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The corneal endothelial transplantation involves the transfer and attachment of a single-layered corneal endothelial tissue to the narrow space between the cornea and iris. Given the high risk of damage to the endothelial tissue and surrounding corneal tissues when using sharp instruments inserted externally to apply force during the process, the development of a device capable of transferring corneal endothelial tissue using a magnetic field became necessary. This study aims to develop a magnetic control device for transferring corneal endothelial tissue with attached magnetic particles to the transplant site, validate its appropriate transfer capabilities, and assess its applicability to corneal endothelial transplantation. For this purpose, a magnetic field-generating manipulation device equipped with four electromagnets controlled by a joystick and microcomputer was developed. Through simulated experiments, the strength of the magnetic field and the attraction force on the tissue were predicted, and the actual magnetic field strength was measured for validation. To measure the magnetic transfer force, experiments were conducted by towing corneal endothelial tissue fixed with 6 mg, 12 mg, and 18 mg plastic weights. Subsequently, the tissue's transfer speed was measured after applying continuous and pulsed magnetic fields. The results confirmed the feasibility of tissue transfer using the magnetic control device, and it was observed that pulsed magnetic fields led to faster transfer speeds and easier control compared to continuous magnetic fields. Exploratory animal experiments using rabbits were conducted to simulate real surgical conditions, confirming the feasibility of corneal endothelial tissue transfer and attachment.

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Endothelial transplantation has recently been accepted worldwide, in the long history of corneal transplantation. The introduction of endothelial keratoplasty (Descemet stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty) has enabled us to expand the surgical indications owing to the low incidence of rejection and quick recovery of visual function. New technologies have been developed to ensure stable postoperative outcomes with a shorter learning curve, such as transplantation using cultured human endothelial cells and induced pluripotent stem cells (iPS) or new devices such as artificial endothelium. This review discusses the history and characteristics of corneal transplantation alongside new treatment options that may offer hope for patients with endothelial disease in the future.

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INTRODUCTION: To report the first endothelial keratoplasty procedures performed using a 3D digital head-mounted ophthalmic exoscope. METHODS: Three patients underwent Descemet stripping automated endothelial keratoplasty (DSAEK) using a 3D digital ophthalmic exoscope (Beyeonics One, Beyeonics Vision, Haifa, Israel) at the Tel Aviv Sourasky Medical Center, Tel Aviv, Israel. RESULTS: All procedures were uneventful, leading to resolution of corneal edema and vision improvement. Surgeons reported excellent visualization and minimal lag, almost negligible, with the benefits of improved ergonomics and the use of head gestures to control zoom, focus, brightness, and panning. There were no postoperative complications. CONCLUSION: The new 3D digital ophthalmic exoscope system can be successfully used in DSAEK surgery with potential advantages in ergonomics, picture quality, and image control. Further studies can compare this system with either standard operating microscopes or 3D heads-up display systems.

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PURPOSE: To compare clinical outcome and complications of Descemet stripping automated keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK). METHODS: This is a retrospective study of the first consecutive cases of DSAEK and DMEK performed by a single surgeon at a tertiary referral centre. Best-corrected visual acuity (BCVA), postoperative complications, rate of rebubbling and regraft were the main outcome measures. RESULTS: The study included 241 eyes, 116 subjected to DSAEK and 125 to DMEK. Fuchs endothelial dystrophy (FED) was the predominant diagnosis in both groups. Mean BCVA at all follow-ups up to 2 years was in favour of DMEK. Median BCVA (decimal) at 1 year was 0.4 (0.13-0.60; interquartile range) for the DSAEK and 0.8 (0.6-1.0) for the DMEK group, p<0.001. Preoperative BCVA in the DSAEK group was lower than in DMEK. There was no significant difference in visual improvement between groups at 1 year postoperatively. The most common postoperative complication in both groups was a pupillary block with high intraocular pressure, 27% and 34% respectively. This was not affected by the presence of an iridectomy/iridotomy. In the DMEK group, gas provided significantly better adherence than air (p=0.020). Rebubbling for partial/total detachment was performed in 7% (DSAEK) and 11% (DMEK) of cases, p=0.361. Regraft within 2 years was performed in 13% of eyes in the DSAEK and 17% in the DMEK group, p=0.450. No case of graft rejection occurred. CONCLUSION: Both DSAEK and DMEK provide overall satisfying outcome and the two techniques do not differ significantly in postoperative pupillary block, detachment rate, early graft failure or graft rejection. However, differences at baseline may have influenced or obscured potential differences. In DMEK procedures, gas seems to facilitate early graft adherence.

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Corneal endothelial dysfunction is a major cause of corneal blindness and is mainly treated by corneal transplantation. However, the global shortage of donor cornea hampers its application. Intracameral injection of cultured primary corneal endothelial cells (CECs) was recently confirmed in clinical trials. However, abnormal adhesion of the grafted CECs affects the application of this strategy. In this study, we explored if laminin 511 (LN511) improves the therapeutic function of the intracameral CEC injection for corneal endothelial dysfunction. To mimic the late stage of corneal endothelial diseases, intense scraping was developed to remove CECs and extracellular matrix of the posterior Descemet's membrane (DM) without DM removal in rabbits. Then, Dulbecco's phosphate-buffered saline (DPBS) and LN511 were intracamerally injected as the control and intervention groups, respectively. We found that the injected LN511 could settle and form a coating on the posterior surface of DM. After CEC transplantation, corneal clarity of rabbits in the LN511 group was rapidly recovered within 7 days, whereas the corneal recovery took 14 days in the DPBS group. Corneal thickness of LN511 group decreased to 413.3 ± 20.8 µm 7 days after operation, which was significantly lower than 1086.3 ± 78.6 µm of DPBS group (p < 0.01). Moreover, for the grafted CECs, LN511 promoted the rapid adhesion, tight junction formation, and expression of Na+/K+-ATPase and ZO-1. In vitro analysis revealed that the functions of LN511 on the cultured human CECs mechanistically depended on the cell density and the nuclear-cytoplasmic translocation of the Yes-associated protein. Our study demonstrated that LN511 precoating promoted the adhesion of the transplanted CECs and enhanced the functional regeneration of the corneal endothelium. Thus, our data suggested that the strategy of LN511 precoating and CECs' intracameral injection could be a potential method for the therapy of corneal endothelial dysfunction. Impact statement Intracameral injection of cultured corneal endothelial cells (CECs) is a potential alternative therapy for corneal endothelial dysfunction and has been proven to be effective in clinical trials. However, abnormal adhesion of the grafted CECs affects its application. In this study, intense scraping was developed to remove CECs and extracellular matrix of the posterior Descemet's membrane (DM) without DM removal for the therapy of late stage of corneal endothelial diseases. Laminin 511 was intracamerally injected to form a coating, improve the posterior DM, enhance the adhesion of the grafted CECs, and promote the functional regeneration of CEC transplantation through Yes-associated protein signaling.

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PURPOSE: The aim of this study was to describe the postoperative outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) performed using our newly developed graft inserter (NS Endo-Inserter) and compare the findings with those for DSAEK performed using the Busin glide. PATIENTS AND METHODS: In this retrospective, case-control, institutional study, we studied the clinical outcomes of DSAEK performed using the NS Endo-Inserter (NS group, n=13) or the Busin glide (Busin group, n=10) for patients with corneal endothelial dysfunction. Clinical parameters, including the distance-corrected visual acuity (DCVA), endothelial cell (EC) loss, and intraoperative/postoperative complications, were assessed over a 6-month follow-up period. RESULTS: At 6 months after surgery, the mean DCVA showed no significant difference between the two groups. EC loss at 3 and 6 months after DSAEK was 9.1%±20.7% and 18.2%±22.6%, respectively, in the NS group and 44.0%±25.5% and 46.5%±23.3%, respectively, in the Busin group; differences between groups were statistically significant at both 3 and 6 months (P=0.024 and P=0.016, respectively). Anterior chamber hemorrhage was observed in one patient in the Busin group. Rebubbling after surgery was required for one eye in the Busin group. No complications were observed in the NS group. CONCLUSION: Our newly developed graft inserter for DSAEK may cause significantly less EC damage than the conventional pull-through technique using the Busin glide. Our inserter permits safe endothelial graft delivery without anterior chamber collapse and can result in successful graft attachment without complications at 6 months after surgery.

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We aimed to bioengineer a scaffold that can facilitate the transplantation of corneal endothelial cells (CEC), given the global shortage of cadaveric donor tissues. Although agarose (A) has outstanding biocompatibility and mechanical properties, it natively does not permit cell adhesion. In this study, agarose was modified with different attachment signals: GRGD (giving AR as product), lysine (AK), poly lysine (AP), and fish-derived gelatin (AG). Samples with varying conjugation ratios were prepared. All products formed bulk hydrogels, which were then collapsed into ultrathin membranes in a controlled environment. Membranes were evaluated for their ability to support attachment of various cell types. Cells, however, preferred the AG series of membrane. Notably, primary rabbit CEC remained attached and viable for ⩾4 weeks. The cells also stained positive for CD166, ZO-1 and Na+/K+ ATPase, indicative of function. The hydrated AG membranes allowed >96% transmittance of visible light. The membranes were typically ∼15 µm thick and did not swell significantly after immersion in PBS. Tensile strength was 49-60 MPa, while young's modulus was 525-596 MPa. This membrane thus offers great promise as a scaffold for CEC during endothelial keratoplasty.

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Corneal endothelium is a single layer of hexagonal cells that maintains the corneal transparency and thickness through its barrier and pump function. For the treatment of corneal endothelial dysfunction, the transplantation of tissue-engineered corneal endothelium and direct injection of cultured corneal endothelial cells were developed because of the severe shortage of donor cornea worldwide. However, the technique difficulty or safety risk still remained. In this study, we report a novel mini-sheet injection for the cultured corneal endothelial cell transplantation and compare with the effects of single-cell injection in rabbit model. Compared with the reported single-cell injection, mini sheets promoted the adhesion and tight junction formation after injection. Rabbit corneal clarity and thickness were rapidly recovered after 7 days of mini-sheet injection, compared with 14 days of single-cell injection. Moreover, typical endothelial morphology was observed as early as 7 days after the mini-sheet injection, whereas until 21 days after the single-cell injection. These results demonstrate that the novel mini-sheet injection of corneal endothelial cells exhibited rapid adhesion, tight junction formation, and corneal clarity recovery, which may represent a more efficient method for the transplantation of cultured corneal endothelial cells.

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Corneal endothelial transplantation has achieved good results in domestic and foreign clinical applications , which has become the preferred method for treatment of severe corneal endothelial lesion .Corneal endothelial transplantation retained the patients′autologous healthy corneal epithelum , Bowman′s membrane and the strooma , as far as possible to ensure the integrity of the ocular sur-face, reduce the astigmatism.It had some advantages such as small invasiveness , less rejection, and faster visual recovery .Descemet stripping endothelial keratoplasty is the mianstream mode of operation , then the advanced femtosecond laser Descemet′s membrane en-dothelial keratoplasty were developed .We review the development course , operation methods , and complications of corneal endothelial transplantation in this paper .