Trends and Surgeon Variations in Early Regrafts After Endothelial Keratoplasty: Analysis of the National Medicare Data Set.

PURPOSE: The aims of this study were to determine national-level trends in early regraft rates and examine patient-level and surgeon-level characteristics associated with early regrafts. METHODS: This was a retrospective, cohort study. We identified beneficiaries aged 65 years or older in the 2011 to 2020 Medicare carrier claims data set who underwent Endothelial keratoplasty (EK) and subsequently underwent an early regraft. The incidence of early regraft for each year was calculated and patient-level and surgeon-level characteristics associated with regrafts were examined using a multivariable regression model. RESULTS: Of 114,383 EK procedures, 4119 (3.60%) were followed by an early regraft, with no significant variations in the rates between years ( P = 0.59). Factors associated with higher odds of early regraft were Black compared with White race (OR 1.151; 95% confidence interval (CI) 1.018-1.302) and the highest quartile of income versus the lowest quartile (OR 1.120; 95% CI 1.002-1.252). Factors associated with lower odds were female sex (OR 0.889; 95% CI 0.840-0.942), receiving surgery in a hospital-based outpatient department versus an ambulatory center (OR 0.813; 95% CI 0.740-0.894), and having a surgeon with the highest quartile of annual EK volume versus the lowest (OR 0.726; 95% CI 0.545-0.967). Early regraft rates among surgeons ranged from 0% to 58.8% with a median [interquartile range] of 3.13 [0-6.15]. CONCLUSIONS: We found no significant increases in the early regraft rates over the past decade in the United States. Patient male sex and Black race, ambulatory surgery center-based location of the surgery, and low surgeon EK volume were associated with early regrafts. Substantial surgeon variability in regraft rates may indicate opportunities for improvement through development of best practices on perioperative management and patient counseling.

Trends in Early Graft Failure Leading to Regrafting After Endothelial Keratoplasty in the United States.

PURPOSE: The purpose of this study was to report trends in the prevalence of early graft failure after endothelial keratoplasty in the United States. METHODS: Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK) graft volumes were collected from records maintained by 6 major eye banks in the United States from January 1, 2013, to December 31, 2018. The prevalence and presumed cause of early graft failures (defined as a graft with persistent edema or regrafted within 8 weeks after keratoplasty) each year were sourced from surgeon-reported adverse events. Failed graft cases from the 3 eye banks were compared with nonfailures at the donor and recipient levels to perform subset analysis of factors associated with early graft failure. RESULTS: A total of 51,887 endothelial keratoplasty tissues were distributed during the study period; 72% were DSAEK grafts. The total number of early graft failures reported was 168 of 14,284 (1.18%) for DMEK and 322 of 37,603 (0.86%) for DSAEK. Early DMEK failures decreased from 2013 (7.69%) to 2018 (0.68%). In generalized linear mixed model analyses adjusting for donor tissue characteristics, recipient age, and diagnosis, an association of borderline significance was found between higher donor age and early failure [odds ratio (95% confidence interval): 1.03 (1.00-1.05); unit change of 1 yr] and DSAEK [odds ratio 1.02 (1.00-1.04); unit of change 1 yr] cases. CONCLUSIONS: The proportion of early graft failures in DMEK decreased over time and was comparable with failure rates in DSAEK at the end of the study period. The surgical learning curve might have played a role.

Primary Graft Failure, Infection, and Endothelial Cell Density in Corneal Transplants With Increased Death-to-Preservation Time.

PURPOSE: To ascertain whether death-to-preservation time (DPT) is associated with donor endothelial cell density (ECD), primary graft failure (PGF), and infection. METHODS: Donor corneas aged older than 10 years with ECD 2000 to 4500 cells/mm2 were procured between 2011 and 2018 by a single eye bank. Donor corneas were analyzed retrospectively for the main outcome measures of PGF, infection, and ECD. Means and proportions of study parameters were compared between corneas with long and short DPT, defined as greater or less than 14 hours, respectively, excluding corneas with a history of intraocular surgery or diabetes. Multivariate analyses were performed using logistic regression, adjusting for donor age at time of death, history of diabetes mellitus, and history of cataract surgery. RESULTS: Among 12,015 corneas, those with long DPT had a statistically but not clinically significant higher ECD than that of corneas with short DPT (2754 vs. 2724 cells/mm2, P < 0.01). There was no difference in PGF and infections in corneas with long versus short DPT (0.28% vs. 0.26%, P = 0.86; 0.43% vs. 0.29%, P = 0.51, respectively). CONCLUSIONS: Longer DPT is not associated with a clinically meaningful reduction in donor ECD, PGF, or infection.

Early Complications With Preloaded Descemet Membrane Endothelial Keratoplasty Are Not Dependent on Optisol-GS Washout or Trypan Blue Restaining.

PURPOSE: To describe the intraoperative and early postoperative complications using preloaded Descemet membrane endothelial keratoplasty (DMEK) grafts with intraocular injection of the graft in Optisol-GS and omission of trypan blue restaining. METHODS: This is a retrospective case series of 132 consecutive eyes with Fuchs endothelial dystrophy or endothelial failure who underwent DMEK using preloaded donor tissue prepared as previously described. The graft was not restained with trypan blue by the surgeon, and Optisol-GS was injected with the graft into the eye instead of being rinsed from the injector. Early postoperative complications (0-8 wk) including intraoperative fibrin formation, intraocular inflammation, elevated intraocular pressure, partial graft detachment requiring rebubble, and early graft failure were recorded. RESULTS: No eyes developed intraoperative fibrin formation or postoperative inflammation (such as toxic anterior segment syndrome) or elevated intraocular pressure. For eyes with Fuchs corneal dystrophy, our rebubble rate was 21% (22/106 eyes). Early graft failure was noted in 2% (3/132 eyes), which is similar to previous reports. CONCLUSIONS: Our results suggest that injection of Optisol-GS into the anterior chamber during DMEK graft injection does not lead to increases in intraoperative or early postoperative complications. Trypan blue restaining is not necessary for intraoperative visualization. This simplification can reduce graft manipulation and save time and resources for this procedure.

Surgeon Preference for Endothelial Keratoplasty Techniques.

PURPOSE: To examine barriers and facilitators to adoption of Descemet membrane endothelial keratoplasty (DMEK) for treatment of endothelial dysfunction. METHODS: Anonymous electronic surveys were emailed to surgeons ordering corneal transplant tissue in the past 18 months from 2 eye banks in the United States (US). RESULTS: Of 365 surgeons emailed, 118 (32%) completed the survey. Most respondents were located at an urban site (59%), were in private practice (64%), and had been in practice for >10 years (53%). Participants performing DMEK (n = 70) were more likely to have been in practice for ≤10 years than those not performing DMEK (56% vs. 35%, respectively, P = 0.03). Among respondents not performing DMEK (n = 48, 41%), the most frequently reported barriers were technical difficulty (n = 30, 63%), a lack of experience (n = 29, 60%), low surgical volume (n = 20, 42%), and risk of postoperative complications (n = 19, 40%). Most (n = 46, 96%) respondents not performing DMEK were interested in doing so, with the following reported as helpful resources: wet laboratory courses (n = 35, 73%), eye bank-prepared tissue: preloaded/prestripped (n = 32, 67%), back-up tissue in case of inadvertent graft damage (n = 29, 60%), higher surgical volume to support the learning curve (n = 28, 58%), and surgical mentorship (n = 22, 46%). Only a minority wanted more data to highlight superiority over other EK procedures (n = 12, 25%). CONCLUSIONS: There is substantial interest in learning to perform DMEK among the surgical community. Barriers identified in this survey may be addressed to help surgeons increase DMEK adoption.

Prelamellar Dissection Donor Corneal Thickness Is Associated With Descemet Stripping Automated Endothelial Keratoplasty Operative Complications in the Cornea Preservation Time Study.

PURPOSE: To identify donor and recipient factors, including eye bank tissue observations, predictive of operative complications in the Cornea Preservation Time Study. METHODS: One thousand three hundred thirty study eyes undergoing Descemet stripping automated endothelial keratoplasty for Fuchs dystrophy or pseudophakic/aphakic corneal edema were randomized to receive a donor cornea with preservation time (PT) of 0 to 7 days (N = 675) or 8 to 14 days (N = 655). Donor factors included demographics, prelamellar corneal and postlamellar lenticule dissection thickness, central endothelial cell density, and tissue processing time. Recipient factors included demographics, intraocular pressure, and glaucoma medications or surgery (trabeculectomy, laser trabeculoplasty). Eye bank observations included donor tissue folds, pleomorphism/polymegethism, and endothelial cell abnormalities. Possible tissue-related operative complications were recorded including difficult donor lenticule unfolding and positioning. Multivariable logistic regression with backward selection was used to identify statistically significant (P < 0.01) associations between factors and operative complications. RESULTS: The only factor predictive of operative complications [58 (4.4%) of 1330 surgeries] was prelamellar dissection donor corneal thickness (P = 0.002). For every 50 µm of donor corneal thickness prior to lamellar dissection, operative complication odds increased by 40% (odds ratio [99% confidence interval (CI)]: 1.40 [1.06-1.83]) adjusting for PT and whether the epithelium was on or off. The estimated mean prelamellar dissection donor corneal thickness for PT 0 to 7 days was 537 µm (99% CI: 516 µm-558 µm) compared with 567 µm (99% CI: 546 µm-588 µm) for PT 8 to 14 days (P < 0.001). CONCLUSIONS: Thicker donor tissue (prelamellar dissection) is associated with operative complications and should be considered in tissue selection for Descemet stripping automated endothelial keratoplasty lenticule preparation.

Effect of Graft Attachment Status and Intraocular Pressure on Descemet Stripping Automated Endothelial Keratoplasty Outcomes in the Cornea Preservation Time Study.

PURPOSE: To examine the association of donor, recipient, and operative factors on graft dislocation after Descemet stripping automated endothelial keratoplasty (DSAEK) in the Cornea Preservation Time Study (CPTS) as well as the effects of graft dislocation and elevated IOP on graft success and endothelial cell density (ECD) 3 years postoperatively. DESIGN: Cohort study within a multi-center, double-masked, randomized clinical trial. METHODS: 1090 individuals (1330 study eyes), median age 70 years, undergoing DSAEK for Fuchs endothelial corneal dystrophy (94% of eyes) or pseudophakic or aphakic corneal edema (6% of eyes). Recipient eyes receiving donor corneal tissue randomized by preservation time (PT) of 0-7 days (N = 675) or 8-14 days (N = 655) were monitored for early or late graft failure through 3 years. Donor, recipient, operative, and postoperative parameters were recorded including graft dislocation (GD), partial detachment, and pre- and post-operative IOP. Pre- and postoperative central donor ECD were determined by a central image analysis reading center. Proportional hazards, mixed effects, and logistic regression models estimated risk ratios and (99% confidence intervals). RESULTS: Three independent predictive factors for GD were identified: a history of donor diabetes (odds ratio [OR]: 2.29 [1.30, 4.02]), increased pre-lamellar dissection central corneal thickness (OR: 1.13 [1.01, 1.27] per 25µ increase), and operative complications (OR: 2.97 [1.24, 7.11]). Among 104 (8%) eyes with GD, 30 (28.9%) developed primary donor or early failure and 5 (4.8%) developed late failure vs. 15 (1.2%; P < .001) and 29 (2.4%; P = .04), respectively, of 1226 eyes without GD. 24 (2%) of 1330 study eyes had early acutely elevated postoperative IOP that was associated with a higher risk of graft failure through 3 years (hazard ratio: 3.42 [1.01, 11.53]), but not with a lower mean 3-year ECD (mean difference 61 (-479, 601) cells/mm2, P = .77). History of elevated postoperative IOP beyond 1 month was not significantly associated with 3-year graft success or ECD. CONCLUSIONS: Donor diabetes, increased donor corneal thickness, and intraoperative complications were associated with an increased risk of GD. Early acutely elevated postoperative IOP and GD significantly increased the risk for graft failure following DSAEK.

Optical Coherence Tomography Assessment of the Cornea During Corneal Swelling: Should the Term "Descemet Membrane Folds" Be Reconsidered?

PURPOSE: Previous work has suggested that Descemet membrane (DM) folds arise in response to corneal swelling. However, their origin has not been closely explored. In this study, we used optical coherence tomography to evaluate whether DM folds arise secondary to folds in the middle stroma. METHODS: Serial optical coherence tomography images of donor cornea pairs in deionized water were taken for each of the following corneal manipulations: 1) untreated, 2) DM and the endothelium removed, 3) excised in the region of the deep middle/posterior stroma, and 4) excised in the middle stroma. RESULTS: For intact corneas, increasing duration in deionized water was marked by a progressive increase in corneal thickness and number of folds along the posterior surface. With DM and the endothelium removed, a similar phenomenon was observed. In the third set of corneas, the plane of resection created a structural separation in the region of the deep middle/posterior stroma. Folds were seen originating anterior to the resection plane. For corneas with the posterior and part of the middle stroma removed, the typical folds on the posterior surface as seen in the previous conditions were not observed. Instead, less numerous and smaller irregularities of the posterior surface of the resection plane were present. CONCLUSIONS: Folds in DM associated with corneal edema originate in the middle and posterior stroma and are secondarily transmitted into DM. On the basis of the stromal origin of these anatomic changes, "stromal folds" should be considered a more accurate term to replace "Descemet membrane folds."

Reports of Post-keratoplasty Infections for Eye Bank-prepared and Non-Eye Bank-prepared Corneas: 12 Years of Data From a Single Eye Bank.

PURPOSE: To examine postoperative reports of infection rates for eye bank-prepared and non-eye bank-prepared corneas from January 1, 2006 to December 31, 2017, from a single eye bank. METHOD: A retrospective review of reported fungal and bacterial infections with corneal transplant surgeries using corneas distributed by our eye bank was conducted. The reported number of infections for corneas that underwent eye bank preparation (pre-cut and pre-stripped corneas) and for those distributed without eye bank preparation was quantified. The potential association between infection rates in tissue prepared by the eye bank and those in corneas that had no additional eye bank processing was also examined. RESULTS: Four of 17,035 corneas distributed during the study period were associated with fungal infections (1 eye bank-prepared and 3 non-eye bank-prepared corneas) and were attributed to the tissue after investigation by eye bank medical directors. There was no ascending trend of infections reported with eye bank-prepared corneas in the first 3 years (2 of 1054 corneas, 0.19%) compared with that in the last 3 years of the study period (6 of 3500 corneas, 0.17%; P = 0.901) when the eye bank distributed 3 times more prepared corneas than non-eye bank-prepared corneas. A significant increase in the numbers of reported infections for non-eye bank-prepared corneas was observed between these 3-year intervals (0.1% in the first 3 years to 1.58% in the last 3 years; P = 0.001). CONCLUSIONS: Reports of infections remained low despite increased use of eye bank-prepared tissue. These results suggest that factors other than eye bank tissue preparation should be considered when investigating potential sources of pathogen contamination in donor corneas.

Comparison of Donor Cornea Endothelial Cell Density Determined by Eye Banks and by a Central Reading Center in the Cornea Preservation Time Study.

PURPOSE: To evaluate agreement between eye banks (EBs) and a reading center on endothelial cell density (ECD) determinations in the Cornea Preservation Time Study. METHODS: The Cornea Image Analysis Reading Center (CIARC) performed variable frame image analysis on EB-obtained-preoperative central endothelial images (after lamellar dissection for Descemet stripping automated endothelial keratoplasty by the EBs or before shipping, if surgeon prepared) to determine ECD. The EBs performed their usual method of ECD determination. The CIARC and EBs also provided ECD determinations from screening central endothelial images taken by the EBs during donor evaluation. Two independent masked CIARC readers determined ECD with measurements averaged. RESULTS: The mean preoperative ECD was 15 cells/mm greater by the EBs than by CIARC (N = 1286, P < 0.001) with 95% limits of agreement of (-644, 675 cells/mm). The limits of agreement in preoperative ECD were wider in the After-Lamellar-Dissection Group (-687, 683 cells/mm) than in the Before Shipping Group [(-505, 633 cells/mm); P = 0.03]. The EBs-determined preoperative ECD was within 10% of the CIARC-determined ECD for 886 (69%) image sets, with 236 (18%) higher by >10% and 164 (13%) lower by >10%. Excellent agreement appeared between the EBs and CIARC when 100-300 cells could be analyzed in contrast to <100 cells (SD = 308 cells/mm vs. SD = 603 cells/mm; P < 0.001). CONCLUSIONS: The mean ECD by the EBs and CIARC were similar, but there was considerable variability between determinations for individual corneas. Agreement improved between the 2 measurements when more than 100 cells were able to be analyzed.

Reduction of Donor Cornea Exposure to Repeat Warming Cycles and Evaluation Times After Implementation of a Rapid Warming Protocol.

PURPOSE: To compare tissue evaluation times and specular image quality before and after the implementation of rapid tissue warming at a single eye bank. METHODS: This retrospective study compares the evaluation of 494 donor corneas. All corneas were stored in Optisol-GS. Group 1 contained 247 corneas evaluated immediately before implementation of a tissue incubator and tissue warming protocol. Group 2 contained 247 corneas evaluated immediately after implementation. Total evaluation times (including specular microscopy, optical coherence tomography for corneal thickness measurements, and 2 slit-lamp examinations) were calculated and compared. Representative specular images of donor corneas were rated and compared using a previously described scale by 2 masked readers. RESULTS: Donor tissue characteristics were not significantly different between both groups (age, P = 0.87; sex, P = 0.93; endothelial cell densities, P = 0.47; and death-to-preservation times, P = 0.18). The mean total evaluation time for group 2 corneas was ∼3 hours, with 97% (201/208) of evaluations completed on the same day. In contrast, only 73% (164/225) of corneas from group 1 were completely evaluated in 1 day, and the mean evaluation time for those corneas was ∼4.25 hours (P < 0.01). Specular images of corneas from group 2 were rated 1 grade higher, on average, than those from group 1 (n = 247 in each group, P < 0.01). Furthermore, 71% of specular images from group 2 were categorized as "good" or "excellent" quality, whereas only 30% of corneas from group 1 received those ratings. CONCLUSIONS: Rapid tissue warming cuts down on tissue evaluation time and reduces the time donor corneas are out of cold storage. Better specular images were obtained after implementation of the rapid warming protocol.

Cumulative Endothelial Cell Loss in Descemet Membrane Endothelial Keratoplasty Grafts From Preparation Through Insertion With Glass Injectors.

PURPOSE: Evaluation of cumulative Descemet membrane endothelial keratoplasty endothelial cell loss (ECL) from preparation through injection using 2 different glass injectors. METHODS: Eighteen Descemet membrane endothelial keratoplasty grafts with "S" stamps were prepared by eye bank technicians. Nine grafts were assigned to injection with a modified glass Jones tube injector with a 2.4-mm opening and 9 were assigned to injection with the DORC glass pipette injector (<1.5-mm opening). The grafts were prepared and loaded into the injectors using the standard surgical technique, ejected onto a bed of viscoelastic on a glass slide, and unscrolled using viscoelastic. The grafts were stained with the vital dye Calcein-AM, then digitally imaged and analyzed using FIJI. The percentage of ECL was calculated by measuring the area of nonfluorescent pixels and dividing it by the total graft area pixels. A statistical comparison was performed using a 2-tailed unpaired t test. RESULTS: Grafts injected using the DORC injector versus Jones tube injector had ECL of 29.2% ± 8.5% [95% confidence interval (CI)] versus 23.0% ± 5.1% (95% CI), respectively. This difference was not statistically significant (P = 0.17); however, the patterns of ECL on the grafts was different between injectors. Peripheral ECL caused by trephination and surgeon grasp sites accounted for 7.5% ± 1.2% (95% CI). CONCLUSIONS: There was no statistical difference in ECL between the 2 injectors. There were characteristic differences in patterns of ECL seen between injectors, which may be clinically relevant and indicate the types of stress that grafts are exposed to during passage through various injectors.

Light scattering measurements in electron-beam sterilized corneas stored in recombinant human serum albumin.

Irradiated corneal tissues have been used for a variety of ophthalmic procedures including glaucoma drainage device covers and lamellar grafts. The maintenance of corneal clarity is important, as light obstructions resulting from processing or long-term storage of irradiated corneas may negatively affect vision and postoperative cosmesis. It has been reported that corneal tissues can be preserved in human serum albumin (HSA), however, the clarity of corneas after long-term storage in HSA has not been well described. Furthermore, the use of donor-pooled serum increases the risk for transmission of blood-borne diseases and may induce an immune response in the recipient. Here, we examined changes in corneal clarity due to electron-beam (e-beam) irradiation and storage in a recombinant human serum albumin (rHSA). Dark-field microscopy was employed to examine the light scattering effects of fresh and irradiated corneas. Compared to measurements taken prior to tissue preparation and e-beam treatment, irradiated corneas showed an average 2.6% increase in light scattering (P = 0.002). Irradiated corneas stored in rHSA at room-temperature for 20 months showed an average increase of 11.6% light scattering compared to fresh corneas (P â‰ª 0.01), but did not negatively affect the visualization of printed text, and were deemed suitable for transplant use. Therefore, the slight increase in cornea light scattering, and resulting reduction in corneal clarity, after e-beam treatment and long-term storage in rHSA may not be clinically significant. These results suggest that e-beam sterilized corneal grafts may be used as an alternative to fresh tissue for certain ophthalmic applications.

Validity of Postmortem Glycated Hemoglobin to Determine Status of Diabetes Mellitus in Corneal Donors.

PURPOSE: To examine the stability of postmortem glycated hemoglobin (HbA1c) measurement and its relationship to premortem glycemia. METHODS: Postmortem blood samples were obtained from 32 donors (8 known diabetic) and shipped on ice to a central laboratory to examine the stability of HbA1c measurements during the first 9 postmortem days. Thirty-nine other suspected diabetic donors underwent comparison of premortem and postmortem HbA1c measurements. RESULTS: Postmortem HbA1c measurements remained stable after 9 postmortem days (all measurements within ±0.2% from baseline with a mean difference of 0.02% ± 0.10%). Of the premortem measurements obtained within 90 days before death, 79% were within ±1.0% of the postmortem measurements compared with 40% for measurements more than 90 days apart. Three of the postmortem HbA1c measurements exceeded 6.5% (considered a threshold for diabetes diagnosis), although the medical histories did not indicate any previous diabetes diagnosis. CONCLUSIONS: Postmortem HbA1c testing is feasible with current eye bank procedures and is reflective of glycemic control of donors during 90 days before death. HbA1c testing could potentially be a useful adjunct to review of the medical history and records for donor assessment for endothelial keratoplasty suitability and long-term graft success.

Rapid Warming of Donor Corneas Is Safe and Improves Specular Image Quality.

PURPOSE: To determine whether warming donor corneas to near-physiological temperatures can safely shorten warming times while providing high-quality specular images during tissue evaluation. METHODS: Mated corneas were warmed at room temperature (RT) or at 35°C for 4 hours upon removal from cold storage. Specular images and endothelial cell densities were acquired and rated every hour. Additional mated corneas were subjected to 2 rounds of 4-hour incubation at either RT or 35°C. Endothelial cell loss (ECL) was quantified 14 days after the initial incubation using Calcein-acetoxymethyl (Calcein-AM) and FIJI trainable segmentation. Cultures inoculated with common ocular pathogens were subjected to 2 warming cycles at RT for 4 hours or 35°C for 2 hours. Colony counts were taken over the course of 2 weeks after inoculation. RESULTS: Specular image quality ratings were consistently higher for corneas warmed at 35°C compared with those at RT. Image quality ratings for corneas warmed at 35°C for 1.5 hours were higher than corneas warmed at RT for 4 hours (P = 0.04). No differences in ECL were observed between the 2 warming conditions (RT = 13.1% ± 7.6% ECL, 35°C = 13.9% ± 6% ECL, P = 0.75). There was no difference in colony counts for pathogens tested between the 2 warming conditions. CONCLUSIONS: Warming donor corneas to near-physiological temperatures for a short time can increase specular image quality while reducing the time tissues are unrefrigerated at eye banks. This method allows for more efficient specular imaging without inducing additional ECL or increasing pathogen growth.

Evaluation and Quality Assessment of Prestripped, Preloaded Descemet Membrane Endothelial Keratoplasty Grafts.

PURPOSE: To determine graft quality and feasibility of Descemet membrane endothelial keratoplasty (DMEK) grafts that are prestripped and preloaded into injectors by eye bank technicians before shipping to surgeons. METHODS: DMEK grafts (n = 31) were prepared from donor corneas and preloaded into Straiko Modified Jones tubes and set inside viewing chambers filled with 20 mL of Optisol-GS. Preloaded grafts were evaluated using specular microscopy and slit-lamp biomicroscopy. Endothelial cell loss (ECL) was captured by vital dye staining and quantified using FIJI. A subset of preloaded tissues was subjected to a shipping validation and 5-day storage assay. Fourteen additional DMEK grafts (not preloaded) were examined to quantify damage resulting from prestripping alone. RESULTS: Specular microscopy was able to be performed for all preloaded tissues. Average ECL for preloaded tissues quantified by vital dye staining and FIJI after overnight storage was 16.8% ± 5.9%, and differed from slit-lamp ECL estimation by an average of 5.3% ± 3.6%. The average damage caused by prestripping alone was 9.3% ± 5.9%, and it was significantly less than that of preloaded tissues (P < 0.01). Average ECL for preloaded tissues subjected to round-trip shipping events was 18.5% ± 12.4%, and ECL for tissues stored at 4°C for 5 days after preloading was 13.1% ± 9.5%. CONCLUSIONS: It is possible to prepare, evaluate, and ship DMEK grafts loaded inside a glass carrier and viewing chamber. The ability to evaluate tissues after processing allows for adherence to the Eye Bank Association of America Medical Standards, and for surgeons to receive the most accurate tissue information.

Donor Endothelial Cell Density Measurements Do Not Change Immediately After DMEK Preparation.

PURPOSE: To evaluate a single eye bank's measurement of endothelial cell density (ECD) of Descemet membrane endothelial keratoplasty (DMEK) grafts before and after preparation using 2 separate counting methods. METHODS: A series of 60 donor tissues were prepared for DMEK surgery. One to 4 specular images of the central endothelium were taken both before and after preparation, and ECDs were evaluated for a total of 345 unique images. Images were then masked and provided to the Cornea Image Analysis Reading Center (CIARC) for independent analysis. RESULTS: Before preparation, average eye bank-determined ECD with the center method was 2678 ± 259 cells/mm and was 2599 ± 280 cells/mm CIARC-determined by the variable frame method (P < 0.001, n = 176). After preparation, eye bank-determined ECD was 2719 ± 265 cells/mm and CIARC-determined ECD was 2615 ± 344 cells/mm (P < 0.001, n = 169). The difference in ECD before and after DMEK preparation was not found to be statistically significant when evaluated using either analysis method (P = 0.19; P = 0.64) before and after preparation, respectively. CONCLUSIONS: Although the absolute ECD value may differ by the analysis method statistically, pre- and post-DMEK preparation ECDs did not significantly change by either analysis method. Other methods such as vital staining to assess tissue damage after preparation in conjunction with specular microscopy are suggested.

Descemet Membrane Endothelial Keratoplasty (DMEK) Tissue Preparation: A Donor Diabetes Mellitus Categorical Risk Stratification Scale for Assessing Tissue Suitability and Reducing Tissue Loss.

PURPOSE: This study assessed a novel diabetes mellitus (DM) rating scale in relation to its utility in reducing Descemet membrane endothelial keratoplasty (DMEK) tissue preparation failure. METHODS: A 5-point DM rating scale was defined, in which 1 demonstrated relatively good health associated with DM and 5 represented comorbidities associated with DM. A chart review from consecutive donors who had at least 1 tissue prepared for DMEK was performed. Using the donor profile, the first tissue processed from each donor was categorized according to the DM severity and if the tissue passed or failed the DMEK preparation. Failure rates per rating group were evaluated using logistic regression and odds of preparation failure. RESULTS: A total of 125 tissues prepared for DMEK were categorized based on the defined DM rating scale. Of these, 9 tissues were rated 1 (11.1% failure), 25 were rated 2 (0% failure), 31 were rated 3 (6.5% failure), 24 were rated 4 (16.7% failure), and 36 were rated 5 (30.6% failure). The odds ratios were significant for tissues rated as 5 and 3 (P < 0.05). No other rating categories were found to influence the odds of failure. A χ test comparing categories of low risk (1-3) and high risk (4-5) was also performed (P = 0.001). CONCLUSIONS: The DM rating scale does seem to stratify the risk of preparation failure associated with the severity of DM and associated comorbidities. Inclusion of some diabetic donors for the preparation of DMEK grafts may be warranted given proper screening of the donor history and application of the rating scale.