Endothelial Keratoplasty Techniques Research Articles

Modified thin manual Descemet stripping endothelial keratoplasty with air-guided, non-pachymetric donor lenticule dissection: outcomes of graft thickness and complication rate.

To describe a modified technique of donor lenticule dissection for thin manual Descemet stripping endothelial keratoplasty (TM-DSEK). Donor material was soaked in balanced salt solution (BSS) for 30min, before being mounted on an artificial anterior chamber (AAC). Rather than BSS, the AAC was filled with filtered air, resulting in a visible reflection at the corneal endothelium-air interface. This reflection served as a landmark for the depth of the dissection, facilitating the creation of a thin lenticule with low risk of perforation. Dissection was commenced at a standardized depth of 500 microns, with no initial pachymetry necessary. Totally 29 donor corneas were dissected by a novice TM-DSEK surgeon. Dissection time, central graft thickness at 2mo and complications were analysed. Results were similar to other endothelial keratoplasty techniques, despite the cases being performed by a novice DSEK surgeon. Mean dissection time was 7min (range 6-10). One graft perforation occurred (3.45%), but the air tamponaded the break and enabled dissection to be restarted and completed from a different location. Mean central graft thickness after at least two months follow-up was 106 microns (range 25-170). A problem with manual DSEK is the risk of graft perforation by attempting to dissect too thin a lenticule, or creating a thick graft due to fear of perforating. This modified air-guided technique addresses this problem, and is recommended for surgeons either embarking on the learning curve, or who wish to achieve more consistently thin grafts while reducing perforation rates.

Optimizing pre-Descemet endothelial keratoplasty technique.

Pre-Descemet endothelial keratoplasty (PDEK) is an alternative technique to Descemet membrane endothelial keratoplasty (DMEK). The preparation of PDEK tissue by pneumatic dissection is simple and reproducible. The PDEK clamp helps to consistently obtain a type 1 big bubble. The mean size of type 1 big bubble is 7.255 ± 0.535 × 6.745 ± 0.668 mm. The volume of air required to obtain type 1 big bubble is 0.14 to 0.37 mL. Dissection of PDEK tissue can be achieved by trephination or manual excision. Insertion of tissue into the recipient eye can be by injection or pulling. Unfolding techniques used for PDEK are similar to those used in DMEK. Unlike DMEK, PDEK tissue is easier to handle and unscroll and allows use of younger donors. It could help surgeons converting to endothelial keratoplasty, with significant advantages in preparation, handling, and unscrolling in the eye.

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

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. 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. 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. The ex vivo and pilot clinical studies suggest that E-DMEK shows acceptable rates of ECL, with safe and promising early clinical outcomes.

Lamellar Dissection Technique for Descemet Membrane Endothelial Keratoplasty Graft Preparation

To describe a novel lamellar dissection technique for Descemet membrane endothelial keratoplasty (DMEK) graft preparation, and to evaluate the rate of endothelial cell loss (ECL) and graft preparation failure associated with this technique. We conducted an ex vivo laboratory-based study comparing ECL between the lamellar dissection and peeling techniques. Eight pairs of human donor corneas underwent calcein acetoxymethyl staining-all right eyes underwent the peeling technique and all left eyes underwent the lamellar dissection technique. ECL was quantified by image analysis with trainable segmentation software and compared between groups. We also conducted a retrospective analysis of 161 consecutive DMEK graft preparations by a single surgeon using the lamellar dissection technique from 2010 to 2018. Data on donor characteristics and graft preparation failures were obtained. Baseline donor characteristics were comparable in both arms of the laboratory-based study. Mean (SD) ECL with the lamellar dissection and peeling techniques was 13.8% (4.2%) and 11.2% (6.1%), respectively. There was no significant difference between the two (P = 0.327). In the clinical series, there were 2 graft preparation failures in 161 cases (1.2%). Among cases performed on diabetic donor tissue, the rate of graft preparation failure was 4.7%. The lamellar dissection technique has a similar rate of ECL compared with the peeling technique for DMEK graft preparation. This technique also has a low rate of graft preparation failure and may be a useful technique for diabetic donor tissue.

Step-by-step Descemet's membrane endothelial keratoplasty surgery.

With the success of Descemet's stripping automated endothelial keratoplasty (DSAEK) technique providing better outcomes in visual prognosis and theoretically lower rejection rate than penetrating keratoplasty, DSAEK dominated the realm of endothelial keratoplasty for the past decade. However, Descemet's membrane endothelial keratoplasty (DMEK) has become more and more popular worldwide due to its even lower rejection rate, faster visual recovery, better visual outcome, and lower long-term endothelial loss. In this article, we demonstrate the techniques and nuances of DMEK surgery in detail for corneal specialists who are beginning their DMEK surgeries.

"Ghost DMEK" Technique: Circular Peripheral Staining of Descemet's Membrane Endothelial Keratoplasty Grafts.

To describe the ghost Descemet's membrane endothelial keratoplasty (DMEK) technique that allows for real-time evaluation of DMEK graft orientation, location, and folding status within the anterior chamber, by simple observation at the surgical microscope. This is a retrospective case series done in a university hospital. The study included 10 patients who underwent ghost DMEK surgery because of corneal endothelial insufficiency for Fuchs' endothelial dystrophy (N = 5), pseudophakic bullous keratopathy (N = 2), and failed previous posterior lamellar keratoplasty (N = 3). Cases were reviewed for feasibility of graft preparation, intra- and postoperative complications, postoperative clearing of the cornea, corrected distance visual acuity, and endothelial cell loss. All graft preparations were uneventful. The circular staining was readily apparent and did not fade away during surgery. Graft orientation and folding status were determined using only direct observation through the operating microscope. Complications included one intraoperative hyphema, one graft detachment requiring rebubbling, and one pupillary block on the first postoperative day, which was resolved surgically. At last visit, 8 of 10 eyes had visual acuity of 6/12 or better and 7 of 10 eyes had visual acuity of 6/8.5 or better. Mean cell loss rates 1 to 3 months postoperatively were 48% ± 17% (range, 22%-71%). All corneas were clear by the first to second postoperative month. Mean follow-up time was 3 months (range, 1-8 months). Peripheral staining of DMEK grafts (ghost DMEK) is a simple and effective method for graft visualization in the anterior chamber, obviating the need for trypan blue staining and other techniques and devices currently used for the identification of graft orientation and folding status, thus simplifying and shortening surgery.

Pre-Descemet’s Endothelial Keratoplasty (PDEK): Learning Curve in the First Brazilian Cases

Purpose: To describe the learning curve of pre-descemet endothelial keratoplasty (PDEK) and the intraoperatory findings of the first 5 cases performed at Federal University of Sao Paulo. Methods: Five PDEK procedures were performed by the same surgeons; four cases used pneumodissection and one case used reverse hydro-bubble technique to obtain the donor graft. All cases were recorded and the following intraoperative variables were measured: type of bubble obtained, button size used and time of opening and centralization of the graft in the recipient anterior chamber. Results: Type-1 Big Bubble (BB) was achieved in three of the four cases that air dissection was used. In the fourth case of pneumodissection, there was simultaneous formation of type-1 and type-2 BB. When balanced saline solution was used for dissection, type-2 BB was obtained. Every time type-2 BB was formed, the procedure was then converted to Descemet Membrane Endothelial Keratoplasty (DMEK). When only type-1 BB was achieved, the PDEK was uneventful with an easier, manipulation of the tissue and a quicker opening in the recipient anterior chamber. Namely, grafts that included pre-Descemet’s layer were less elastic and less curled. The graft size used varied from 7.50 to 7.75mm. Conclusion: PDEK is a recent technique of endothelial keratoplasty. Early outcomes suggest potential advantages in the learning curve over the prior procedures, especially by the facilitated manipulation of PDEK graft in the anterior chamber. Although results with this technique seem promising, the potential advantages need to be confirmed with long-term postoperative follow-up.

Five Keratoplasties From One Donor Cornea.

To describe the feasibility of same-day, consecutive use of a single donor cornea in 5 patients with corneal pathology, who required anterior lamellar and endothelial keratoplasties. Descemet membrane (DM) with endothelium was completely stripped from a single corneoscleral button and punched out from the endothelial side with a circular, standard punch. Using a custom-made punch for linear cutting of DM, we obtained 4 quarter-grafts (Q-graft). The denuded and punched-out corneal stroma was transplanted in 1 patient with keratoconus, using the big-bubble deep anterior lamellar keratoplasty (DALK) technique. The 4 DM Q-grafts were consecutively transplanted to 4 patients with Fuchs dystrophy using the quarter Descemet membrane endothelial keratoplasty (Q-DMEK or 1/4 DMEK) technique. All surgical procedures were performed successfully during 1 surgical session. No intraoperative or postoperative complications requiring intervention were observed. Six months after surgery, the decimal best-corrected visual acuity achieved was 0.66 after DALK and 0.95 ± 0.1 (range, 0.8-1.0) in the 4 Q-DMEK cases; the endothelial cell density was 1680 ± 254 cells/mm (range, 1492-2039 cells/mm). Six months postoperatively, all corneas were clear. In this limited series, we demonstrate that 1 donor cornea can be successfully used for 5 recipients. Although performing DALK and Q-DMEK on a single day is technically challenging, it is feasible and can dramatically reduce the shortage and the cost of corneal tissue. Strict case selection is necessary. Further study on this approach is required.

Lamellar keratoplasty techniques.

Lamellar keratoplasty (LK) has revolutionized corneal graft surgery in several ways. Deep anterior LK (DALK) has eliminated risk of failure due to endothelial rejection. Endothelial keratoplasty (EK) has almost eliminated induced astigmatism and the “weak” graft–host junction as seen with penetrating keratoplasty (PK) and also reduced the risk of endothelial rejection. LK provided new insights into posterior corneal anatomy that led to better understanding and performance of DALK and to the development of another EK procedure, namely pre-Descemet's EK (PDEK). Surgical procedures for LK were further refined based on the improved understanding and are able to deliver better surgical outcomes in terms of structural integrity and long-term patient satisfaction, reducing the need of further surgeries and minimizing patient discomfort. In most specialist centers, anterior lamellar techniques like DALK and EK techniques like Descemet's stripping EK (DSEK) and Descemet's membrane EK (DMEK) have replaced the full-thickness PK where possible. The introduction of microkeratome, femtosecond laser, and PDEK clamp have made LK techniques easier and more predictable and have led to the innovation of another LK procedure, namely Bowman membrane transplant (BMT). In this article, we discuss the evolution of different surgical techniques, their principles, main outcomes, and limitations. To date, experience with BMT is limited, but DALK has become the gold standard for anterior LK. The EK procedures too have undergone a rapid transition from DSEK to DMEK and PDEK emerging as a viable option. Ultrathin-DSEK may still have a role in modern EK.

Vent Incisions to Facilitate Peripheral Unfolding of the DMEK Graft.

To present the results of 15 cases in which a modified technique of Descemet membrane endothelial keratoplasty (DMEK) with vent incisions was used to assist unfolding of tight peripheral inward folds. This is a retrospective case series of 15 consecutive eyes that underwent a modified vent incision technique for DMEK. Six oblique, small-size (1 mm) vent incisions parallel to the limbus and 3.5 mm from the center were performed after descemetorhexis. The graft was opened with standard no-touch techniques and was partially attached to the stroma with air injection. Then, in cases with remaining tight inward folds despite gentle corneal tapping, jets of balanced salt solution were pulsed through the vent incisions directed at the peripheral folds to achieve complete unfolding. Descemet membrane endothelial keratoplasty was performed in 2 phakic eyes (14%) and 13 pseudophakic eyes (86%). Six cases (40%) required fluid injection through the vent incisions: 3 corresponded to grafts from younger donors (54, 41, and 29 years old), and 3 had a 9.0-mm-sized graft. Complete graft unfolding was successfully achieved in 14 cases (93%), and in 1 case (7%), peripheral folds remained because of spontaneous bleeding in the anterior chamber. A clear cornea was achieved in all cases, and there were no postoperative complications associated with the vent incisions. This technique provides a different DMEK no-touch approach that could be used in challenging cases of graft unfolding such as young donors and/or large-sized grafts. It may also avoid excessive unfolding times and direct manipulation that are related to higher endothelial cell loss.

Descemet stripping automated endothelial keratoplasty.

Endothelial keratoplasty is at present the gold standard for surgical treatment of corneal endothelial pathologies not associated with significant corneal scar. Tremendous progress has been made in recent years in improving the technology of endothelial keratoplasty techniques, such as descemet stripping automated endothelial keratoplasty (DSAEK) and descemet membrane endothelial keratoplasty. In this review, we discuss the current techniques and outcomes of DSAEK.

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

To evaluate a novel technique of Descemet membrane endothelial keratoplasty (DMEK) donor insertion using the EndoGlide pull-through device. Prospective, interventional cases series. 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 3months from surgery. 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. 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.

Greffe lamellaire endothéliale assistée au laser Excimer (ExALEK) : technique et résultats

The purpose of this study is to describe a technique for thin endothelial lamellar keratoplasty and to present the results for endothelial transplant performed at the University Hospital of Nantes. This paper is a retrospective, single-center descriptive study conducted at the University Hospital of Nantes from September 2010 to May 2014, at first for anatomical or analgesic indications (group 1) and then extended to visual indications (group 2). Patients were followed for 12 months. The preparation of the endothelial graft includes an excimer-laser ablation of the residual stromal bed after lamellar keratectomy by manual deep anterior approach. Seventy surgeries were analyzed. The etiologies were mainly Fuchs Dystrophy, secondary endothelial dystrophy and post-penetrating keratoplasty endothelial failure. Fifty-three patients were integrated in group 1 and seventeen patients in group 2. In group 1, the mean VA at 12 months was 0.70 ± 0.30 Log MAR (0.2 decimal equivalent). In group 2, the mean VA at 12 months was 0.28 ± 0.12 Log MAR (0.5 decimal equivalent). Pachymetry decreased from 740 ± 125.1 μm preoperatively to 613.4 ± 73.4 μm at 12 months. The average central thickness of the graft was 84.1 ± 28.9 μm at 1 month and 80.2 ± 29.4 μm at 12 months. The advantage of this new surgical technique is that it is a rapid and repeatable method allowing thin grafts with satisfactory functionality and easy handling. Its performance independent of the scheduled surgery, allows for predictable organization in the operating room.

Changing trends in corneal graft surgery: a ten-year review.

To review indications and corneal tissue use for penetrating and lamellar surgery between 2002 and 2011. The surgical reports of corneal grafts performed during 2002-2011, using tissues supplied by the Eye Bank of Piedmont (Italy), were reviewed retrospectively. Patient demographic data, date of intervention, indication for surgery, and surgical technique used were recorded. Surgical techniques included penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK) and endothelial keratoplasty (EK). The χ (2) test was used to compare the distribution of indications and types of surgical technique used, for corneal grafts done during 2002-2006 versus those done during 2007-2011. The number of corneal grafts increased by 30.7% from 2002-2006 to 2007-2011 (from 1567 to 2048). Comparing the two periods, both main indications and surgical techniques changed significantly. In 2007-2011, the proportion of interventions for aphakic/pseudophakic bullous keratopathy (from 16.8% to 21.3%), graft failure (from 16.4% to 19.1%) and Fuchs endothelial dystrophy (from 12.8% to 16.7%) all increased significantly (P<0.05), while those for keratoconus decreased significantly (from 35.6% to 27.3%; P<0.001). In 2007-2011, the proportion of PK decreased significantly (from 92.4% to 57.2%; P<0.001) while that of EK and DALK went from 0.4% to 30.2% (P<0.001) and from 7.2% to 12.6% (P<0.001) respectively. During 2002-2011 the number of interventions increased significantly for corneal endothelial diseases and graft failure. The growing demand for interventions for these diseases corresponded to the widespread adoption of EK techniques. The use of DALK also increased, but more moderately than EK procedures.

Outcomes of Descemet membrane endothelial keratoplasty, Descemet stripping automated endothelial keratoplasty and penetrating keratoplasty from a single centre study.

According to some pioneer surgeons, lamellar endothelial keratoplasty techniques (EK), including Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK), yield excellent clinical results. However, there is a lack of studies with high levels of evidence and results of large national keratoplasty registers are contradictory. Therefore, two large cohorts of DMEK and DSAEK procedures are compared to a cohort of penetrating keratoplasty (PK). The study reports 868 keratoplasty procedures at a single centre (694 eyes with Fuchs endothelial dystrophy (FED) and 174 with bullous keratopathy (BK)). Patients underwent DMEK (450 eyes), DSAEK (89 eyes), or PK (329 eyes). Postoperative visual acuity, endothelial cell density (ECD), rate of regrafting, and rejections were recorded. Visual acuity recovers faster and to a greater extent in EK compared to PK. DMEK performs better than DSAEK. ECD drops faster initially for EK compared to PK. In EK the rate of regrafting is higher than in PK (7 % in DMEK, 20 % in DSAEK and 2 % in PK in FED). The rejection rate is lowest following DMEK (7 % after DMEK, 21 % after DSAEK and 18 % after PK in FED). In contrast to recent reports from national keratoplasty registers, the overall clinical outcome of EK in FED and BK is superior to PK. Including ocular comorbidities and learning curves, these data reflect a realistic setting for comparing the different keratoplasty techniques. Corneal surgeons may be encouraged to preferentially use DMEK in FED and BK.

Survey of Experts on Current Endothelial Keratoplasty Techniques.

ObjectiveTo survey cornea specialists’ opinions on different endothelial keratoplasty techniques and to gauge the perceived need for and utility of a randomized controlled trial (RCT) comparing them.MethodsA short survey was distributed to a group of cornea specialists at the Endothelial Keratoplasty Group meeting at the American Academy of Ophthalmology meeting in November 2015.ResultsThirty-three of 80 practicing surgeons present at the EKG meeting participated in the survey, yielding a response rate of 41%. Ninety-seven percent (n=32) of our respondents reported performing Descemet’s Stripping Endothelial Keratoplasty (DSEK) regularly, and 70% reported having performed Descemet’s Membrane Endothelial Keratoplasty (DMEK) at least once (n=23). While most respondents (n=26, 79%) thought there was at least some evidence that DMEK is superior to DSEK in terms of visual acuity, there was less certainty about comparing ultrathin-DSEK (UT-DSEK) to DMEK with 48% (n=16) thinking there was at least some evidence of DMEK’s superiority, 6% (n=2) thinking there was at least some evidence of UT-DSEK’s superiority, and 30% (n=10) unsure. Seventy-two percent (n=23) of respondents thought an RCT comparing visual acuity outcomes in UT-DSEK versus DMEK would be at least moderately beneficial, and 82% (n=27) reported they were at least moderately likely to change their EK technique based on the results of said RCT.ConclusionThere is substantial interest in an RCT comparing visual acuity outcomes in UT-DSEK versus DMEK.

Femtosecond Laser-Assisted Deep Lamellar Endothelial Keratoplasty: A New Approach to a Forgotten Technique.

To review indications and clinical results for a hybrid deep lamellar endothelial keratoplasty (Femto-DLEK) technique combining contemporary donor tissue preparation and implantation techniques with femtosecond laser-assisted dissection of the host tissue. A retrospective analysis of consecutive cases of Femto-DLEK performed between 2011 and 2014 at Moorfields Eye Hospital, London, was conducted. All patients underwent manifest refraction and optical coherence tomography examination at their most recent review visit. Secondary interventions, graft rejection, and graft failure were recorded alongside corrected distance visual acuity. Femto-DLEK was performed in 7 eyes of 7 cases. Mean postoperative follow-up duration was 19 months. Indications included revision of deep anterior lamellar keratoplasty (n = 4), revision of failed Descemet stripping endothelial keratoplasty in cases with an anterior chamber intraocular lens (n = 2), and primary surgery in cases of dense posterior stromal copper deposition. All corneas were recorded as clear by 6 weeks after surgery. Median (range) preoperative corrected distance visual acuity was 6/60 (6/9-1/60), which improved to 6/9 (6/6-6/24) at final review. Tissue bridges requiring significant additional manual lamellar dissection were present in all 4 cases in which deep stromal femtosecond laser lamellar dissection was performed. Femtosecond laser host dissection in the remaining cases was restricted to only a posterior side-cut. Femto-DLEK is a useful alternative endothelial keratoplasty modality for a narrow range of indications. The femtolaser posterior side-cut facilitates DLEK, but further development of the Femto-DLEK technique is required to optimize the combination with deep lamellar host dissection.

Pre‐Descemets Endothelial Keratoplasty (PDEK)

SummaryThe most popular endothelial keratoplasty (EK) technique is Descemets stripping endothelial keratoplasty (DSEK). Descemets membrane endothelial keratoplasty (DMEK) has advantages but is technically challenging. In 2013 Dua et al reported a pre‐Descemets layer (Dua's layer, DL) in the posterior cornea and suggested how this could be exploited for EK. This was later developed and performed as Pre‐Descemets endothelial keratoplasty (PDEK).PDEK tissue is harvested by injecting air into the donor cornea and creating a type‐1 big bubble (BB). The posterior bubble wall composed of endothelial cells, DM and DL is excised and inserted in the recipient eye. This tissue rolls less than DMEK tissue and is more robust allowing easy handling and unrolling in the eye. It can also be physically centred in the anterior chamber. The limitations are that on occasions a type‐2 BB may form requiring a DMEK procedure. The PDEK graft size is smaller being limited by the size of the BB (around 8.5 mm). However, PDEK tissue can be taken form very young eyes with higher cell counts. Initial results, with regard to complications, visual acuity, refractive error and OCT changes are very encouraging making PDEK a viable option for EK.

Descemets membrane endothelial keratoplasty (DMEK)

SummaryDescemet's membrane endothelial keratoplasty (DMEK) has emerged as the superior technique for endothelial keratoplasty (EK) in routine cases to selectively replace diseased endothelium in patients with Fuchs endothelial dystrophy and pseudophakic bullous keratopathy. Despite all the advantages of DMEK the overall procedure is challenging for the surgeon. Crucial yet difficult steps of DMEK include: (1) Preparation of an intact donor lamella (D.M. and endothelium), (2) Transfer of the graft into the anterior chamber, (3) Unfolding and orientation of the graft, and (4) Final successful attachment after air filling. In my presentation I will demonstrate clearly how to perform these different steps safely and reproducibly.

Stamping an S on DMEK Donor Tissue to Prevent Upside-Down Grafts: Laboratory Validation and Detailed Preparation Technique Description.

To report endothelial cell loss (ECL) caused by a novel S-stamp preparation technique for Descemet membrane endothelial keratoplasty (DMEK). Six cadaveric human corneas were prepared for DMEK transplantation using a single standardized technique, including the application of a dry ink gentian violet S-stamp to the stromal side of Descemet membrane. Endothelial cell death was evaluated and quantified using computerized analysis of vital dye staining. ECL caused by the S-stamp was 0.6% (range 0.1%-1.0%), which comprised less than one-tenth of the total ECL caused by our preparation of the DMEK graft from the start to finish, including recovery, prestripping, S-stamping, and trephination (13.7% total ECL, range 9.9%-17.6%). Our novel S-stamp donor tissue preparation technique is intuitive to learn and holds the promise of preventing iatrogenic primary graft failure due to upside-down grafts without causing unacceptable increases in ECL.