Evaluation of Efficacy, Efficiency, and Cell Viability of a Novel Descemet Membrane Endothelial Keratoplasty Graft Preparation Device, DescePrep, in Nondiabetic and Diabetic Human Donor Corneas.

PURPOSE: The purpose of this study was to evaluate the safety, efficacy, and efficiency of a Descemet membrane endothelial keratoplasty (DMEK) graft preparation device, DescePrep, through measurement of graft viability, yield, and preparation time in both healthy and diabetic (high-risk) donor eyes. METHODS: Twenty nondiabetic and 10 diabetic donor corneas were processed using DescePrep, which standardizes the liquid bubble technique. Corneas were stained with trypan blue and then processed. Cell counts through specular microscopy, optical coherence tomography imaging, and slit-lamp analysis were used for the evaluation of graft separation and viability in 5 nondiabetic corneas. The remaining 25 corneas (15 nondiabetic and 10 diabetic) were evaluated for preparation success rate and processing time. Ten corneas (5 nondiabetic and 5 diabetic) were randomly selected for further evaluation of global cell loss through staining. RESULTS: Ninety-seven percent of corneas (29 of 30) were prepared successfully with DescePrep. The average preparation time was 2.83 ± 1.8 minutes. There was no significant difference in the time of preparation between the nondiabetic and diabetic groups (P = 0.077). The overall average cell death after processing was 7.9% ± 3.7% for all corneas. There was no significant difference in cell viability between diabetic and nondiabetic tissues after DescePrep processing (P = 0.769). CONCLUSIONS: DescePrep is a new DMEK preparation technique that can process both nondiabetic and diabetic donor corneas at high yields in minutes. High-yield preparation of diabetic corneas may offer eye banks access to a larger donor pool, which is important because the demand for DMEK grafts continues to rise worldwide.

New surgical maneuver to position the graft in a descemet stripping with automated endothelial keratoplasty surgery / Nova manobra cirúrgica para posicionar o enxerto em cirurgia de ceratoplastia endotelial com desnudamento automatizado da Descemet

ABSTRACT Objective: To describe a new surgical maneuver to position the graft in a Descemet Stripping with Automated Endothelial Keratoplasty (DSAEK) surgery. Methods: Case series. Results: This technique allows a correct repositioning of the graft in a minimally invasive way. Conclusion: This new surgical maneuver was successful in manipulating the graft in DSAEK surgery and therefore might be effective and safe.

RESUMO Objetivo: Descrever uma nova manobra cirúrgica para posicionar o enxerto em uma cirurgia de ceratoplastia endotelial automatizada com desnudamento da Descemet. Métodos: Série de casos. Resultados: A técnica permitiu o correto reposicionamento do enxerto de forma minimamente invasiva. Conclusão: Esta nova manobra cirúrgica foi bem-sucedida para manipular o enxerto na cirurgia ceratoplastia endotelial automatizada com desnudamento da Descemet e, portanto, pode ser eficaz e segura.

Preloaded Descemet Membrane Endothelial Keratoplasty Grafts With Endothelium Outward: A Cross-Country Validation Study of the DMEK Rapid Device.

PURPOSE: To validate the "Descemet membrane endothelial keratoplasty (DMEK) Rapid" device for the cross-country transportation of preloaded DMEK grafts preserved with endothelium outward. METHODS: DMEK grafts were stripped and loaded in the DMEK Rapid device with tissue culture medium (TCM) or transport medium (TM) with endothelium outward. The device was mounted in a 40-mL flask and preserved for 4 days on a rocker to simulate transportation (study A, n = 24) or shipped in the TM from Italy to the United Kingdom (study B, n = 9) and evaluated within 72 hours. All the tissues were stained with Alizarin red. Viability of the cells was checked postsimulations and posttransportation and was confirmed using live/dead staining. Expression of tight junction proteins was evaluated. RESULTS: In study A, the endothelial cell loss observed from the TCM group was 20.8% (±5.2) compared with 19.5% (±6.7) from the TM group (P = 0.41) after transport simulation. Alizarin red showed minimal uncovered areas in both groups. There were no statistical differences in viability between the TM (80.83%) and TCM groups (78.83%). In study B, 12.9% (±7.8) endothelial cell loss was observed after transporting the tissues from Italy to the United Kingdom with no significant difference between prestrip and posttransportation (P = 0.05). Alizarin red staining did not show any uncovered area. Live/dead analysis showed 85.16% cell viability after transportation. zonula occludens-1 (ZO-1) was expressed in all tissues. CONCLUSIONS: The DMEK Rapid device is safe for preloading and shipping DMEK grafts internationally with endothelium outward within 72 hours when preserved in the transport media.

Descemet Membrane Endothelial Keratoplasty With a Pull-Through Insertion Device: Surgical Technique, Endothelial Cell Loss, and Early Clinical Results.

PURPOSE: To describe a surgical technique for Descemet membrane endothelial keratoplasty (DMEK) using a pull-through, endothelium-in insertion device, the DMEK EndoGlide. We evaluated the endothelial cell loss (ECL) associated with the EndoGlide-DMEK (E-DMEK) technique in both ex vivo and prospective clinical studies. METHODS: The ex vivo study involved calcein acetoxymethyl staining and preparation of DMEK grafts, which were trifolded endothelium-in, loaded into the EndoGlide, pulled through, and unfolded in imaging dishes. Inverted fluorescent microscopy was performed, and ECL was quantified using trainable segmentation software. The prospective clinical series describes the outcomes of consecutive surgeries using the E-DMEK technique. Grafts were pulled through the EndoGlide with forceps and unfolded in the anterior chamber endothelium-down. Our main outcome measure was ECL in both studies. RESULTS: In the ex vivo study with 9 human donor corneas, mean ECL was 15.2% ± 5.4% (n = 9). In our clinical series of 69 eyes, leading indications for surgery were pseudophakic/aphakic bullous keratopathy (47.8%), previous failed grafts (23.2%), and Fuchs endothelial dystrophy (18.8%). Rebubbling and primary graft failure rates related to E-DMEK were 11.6% and 1.5%, respectively. Among eyes with at least 6 months of follow-up, mean preoperative endothelial cell density was 2772 (range 2457-3448) cells/mm, and postoperative endothelial cell density was 1830 (range 541-2545) cells/mm. Mean ECL was 33.6% (range 7.5-80.4; n = 32) at the 7.1 (range 6-11) months follow-up. CONCLUSIONS: The ex vivo and pilot clinical studies suggest that E-DMEK shows acceptable rates of ECL, with safe and promising early clinical outcomes.

Hybrid Descemet Membrane Endothelial Keratoplasty (H-DMEK): results of a donor insertion pull-through technique using donor stroma as carrier.

AIM: To evaluate the outcomes and complications of hybrid Descemet membrane endothelial keratoplasty (H-DMEK) using a Descemet stripping automated endothelial keratoplasty (DSAEK) pull-through donor inserter and donor stroma as carrier. METHODS: This was a retrospective interventional case series of eyes with bullous keratopathy (BK) and Fuchs endothelial corneal dystrophy (FECD), which underwent H-DMEK, performed using a bimanual pull-through technique using DSAEK-prepared donor stroma as carrier and the EndoGlide Ultrathin DSAEK donor insertion device. Complex cases with tube shunts, trabeculectomy, aphakia, aniridia, previous vitrectomy, keratoplasty or combined with intraocular lens exchange, were also included. The outcome measures were intraoperative and postoperative complications, best corrected visual acuity (BCVA) and endothelial cell loss after surgery. RESULTS: Of the 85 eyes from 79 patients, 43.5% (n=37) had BK, 28.2% (n=24) had FECD while 24.7% (n=21) had failed grafts. DMEK was performed in 37 complex eyes (43.5%). Four eyes (4.7%) required rebubbling for graft detachment and two cases of graft failure were observed. A BCVA of 20/25 or better was attained in 44.7% and 57.1% of eyes without pre-existing ocular pathology at 6 and 12 months, respectively. The overall endothelial cell loss was 32.2%±20.5% at 6 months, which improved from 37.2%±20.9% to 24.2%±17.5%, comparing the first 40 and last 45 cases (p=0.012). CONCLUSION: Hybrid DMEK offers a controlled 'pull-through' technique of donor insertion in the 'endothelium-in' configuration, which may be useful especially in complicated eyes. More studies are needed to confirm the long-term endothelial cell loss and graft survival associated with this technique.

Quantitative and Qualitative Differences in Endothelial Cell Loss Between Endothelium-In Versus Endothelium-Out Loading in Descemet Membrane Endothelial Keratoplasty.

PURPOSE: This study compares endothelial cell loss (ECL) between donor grafts loaded in the Geuder Glass Cannula and the Coronet EndoGlide made specifically for Descemet membrane endothelial keratoplasty (DMEK). METHODS: Prestripped tissues using the submerged cornea using backgrounds away (SCUBA) technique were obtained from an eye bank. Donor grafts were loaded with the Geuder Glass Cannula or Coronet DMEK EndoGlide. Grafts were then ejected directly onto a glass slide, stained, and imaged with confocal fluorescent microscopy. Trainable Fiji (ImageJ) segmentation software was used to quantify ECL. RESULTS: Twenty-three total tissue samples were tested. Eleven grafts were loaded using the Geuder, and 12 were loaded with the Coronet. Preloading graft endothelial cell density was comparable between Geuder (2436 ± 581 cells/mm) and Coronet (2577 ± 483 cells/mm) groups with P = 0.56. Other baseline characteristics including donor age and time from death to loading were comparable (P = 0.73 and P = 0.66, respectively). Average ECL was 11.3% ± 3.0% in the Geuder group versus 7.2% ± 7.0% in the Coronet group and not significantly different (P = 0.07). When observing patterns of cell loss, grafts loaded in the Coronet DMEK EndoGlide resulted in more focal forceps grabs and trifold patterns. Grafts loaded with the Geuder Glass Cannula yielded more diffuse stippled stress lines. CONCLUSIONS: Our results suggest comparable ECL between Geuder (endothelium-out) and Coronet (endothelium-in) DMEK EndoGlide tissue injection techniques. Patterns of ECL in the Coronet group correlated with forceps grabs, but this study suggests that additional manipulation of tissue does not result in higher ECL.

Clinical Evaluation of the "Lifeline Suture" Technique for DSAEK in Cases Without Posterior Capsule Using a Novel Donor Insertion Device.

PURPOSE: This study investigated preliminary clinical outcomes of a suture pull-through technique for Descemet stripping automated endothelial keratoplasty (DSAEK) termed the "lifeline suture" technique using a newly developed donor inserter (NS Endo-Inserter: NSI; Hoya Co, Ltd, Tokyo, Japan) in cases of bullous keratopathy without posterior capsule. METHODS: Six aphakic eyes without posterior capsule from 6 patients (mean age 73.8 ± 11.9 years) with bullous keratopathy were enrolled. DSAEK alone or as a vitreocorneal surgery was performed. Donor tissue was pulled into the anterior chamber using the NSI and a 9-0 polypropylene "lifeline suture" to prevent donor tissue from slipping into the vitreous cavity, which was removed at the end of surgery. Intraoperative and postoperative complications and 6-month postoperative central donor endothelial cell densities were measured and compared with preoperative values along with 6-month best-corrected visual acuity. RESULTS: All donors were successfully loaded into the NSI and then pulled into the anterior chamber using the lifeline suture. No intraoperative complications, graft dislocation, or primary graft failures were noted. Six months postsurgery, mean endothelial cell density was 2027 ± 747 cells/mm (mean loss 27.2 ± 28.1%) and mean best-corrected visual acuity improved to 0.31 decimal (P = 0.018). CONCLUSIONS: In this preliminary case series of bullous keratopathy without posterior capsule, DSAEK outcomes using the novel NSI donor inserter with lifeline suture were comparable or better than the results expected with conventional strategies. Thus, this technique enabled apparently safe DSAEK, preventing donor migration into the vitreous cavity while maintaining a stable anterior chamber, and is suitable for complex eyes including aphakia, lacking posterior capsule, or avitreal.

Microkeratome-assisted ultrathin Descemet's stripping automated endothelial keratoplasty: A randomized trial comparing single-pass versus double-pass technique.

Purpose: To compare the outcomes of two techniques, for preparation of microkeratome-assisted ultrathin grafts for Descemet's stripping automated endothelial keratoplasty (DSAEK). Methods: The study involved 20 eyes of 20 patients with pseudophakic bullous keratopathy, randomized into two groups. Group 1 eyes underwent microkeratome-assisted DSAEK using the single-pass technique for lenticule preparation, whereas group 2 eyes underwent microkeratome-assisted DSAEK using the double-pass technique. Patients were followed up till 6 months, postoperatively. Best-corrected visual acuity (BCVA) at final follow-up was considered as the primary outcome measure, whereas graft thickness (GT) contrast sensitivity and endothelial cell loss were considered as the secondary outcome measures. A P value of <0.05 was considered as statistically significant. Results: Baseline characteristics of two groups were comparable. The mean central GT was comparable in both groups at 6 months follow-up [group 1: 98 ± 24.46 µm, group 2: 129 ± 31.46 µm (P = 0.18)]. Both groups fared equally in terms of BCVA (P = 0.33). Contrast sensitivity was significantly better in group 1 eyes (P = 0.045). A statistically significant negative correlation was found between postoperative BCVA and postoperative GT (R = -0.728, P = 0.016). The percentage endothelial cell loss was slightly higher in group 2 eyes, although not statistically significant. Two eyes in group 2 experienced complications during lenticule preparation. None of the eye experienced any complication in the postoperative period. Conclusion: Both techniques provided grafts with comparable thickness and endothelial cell loss and were associated with comparable BCVA, at final follow-up visit. The contrast sensitivity was, however, better in eyes receiving grafts prepared with the single-pass technique.

Safety of Long-Term Storage and Shipping of Prestripped, Prestained, and Preloaded Descemet Membrane Endothelial Keratoplasty Tissue.

PURPOSE: The purpose of this study was to determine the safety of long-term storage and shipping of prestripped, prestained, and preloaded Descemet membrane endothelial keratoplasty (pDMEK) grafts. METHODS: A total of 33 cadaveric corneas were prestripped, prestained, and preloaded using modified Jones tube injectors as pDMEK. The corneas were masked to groups that were prepared <9 hours (control), 48 hours, and 72 hours before unloading and analysis. The 48- and 72-hour tissues were shipped by airfreight on each day before arrival to simulate domestic and international shipping. The corneas were then stained using Calcein AM vital dye (Molecular Probes, Eugene, OR) and imaged using an inverted confocal microscope. Primary outcome measures were endothelial cell loss (ECL, %) and sustainability of staining. MetaMorph software (Molecular Devices, Downingtown, PA) was used to quantify ECL, and staining was evaluated subjectively using all-or-none rating. RESULTS: There was no difference in the mean ECL for the control, 48-hour, and 72-hour groups, which were 25.1% ± 8.8%, 26.4% ± 17.5%, and 19.2% ± 11.5%, respectively (P = 0.45; Kruskal-Wallis test). In all tissues of each group, no loss of staining was identified at each time point of analysis. CONCLUSIONS: ECL in pDMEK tissue prepared 48 and 72 hours in advance and shipped using standard methods is similar to that in pDMEK tissue prepared on the same day. These findings support the safety of domestic and international shipping of pDMEK grafts.

Effect of Air Injection Depth on Big-bubble Formation in Lamellar Keratoplasty: an Ex Vivo Study.

This study evaluated the effect of air injection depth in the big-bubble (BB) technique, which is used for corneal tissue preparation in lamellar keratoplasty. The BB technique was performed on ex vivo human corneoscleral buttons using a depth-sensing needle, based on optical coherence tomography (OCT) imaging technology. The needle tip, equipped with a miniaturized OCT depth-sensing probe, was inserted for air injection at a specified depth. Inside the corneal tissue, our needle obtained OCT line profiles, from which residual thickness below the needle tip was measured. Subjects were classified into Groups I, II, III, and IV based on injection depths of 75-80%, 80-85%, 85-90%, and >90% of the full corneal thickness, respectively. Both Type I and II BBs were produced when the mean residual thicknesses of air injection were 109.7 ± 38.0 µm and 52.4 ± 19.2 µm, respectively. Type II BB (4/5) was dominant in group IV. Bubble burst occurred in 1/16 cases of type I BB and 3/16 cases of type II BB, respectively. Injection depth was an important factor in determining the types of BBs produced. Deeper air injection could facilitate formation of Type II BBs, with an increased risk of bubble bursts.

Safety analysis and results of a borosilicate glass cartridge for no-touch graft loading and injection in Descemet membrane endothelial keratoplasty.

PURPOSE: The aim of this study was to investigate the clinical outcome after standardized DMEK using a glass injector. METHODS: A total of 254 patients undergoing DMEK surgery using a disposable DMEK borosilicate glass cartridge system were included in this retrospective study. The mean follow-up time was 13.2 months (SD ± 8.1, range 6-36 months). The used glass cartridge system has an aperture diameter of 1.6 mm and a posterior loading orifice of 4.29 mm. Scanning electron microscopy (SEM) was used for estimation of the surface relief of the glass cartridge and comparison with a standard plastic injector cartridge. RESULTS: Mean endothelial cell count of donor grafts was 2465 cells/mm2 (SD ± 199). After 6 weeks of DMEK endothelial cell count decreased by - 28.6% to 1759 cells/mm2 (SD ± 435) (Wilcoxon p = 0.001) and remained stable at the final follow-up at 1735 cells/mm2 (SD ± 442) (Wilcoxon p = 0.89). SEM showed smoother surface of the glass cartridge in comparison with a plastic cartridge. CONCLUSION: This study showed that this simple and effective DMEK cartridge seems to be a safe and viable device for minimized graft manipulation during DMEK surgery.

Comparison of endothelial cell loss and complications following DMEK with the use of three different graft injectors.

PurposeTo compare endothelial cell loss and complications following Descemet membrane endothelial keratoplasty (DMEK) with use of three commercially available injectors.MethodsFrom 179 consecutive DMEK procedures, 66 cases with uncomplicated graft preparation and completed 12-month follow-up were included in this retrospective study. According to the injector used, 3 groups were formed: group 1 (D.O.R.C. injector, n=16), group 2 (Geuder injector, n=24), and group 3 (Pasteur laboratory pipette, n= 26). Endothelial cell density (ECD) and endothelial cell loss were evaluated preoperatively and at 3, 6 and 12 months postoperatively; surgery-related complications were recorded.ResultsDonor ECD was 2416±179 cells/mm2 (group 1), 2417±164 cells/mm2 (group 2), and 2478±234 cells/mm2 (group 3). At 12 months postoperatively ECD was 1473±403 cells/mm2 (group 1), 1379±317 cells/mm2 (group 2), and 1316±456 cells/mm2 (group 3) (P=0.533, ANOVA). Endothelial cell loss 12 months postoperatively was 39±15% (group 1), 43±13% (group 2), and 47±17% (group 3) (P=0.386, ANOVA). A single case of iris bleeding and reflux of the graft out of the anterior chamber (both in group 3) was noted. Partial graft detachment occurred in group 1 (n=1), group 2 (n=5), and group 3 (n=7) and rebubbling was performed in 6% (group 1), 17% (group 2), and 27% (group 3).ConclusionsTo our knowledge, this is the first clinical study assessing the safety of three different DMEK injectors. Group 1 (D.O.R.C injector) showed the least and group 3 (Pasteur laboratory pipette) the highest endothelial cell loss without reaching statistical significance at 12 months after surgery. Therefore, the graft injector may be chosen according to surgeon's preference.

Comparison of the Endosaver with noninjector techniques in Descemet's stripping endothelial keratoplasty.

PURPOSE: Minimal loss of corneal endothelial cells during corneal transplantation is a major target but remains a point of controversy among specialists. Hence, the available method to best achieve this continues to stir progress in the field. The aim of this study is to evaluate the use of the Endosaver injector device for graft insertion in Descemet's stripping endothelial keratoplasty (DSEK) and compare the visual outcomes and endothelial cell survival between the Endosaver injector and Goosey grasping forceps insertion techniques. METHODS: This was a retrospective, interventional, consecutive case series undertaken at the University of Southampton Eye Department to assess outcomes of DSEK using the Endosaver injector device compared to noninjector DSEK insertion. Postoperative specular microscopy alongside manifest refraction at 6 and 12 months was evaluated and compared. Mann-Whitney U-test was employed for the statistical analysis of data. RESULTS: Both the Endosaver and Goosey forceps groups showed an improvement in best corrected visual acuity. No significant statistical difference was found in preoperative and postoperative best-corrected visual acuity between the Endosaver and non-Endosaver insertion groups. Mean preoperative endothelial cell count was 2660 (±130) for the Endosaver group and 2608 (±66) for the non-Endosaver group. Postoperative endothelial counts at 6 and 12 months showed a significant difference between the Endosaver: 2104 (±199)-1896 (±226) and the non-Endosaver: 1492 (±207)-1314 (±224) (P < 0.005) groups, respectively. CONCLUSION: The Endosaver injection device is associated with less trauma to endothelium during graft insertion due to the minimal touch technique employed. A smaller insertion wound of 4.0 mm compared to noninjector cases enabled a more stable system during surgery with no or minimal anterior chamber shallowing. The combination of a stable host with minimal endothelial graft handling and subsequent trauma potentially leads to higher endothelial cell counts when the Endosaver injection device is used compared to forceps insertion.

New Graft Insertion Device for Descemet Stripping Automated Endothelial Keratoplasty.

PURPOSE: Corneal endothelial dysfunction is a major indication for corneal graft surgery worldwide, and although surgical intervention through a range of posterior lamellar surgeries has proven to be hugely beneficial, challenges remain. This is especially so where the anterior chamber is relatively shallow, as is often the case in the Asian population, though not exclusively so. In this study, we introduce a new insertion device to deliver endothelial graft tissue for Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: A new surgical tool was designed and manufactured so as to enable a 1-step insertion of corneal graft tissue into the anterior chamber based on a pressure-flow concept, rather than the a pull-through one. This was tested ex vivo to assess endothelial cell damage, and then performed in 12 first-in-human surgeries. RESULTS: Precut DSAEK lenticules implanted in donor corneas ex vivo through the new technique showed that less endothelial cell damage occurs compared with a pull-through technique. Grafts were successful in all patients receiving the new surgery, with no cases of primary graft failure. CONCLUSIONS: The newly developed DSAEK inserter is a simple and useful tool for endothelial graft delivery, lessening intraoperative mechanical stress on the graft tissue.

[Critical endothelial procedures during posterior lamellar graft preparation and transplantation]. / Endothelkritische Prozeduren während der Herstellung und Transplantation posteriorer lamellärer Hornhauttransplantate.

BACKGROUND: In view of the very low proliferation rate and functional importance of the corneal endothelium in maintaining corneal transparency, safeguarding the integrity of this monolayer plays a central role in posterior lamellar corneal transplantation. Several critical endothelial procedural stages are necessary to carry out such a transplantation. OBJECTIVE: This article presents various preparatory and operative approaches for carrying out the necessary and critical stages within the framework of posterior lamellar corneal transplantation and concentrates on the question of optimization. METHODS: A review of our own studies and studies of other groups is presented. RESULTS: For the performance of critical endothelial procedural steps, a variety of approaches are available. These range from preparation and insertion of the transplant, through the manipulation during centralization up to the effects of postoperative air or gas bubble tamponade. CONCLUSION: Because endothelial damage can permanently impair the integrity of lamellar transplants, a minimal handling and no touch policy should be strived for in all critical procedures. Long-term data on the follow-up course will show which of the procedures favored by various authors lead to the best postoperative results.

First experience of nDSAEK with heads-up surgery: A case report.

PURPOSE: To report a case of non-Descemet Stripping Automated Endothelial Keratoplasty (nDSAEK) using heads-up surgery. CASE/INTERVENTION: The case was a 72-years-old man who had history of left eye blunt trauma since childhood. One year ago, the patient was diagnosed to have left posttraumatic bullous keratopathy. The patient underwent lt nDSAEK by using the heads-up three-dimensional (3D) system last July. The surgery was performed with a Rescan 700 surgical microscope (Carl Zeiss), which is integrated with intraoperative optical coherence tomography (iOCT) system. During surgery, the surgeon and audience wore 3D passive polarized glasses. A 42 inch high-definition (HD) display and 2 HD cameras (Sony) were used. With this 3D system, the nDSAEK procedure before the graft insertion into the anterior chamber was easy especially with available high magnification. Also, using iOCT of the system enables the surgeon to detect any residual fluid at the donor graft-recipient interface and locate its place to be drained. The only disadvantage of the system was the difficulty in the detection of nDSAEK graft depth in the anterior chamber, which required frequent focus change during the surgery. Although the surgeon frequently adjusted the focus for clear stereoscopic view of the graft, he did not feel any eye strain or discomfort. All other steps of the procedure were performed without any problem and postoperative course of the patient was good. CONCLUSION: Using heads-up surgery for performing anterior segment surgeries is encouraging and promising.

Finite Element Analysis of Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) Surgery Allograft to Predict Endothelial Cell Loss.

PURPOSE: To develop high fidelity finite element (FE) models of the Descemet's stripping automated endothelial keratoplasty (DSAEK) allograft to estimate the stress distributions generated on the allograft during its deformed state in popular allograft insertion configurations and qualitatively correlate the stress distributions to postsurgical endothelial cell (EC) loss. MATERIALS AND METHODS: Corneal allograft simulation was performed using ANSYS (Canonsburg, PA, USA) utilizing isotropic nonlinear hyperelastic corneal material properties to evaluate the stress distributions generated on the DSAEK allograft during popular allograft insertion configurations, namely forceps, taco, and double-coil insertion configurations. The gathered FE simulation results were qualitatively compared with published clinical studies to verify the simulation results. RESULTS: The FE simulation results demonstrate that high stress regions predicted by FE model results correctly predict the areas of postsurgical EC loss as published in the studies available in open literature. The FE simulation stress magnitude results suggest that highest EC loss due to mechanical bending trauma occurs in double-coil configuration followed by forceps and then taco configuration. CONCLUSIONS: The results of the presented FE simulation study highlight that allograft regions with high stress distribution demonstrate postsurgical EC loss in clinical studies. The modeling procedures presented in this research can be utilized to develop novel surgical devices/techniques that can modulate the postsurgical EC loss due to mechanical bending trauma and facilitate allograft unfolding inside the AC, thereby improving the results of the DSAEK surgical procedure.

Reproducibility of single-pass donor DSAEK tissue preparation with the MORIA single-use microkeratome.

PURPOSE: To assess the reproducibility of single-pass cutting for preparation of ultra-thin (≤120µm) donor cornea grafts in Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: All consecutive patients of DSAEK performed using the MORIA One Use microkeratome (MORIA, Antony, France) in between June 2014 and August 2015. Patient and donor central corneal thickness (CTT), microkeratome head, remaining stromal bed thickness (RSBT), number of cut and graft thickness at 1 month and 6 months postoperatively were recorded in this single-center prospective study. RESULTS: The mean preoperative donor graft CCT was 569.0±45.1µm and the mean donor endothelial graft CCT immediately after the cut was 116.5±28.7µm. At 1 month postoperatively, the mean CCT was 102.8±35.9µm. At 6 months, the mean CCT was 89.4±26.2µm. In all eyes, the mean CCT decreased from the post-cut (116.5±28.7µm) to the last visit (89.4±26.2µm) (P<0.01) due to in vivo deturgesence of the graft. We obtained 77.5% ultra-thin DSAEK immediately after the cut, 77.5% at 1 month and 89.8% after 6 months. CONCLUSION: Single-pass technique with the MORIA One Use microkeratome offers safe and reproducible DSAEK tissue preparation and allows achieving ultra-thin DSAEK in 89.8% of cases.

Descemet Membrane Endothelial Keratoplasty: Preliminary Results of a Donor Insertion Pull-through Technique Using a Donor Mat Device.

PURPOSE: To evaluate a novel technique of Descemet membrane endothelial keratoplasty (DMEK) donor insertion using the EndoGlide pull-through device. DESIGN: Prospective, interventional cases series. METHODS: We performed DMEK using the EndoGlide technique with a protoype donor carrier device (Descemet Mat, or D-Mat) in 30 patients by a single surgeon (including learning curve). Clinical data and donor and recipient characteristics were tracked from our prospective Singapore Corneal Transplant Registry. Main outcome measures were intraoperative complications and the incidence of postoperative graft detachment and primary graft failures within 3 months from surgery. RESULTS: In our preliminary study of 30 eyes in 30 patients (73% female, mean age 64.5 ± 8.3 years), we observed 3 cases (10%) of partial donor detachment requiring rebubbling and 1 (3%) primary donor failure. Twenty of 30 eyes (66.7%) achieved ≥20/25 3-month best spectacle-corrected visual acuity. Six-month endothelial cell loss reduced from 65% ± 13% to 48% ± 11% (P = .02) comparing the first and last 15 cases. With the exception of 1 case with excessive fibrin formation, we did not experience any further intraoperative complications related to donor tissue insertion, incomplete tissue unfolding, donor tissue malposition, or incorrect orientation. CONCLUSION: Our study suggests that the described technique allows for donor control and insertion in the correct orientation with the endothelium facing down. Further studies are required to confirm if this DMEK donor insertion technique can lead to reduced endothelial cell loss and better graft survival.