Preclinical testing of small diameter Descemet membrane endothelial keratoplasty grafts to increase tissue availability

In this study, we describe a process of preparing, surgically manipulating, and validating a novel "small diameter" 4mm circular Descemet membrane endothelial keratoplasty (DMEK) graft in vitro. Three small diameter DMEK grafts can be prepared from a single donor endothelium and could, therefore, potentially expand the donor pool. Prior to clinical use, however, we aimed to examine each step of the process to determine the effect on the endothelial cell loss and whether or not cells retained their capacity to migrate uniformly. For this study, circular small diameter grafts, obtained from twelve corneas of ten donors deemed ineligible for transplantation, were included. Small diameter DMEK graft preparation was successful in all cases (n = 36). Endothelial cell density (ECD), determined in the eye bank on seventeen grafts, showed an average decrease from 2413 (+/- 189) cells/mm(2) before to 2240 (+/- 413) cells/mm(2) after preparation. Twenty-four grafts were used to simulate DMEK-surgery in vitro and were successfully stained with 0.06% trypan blue, loaded into a straight DMEK-injector, unfolded, positioned, and centered within the circular similar to 4mm descemetorhexis. The estimated % area populated by viable cells on the grafts decreased from on average 92 (+/- 3) % before to 78 (+/- 10) % (n = 4) after in vitro surgery. Cells displayed a capacity for uniform cell migration from all edges of the graft (n = 4) when embedded in the 3D hydrogel system. Our data show, that by using an in vitro model of DMEK-surgery it was possible to test the 4mm circular DMEK grafts from eye bank preparation to surgical implantation. The cell loss after in vitro surgery was comparable with the in vivo ECD decline early after DMEK and the capacity of the cells to migrate to potentially cover bare stroma indicates that these small diameter grafts may be a viable clinical option to treat central endothelial disease.Ophthalmic researc

Phacoemulsification after descemet membrane endothelial keratoplasty : incidence and influence on endothelial cell density

PURPOSE: To analyze the incidence of cataract extraction after Descemet membrane endothelial keratoplasty (DMEK) in phakic eyes and to evaluate the effect of phacoemutsification after DMEK on the donor endothelial cell density (ECD).METHODS: The clinical data of phakic patients with DMEK were examined. From this cohort, all patients who subsequently underwent phacoemutsification after DMEK were reviewed. Data from a prospectively collected dataset were analyzed, including demographic profile, ECD, corrected distance visual acuity (CDVA), central corneal thickness (CCT), and complications.RESULTS: From a series of 261 phakic patients with DMEK, 35 eyes (13.4%) required cataract surgery within the mean follow-up period of 54.2 +/- 28 months. The mean time from DMEK to phacoemutsification was 18 +/- 13 months (range: 3 69 months). The probability of cataract extraction after DMEK was 0.06 (95% CI: 0.03 to 0.09) at 1 year and 0.17 (95% CI: 0.12 to 0.22) at 10 years, respectively. ECD decreased from 1,314 +/- 524 cells/mm(2) before phacoemulsification to 1,167 +/- 443 cells/mm(2) (-11%) at 1 to 6 months postoperatively (P = .333). CDVA improved from 0.27 +/- 0.13 tog MAR preoperatively to 0.07 +/- 0.12 logMAR at 1 to 6 months postoperatively. CCT before phacoemulsification was 532 +/- 46 mu m and remained stable at 539 +/- 56 mu m at 1 to 6 months after phacoemulsification. Phacoemulsification did not elicit DMEK graft detachment in any of the eyes studied.CONCLUSIONS: The incidence and 10-year projection of cataract extraction in phakic eyes with DMEK was relatively tow. Phacoemulsification after DMEK provided excellent CDVA outcomes, did not induce graft detachment, and was associated with an acceptable decrease in ECD.Ophthalmic researc

Phacoemulsification After Descemet Membrane Endothelial Keratoplasty: Incidence and Influence on Endothelial Cell Density

PURPOSE: To analyze the incidence of cataract extraction after Descemet membrane endothelial keratoplasty (DMEK) in phakic eyes and to evaluate the effect of phacoemutsification after DMEK on the donor endothelial cell density (ECD).METHODS: The clinical data of phakic patients with DMEK were examined. From this cohort, all patients who subsequently underwent phacoemutsification after DMEK were reviewed. Data from a prospectively collected dataset were analyzed, including demographic profile, ECD, corrected distance visual acuity (CDVA), central corneal thickness (CCT), and complications.RESULTS: From a series of 261 phakic patients with DMEK, 35 eyes (13.4%) required cataract surgery within the mean follow-up period of 54.2 +/- 28 months. The mean time from DMEK to phacoemutsification was 18 +/- 13 months (range: 3 69 months). The probability of cataract extraction after DMEK was 0.06 (95% CI: 0.03 to 0.09) at 1 year and 0.17 (95% CI: 0.12 to 0.22) at 10 years, respectively. ECD decreased from 1,314 +/- 524 cells/mm(2) before phacoemulsification to 1,167 +/- 443 cells/mm(2) (-11%) at 1 to 6 months postoperatively (P = .333). CDVA improved from 0.27 +/- 0.13 tog MAR preoperatively to 0.07 +/- 0.12 logMAR at 1 to 6 months postoperatively. CCT before phacoemulsification was 532 +/- 46 mu m and remained stable at 539 +/- 56 mu m at 1 to 6 months after phacoemulsification. Phacoemulsification did not elicit DMEK graft detachment in any of the eyes studied.CONCLUSIONS: The incidence and 10-year projection of cataract extraction in phakic eyes with DMEK was relatively tow. Phacoemulsification after DMEK provided excellent CDVA outcomes, did not induce graft detachment, and was associated with an acceptable decrease in ECD.Ophthalmic researc

Spontaneous corneal clearance after graft detachment in DMEK

Descemet Membrane detachment is a potential complication after Descemet Membrane Endothelial Keratoplasty (DMEK). Here, we present a unique case of a DMEK surgery in a complicated eye that suffered a nearly complete DMEK graft detachment and later a graft opacification with a pseudo-anterior chamber. In Mid-November 2020, a planned DMEK was performed in a 64-year-old male patient due to corneal decompensation. Four months after DMEK, a fibrotic DMEK graft was seen across the anterior chamber with a pseudo-anterior chamber; however, the recipient cornea showed complete clearance with an endothelial cell count of about 1204 cells/mm2 and a best-corrected visual acuity of 20/25. Three months later, we observed a significant opacification of the detached graft, and the best-corrected distance visual acuity decreased to 20/63. We proceeded with the graft removal without performing a second DMEK. Ten months after graft removal, the cornea remained clear with an endothelial cell count of about 510 cells/mm2, and the best-corrected visual acuity was 20/25

Prospective evaluation of clinical outcomes between pre‐cut corneal grafts prepared using a manual or automated technique: with one‐year follow‐up

Purpose: Posterior lamellar corneal surgery is considered the standard of care for irreversible endothelial cell dysfunction. Pre-cut grafts can be prepared either manually (Descemet stripping endothelial keratoplasty; DSEK) or mechanically (Descemet stripping automated endothelial keratoplasty; DSAEK). We performed a head-to-head clinical comparison between DSEK and DSAEK grafts. Methods: All DSEK and DSAEK procedures performed by two corneal specialists at the University Medical Center Utrecht from 1 January 2016 through 31 October 2016 were prospectively included. Pre-cut grafts were delivered by two eye banks, which either exclusively prepared the DSEK or DSAEK grafts. Preoperative and postoperative measurements were obtained, and all surgical events and adverse events were recorded. Results: A total of 21 DSEK and 53 DSAEK procedures were included for analysis; the two groups were similar at baseline, with the exception of graft endothelial cell density, which was 2531 ± 67 versus 2748 ± 148 cells/mm 2 , respectively (p < 0.001). At the one-year follow-up visit, corrected distance visual acuity and endothelial cell loss were similar between the groups. Mean pachymetry was significantly lower in the DSEK group (521 ± 39 versus 588 ± 59 μm; p < 0.001), whereas the rebubbling rate was significantly higher in the DSEK group (47.6% versus 18.9%; p = 0.001). Finally, three grafts in the DSEK group experienced failure compared to one graft in the DSAEK group (14% versus 1.9%, respectively). Conclusion: Manually dissected and microkeratome-dissected grafts performed similarly with respect to vision and endothelial cell loss assessed one year after surgery. The higher incidence of graft failure among manually dissected (i.e. DSEK) grafts may be attributable to reduced relative thickness compared to DSAEK grafts and/or the resulting differences in tissue handling and the surgeon's learning curve