Risk factors for endothelial cell loss after Descemet membrane endothelial keratoplasty (DMEK)

Descemet Membrane Endothelial Keratoplasty With and Without Graft Deswelling: A Prospective Clinical Study

PURPOSE

The purpose of this study was to assess whether omission of dextran from corneal organ culture medium alters the outcome of Descemet membrane endothelial keratoplasty.

METHODS

Participation in this single-center, multisurgeon, prospective, randomized, comparative clinical trial was offered to patients scheduled for Descemet membrane endothelial keratoplasty between April 2020 and May 2022. Patients received grafts from corneas deswollen in organ culture medium-containing 6% dextran T-500 or from corneas that were not deswollen. Corrected distance visual acuity (CDVA), graft detachment, central corneal thickness (CCT), and corneal endothelial cell counts were measured at different time points up to 12 months postoperatively.

RESULTS

Grafts stored with dextran were transplanted in 92 patients, and grafts stored without dextran were transplanted in 102 patients. Mean donor age and endothelial cell counts did not differ significantly between both groups. Mean (±SD) postmortem time in hours was 23.9 ± 11.8 in grafts that were deswollen and 28.2 ± 13.8 in grafts that were not deswollen (P = 0.02). The groups did not show any significant difference at baseline regarding sex, CDVA, or CCT. In the group with dextran, patients had a mean age of 72.5 ± 9.9 years versus 69.5 ± 8.7 in the group without dextran (P = 0.03). CDVA improved and CCT decreased significantly in both groups. No differences were detected between the groups regarding CDVA, CCT, endothelial cell counts, or rebubbling rates.

CONCLUSIONS

This study did not detect any evidence that the omission of dextran from organ culture medium negatively affects the outcomes of Descemet membrane endothelial keratoplasty.

Different Course of Immune Reactions and Endothelial Cell Loss after Penetrating Low-Risk Keratoplasty and Descemet Membrane Endothelial Keratoplasty for Fuchs Endothelial Dystrophy

BACKGROUND

The aim of this study was to compare the incidence of immune reactions and endothelial cell loss after penetrating keratoplasty (PKP) vs. Descemet membrane endothelial keratoplasty (DMEK) in patients with Fuchs endothelial dystrophy (FED).

PATIENTS AND METHODS

In the present retrospective study, a total of 962 surgeries (225 excimer laser PKP and 727 DMEK) of 700 patients performed between 28.06.2007 and 27.08.2020 in the Department of Ophthalmology at Saarland University Medical Center UKS were statistically evaluated. On the one hand, the prevalence and the temporal course of the immune reactions that occurred were analysed using the Kaplan-Meier method, as well as the effect of the immune reactions on the endothelial cells and corneal thickness. Secondly, endothelial cell density, pleomorphism, and polymegethism of the endothelial cells were evaluated for the time points U1 = preoperative, U2 = 6 weeks postoperative, U3 = 6 to 9 months postoperative, U4 = 1 to 2 years postoperative, and U5 = 5 years postoperative. In addition, statistical tests were carried out for differences between the two types of surgery and in the longitudinal course.

RESULTS

A total of 54 immune reactions occurred during the observed period, whereby the probability of such a reaction was significantly greater in the PKP group with 8.9% than in the DMEK group with 4.5% (p = 0.011). The comparison of the two Kaplan-Meier curves also showed a significant difference between the two surgical techniques in the log-rank test (p = 0.012). The endothelial cell loss due to the immune reaction was only significant in PKP (p = 0.003). For all surgical procedures, endothelial cell density decreased significantly with time in both surgical techniques (p < 0.0001 in each case), but more strongly with DMEK than with PKP (p < 0.0001). Furthermore, this cell density was significantly higher with PKP than with DMEK for the whole observation time (p < 0.0001). Polymegethism decreased significantly in the DMEK group (p < 0.0001). Pleomorphism was significantly higher, on average, in DMEK than in PKP (p < 0.0001).

CONCLUSION

The prognosis of DMEK in patients with FED seems to be more favourable after immune reactions than that of PKP, as not only were immune reactions less frequent, but they were also milder. However, endothelial cell density was significantly higher in the PKP group during the entire follow-up.

Combined or sequential DMEK in cases of cataract and Fuchs endothelial corneal dystrophy-A systematic review and meta-analysis

To compare the outcomes of Descemet membrane endothelial keratoplasty (DMEK) performed after phacoemulsification and intraocular lens (IOL) implantation (sequential DMEK) and DMEK combined with phacoemulsification and IOL implantation (combined DMEK) in patients with Fuchs endothelial corneal dystrophy (FECD) and cataract. Systematic literature review and meta-analysis performed according to the PRISMA guidelines and registered in PROSPERO. Literature searches were conducted in Medline and Scopus. Comparative studies reporting sequential DMEK and combined DMEK in FECD patients were included. The main outcome measure of the study was the corrected distance visual acuity (CDVA) improvement. Secondary outcomes were postoperative endothelial cell density (ECD), rebubbling rate and primary graft failure rate. Bias risk was assessed and a quality appraisal of the body of evidence was completed using the Cochrane Robin-I tool. A total of 667 eyes (5 studies) were included in this review, 292 eyes (43.77%) underwent a combined DMEK, while 375 (56.22%) eyes underwent a sequential DMEK surgery. We found no evidence of a difference between the two groups (mean difference, 95% CI) regarding: (1) CDVA improvement (-0.06; -0.14, 0.03 LogMAR; 3 studies, I2 : 0%; p = 0.86); (2) postoperative ECD (-62; -190, 67 cells/mm2 ; 4 studies, I2 : 67%; p = 0.35); (3) rebubbling (risks ratio: 1.04; 0.59, 1.85; 4 studies, I2 : 48%; p = 0.89); and primary graft failure rate (risks ratio: 0.91; 0.32, 2.57; 3 studies, I2 : 0%; p = 0.86). Of all the 5 non-randomized studies, all (100%) were graded as low quality. The overall quality of the analysed studies was low. Randomized controlled trials are needed to confirm no difference or superiority of one approach in terms of CDVA, endothelial cell count and postoperative complication rate between the two arms.

New forceps free injection technique for delivering descemet membrane endothelial keratoplasty preloaded endothelium-in grafts

PURPOSE

To describe a new method for delivering DMEK grafts into the recipient's eye with endothelium inward configuration using a no-forceps injection technique.

METHODS

We retrospectively review 11 patients that underwent DMEK surgery at our institution using a no-forceps injection technique. The graft was preloaded into an intraocular lens (IOL) cartridge and connected to an anterior chamber maintainer (ACM). A 5 ml non luer lock syringe was inserted into the other end of the ACM to create a one-flow system. The cartridge was inserted into the posterior end of an injector, and the graft was successfully delivered into the recipient's eye.

RESULT

Twelve eyes of 11 patients were included. Mean follow-up was 9.16 ± 1.3 months. At baseline, mean best corrected visual acuity (BCVA) was 0.76 ± 0.13 logMAr and mean endothelial cell density (ECD) was 2619.00 ± 115.89 cells/mm2. At follow-up, BCVA significantly improved to 0.22 ± 0.05 logMAR (p = 0.003). Although we observed a significant reduction in ECD at follow-up (1688 ± 182.20, p = 0.002), our patients lost only 35.69 ± 6.36% of endothelial cells.

CONCLUSION

Our technique can help surgeons safely deliver an endothelium-in graft into the recipient's eye. The method doesn't require the use of a forceps, minimizing the risk of endothelial cell loss or graft damage.

Non-invasive endothelial cell density measurement of in toto pre-stripped DMEK-roll - impact of pre- and intraoperative endothelial cell loss on postoperative midterm clinical outcome

BACKGROUND/OBJECTIVES

To measure the endothelial cell density (ECD) of the in toto pre-stripped endothelial Descemet membrane lamellae (EDML) and to describe the impact of pre- and intraoperative endothelial cell loss (ECL) on postoperative midterm clinical outcome.

SUBJECTS/METHODS

The ECD of 56 Corneoscleral Donor Discs (CDD) was first measured with an inverted specular microscope (t0pre). The measurement was then repeated non-invasively after the preparation of the EDML (t0post). DMEK was performed the next day using these grafts. Follow-up examinations took place 6 weeks, 6 months and 1 year postoperatively where the ECD was assessed. In addition, the impact of ECL 1 (during preparation) and ECL 2 (during surgery) on the ECD, visual acuity (VA) and pachymetry at 6 months and 1 year was investigated.

RESULTS

The average ECD (in cells/mm²) at time points t0pre, t0post, 6 weeks, 6 months & 1 year was 2584 ± 200, 2355 ± 207, 1366 ± 345, 1091 ± 564 and 939 ± 352. The average logMAR VA and pachymetry (in µm) was 0.50 ± 0.27 and 597 ± 63, 0.23 ± 0.17 and 535 ± 54, 0.16 ± 0.12 and 535 ± 54, 0.06 ± 0.08 and 512 ± 37, respectively The ECL 1 (9% on average) had no significant impact on the main outcome measures after 6 months and 1 year (p > 0.11). The ECL 2 correlated significantly with the ECD and the pachymetry at 1 year postop (p < 0.02).

CONCLUSION

Our results indicate that the non-invasive ECD measurement of the prestripped EDML roll before its transplantation is feasible. Despite significantly decreasing ECD up to 6 months postoperatively, visual acuity further improved and thickness further decreased up to 1 year postoperatively.

DMEK outcome after one year - Results from a large multicenter study in Germany

PURPOSE

Descemet membrane endothelial keratoplasty (DMEK) accounts for >50% of all corneal transplants in Germany. So far, no data from such a large multicenter study have been published.

METHODS

This retrospective study included 3200 DMEKs at seven departments performed for Fuchs endothelial corneal dystrophy (FECD) or bullous keratopathy (BK). We evaluated best corrected visual acuity (BCVA, logMAR), endothelial cell density (ECD, cells/mm² ), minimal corneal thickness (CT, μm), rebubbling-, primary transplant failure- and immune reaction-rate. Changes over time were evaluated by linear mixed models for repeated measures and correlation with case number by center by weighted linear regression.

RESULTS

For patients without vision-limiting comorbidities (74% of all analysed eyes, n = 2270), mean BCVA improved from 0.6 ± 0.4 logMAR to 0.2 ± 0.2 logMAR 6 months (p < 0.001, n = 1441) and 0.1 ± 0.2 logMAR 12 months (p = 0.001, n = 1402) postoperatively. BK- had a worse BCVA compared to FECD-patients (0.3 ± 0.5 vs. 0.1 ± 0.2 logMAR [p < 0.001] at 1 year). ECD declined from 2465 ± 259 cells/mm² (n = 2876 preoperatively) to 1587 ± 433 cells/mm² after 12 months (p < 0.001, n = 1237). Mean rebubbling rate was 0.4 ± 0.7/eye. 784 eyes (25%) received at least one rebubbling. More rebubblings correlated with a lower ECD, a worse BCVA, a higher CT, and higher transplant failure and rejection rates (p < 0.001, p = 0.013 for BCVA at 12 months). A single rebubbling did not influence the BCVA (p = 0.785). Graft failure rate was 3% (n = 67), rejection rate 1.5% (n = 48).

CONCLUSION

Descemet membrane endothelial keratoplasty increases visual acuity with low transplant failure- and rejection-rates. FECD has a better outcome than BK. Since a quarter of all patients need a rebubbling, this should be included in the informed consent. Remarkably, one rebubbling has no influence on the outcome.

Cytoprotective Effects of Human Platelet Lysate during the Xeno-Free Culture of Human Donor Corneas

We evaluated the suitability of 2% human platelet lysate medium (2%HPL) as a replacement for 2% fetal bovine serum medium (2%FBS) for the xeno-free organ culture of human donor corneas. A total of 32 corneas from 16 human donors were cultured in 2%FBS for 3 days (TP1), then evaluated using phase contrast microscopy (endothelial cell density (ECD) and cell morphology). Following an additional 25-day culture period (TP2) in either 2%FBS or 2%HPL, the pairs were again compared using microscopy; then stroma and Descemet membrane/endothelium (DmE) were processed for next generation sequencing (NGS). At TP2 the ECD was higher in the 2%HPL group (2179 ± 288 cells/mm²) compared to 2%FBS (2113 ± 331 cells/mm²; p = 0.03), and endothelial cell loss was lower (ECL HPL = -0.7% vs. FBS = -3.8%; p = 0.01). There were no significant differences in cell morphology between TP1 and 2, or between 2%HPL and 2%FBS. NGS showed the differential expression of 1644 genes in endothelial cells and 217 genes in stromal cells. It was found that 2%HPL led to the upregulation of cytoprotective, anti-inflammatory and anti-fibrotic genes (HMOX1, SERPINE1, ANGPTL4, LEFTY2, GADD45B, PLIN2, PTX3, GFRA1/2), and the downregulation of pro-inflammatory/apoptotic genes (e.g., CXCL14, SIK1B, PLK5, PPP2R3B, FABP5, MAL, GATA3). 2%HPL is a suitable xeno-free substitution for 2%FBS in human cornea organ culture, inducing less ECL and producing potentially beneficial alterations in gene expression.

Risk Factors for Descemet Membrane Endothelial Keratoplasty Rejection: Current Perspectives- Systematic Review

Descemet membrane endothelial keratoplasty (DMEK) is a corneal endothelial transplantation procedure with selective removal of a patient's defective Descemet membrane and endothelium. It is replaced with a healthy donor Descemet membrane and endothelium without a stromal component. Corneal graft rejection can be at the level of epithelium, stroma as well endothelium. DMEK graft rejection is relatively less common than rejection with DSAEK or penetrating keratoplasty, and a good outcome may be achieved with prompt management. The clinical picture of DMEK rejection is usually similar to endothelial rejection in Descemet Stripping Endothelial Keratoplasty (DSEK/DSAEK), which generally manifests as pain, redness, reduction in visual acuity, stromal edema, endothelial rejection line, keratic precipitates at the back of the cornea and corneal neovascularization. However, more subtle forms of rejection or immune reactions are more common in DMEK compared to DSAEK eyes. Early clinical diagnosis, prompt intervention, and meticulous management safeguard visual acuity and graft survival in these cases. Intensive topical steroids form the mainstay in the management of DMEK rejection. Sometimes, oral or intravenous steroids or other systemic immunomodulators may be required. DMEK graft failure can be primary or secondary, and failure usually requires a second procedure in the form of repeat DMEK or DSEK or penetrating keratoplasty (PKP). A detailed literature search was performed using search engines such as Google Scholar, PubMed, and Google books, and a comprehensive review on DMEK rejection was found to be lacking. This review is a comprehensive update on the risk factors, pathophysiology, primary and secondary graft failure, recent advances in diagnosis, prevention of rejection, and updates in the management of DMEK rejection. The review also discusses the differential diagnosis of DMEK failure and rejection, prognosis, and future perspectives considering DMEK failure and rejection.

Postoperative, but not preoperative, central corneal thickness correlates with the postoperative visual outcomes of Descemet membrane endothelial keratoplasty

Descemet membrane endothelial keratoplasty (DMEK) restores visual acuity in patients with progressive corneal endothelial diseases such as Fuchs endothelial corneal dystrophy (FECD). However, patients often prefer to delay the surgery as long as possible, even though outcomes are poorer in advanced FECD. A recent study proposed that preoperative central corneal thickness (CCT) of ≥625 μm associated with worse best spectacle-corrected visual acuity (BSCVA) after DMEK for FECD. Since this threshold could signal to both surgeons and patients when to perform DMEK, we further explored the relationship between CCT and BSCVA with a retrospective cohort study. The cohort consisted of all patients with FECD who underwent DMEK in a tertiary-care hospital in 2015-2020 and were followed for 12 months. Extremely decompensated corneas were not included. Relationships between preoperative CCT and BSCVA on days 8 and 15 and months 1, 3, 6, and 12 were examined with Pearson correlation analyses. Eyes with preoperative CCT <625 or ≥625 μm were also compared in terms of postoperative BSCVA. Relationships between postoperative CCT and final BSCVA were also explored. The cohort consisted of 124 first-operated eyes. Preoperative CCT did not correlate with postoperative BSCVA at any timepoint. Eye subgroups did not differ in postoperative BSCVA. However, postoperative CCT at 1-12 months correlated significantly with 12-month BSCVA (r = 0.29-0.49, p = 0.020-0.001). Thus, postoperative, but not preoperative, CCT correlated with postoperative BSCVA. This phenomenon may reflect factors that distort preoperative CCT measurements but disappear after surgery. This observation and our analysis of the literature suggest that while there is a relationship between CCT and post-DMEK visual acuity, preoperative CCT measurements may not always adequately reflect that relationship and may therefore not be a reliable predictor of DMEK visual outcomes.

Surgical goniolens for tag identification and removal in DMEK surgery

INTRODUCTION

We describe a novel technique for identifying endothelial Descemet membrane (DM) tags remaining after descemetorhexis in patients undergoing Descemet membrane endothelial keratoplasty (DMEK) surgery.

METHODS

A surgical goniolens is applied to the corneal surface after descemetorhexis in order to visualize the peripheral inner corneal layer at 360° and identify endothelial-DM tags.

RESULTS

A detailed visualization of the peripheral inner corneal layer is possible using goniolens, without using any staining in the anterior chamber.

CONCLUSION

The technique may be used to screen the posterior corneal surface for any retained endothelial-DM tags. It may to lower the risk of remaining tags and indirectly lower the incidence of DMEK graft detachment.

The need of rebubbling in case of small graft detachments after Descemet Membrane Endothelial Keratoplasty (DMEK)

Purpose

To investigate the need of rebubbling for small graft detachments after Descemet Membrane Endothelial Keratoplasty (DMEK).

Methods

In this retrospective study we evaluated 111 eyes from 111 patients that showed graft detachment after DMEK surgery and have achieved graft adherence by injection of air or 20% sulfur hexafluoride (SF6) to the anterior chamber (rebubbling group; n = 57) or by spontaneous adherence without intervention (control group; n = 54) at final examination. Subgroups in terms of the maximum height and in terms of the detachment area in relation to graft area were formed. Outcome measures were the increase in best-corrected visual acuity (BCVA) and the decrease in central corneal thickness (CCT) from the measurement before DMEK to six months after surgery and postoperative endothelial cell density.

Results

BCVA increased in the rebubbling group and the control group, the difference being 0.22 logMAR, p = 0.048. For eyes with a maximum height less than 500  µm, the increase of BCVA was 0.39 ± 0,36 logMAR in the control group and 0.62 ± 0,53 logMAR in the rebubbling group, p = 0.045. There was no difference of statistical significance of BCVA between both groups regarding the detachment area of less than 20% in relation to graft area. The mean decrease in CCT and postoperative endothelial cell density showed no significant difference between the rebubbling group and the control group.

Conclusion

Compared to spontaneous graft adherence, a rebubbling shows no beneficial effect on the clinical outcome for small detached DMEK grafts. Rebubbling does not decrease postoperative endothelial cell density.

The Descemet Membrane Endothelial Keratoplasty (DMEK) "Wave Maneuver"

A novel technique for Descemet membrane endothelial keratoplasty (DMEK) graft handling and centration without the endothelium touching the posterior part of the anterior chamber (AC), is presented here. It is particularly suitable for vitrectomized eyes, deep AC, and AC intraocular lenses (ACIOLs), potentially reducing surgery time and endothelial cell loss during surgery. This retrospective interventional case series includes 27 eyes with complex ocular pathology. All utilized a “Wave maneuver” to center an early elevated graft without completing graft centration on the bottom of the AC. Successful graft attachment and centration were evaluated intra and post-operatively. Best-corrected visual acuity (BCVA), central corneal thickness (CCT), and donor endothelial cell density (ECD) were measured pre-operatively, and three and six months post-operatively. DMEK grafts were successfully attached and centered in all cases. No maneuver-related complications were observed intraoperatively. BCVA improved from a pre-operative 0.2 ± 0.63, to 0.43 ± 0.49 and 0.76 ± 0.51 at the three- and six-month follow-ups, respectively (p < 0.01). CCT decreased from a pre-operative 742 ± 118, to 546 ± 87 and 512 ± 67 at three and six months, respectively (p < 0.01). ECD decreased from 2878 ± 419 cells/mm2 to 1153 ± 466 cells/mm2 at three and six months, respectively (p < 0.01). The “Wave maneuver” may be very beneficial in DMEK cases where the AC is either very deep or the bottom of the AC is compromised. The “Wave maneuver” learning curve was brief.

Ability of routinely collected clinical factors to predict good visual results after primary Descemet membrane endothelial keratoplasty: a cohort study

Background

A comprehensive analysis of routinely collected pre/perioperative demographic/clinical factors that could predict final visual acuity after primary Descemet membrane endothelial keratoplasty (DMEK) has not been conducted previously.

Methods

A retrospective monocenter cohort study was performed with consecutive patients with Fuchs endothelial corneal dystrophy (FECD) who underwent DMEK or triple-DMEK (DMEK combined with cataract surgery) in 2016–2020 in a French tertiary-care hospital. DMEK-only patients were pseudophakic. Patients were followed for 12 months. Surgery was considered successful when 12-month best-corrected visual acuity (BCVA) was ≤0.1 logMAR (≥0.8). Exploratory multivariate analysis was conducted with the following routinely collected variables to determine their ability to predict 12-month BCVA: patient age and sex; graft donor age; triple DMEK; preoperative values of BCVA, endothelial cell density (ECD), central corneal thickness (CCT), and mean anterior keratometry; and rebubbling.

Results

Of 100 eyes (100 patients; mean age, 72 years; 61% female), 81 achieved a 12-month BCVA of ≤0.1 logMAR. Logistic regression analysis showed that older age was a significant prognosticator for 12-month BCVA > 0.1 logMAR (Odds Ratio = 0.914, 95% confidence intervals = 0.846–0.987; p = 0.02).

Conclusions

An older age associated with worse visual acuity outcomes after DMEK. This was confirmed by our analysis of the literature and supports the notion that DMEK should be conducted without delay once symptoms appear. Patient sex, donor age, triple-DMEK, and anterior keratometry also did not predict final BCVA in the literature. Preoperative CCT, ECD, and BCVA, and rebubbling occasionally appear in the literature as BCVA predictors, possibly reflecting an underlying ECD-BCVA axis.

Endothelial failure and rejection in recipients of corneas from the same donor

Objective

To determine whether patients who receive corneas from the same donor have similar risks of endothelial failure and rejection.

Methods and Analysis

Patients with Fuchs endothelial dystrophy (FED) and pseudophakic bullous keratopathy (PBK) who received their first corneal transplant between 1999 and 2016 were analysed. Patients receiving corneas from donors who donated both corneas for the same indication were defined as ‘paired’. Gray’s test was used to compare the cumulative incidence of endothelial failure and rejection within 5 years post-transplant for ‘paired’ and ‘unpaired’ groups. Cox regression models were fitted to determine whether there was an association between recorded donor characteristics (endothelial cell density (ECD), age and sex and endothelial graft failure and rejection.

Results

10 838 patients were analysed of whom 1536 (14%) were paired. The unpaired group comprised 1837 (69%) recipients of single corneal donors and 7465 (69%) donors who donated both corneas for another indication. ECD was lower for unpaired single cornea donors (p<0.01). There was no significant difference in endothelial graft failure or rejection between paired and unpaired groups for FED (p=0.37, p=0.99) or PBK (p=0.88, p=0.28) nor for donor ECD, age, sex and paired donation after adjusting for transplant factors (across all models p>0.16 for ECD, p>0.32 for donor age, p>0.14 for sex match and p>0.17 for the donor effect).

Conclusion

The absence of a significant difference in graft outcome for corneal transplants for FED and PBK between paired and unpaired donors may reflect a homogeneous donor pool in the UK.

Impact of vaccination on keratoplasty

PURPOSE OF REVIEW

Corneal graft rejection has been reported after coronavirus disease 2019 (COVID-19) vaccination. The purpose of this review is to evaluate the literature regarding corneal graft rejection after vaccination, including rejection rates and risk factors. We aim to create a framework to identify patients who are at higher risk for graft rejection and may warrant consideration of prophylactic interventions.

RECENT FINDINGS

Graft rejection has been reported following administration of mRNA, viral vector, and inactivated whole-virion COVID-19 vaccines. Most cases had additional risk factors associated with rejection. Vaccination increases circulation of proinflammatory cytokines, CD4+ and CD8+ T-cell responses, and antispike neutralizing antibody, all of which may contribute to graft rejection. Two prospective studies have found no relationship between recent vaccination and rejection but 20% of cornea specialists report to have seen a vaccine-associated rejection and 22% recommend delaying vaccination in certain circumstances. Many specialists recommend prophylactic topical corticosteroids before and after vaccination to mitigate rejection risk but there is no evidence to support this practice on a wider scale.

SUMMARY

Our framework identified 96.8% of penetrating keratoplasty patients with vaccine-associated rejection as higher risk. Further research is needed in order to develop evidence-based guidelines.

Comparison of triple-DMEK to pseudophakic-DMEK: A cohort study of 95 eyes

Previous comparative studies show that triple Descemet membrane endothelial keratoplasty (DMEK) (i.e. phacoemulsification followed immediately by DMEK) has either equivalent or better visual outcomes than DMEK in pseudophakic patients. To resolve this discrepancy, a retrospective cohort study was conducted. All consecutive patients with Fuchs Endothelial Corneal Dystrophy who underwent triple or pseudophakic DMEK in 2015–2019 in a tertiary-care hospital (France) and were followed for >12 months were compared in terms of best spectacle-corrected visual acuity (BSCVA), final refractive outcomes, and endothelial-cell loss at 12 months as well as rebubbling rates. The triple-DMEK (40 eyes, 34 patients) and pseudophakic-DMEK (55 eyes, 43 patients) groups were similar in terms of age and other baseline variables. They also did not differ in final BSCVA (both 0.03 logMAR), final endothelial-cell loss (54% vs. 48%), or astigmatism (-1.25 vs. -1 D). At 12 months, triple-DMEK associated with significantly smaller residual hyperopia (0.75 vs. 1 D; p = 0.04) and spherical equivalence (0 vs. 0.5 D; p = 0.02). Triple-DMEK also tended to associate with more frequent rebubbling (40% vs. 24%, p = 0.09). In conclusion, while triple-DMEK and pseudophakic-DMEK achieved similar visual acuity improvement, triple-DMEK was superior in terms of final sphere and spherical refraction but also tended to have higher complication rates.

Management of Late Descemet's Membrane Detachment After Penetrating Keratoplasty in Keratoconus

PURPOSE

The purpose of this study was to describe the feasibility of Descemet membrane endothelial keratoplasty (DMEK) as a treatment modality for spontaneous detachment of DM (DMD) decades after penetrating keratoplasty (PK) for keratoconus.

METHODS

We describe the clinical characteristics and therapeutic surgical approach in 6 eyes of 5 patients with DMD. Clinical images, anterior segment optical coherence tomography scans, and histological findings are presented.

RESULTS

Mean age of patients at time of diagnosis was 60 years (range 56-66 years). Mean interval between PK and occurrence of DM detachment was 36 years (range 29-45 years). In 4 of 6 eyes, air injections into the anterior chamber were initially attempted to reattach DM to the stroma but without long-lasting effect. Two eyes underwent repeat PK because of pronounced ectasia after long-standing DMD and stromal scars. DMEK was performed successfully in 4 eyes leading to an increase in visual acuity and a reduction in central corneal thickness. Electron microscopy showed abnormal vacuolar inclusions and collagenous material in the posterior nonbanded layer and a separation of the anterior banded layer from the posterior nonbanded layer.

CONCLUSIONS

This case series provides evidence that DMEK is a viable option in eyes with spontaneous DM detachment after PK. Visual outcome is limited by the persisting high astigmatism in the ectatic cornea. Illustrated by a small series of patients, the results of DMEK in this condition are presented and new findings about the pathophysiology are given.

Identification of the preoperative and perioperative factors that predict postoperative endothelial cell density after Descemet membrane endothelial keratoplasty: A retrospective cohort study

Low postoperative endothelial-cell density (ECD) plays a key role in graft failure after Descemet-membrane endothelial keratoplasty (DMEK). Identifying pre/perioperative factors that predict postoperative ECD could help improve DMEK outcomes. This retrospective study was conducted with consecutive adult patients with Fuchs-endothelial corneal dystrophy who underwent DMEK in 2015–2019 and were followed for 12 months. Patients underwent concomitant cataract surgery (triple-DMEK) or had previously undergone cataract surgery (pseudophakic-DMEK). Multivariate analyses assessed whether: patient age/sex; graft-donor age; preoperative ECD, mean keratometry, or visual acuity; triple DMEK; surgery duration; surgical difficulties; and need for rebubbling predicted 6- or 12-month ECD in the whole cohort or in subgroups with high/low ECD at 6 or 12 months. The subgroups were generated with the clinically relevant threshold of 1000 cells/mm². Surgeries were defined as difficult if any part was not standard. In total, 103 eyes (95 patients; average age, 71 years; 62% women) were included. Eighteen eyes involved difficult surgery (14 difficult graft preparation or unfolding cases and four others). Regardless of how the study group was defined, the only pre/perioperative variable that associated significantly with 6- and 12-month ECD was difficult surgery (p = 0.01, 0.02, 0.05, and 0.0009). Difficult surgery also associated with longer surgery duration (p = 0.002). Difficult-surgery subgroup analysis showed that difficult graft dissection associated with lower postoperative ECD (p = 0.03). This association may reflect endothelial cell loss due to excessive graft handling and/or an intrinsic unhealthiness of the endothelial cells in the graft that conferred unwanted physical properties onto the graft that complicated its preparation/unfolding.

Descemet's membrane endothelial keratoplasty (DMEK) tissue type and endothelial cell loss over time

OBJECTIVE

To investigate endothelial cell loss after Descemet's membrane endothelial keratoplasty (DMEK) when surgery is performed with surgeon-loaded tissue versus preloaded tissue.

METHODS

The endothelial cell count over time of patients who underwent the last DMEK surgery by a single surgeon with surgeon-loaded tissue from 2014-2017 was compared to that of patients who underwent the first DMEK surgery by different single surgeon with preloaded tissue from 2017-2020.

RESULTS

Baseline characteristics, including age, sex, and baseline endothelial cell count of DMEK grafts, were not statistically different between the groups. Endothelial cell loss both immediately after surgery and continuing over a 4-year period after surgery was greater in the surgeon-loaded DMEK group compared to the preloaded DMEK group based on log-regression curve analysis. Endothelial cell loss was statistically significantly greater at 1 year, 2 years, 3 years, and 4 years after DMEK surgery with surgeon-loaded tissue compared to preloaded tissue on analysis of variance testing.

CONCLUSION

Preloaded DMEK tissue has significantly less endothelial cell loss both initially after surgery and over time compared to surgeon-loaded DMEK tissue, providing support for use of preloaded DMEK tissue for surgery.

Graft survival of Descemet membrane endothelial keratoplasty (DMEK) in corneal endothelial decompensation after glaucoma surgery

Purpose

This study aims to assess the results, rebubbling rate, and graft survival after Descemet membrane endothelial keratoplasty (DMEK) with regard to the number and type of previous glaucoma surgeries.

Methods

This is a clinical retrospective review of 1845 consecutive DMEK surgeries between 07/2011 and 08/2017 at the Department of Ophthalmology, University of Cologne. Sixty-six eyes were included: group 1 (eyes with previous glaucoma drainage devices (GDD); n = 27) and group 2 (eyes with previous trabeculectomy (TE); n = 39). Endothelial cell loss (ECL), central corneal thickness, graft failure, rebubbling rate, and best spectacle-corrected visual acuity (BSCVA) up to 3 years after DMEK were compared between subgroups of patients with different numbers of and the two most common types of glaucoma surgeries either GDD or TE or both.

Results

Re-DMEK rate due to secondary graft failure was 55.6% (15/27) in group 1 and 35.9% in group 2. The mean graft survival time in group 1 was 25 ± 11 months and 31.3 ± 8.6 months in group 2 (p = 0.009).

ECL in surviving grafts in group 1 was 35% (n = 13) at 6 months, 36% at 12 months (n = 8), and 27% (n = 4) at 2 years postoperatively. In group 2, ECL in surviving grafts was 41% (n = 10) at 6 months, 36% (n = 9) at 12 months, and 38% (n = 8) at 2 years postoperatively. Rebubbling rate in group 1 was 18.5% (5/27) and 35.9% (14/39) in group 2 (p = 0.079).

Conclusion

Eyes with previous GDD had no higher risk for an increased rebubbling rate but a higher risk for a re-DMEK due to secondary graft failure with a mean transplant survival time of about 2 years. Compared to eyes with preexisting glaucoma drainage device, eyes after trabeculectomy had less secondary graft failures and a longer mean graft survival rate.

Descemet's Membrane Endothelial Keratoplasty and Phacoemulsification: Combined versus Sequential Surgery

Purpose:

To compare the outcomes of Descemet's membrane endothelial keratoplasty (DMEK) combined with phacoemulsification versus DMEK following phacoemulsification.

Methods:

In this interventional retrospective comparative nonrandomized case series study, patients with Fuchs endothelial corneal dystrophy (FECD) with either cataract or previous cataract surgery with intraocular lens (IOL) implantation were assigned to one of the two groups according to lens status. Group 1 included patients who had cataract and FECD and would undergo triple procedure (phacoemulsification with IOL implantation and DMEK), whereas Group 2 included patients who had FECD and had phacoemulsification with IOL implantation earlier and would undergo DMEK only as a sequential procedure.

Results:

Postoperative best corrected visual acuity (BCVA) in both groups at 1 week, 1 month, 3 months, and 6 months revealed a statistically nonsignificant difference between the two groups with mean logMAR BCVA at 6 months of 0.07 ± 0.18 and 0.07 ± 0.19 in Group 1 and Group 2, respectively (P > 0.05). The drop in endothelial cell density by the end of the 6^th postoperative month was by 39.44% ±7.92 and 38.73% ±8.10 in the triple-procedure group and DMEK only group, respectively (P = 0.005). Total postoperative complications rate and the rebubbling rate were statistically similar between both groups with 13.5% and 12.5% rebubbling rate in Group 1 and Group 2, respectively (P > 0.05).

Conclusion:

Visual outcomes, endothelial cell loss, and rebubbling rate are comparable when DMEK is combined with phacoemulsification or when it is performed as staged procedure, without statistically significant difference in the outcomes.

Aqueous humour cytokine profiles after Descemet's membrane endothelial keratoplasty

The aim of this study was to compare aqueous humour (AqH) cytokine profiles before and after Descemet's membrane endothelial keratoplasty (DMEK) in eyes with bullous keratopathy (BK) and age-matched normal eyes. A total of 49 participants (mean age 75.0 ± 13.5 years) were divided into three groups: (1) BK patients scheduled for DMEK (BK group); (2) patients after DMEK (DMEK group; average postoperative time 1,018 ± 460 days); and (3) control participants without corneal endothelial disease scheduled for cataract surgery (control group). AqH (0.2 mL) was collected from all participants, and the levels of various AqH cytokines were simultaneously measured using a multiplex bead immunoassay. The DMEK group exhibited significantly lower concentrations of several pro-inflammatory cytokines, such as IL-1β, IL-5, IL-6, IL-10, and IL-8, and granulocyte colony stimulating factor than the BK group. In addition, the levels of IL-1β and IL-5 were significantly lower in the DMEK group than in the control group. The AqH levels of several pro-inflammatory cytokines were significantly reduced after DMEK, indicating that regeneration of the endothelial pump owing to the transplantation of a healthy endothelium might have a positive effect on anterior chamber inflammation.

Outcomes of Descemet Membrane Endothelial Keratoplasty in Bangkok, Thailand

Purpose

To investigate the medium-term clinical outcomes and risk factors for primary graft failure after Descemet membrane endothelial keratoplasty (DMEK) in Thai patients.

Patients and Methods

This is a single-center retrospective cohort study. Sixty-two eyes of 62 patients who underwent DMEK at Ramathibodi Hospital, Bangkok, Thailand, with a minimum of 24-month follow-up were recruited. Preoperative donor and recipient characteristics, intraoperative data, and postoperative outcomes including best-corrected visual acuity (BCVA), graft clarity, endothelial cell density (ECD), central corneal thickness (CCT), and complications were evaluated at 1, 3, 6, 12, and 24 months after surgery.

Results

The mean age of the patients was 67.2 ± 9.9 years, and 52% were female. The mean follow-up time was 37.5 ± 11.0 months. The most common indications for DMEK were Fuchs' endothelial corneal dystrophy (FECD) (53.2%) and pseudophakic bullous keratopathy (PBK) (17.7%). Nearly half of patients had triple-DMEK. The median preoperative BCVA was 20/400. Postoperative BCVA of ≥ 20/40 was reached in 37.1% and of ≥ 20/20 in 6.5% after 1 month which increased to 54.8% and 17.7% after 3 months; and to 67.7% and 27.4% after 24 months. Endothelial cell loss (ECL) at 3, 6, 12, and 24 months was 30.5%, 33.8%, 44.4%, and 45.9%, respectively. Graft diameter was the single factor, showing a significant relationship with postoperative ECD. Most frequent postoperative complications included graft detachment (22.6%), increased IOP/glaucoma (17.7%), and primary graft failure (16.1%). In univariate analysis, death-to-operation time and the diagnosis of PBK were significantly associated with the occurrence of primary graft failure.

Conclusion

DMEK is a safe, effective, and feasible treatment for endothelial failure in Asian eyes. Careful case selection, use of relatively fresh donor tissues, and appropriate surgical techniques can prevent primary graft failure and facilitate optimal outcomes following surgery.

Endothelial Cell Viability after DMEK Graft Preparation

Aim: To evaluate the effect of graft preparation and organ-culture storage on endothelial cell density (ECD) and viability of Descemet membrane endothelial keratoplasty (DMEK) grafts.Materials and methods: DMEK grafts (n = 27) were prepared at Amnitrans EyeBank Rotterdam from 27 corneas (15 donors) that were eligible for transplantation but could not be allocated due to the Covid-19-related cancellation of elective surgeries. Cell viability (by Calcein-AM staining) and ECD of five grafts originally scheduled for transplantation were evaluated on the originally planned surgery day, whereas 22 grafts from paired donor corneas were evaluated either directly post-preparation or after 3-7 days of storage. ECD was analyzed by light microscopy (LM ECD) and Calcein-AM staining (Calcein-ECD).Results: Light microscopy (LM) evaluation of all grafts showed an unremarkable endothelial cell monolayer directly after preparation. However, median Calcein-ECD for the five grafts initially allocated for transplantation was 18% (range 92-73%) lower than median LM ECD. For the paired DMEK grafts, Calcein-ECD determined by Calcein-AM staining on the day of graft preparation and after 3-7 days of graft storage showed a median decrease of 1% and 2%, respectively. Median percentage of central graft area populated by viable cells after preparation and after 3-7 days of graft storage was 88% and 92%, respectively.Conclusion: Cell viability of most of the grafts will not be affected by preparation and storage. Endothelial cell damage may be observed for some grafts within hours after preparation, with insignificant additional ECD changes during 3-7 days of graft storage. Implementing an additional post-preparation step in the eye bank to evaluate cell density before graft release for transplantation may help to reduce postoperative DMEK complications.

Effect of Six-Month Postoperative Endothelial Cell Density on Graft Survival after Descemet Membrane Endothelial Keratoplasty

PURPOSE

To analyze if 6-month endothelial cell density (ECD) affects long-term ECD outcome and graft survival 5 years after Descemet membrane endothelial keratoplasty (DMEK) in eyes with Fuchs endothelial corneal dystrophy (FECD).

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 585 DMEK eyes were included. The study group was divided into 4 groups based on 6-month ECD quartiles: group 1 (n = 146) with 313 to 1245 cells/mm², group 2 (n = 148) with 1246 to 1610 cells/mm², group 3 (n = 145) with 1611 to 1938 cells/mm², and group 4 (n = 146) with 1939 to 2760 cells/mm². Group 1 was further split into subgroups 1a (n = 36) with 6-month ECD of ≤828 cells/mm², 1b (n = 37) with 829 to 1023 cells/mm², 1c (n = 37) with 1024 to 1140 cells/mm², and 1d (n = 36) 1141 to 1245 cells/mm².

METHODS

Descemet membrane endothelial keratoplasty.

MAIN OUTCOME MEASURES

Long-term ECD, graft survival, and postoperative complication rates.

RESULTS

For group 1, 6-month ECD decreased from 951 (±233) cells/mm² (n = 146) to 735 (±216) cells/mm² (n = 99) at 5 years postoperatively. Group 1 graft survival probability was 0.95 (95% confidence interval [CI], 0.91-0.99] at 5 years postoperatively, which was lower than for groups 2 to 4 (P = 0.001). Five-year graft survival in subgroup 1a was 0.79 (95% CI, 0.67-0.94), which was lower than in subgroups 1b to 1d (P = 0.001). Preoperative ECD did not influence graft survival (P = 0.400), and higher 6-month ECD values were associated with lower graft failure rates (hazard ratio, 0.994; 95% CI, 0.99-1.00; P = 0.001).

CONCLUSIONS

Six-month ECD is associated with DMEK graft survival. High early cell loss after DMEK negatively affects long-term ECD outcome and graft survival. Grafts in the lowest 6-month ECD subgroup (≤828 cells/mm²) are at higher risk of failure within 5 years after DMEK. To ensure sufficiently high 6-month ECD, preoperative graft quality assessment should be optimized, and cellular stress induced to the graft should be minimized. Additionally, developing therapeutic options for the treatment of low postoperative ECD could further improve DMEK graft longevity.

Endothelial Keratoplasty Update 2020

ABSTRACT

Endothelial keratoplasty has revolutionized the treatment of corneal endothelial dysfunction and lowered the threshold for treatment by providing rapid visual rehabilitation and setting a high standard for safety and efficacy. Over time, endothelial keratoplasty techniques have evolved toward the use of thinner tissue to optimize visual outcomes; refinements have facilitated donor tissue preparation, handling, and attachment; and adaptations have expanded utilization in eyes with challenging ocular anatomy. Despite early concerns about graft longevity, emerging 10-year endothelial cell loss and graft survival data have been encouraging. A shortage of human donor corneas restricts utilization in many areas of the world and is driving a search for keratoplasty alternatives. Further work is needed to expand the donor supply, minimize impediments to adoption, optimize graft survival, and improve refractive predictability.

Long-Term Outcome of Descemet Membrane Endothelial Keratoplasty in Eyes With Fuchs Endothelial Corneal Dystrophy Versus Pseudophakic Bullous Keratopathy

PURPOSE

The aim of this study was to compare the long-term outcome of Descemet membrane endothelial keratoplasty (DMEK) in patients with Fuchs endothelial corneal dystrophy (FECD) and pseudophakic bullous keratopathy (PBK).

METHODS

Records of consecutive DMEK surgeries performed between 2015 and 2016 at the Department of Ophthalmology, Cologne, Germany, were retrospectively reviewed from the prospective Cologne DMEK Database. Eyes with either PBK or FECD with a complete 3-year follow-up were enrolled. Main outcome parameters included central corneal thickness (CCT), peripheral corneal thickness (PCT), best spectacle-corrected visual acuity (BSCVA, logarithm of the Minimum Angle of Resolution), and endothelial cell count (ECC) before and after DMEK.

RESULTS

Four hundred two eyes from 402 patients were included (FECD n = 371, PBK n = 31). Preoperatively, CCT (FECD: 681.91 ± 146.78 μm; PBK: 932.25 ± 319.84 μm) and PCT (FECD: 732.26 ± 98.22 μm; PBK: 867.54 ± 88.72 μm) were significantly higher in the PBK group (P < 0.01). Three years after DMEK, CCT (FECD: 526.56 ± 27.94 μm; PBK 663.71 ± 132.36 μm) was significantly lower in both groups compared with the preoperative values (P < 0.01), whereas PCT showed no significant difference. PCT increased during the course in the PBK group from month 12 after DMEK (12 mo: 783.73 ± 127.73 μm; 24 mo: 837.50 ± 110.19 μm; 36 mo: 857.79 ± 140.76 μm). The increase in PCT correlated with an accelerated ECC loss starting 12 months after DMEK (P = 0.036). Before DMEK, BSCVA in FECD was significantly higher (P < 0.001) compared with that in PBK. After 3 years, BSCVA improved in FECD and PBK eyes without significant difference (P = 0.239).

CONCLUSIONS

Visual acuity after DMEK in PBK and FECD seems to be comparable during the long-term follow-up. Peripheral and central corneal edema seems to recur faster in eyes with PBK than in those with FECD. Therefore, using a donor graft with higher ECC or possibly a larger graft could be a promising approach for PBK patients.

The Cologne rebubbling study: a reappraisal of 624 rebubblings after Descemet membrane endothelial keratoplasty

Background/Aims

To analyse graft detachments prior to rebubbling, the influence of rebubbling on the postoperative outcome after Descemet membrane endothelial keratoplasty (DMEK) and the need for rebubbling on the contralateral eye.

Methods

In this retrospective cohort study, out of 1541 DMEKs, optical coherence tomography scans and clinical records of 499 eyes undergoing rebubbling after DMEK at the University Hospital of Cologne, Cologne, Germany, were examined. Main Outcome measures were (a) number, localisation and size of graft detachments; (b) influence of rebubbling/s on postoperative outcome after 12 months; and (c) rebubbling risk of the contralateral eye after DMEK.

Results

Mean number of detachment areas was 2.02±0.9. Mean lateral diameter of all detachments was 4534.76±1920.83 μm. Mean axial diameter was 382.53±282.02 μm. Detachments were equally distributed over all regions of the cornea. Best spectacle corrected visual acuity ( BSCVA) after 12 months was 0.197±0.23 logarithm of the minimum angle of resolution, endothelial cell density (ECD) was 1575.21±397.71 cells/mm2and mean central corneal thickness (CCT) was 566.37±68.11 μm. BSCVA, CCT, ECD or endothelial cell loss of all rebubbled patients were not influenced by the number of rebubblings or the time between DMEK and rebubbling. Of the rebubbled patients, which received a DMEK subsequently on the other eye, 193 (58.8%) also received a rebubbling, which was significantly higher, when compared to the overall rebubbling rate of 32.3% (p=0.000).

Conclusions

The overall number of rebubblings has no influence on the postoperative outcome after DMEK, if a rebubbling becomes necessary. Patients who received a rebubbling on one eye have an elevated risk for a rebubbling on the fellow eye.