Descemet Membrane Endothelial Keratoplasty Tissue Research Articles

Perceived difficulties and barriers to uptake of Descemet's membrane endothelial keratoplasty among surgeons.

Purpose: To determine barriers related to implementation of Descemet's membrane endothelial keratoplasty (DMEK) among corneal surgeons.Methods: This was a multicenter survey study of all corneal surgeons who participated in a DMEK wet lab organized by the Netherlands Institute for Innovative Ocular Surgery. Data related to barriers limiting uptake of DMEK surgery, self-perceived levels of competence, and difficulty with different steps of DMEK surgery were analyzed.Results: The survey response rate was 31% (22 of 72). The most common barrier to uptake of DMEK surgery identified was anxiety related to incorrect insertion of the tissue and the need to regraft (64%, 14 of 22), followed by anxiety related to tissue preparation (50%, eleven of 22). Surgeons also felt anxious regarding the possibility of rebubbling with initial DMEK (41%, nine of 22). Steps related to DMEK graft (76%) preparation, tissue insertion (41%), and graft unfolding (72%) were identified as the most difficult steps to learn by the respondents.Conclusion: The DMEK learning curve, especially for the novice surgeon, may be shortened by seeking educational resources, including wet labs and surgical videos. Eye banks may facilitate adoption of DMEK by making validated DMEK tissue more accessible to surgeons globally.

Trephine- and dye-free technique for eye bank preparation of pre-stripped Descemet membrane endothelial keratoplasty tissue.

We describe a rapid and easy technique for the preparation of pre-stripped Descemet membrane (DM) endothelial keratoplasty (DMEK) tissue in the eye bank, without the use of dye or trephining by the eye bank technician. After drawing 2 radial marks 90° apart on the scleral rim of the cornea, a circumferential incision was made internal to the trabecular meshwork and the edge of the DM opposite to the marked area was scored and gently peeled towards the marked area. Finally, the peeled DM was gently unrolled and attached to the posterior stromal bed via absorbing excess liquid from the periphery. The prepared DMEK tissue while reattached on the posterior aspect of the cornea was subjected to slit-lamp biomicroscopic and specular microscopic examinations. In case of proper preparation of DMEK tissue and suitability of endothelial cells for DMEK surgery, the tissue was distributed for transplantation. At the time of surgery, trypan blue staining was performed by the cornea surgeon before DM trephination. Duration of DMEK tissue preparation, uneventful preparation, post-preparation endothelial cell loss, surgeon's satisfaction, and intra- and post-operative attachment of the tissue were investigated variables in this study. Over a 2-year period, 28 DMEK tissues were successfully prepared from 30 corneas using our new technique. The median duration of DMEK preparation was 100s. The area of endothelial cell loss was 1.8% ± 1.2% centrally and 6.2% ± 1.8% in areas close to the forceps contacts. Seven out of the 28 (25%) DMEK tissues were ruined by surgeons during surgery and the overall rate of re-bubbling in 19 transplanted DMEK tissues was 16%. The presented method, which uses no trephining or vital dye, has simplified and expedited the preparation process of pre-stripped DMEK tissue in the eye banks.

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

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. 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. 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. 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.

Negative impact of dextran in organ culture media for pre-stripped tissue preservation on DMEK (Descemet membrane endothelial keratoplasty) outcome.

To assess the morphological and functional outcomes of Descemet membrane endothelial keratoplasty (DMEK) performed with pre-stripped tissue preserved in organ culture medium containing dextran compared to tissue preserved in dextran-free medium. In this retrospective study, we reviewed the clinical records of 103 patients who underwent DMEK surgery with pre-stripped tissue in our department between June 2015 and September 2016. The endothelium-Descemet membrane layer was preserved in organ culture medium for a maximum of 48h for all patients. For group 1, 49 endothelium-Descemet membrane (EDM) were stripped and preserved in medium 1 (dextran-free organ culture medium), while 54 EDM were stripped and preserved in medium 2 (organ culture medium supplemented with 6% dextran T-500) for group 2. Outcome measures included best-corrected visual acuity (BCVA), central corneal thickness (CCT), and endothelial cell density (ECD) of all eyes in both groups at three consecutive postoperative time points: 2weeks, 6weeks, and 6months postoperatively. We also compared the repeat keratoplasty rates between the groups. Group 1 showed a statistically significant better BCVA compared to group 2 at each time point (p < 0.05). The percentage of grafts achieving 0.5 or better after 6months in group 1 was 96% and in group 2, it was 66% (P < 0.001). CCT was significantly lower in group 1 compared to group 2 at 2weeks and 6months after surgery (p < 0.05). ECD was comparable between donor grafts before surgery but was significantly greater in groups 1 after 2 and 6weeks (p < 0.05), but not after 6months. Necessity for repeat keratoplasty (repeat DMEK, subsequent penetrating keratoplasty (PKP)) was significantly lower in group 1 (p < 0.05). Pre-stripped tissue for DMEK preserved in dextran-free medium led to better visual recovery, thinner postoperative corneas, a higher endothelial cell density, and a lower rate of repeat keratoplasty, indicating that dextran has an unfavorable impact on the preservation of pre-stripped DMEK tissue.

Elastin Content and Distribution in Endothelial Keratoplasty Tissue Determines Direction of Scrolling

Descemet membrane endothelial keratoplasty (DMEK) and pre-Descemet endothelial keratoplasty (PDEK) tissues always scroll with the endothelial cells (EC) outside. We designed a study to understand the reason for this behavior. Experimental study. Elastin content in Descemet membrane (DM), pre-Descemet layer (PDL), central and peripheral stroma, sclera, and trabecular meshwork were measured by the Fastin elastin assay kit. Distribution of elastin in DM, PDL, and anterior lens capsule (ALC) were examined by immunohistology. The effect of recombinant elastase enzyme and the effect of complete removal of EC and epithelial cells on the scrolling of DM and ALC, respectively, were studied. PDL showed the highest elastin content among the different tissues studied. Elastin localized as a distinct anterior band in the DM and was uniformly distributed in the PDL demarcating the latter from corneal stroma. Enzymatic treatment of DM with elastase reversed scrolling and corresponded with degradation or disappearance of elastin. Removal of EC did not affect the direction of scrolling. ALC behaved in the same manner with regard to distribution of elastin, scrolling, and removal of epithelial cells. This pattern of elastin distribution in DM explains why DMEK and PDEK tissues always scroll with the EC outside. This behavior is not influenced by the EC. High elastin content and uniform distribution in the PDL suggest a structural difference from the posterior stroma.

Clinical Outcomes of Preloaded Descemet Membrane Endothelial Keratoplasty Grafts With Endothelium Tri-Folded Inwards

To evaluate the initial outcomes and complications of Descemet membrane endothelial keratoplasty (DMEK) using donor tissues tri-folded with the endothelium inwards, preloaded at the Eye Bank, and delivered with bimanual pull-through technique. Prospective, noncomparative, interventional case series. Setting: Eye bank and tertiary care eye department. Forty-six consecutive eyes of 41 patients with Fuchs endothelial dystrophy with or without cataract operated between November 2016 and March 2017. DMEK tissues prepared with SCUBA technique and punched to a diameter of 8.25mm were preloaded with the endothelium tri-folded inwards in an intraocular lens (IOL) cartridge with a 2.2-mm opening filled with the same tissue culture medium contained in the vial used for shipment to the surgeon. Standardized DMEK was performed as a single procedure (n= 15) or in combination with phacoemulsification and IOL implantation (n= 31) within 48 hours from preparation using a bimanual pull-through technique. Preparation and surgical times, intraoperative and postoperative complications, best spectacle-corrected visual acuity (BSCVA), endothelial cell density (ECD), and graft detachment rate. Preparation time averaged 26.2 ± 4.1minutes (range 17-36minutes), while the surgical time from opening of the stoppers to air fill of the anterior chamber never exceeded 9minutes (range 3-9minutes). Surgery was uneventful in all cases. Postoperative complications included graft detachment in 9 of 46 cases (19.6%), successfully managed in all cases by single rebubbling within 6days from surgery, and glaucoma irresponsive to conservative treatment in 1 of 46 cases (2.1%). In all eyes without comorbidities (35 of 40 eyes) BSCVA was 20/25 (0.097 logMAR) or better as early as 3months after surgery. Six months postoperatively, ECD was available in 24 of 25 eyes with an endothelial cell loss calculated as a percentage of the preoperative value determined at the eye bank (ranging from 2500 to 2800 cells/mm2) of 29.5% ± 14.8% (range 8.3%-52.1%). Delivering a preloaded DMEK tissue, tri-folded with the endothelium inwards, minimizes surgical time and costs without negatively affecting the outcomes ofthe procedure.

Preloaded Descemet Membrane Endothelial Keratoplasty Donor Tissue: Surgical Technique and Early Clinical Results.

To describe the technique, advantages, and early complication rates of using Descemet membrane endothelial keratoplasty (DMEK) donor tissue that is prestained and preloaded into an injector at the eye bank and delivered in a storage medium to the surgeon for transplantation 1 to 2 days later. A total of 111 eyes with endothelial failure underwent DMEK using donors that were prestripped, prestained, S-stamped, and preloaded into a Straiko modified Jones tube and delivered in an Optisol-filled viewing chamber 1 to 2 days later. Scroll tightness, time to unscroll and center the tissue, postoperative rebubble rate, and graft failure rate were recorded. Endothelial cell density was measured at 3 and 6 months. All tissues remained well stained with easy visualization at the time of surgery (n = 111). The mean scroll tightness was 2.2 (range: 1-4). The mean time to center and unscroll the tissue was 3.5 minutes (range: 0.5-11.25 min). There was no primary graft failure. There were 16 cases with the placement of another bubble postoperatively (with a 14.4% rebubble rate). Of those 16 cases, 2 required a second rebubble. Endothelial cell loss at 3 and 6 months postoperatively was 26.7% (n = 63 eyes) and 30.9% (n = 67 eyes), respectively. This is the first report of the clinical use of prestained, preloaded tissue for DMEK. The characteristics and handling of the tissue were not different from those of surgeon-loaded tissue. Because punching, staining, and loading the graft intraoperatively is not necessary, the surgery time and risk of damaging donor tissue are reduced when using preloaded tissue.

Partitioning an Artificial Anterior Chamber With a Latex Diaphragm to Simulate Anterior and Posterior Segment Pressure Dynamics: The "DMEK Practice Stage," Where Surgeons Can Rehearse the "DMEK Dance".

To present a novel apparatus for simulating the anterior and posterior segment pressure dynamics involved in executing Descemet membrane endothelial keratoplasty (DMEK) surgery when using a chamber-shallowing technique. An artificial anterior chamber (AAC), 18-mm trephine, latex glove, two 3-mL syringes, and one donor cornea comprising an intact corneoscleral cap from which a DMEK tissue was peeled and punched are required for the model. After making the corneal incisions with the corneoscleral cap mounted on the AAC in the usual fashion, the corneoscleral cap is remounted onto the dried AAC over an 18-mm latex diaphragm. The space between the latex diaphragm and the cornea is filled with saline to pressurize the anterior chamber, and the posterior segment is pressurized with air from a syringe. The resulting apparatus comprises a posterior segment and anterior chamber that exert pressure on each other by way of a distensible latex diaphragm. A novice and experienced DMEK surgeon and 2 eye bank technicians were able to assemble the apparatus and perform the routine steps of a DMEK procedure, including maneuvers that require shallowing the anterior chamber and lowering its pressure. Only one cornea was required per apparatus. We present a novel in vitro model of the human eye that more closely mimics the anterior and posterior segment pressure dynamics of in vivo DMEK surgery than average human and animal cadaveric globes. The model is easy to assemble, inexpensive, and applicable to a range of teaching environments.

Donor Tissue Preparation for Descemet Membrane Endothelial Keratoplasty: An Updated Review.

To provide an overview of the current literature on donor tissue preparation for Descemet membrane endothelial keratoplasty (DMEK). A comprehensive database search without date restrictions was performed in PubMed and in The Cochrane Library in May, 2017. Keywords included Descemet membrane endothelial keratoplasty, corneal transplantation, graft, harvest, dissection, preparation, endothelial cell, and endothelial cell density. Articles aiming to describe or evaluate a technique for DMEK graft preparation were considered eligible and were included in this review. A graft dissection technique that provides consistent tissue qualities and a low risk of preparation failure is essential for surgeons and eye banks preparing DMEK tissue. Various techniques have been described aiming to facilitate DMEK graft dissection, including manual dissection, pneumatic dissection, and hydrodissection. All show a trend toward a no-touch technique, for example, without direct physical tissue manipulation during tissue harvesting, as a potential ideal approach to minimize graft damage. An overview of the current harvesting techniques available for DMEK may benefit corneal surgeons and eye banks in choosing the best approach for each specific user.

Standardizing Descemet Membrane Endothelial Keratoplasty Graft Preparation Method in the Eye Bank-Experience of 527 Descemet Membrane Endothelial Keratoplasty Tissues.

To share the experience and provide a standardized protocol for Descemet membrane endothelial keratoplasty (DMEK) graft preparation. A retrospective study based on 527 prestripped DMEK tissues that were prepared between 2014 and 2017. The experience of using different instruments and techniques has been described, and a standardized technique for preparing DMEK grafts has been identified. The tissues in general were prepared by superficially tapping the endothelial side with a Moria trephine (9.5 mm diameter). The plane of cleavage was identified using a cleavage hook, and the DMEK graft was deadhered from the trephined site throughout the circumference for ease of excising the graft. The DMEK graft was peeled using either one or multiple quadrant methods depending on the challenges faced during excision. The graft was finally marked with the letter "F" to identify the orientation during surgery. Data on endothelial cell loss (ECL) and challenging cases were observed, monitored, and recorded during this period. Less than 1 percent trypan blue-positive cells with tissue wastage of <6% was observed during the study period. Our standardized stripping technique has resulted in an overall ECL of 4.6%. Marking Descemet membrane showed 0.5% cell mortality. Standardizing DMEK technique using specific tools and simple techniques would help new surgeons to decide the instruments and improve their tissue preparation skills also in challenging cases such as previous cataract incisions or horseshoe-shaped tears, further reducing ECL or tissue wastage.

Graft detachment and rebubbling rate in Descemet membrane endothelial keratoplasty

Descemet membrane endothelial keratoplasty (DMEK) is a selective replacement of dysfunctional endothelium with healthy donor Descemet membrane and endothelium. Although the donor preparation and surgical methods still remain a challenge, DMEK is gaining popularity in terms of early rehabilitation and visual outcomes. New and improved donor preparation techniques like prestripped DMEK tissues are being taken up rapidly because of less manipulation that is required in the surgical theatre. Donor graft delivery in the recipient eye has also been improved because of new products like prestripped and preloaded membranes. As DMEK is at its budding stage, only early outcomes have been known so far. Early graft detachment, rebubbling rates, and primary failures are still being studied in DMEK. As there are different techniques that are currently used for preparation and injection of the graft, it becomes difficult to judge the results based on specific inclusion and exclusion criteria. Graft detachment and rebubbling rates have been a huge challenge both during the surgery and also while reporting postoperative data. We highlight the importance of defining graft detachment and rebubbling rates and their surgical relevance, which may also have an impact on graft preparation and insertion techniques.

Endothelium-in versus endothelium-out for Descemet membrane endothelial keratoplasty graft preparation and implantation.

To evaluate the difference between endothelium-in and endothelium-out for Descemet membrane endothelial keratoplasty (DMEK) preparation and implantation using injection method. The study was a randomized, comparative, institutional, laboratory investigation. Eighteen human donor corneas were included. A total of 9.5mm DMEK grafts were stripped and restored on the corneal base with a hinge and preserved in the deswelling medium. The grafts were detached from the hinge and either manually tri-folded with the endothelium on the inside, or allowed to spontaneously roll in phosphate-buffered saline (PBS) with endothelium outwards. The corneas were mounted on an artificial anterior chamber (AAC) and four incisions made using a 15° eye knife for the side ports and slit knife to create a 3.0mm incision for delivery of the graft into the AAC. The grafts with endothelium-in (endo-in) were pulled into a cartridge, whereas those with endothelium-out (endo-out) were aspirated using a modified Jones tube. Both were delivered using an injection method. Central and peripheral endothelial cell density (pre- and post-delivery and after removal), time of preparation and unfolding were measured. Endothelial cell loss postimplantation was 10.53%(±2.82) with endo-in (n=9) compared to 7.56%(±14.74) with endo-out (n=9) (p>0.05). Preparation and unfolding time was 4.43min (±3.43) and 0.96min (±1.10)for endo-in compared to 1.68min (±0.57) and 4.92min (±4.21)for endo-out. A statistical significance between endo-in and endo-out for loading (p=0.04) and unfolding (p=0.023) time was observed. Descemet membrane endothelial keratoplasty tissues can be tri-folded (endo-in) with no significantly less cell loss as compared to endo-out. Spontaneous unfolding of endo-in may reduce overall time and surgical manipulation.

Validation of an endothelial roll preparation for Descemet Membrane Endothelial Keratoplasty by a cornea bank using "no touch" dissection technique.

Descemet Membrane Endothelial Keratoplasty (DMEK) selectively replaces the damaged posterior part of the cornea. However, the DMEK technique relies on a manually-performed dissection that is time-consuming, requires training and presents a potential risk of endothelial graft damages leading to surgery postponement when performed by surgeons in the operative room. To validate precut corneal tissue preparation for DMEK provided by a cornea bank in order to supply a quality and security precut endothelial tissue. The protocol was a technology transfer from the Netherlands Institute for Innovative Ocular Surgery (NIIOS) to Lyon Cornea Bank, after formation in NIIOS to the DMEK "no touch" dissection technique. The technique has been validated in selected conditions (materials, microscope) and after a learning curve, cornea bank technicians prepared endothelial tissue for DMEK. Endothelial cells densities (ECD) were evaluated before and after preparation, after storage and transport to the surgery room. Microbiological and histological controls have been done. Twenty corneas were manually dissected; 18 without tears. Nineteen endothelial grafts formed a double roll. The ECD loss after cutting was 3.3% (n=19). After transportation 7days later, we found an ECD loss of 25% (n=12). Three days after cutting and transportation, we found 2.1% of ECD loss (n=7). Histology found an endothelial cells monolayer lying on Descemet membrane. The mean thickness was 12±2.2µm (n=4). No microbial contamination was found (n=19). Endothelial roll stability has been validated at 3days in our cornea bank. Cornea bank technicians trained can deliver to surgeons an ECD controlled, safety and ready to use endothelial tissue, for DMEK by "no touch" technique, allowing time saving, quality and security for surgeons.

Quantification and Patterns of Endothelial Cell Loss Due to Eye Bank Preparation and Injector Method in Descemet Membrane Endothelial Keratoplasty Tissues.

To evaluate endothelial cell damage after eye bank preparation and passage through 1 of 2 different injectors for Descemet membrane endothelial keratoplasty grafts. Eighteen Descemet membrane endothelial keratoplasty grafts were prepared by Lions VisionGift with the standard partial prepeel technique and placement of an S-stamp for orientation. The grafts were randomly assigned to injection with either a glass-modified Jones tube injector (Gunther Weiss Scientific Glass) or a closed-system intraocular lens injector (Viscoject 2.2; Medicel). After injection, the grafts were stained with the vital fluorescent dye Calcein AM and digitally imaged. The percentage of cell loss was calculated by measuring the area of nonfluorescent pixels and dividing it by the total graft area pixels. Grafts injected using the modified Jones tube injector had an overall cell loss of 27% ± 5% [95% confidence interval, 21%-35%]. Grafts injected using the closed-system intraocular lens injector had a cell loss of 32% ± 8% (95% confidence interval, 21%-45%). This difference was not statistically significant (P = 0.3). Several damage patterns including damage due to S-stamp placement were observed, but they did not correlate with injector type. In this in vitro study, there was no difference in the cell loss associated with the injector method. Grafts in both groups sustained significant cell loss and displayed evidence of graft preparation and S-stamp placement. Improvement in graft preparation and injection methods may improve cell retention.

Contact Lens-Assisted Pull-Through Technique for Delivery of Tri-Folded (Endothelium in) DMEK Grafts Minimizes Surgical Time and Cell Loss

To evaluate the feasibility and outcomes of contact lens-assisted bimanual pull-through delivery of Descemet membrane endothelial keratoplasty (DMEK) tissue trifolded with the endothelium inward. Prospective, noncomparative, interventional case series. Forty-two consecutive eyes of 42 patients with Fuchs endothelial dystrophy with or without cataract. Standardized DMEK was performed as a single procedure (n = 9) or in combination with phacoemulsification and implantation of a posterior chamber intraocular lens (n = 33) using prestripped donor tissue punched to a diameter of 8.25 mm and then trifolded with the endothelium in. Using a sterile soft contact lens as scaffold, the tissue was loaded in this configuration into a disposable cartridge and delivered into the anterior chamber under continuous irrigation using a bimanual pull-through technique to facilitate spontaneous proper unfolding. Surgical time, intraoperative and postoperative complications, visual acuity 3 and 6 months after surgery, and endothelial cell loss 6 months after surgery. Surgery was uneventful in all cases and the time required for the DMEK procedure (from Descemet scoring until final air filling) never exceeded 20 minutes (average, 17.1±1.6 minutes). The only complication observed after surgery was graft detachment (10 of 42 eyes [23.8%]), successfully managed in all cases by single rebubbling within 6 days from surgery. In all eyes with a minimum postoperative follow-up of 6 months (n = 20), best spectacle-corrected visual acuity was 20/25 or better and the average endothelial cell density (±standard deviation) was 2363.8±82.7 cells/mm(2) (range, 2258-2490 cells/mm(2)). The cell loss calculated as a percentage of the preoperative value determined at the eye bank (range, 2500-2700 cells/mm(2)) was 9.9±2.1% (range, 4.1%-11.9%). Delivering DMEK tissue, trifolded with the endothelium inward, reduces surgical trauma to donor cells and facilitates spontaneous unfolding, thus minimizing surgical time.

Graft preparation for hemi-Descemet membrane endothelial keratoplasty (hemi-DMEK)

Background/aimsThere is a substantial shortage of donor tissue for endothelial keratoplasty worldwide. Using two endothelial grafts of one donor cornea may potentially increase the pool of suitable donor tissue for...

Ultrathin DSAEK: The Present Status

The lecture will present a complete review of Descemet Stripping Automated Endothelial Keratoplasty (DSEK), focussing in particular on the development of the technique for the dissection of ultrathin (UT) donor tissue. History as well as basic principles necessary to understand the mechanisms of UT DSAEK will be introduced to the attendees. In setting the indication to UT DSAEK, the author will discuss the role of recipient corneal status, type of endothelial disease, concomitant eye disease (i.e. glaucoma), presence of clear lens and other preoperative factors. The different techniques of conventional DSEK, UT DSAEK and Descemet membrane endothelial keratoplasty (DMEK) will be compared, pointing out the single steps, which are instrumental in facilitating surgery, while improving the final outcome. In case of multiple intervention, combined versus sequential procedures (e.g. phacoemulsification, IOL surgery, vitrectomy, etc.) will be discussed. The authors will highlight advantages and disadvantages of different surgical approaches. Possible implications for eye banking will also be addressed, with particular emphasis on preparation and storage of tissue for UT DSAEK and DMEK. Slides and videos of case studies will illustrate the most common complications (i.e. graft detachment, dislocation, failure, rejection etc.) as well as the appropriate solutions.

Endothelial cell loss following tissue harvesting by pneumodissection for endothelial keratoplasty: an ex vivo study

AimsTo study ex vivo the difference in endothelial cell density (ECD) in tissue harvested by pneumodissection for pre-Descemet's endothelial keratoplasty (PDEK) and Descemet's membrane endothelial keratoplasty (DMEK).MethodsTissue for PDEK and...

Risk Factors for Eye Bank Preparation Failure of Descemet Membrane Endothelial Keratoplasty Tissue

To assess the results of a single eye bank preparing a high volume of Descemet membrane endothelial keratoplasty (DMEK) tissues using multiple technicians to provide an overview of the experience and to identify possible risk factors for DMEK preparation failure. Cross-sectional study. setting: Lions VisionGift and Wilmer Eye Institute at Johns Hopkins Hospital. All 563 corneal tissues processed by technicians at Lions VisionGift for DMEK between October 2011 and May 2014 inclusive. Tissues were divided into 2 groups: DMEK preparation success and DMEK preparation failure. We compared donor characteristics, including past medical history. The overall tissue preparation failure rate was 5.2%. Univariate analysis showed diabetes mellitus (P = .000028) and its duration (P = .023), hypertension (P = .021), and hyperlipidemia or obesity (P = .0004) were more common in the failure group. Multivariate analysis showed diabetes mellitus (P = .0001) and hyperlipidemia or obesity (P = .0142) were more common in the failure group. Elimination of tissues from donors either with diabetes or with hyperlipidemia or obesity reduced the failure rate from 5.2% to 2.2%. Trends toward lower failure rates occurring with increased technician experience also were found. Our work showed that tissues from donors with diabetes mellitus (especially with longer disease duration) and hyperlipidemia or obesity were associated with higher failure rates in DMEK preparation. Elimination of tissues from donors either with diabetes mellitus or with hyperlipidemia or obesity reduced the failure rate. In addition, our data may provide useful initial guidelines and benchmark values for eye banks seeking to establish and maintain DMEK programs.

Diabetes mellitus increases risk of unsuccessful graft preparation in Descemet membrane endothelial keratoplasty: a multicenter study.

The aim of this study was to evaluate preparation outcomes of tissue prepared for Descemet membrane endothelial keratoplasty (DMEK) from diabetic and nondiabetic donors. In this nonrandomized, consecutive case series, DMEK grafts were prepared from diabetic and nondiabetic donors by experienced technicians in 2 eye banks using slightly different, modified submerged manual preparation techniques to achieve "prestripped" graft tissue. Graft preparation results were analyzed retrospectively. The main outcome measure was the rate of unsuccessful (failed) DMEK graft preparations, defined as tears through the graft area that prevent tissue use. A total of 359 corneas prepared from 290 donors (114 diabetic and 245 nondiabetic) were included in the statistical analysis of graft preparation failure. There were no significant differences between diabetic and nondiabetic donor tissue characteristics with respect to donor age, death to preservation time, death to preparation time, endothelial cell density, percent hexagonality, or coefficient of variation. DMEK tissue preparation was unsuccessful in 19 (5.3%) cases. There was a significant difference in the site-adjusted rate of DMEK preparation failure between diabetic [15.3%; 95% confidence interval (CI), 9.0-25.0] and nondiabetic donors (1.9%; 95% CI, 0.8-4.8), and the corresponding site-adjusted odds ratio of DMEK graft preparation failure in diabetic donor tissue versus nondiabetic donor tissue was 9.20 (95% CI, 2.89-29.32; P = 0.001). Diabetes may be a risk factor for unsuccessful preparation of donor tissue for DMEK. We recommend caution in the use of diabetic tissue for DMEK graft preparation. Further study is needed to identify what subset of diabetic donors is at risk for unsuccessful DMEK graft preparation.