Predictive Value of Corneal Donor Demographics on Endothelial Cell Density

The Impact of Donor History of Sleep Apnea on Corneal Tissue Evaluation Parameters

PURPOSE

The goal of this study was to explore whether the donor history of sleep apnea affects corneal tissue evaluation parameters.

METHODS

This was a retrospective study assessing the impact of donor history of sleep apnea in a dataset obtained from the Eversight Eye Bank. Comparative analysis and multivariate regression were used to assess differences in key parameters including endothelial cell density (ECD) and central corneal thickness.

RESULTS

Data analyzed consisted of 50,170 tissues from 25,399 donors with no history of sleep apnea and 5473 tissues from 2774 donors with a history of sleep apnea. Tissue from donors with a history of sleep apnea showed lower ECD than those from donors with no history of sleep apnea (-51 cells/mm2, P < 0.001). Multivariate linear regression demonstrated that history of sleep apnea was a predictor of lower ECD by 13.72 cells/mm2 (P = 0.0264). Secondary analysis demonstrated that underweight and obese body mass indexes were significant predictors of increased ECD in donors with no history of sleep apnea (P < 0.0001, P = 0.025, respectively). Body mass index category was not a significant predictor of ECD in donors with a history of sleep apnea. In a smaller subset of 10,756 tissues, sleep apnea was not a significant predictor of central corneal thickness.

CONCLUSIONS

This is the first study to demonstrate that a donor's history of sleep apnea is associated with a lower ECD in a large eye bank dataset. Future studies are needed to investigate whether history of sleep apnea affects posttransplantation outcomes.

Demographic and Systemic Risk Factors for Persistent Corneal Edema Following Cataract Surgery in Patients With and Without Diabetes

PURPOSE

To identify risk factors associated with the development of corneal edema (CE) and the need for corneal transplantation following cataract surgery.

DESIGN

Retrospective cohort study.

METHODS

Setting: Nation-wide sample of Medicare beneficiaries from 2011-2015.

STUDY POPULATION

Medicare beneficiaries aged over 65 years who received cataract surgery between 2011-2014 with at least 1 year of continuous follow-up. Data was retrieved from the Denominator and Physician Supplier Part B file from the Center for Medicare and Medicaid Services.

MAIN OUTCOME(S) AND MEASURE(S)

The main outcome was the association between demographic characteristics (e.g. age, sex, race/ethnicity) and systemic factors including diabetes status, hypertension, and tobacco use on the incidence of CE and the subsequent need for corneal transplantation following cataract surgery.

RESULTS

Among 187,746 beneficiaries, 67,734 had diabetes and 120,012 did not. Beneficiaries with diabetes were more likely to develop CE compared to those without (Odds ratio [OR] 1.19, 95% Confidence Interval [CI] [1.02-1.40]). Compared to those aged 65-74, beneficiaries aged 75-84 and over 85 were more likely to develop CE (OR 1.29 [1.09-1.52]) and OR 1.96 [1.55-2.46], respectively). Asian (OR 2.42 [1.66-3.40]), Hispanic (OR 2.60 [1.73-3.74]), and North American Native (OR 3.59 [1.78-6.39]) race was associated with increased likelihood of developing CE. North American Native beneficiaries had higher risk of requiring corneal transplantation compared to White beneficiaries (OR 9.30 [2.26-25.31]). Female sex decreased likelihood of requiring corneal transplantation post-operatively (OR 0.56 [0.36-0.87]). Amongst those with diabetes, the presence of proliferative diabetic retinopathy increased the likelihood of developing CE (OR 1.94 [1.05-3.39]).

CONCLUSION

Older age, diabetes, and non-White race elevate the risk of CE following cataract surgery, with race incurring the highest risk. Further research is needed to understand the factors underlying the significantly increased risk of CE in racial and ethnic minorities within the United States.

Assessment of performance and safety of Corneal Chamber hypothermic storage medium and PSS-L corneal rinsing solution in human and porcine corneas

PURPOSE

To prove the safety and performance of the hypothermic corneal storage medium "Corneal Chamber" and the rinsing solution "PSS-L" in support of the new Conformité Européenne (CE) certification process in accordance with the Medical Device Regulation.

METHODS

Fifteen (n=15) human donor corneas and 11 (n=11) porcine corneas were evaluated for the following parameters: endothelial cell density (ECD) and mortality, percentage of hexagonal cells (HEX%), coefficient of cellular area variation (CV%) and corneal transparency at Day 0 and after 14±1 days of storage in Corneal Chamber medium at 2-8°C. Then, the same parameters were assessed after rinsing of corneas in PSS-L for 1 min at room temperature. Evaluation of gentamicin sulfate carryover after corneal storage and PSS-L rinsing was performed by ultra-high performance liquid chromatography analysis on human corneas homogenates.

RESULTS

Human and porcine corneas stored in Corneal Chamber medium showed a good overall quality of the tissue according to the quality parameters evaluated. In particular, mean ECD, HEX% and CV% did not show statistically significant changes at the end of storage and endothelial mortality increased to 3.1±3.3 and 7.8±3.5% in human and porcine corneas, respectively. Tissue rinsing with PSS-L did not affect the quality parameters evaluated before and gentamicin sulfate residues were absent in human corneas.

CONCLUSIONS

Corneal preservation in Corneal Chamber medium at 2-8°C for 14 days and the corneal rinse with PSS-L are safe and effective procedures allowing the preservation of the corneal quality parameters as well as the complete elimination of gentamicin sulfate from the tissues before transplantation.Cite Now.

Impact of demographic factors on corneal donor recovery

PURPOSE

Death-to-preservation time (DTP) is a commonly reported, but infrequently studied, measure of efficiency for the corneal tissue procurement process and is a key screening component for corneal tissue suitability for transplantation. It is unknown whether demographic factors such as race, age, or gender may affect DTP.

METHODS

This retrospective cross-sectional study included all deceased-donor eye tissue collected by CorneaGen Eye Banks between June 1, 2012 and June 30, 2016. Exposure variables of race, age, and gender were independently analyzed with the outcome variable, DTP, using three simple linear regression analyzes. Associations were then confirmed by a multiple linear regression analysis within a single model.

RESULTS

A total of 24,138 unique donors were identified from 48,207 donor eyes. Simple linear regression analysis showed that relative to White donors, Black and Hispanic donors were associated with a 2.40 h (95% CI 2.07-2.74 h, p < 0.001) and 2.48 h (95% CI 2.15-2.80 h, p < 0.001) longer mean DTP, respectively. DTP decreased with increasing age, at a rate of 30 min per every 10 years (95% CI 27-33 min, p < 0.001). Male donors were associated with a 35 min (95% CI 26-44 min, p < 0.001) longer DTP relative to female donors. A multiple linear regression confirmed the results of the three simple linear regressions.

CONCLUSIONS

In a large cohort of corneal donors, non-White race, younger age, and male gender were associated with longer DTP.

Association Between Fuchs Endothelial Corneal Dystrophy, Diabetes Mellitus, and Multimorbidity

PURPOSE

The aim of this study was to assess risk for demographic variables and other health conditions that are associated with Fuchs endothelial corneal dystrophy (FECD).

METHODS

We developed a FECD case-control algorithm based on structured electronic health record data and confirmed accuracy by individual review of charts at 3 Veterans Affairs (VA) Medical Centers. This algorithm was applied to the Department of VA Million Veteran Program cohort from whom sex, genetic ancestry, comorbidities, diagnostic phecodes, and laboratory values were extracted. Single-variable and multiple variable logistic regression models were used to determine the association of these risk factors with FECD diagnosis.

RESULTS

Being a FECD case was associated with female sex, European genetic ancestry, and a greater number of comorbidities. Of 1417 diagnostic phecodes evaluated, 213 had a significant association with FECD, falling in both ocular and nonocular conditions, including diabetes mellitus (DM). Five of 69 laboratory values were associated with FECD, with the direction of change for 4 being consistent with DM. Insulin dependency and type 1 DM raised risk to a greater degree than type 2 DM, like other microvascular diabetic complications.

CONCLUSIONS

Female sex, European ancestry, and multimorbidity increased FECD risk. Endocrine/metabolic clinic encounter codes and altered patterns of laboratory values support DM increasing FECD risk. Our results evoke a threshold model in which the FECD phenotype is intensified by DM and potentially other health conditions that alter corneal physiology. Further studies to better understand the relationship between FECD and DM are indicated and may help identify opportunities for slowing FECD progression.

Characteristics of Semiautomated Endothelial Cell-Density Measurements Among Corneal Donor Eyes

Importance

Endothelial cell density in corneal donor eyes remains a critical component in selecting tissue suitable for corneal transplant.

Objective

To describe an anomaly in endothelial cell density discovered in a large cohort of corneal donor eyes.

Design, Setting, and Participants

Donor information for this cross-sectional study was obtained from the CorneaGen eye bank for donors from June 1, 2012, to June 30, 2016. Endothelial cell density was reported by eye bank technicians for each eye. The retrospective donor data set included donor demographics, endothelial cell count, time of death, medical and surgical history, and suitability for transplant. The donor data set contained information on donated eyes over the 4-year period.

Main Outcomes and Measures

Endothelial cell-density heat map, 2-dimensional binned plots, and bayesian change point analysis.

Results

A total of 48 207 donated eyes were evaluated. Mean (SD) cell count was 2717 (448) cells/mm2, and mean (SD) donor age was 58 (13) years. Heat maps using 2-dimensional binned plots demonstrated accentuated endothelial cell density results particularly at and immediately above 2500 cells/mm2 with a small gap right under this figure. A bayesian change point analysis revealed a change point at exactly this location as well.

Conclusions and Relevance

Data from this cross-sectional study suggest a discontinuity in endothelial cell-density measurements just below 2500 cells/mm2. This anomaly suggests that the semiautomated counting technique used in this cohort preferentially skipped over measurements just below this cutoff. Whether this represents an automation error, or more likely, a subjective human bias, requires further study.

Comparison of Donor Corneal Endothelial Cell Density Determined by Eye Banks and by a Central Image Analysis Reading Center Using the Same Image Analysis Method

PURPOSE

The purpose of this study was to evaluate agreement between eye banks (EBs) and an image analysis reading center on endothelial cell density (ECD) determinations using the same image analysis method.

METHODS

The Cornea Image Analysis Reading Center (CIARC) determined ECD with a single experienced analyst on EB-obtained central endothelial images from donors intended for keratoplasty from 2 eye banks, Eversight and Lions VisionGift, using the Konan center analysis method. The EBs performed ECD determination on their respective sets of images using the same analysis method with experienced eye bank technicians.

RESULTS

The mean age of the 200 donors was 54 years (range 30-75 years). Seventy (35%) of the 200 patients were women, and 57 (29%) were diabetic. The mean ECD was 10 cells/mm2 greater by the EBs than by CIARC (P = 0.39), with 95% limits of agreement of [-304 to 323 cells/mm2]. The mean difference was not substantially changed when the difference between EBs and CIARC ECD was adjusted for sex, donor age, donor diabetes, CV, HEX, number of cells analyzed, and EBs as a random effect (estimated mean difference of 20 cells/mm2 after adjustment in a linear mixed model; P = 0.73). The EB-determined preoperative ECD was within 10% of the CIARC-determined ECD for 178 (89%) image sets, with 15 (8%) higher by >10% and 7 (3%) lower by >10%.

CONCLUSIONS

Well-trained eye bank technicians achieve comparable results for ECD determination with an experienced image analyst from an image analysis reading center when the same image analysis method is used.

The Effects of Donor-Recipient Age and Sex Compatibility in the Outcomes of Deep Anterior Lamellar Keratoplasties

Purpose

Corneal transplantations are the commonest allogenic transplant surgeries performed worldwide. Transplantable grade donor cornea is a finite resource. There is thus an impetus for eye banks to optimize the use of each harvested cornea, and clinicians to minimize the risks of graft rejection and failure. With better survival and lower rejection rates, anterior lamellar keratoplasty has gained popularity as an alternative technique to full-thickness penetrating keratoplasty, for the treatment of corneal stromal diseases. This study evaluated the effects of donor-recipient age- and sex-matching on the outcomes of eyes that had undergone deep anterior lamellar keratoplasty (DALK) surgeries.

Design

Observational cross-sectional study (national corneal graft registry data).

Subjects

All DALK surgeries performed in a tertiary ophthalmic hospital over an 11-year period.

Methods

To analyse the effects of donor-recipient sex-matching, transplantations were classified as “presumed H-Y incompatible” (male donor to female recipient) or “presumed H-Y compatible” (all other donor-recipient sex combinations). For age-matching, differences in donor and recipient ages were calculated. Cox proportional hazards regressions were used to evaluate the influence of donor-recipient sex-matching and age-matching on graft failure and rejection.

Main Outcome Measures

Rates of graft failure and rejection within each group.

Results

401 eyes were included. 271 (67.6%) transplants were presumed H-Y compatible. 29 (7.2%) grafts failed and 9 (2.2%) grafts rejected. There were trends of lower hazard ratios (HRs) in graft failure and rejection in the presumed H-Y compatible group [HRs: 0.59 (95% CI 0.20–1.77, p = 0.34) and 0.93 (95% CI 0.22–3.89, p = 0.926), respectively]. Median difference in age between recipients and donors was 15.0 years (IQR −2.8–34.3). The HRs of graft failure and rejection were not influenced by donor-recipient age [HRs per 1-year increase in age difference: 0.995 (95% CI 0.98–1.01, p = 0.483) and 1.01 (95% CI 0.99–1.03, p = 0.394), respectively].

Conclusion

In eyes that had undergone DALK surgeries, no significant influence of donor-recipient sex- or age-matching on graft rejection and failure was observed. Without strong evidence and the limitations of obtaining sample sizes required for an adequately powered study, the benefits of sex- and age-matching of donors and recipients during graft allocation for DALK surgeries is currently inconclusive.

Demographic profile and clinical course of Fuchs endothelial corneal dystrophy in Mexican patients

PURPOSE

To describe the demographic characteristics and clinical course of Fuchs endothelial corneal dystrophy (FECD) in a Mexican-mestizo population.

METHODS

A retrospective observational and longitudinal study was performed in consecutive patients with the clinical diagnosis of Fuchs endothelial corneal dystrophy seen at our institution. Initial and last follow-up best-corrected visual acuity, slit-lamp findings, and specular microscopy endothelial morphometric parameters were analyzed.

RESULTS

One hundred and two eyes belonging to 51 patients were included in the analysis. Median age at the time of diagnosis was 69 years (range, 25-87 years) with a female-to-male ratio of 3.3:1. Visual loss (40%) followed by glare (13.3%) and fluctuating matutine vision loss (13.3%) was the most common complaints at presentation. Regarding FECD staging, 65 (63.7%) were classified as stage-I FECD, 21 (20.6%) stage-II, and 15 (14.7%) as stage-III. A high percentage of eyes (44.1%) presented visual impairment ( ≤ 20/50) at presentation, and the presence of isolated corneal guttata was the most common stage of presentation (64%) at slit-lamp examination. While fifty-nine (57.8%) eyes did not require any medical or surgical management, 17 (16.7%) eyes were managed with hypertonic saline eyedrops alone or in combination with bandage contact lens, and 18 (17.6%) required corneal transplantation. Penetrating keratoplasty alone (8 eyes, 44.4%), or in combination with cataract extraction and intraocular lens implantation (3 eyes, 16.7%), was the most frequent surgical technique performed.

CONCLUSION

Demographical characteristics of Fuchs dystrophy regarding age at presentation, gender distribution, and clinical stage at the time of diagnosis did not differ significantly from other international reports. Almost 20% of these patients will require keratoplasty during the disease, emphasizing the need for safer and more reproducible keratoplasty techniques.

Challenges in corneal endothelial cell culture

Corneal endothelial cells (CECs) facilitate the function of maintaining the transparency of the cornea. Damage or dysfunction of CECs can lead to blindness, and the primary treatment is corneal transplantation. However, the shortage of cornea donors is a significant problem worldwide. Thus, cultured CEC therapy has been proposed and found to be a promising approach to overcome the lack of tissue supply. Unfortunately, CECs in humans rarely proliferate in vivo and, therefore, can be extremely challenging to culture in vitro. Several promising cell isolation and culture techniques have been proposed. Multiple factors affecting the success of cell expansion including donor characteristics, preservation and isolation methods, plating density, media preparation, transdifferentiation and biomarkers have been evaluated. However, there is no consensus on standard technique for CEC culture. This review aimed to determine the challenges and investigate potential options that would facilitate the standardization of CEC culture for research and therapeutic application.

How to Predict the Suitability for Corneal Donorship?

Background: In Germany, more than one-third of donor corneas harvested are not suitable for transplantation. We evaluated the factors associated with the usability of donor corneas. Method: Data from 2032 consecutive donor corneas harvested at the Rhineland-Palatinate Eye Bank in Mainz, Germany, were retrospectively analyzed. Factors of interest were age, sex, lens status, cause of death, cardiopulmonary resuscitation (CPR), death-to-explantation-interval (DEI), and the influence of these factors on the proportion of discarded donor corneas. Factors associated with endothelial cell density (ECD) were analyzed in a linear regression mixed model. Results: Higher donor age, male gender, pseudophakic lens status, and longer DEI were associated with significantly reduced ECD. With respect to DEI, the estimated cell loss was 7 ± 2 cells/mm²/hour (p < 0.001). Age was associated with a lower ECD of 6 ± 2 cells/mm² per year (p = 0.001). Female ECD was 189 ± 44 cells/mm² higher than male ECD (p < 0.001). Pseudophakic eyes had 378 ± 42 cells/mm² less compared with phakic eyes (p < 0.001). Cause of death did not affect the ECD. Of note, 55% and 38% of corneas harvested on the second and third postmortem day, respectively, and 45% of corneas from donors older than 80 years were still suitable for transplantation. Conclusions: In the context of a growing need for donor corneas, we do not recommend limiting donor age and collection time to 24 h or excluding oncology donors, as is the practice in many countries. Therefore, we propose a mathematical model for better donor preselection.

Challenges and strategies for the delivery of biologics to the cornea

Biologics, like peptides, proteins and nucleic acids, have proven to be promising drugs for the treatment of numerous diseases. However, besides the off label use of the monoclonal antibody bevacizumab for the treatment of corneal neovascularization, to date no other biologics for corneal diseases have reached the market. Indeed, delivering biologics in the eye remains a challenge, especially at the level of the cornea. While it appears to be a rather accessible tissue for the administration of drugs, the cornea in fact presents several anatomical barriers to delivery. In addition, also intracellular delivery barriers need to be overcome to achieve a promising therapeutic outcome with biologics. This review outlines efforts that have been reported to successfully deliver biologics into the cornea. Biochemical and physical methods for achieving delivery of biologics in the cornea are discussed, with a critical view on their efficacy in overcoming corneal barriers.

A Novel Approach of Harvesting Viable Single Cells from Donor Corneal Endothelium for Cell-Injection Therapy

Donor corneas with low endothelial cell densities (ECD) are deemed unsuitable for corneal endothelial transplantation. This study evaluated a two-step incubation and dissociation harvesting approach to isolate single corneal endothelial cells (CECs) from donor corneas for corneal endothelial cell-injection (CE-CI) therapy. To isolate CECs directly from donor corneas, optimization studies were performed where donor Descemet’s membrane/corneal endothelium (DM/CE) were peeled and incubated in either M4-F99 or M5-Endo media before enzymatic digestion. Morphometric analyses were performed on the isolated single cells. The functional capacities of these cells, isolated using the optimized simple non-cultured endothelial cells (SNEC) harvesting technique, for CE-CI therapy were investigated using a rabbit bullous keratopathy model. The two control groups were the positive controls, where rabbits received cultured CECs, and the negative controls, where rabbits received no CECs. Whilst it took longer for CECs to dislodge as single cells following donor DM/CE incubation in M5-Endo medium, CECs harvested were morphologically more homogenous and smaller compared to CECs obtained from DM/CE incubated in M4-F99 medium (p < 0.05). M5-Endo medium was hence selected as the DM/CE incubation medium prior to enzymatic digestion to harvest CECs for the in vivo cell-injection studies. Following SNEC injection, mean central corneal thickness (CCT) of rabbits increased to 802.9 ± 147.8 μm on day 1, gradually thinned, and remained clear with a CCT of 385.5 ± 38.6 μm at week 3. Recovery of corneas was comparable to rabbits receiving cultured CE-CI (p = 0.40, p = 0.17, and p = 0.08 at weeks 1, 2, and 3, respectively). Corneas that did not receive any cells remained significantly thicker compared to both SNEC injection and cultured CE-CI groups (p < 0.05). This study concluded that direct harvesting of single CECs from donor corneas for SNEC injection allows the utilization of donor corneas unsuitable for conventional endothelial transplantation.

Analyse von Einflussfaktoren auf die Eignung von kornealem Spendergewebe in der LIONS Hornhautbank Saar-Lor-Lux, Trier/Westpfalz von 2006 bis 2016

Hintergrund und Ziel der Studie Vor dem Hintergrund des Missverhältnisses zwischen Hornhautverfügbarkeit und -bedarf war das Ziel der Studie, signifikante Einflussfaktoren auf die Eignung sowie die Verwerfungsgründe von kornealem Spendergewebe zu eruieren und damit die Rate verworfener Hornhäute langfristig zu reduzieren.

Patienten und Methoden 4140 Hornhäute von 2083 Spendern wurden zwischen 2006 und 2016 analysiert. Die untersuchten Einflussgrößen umfassten das Alter, das Geschlecht und die medizinische Vorgeschichte der Spender und Prozessierungsfaktoren wie die Post-mortem-Zeit. Die Daten wurden in eine Microsoft-Access-Datenbank übertragen und mittels logistischer Regressionsanalysen mit SPSS 20.0 statistisch ausgewertet. In einem multiplen Regressionsmodell wurden 6 Einflussfaktoren auf die Eignung des Spendergewebes analysiert. Alle Hornhäute, die nicht für eine elektive Keratoplastik infrage kamen, galten hierbei als ungeeignet.

Ergebnisse Ein hohes Spenderalter > 80 Jahre erwies sich im Vergleich zur Referenzgruppe der Spender < 40 Jahre als signifikant negative Einflussgröße auf die Eignung der Hornhaut (p = 0,001). Auch eine vorangegangene Kataraktoperation minderte signifikant die Eignung (p < 0,001). Männliche Hornhäute waren signifikant weniger geeignet als weibliche Hornhäute (p = 0,028). Ein Hypertonus in der Spendervorgeschichte (p = 0,612), eine vorangegangene Chemotherapie (p = 0,745) oder ein Diabetes mellitus (p = 0,321) zeigten keinen Einfluss auf die Eignung. Sepsis (p = 0,026) und Multiorganversagen (MOV; p < 0,001) als Todesursachen des Spenders resultierten in signifikant höheren Verwerfungsraten aufgrund von Kontamination des Kulturmediums. Hornhäute, bei denen die Blutentnahme mehr als 12 h seit Versterben des Spenders zurücklag, mussten signifikant häufiger wegen einer positiven Spenderserologie verworfen werden (p < 0,001).

Schlussfolgerungen Faktoren wie eine vorangegangene Kataraktoperation und ein hohes Spenderalter verringerten die Eignung des Spendergewebes. Ein Diabetes, ein Hypertonus und eine Chemotherapie in der Spendervorgeschichte zeigten keinen statistisch signifikanten Einfluss auf die Eignung. Todesursachen wie Sepsis und Multiorganversagen erhöhten die Kontaminationsrate des Kulturmediums. Eine postmortale Blutentnahme nach mehr als 12 h geht mit einem erhöhten Risiko für ein positives Serologieergebnis einher.