: Decreased adhesion forces and elastic modulus in eye bank prepared tissues may contribute to increased rebubbling rates., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)