Descemet's membrane endothelial keratoplasty with scraping without descemetorhexis (DMEK-SWD) in a failed penetrating keratoplasty

Purpose:To report the outcomes of corneal transplantation utilizing corneas retrieved from donors with chronic kidney disease (CKD).Methods:Outcomes of corneal transplantation (optical PK and EK) performed from Jan 2018 to Dec 2018 utilizing donor corneas retrieved from CKD patients was performed retrospectively.Results:Of the total of 233 donor corneas retrieved from CKD, 135 (57.9%) were utilized for transplantation after the routine screening protocol of the eye bank. Mean age of the donors was 56.2 ± 13.5 years. The mean endothelial cell density on specular microscopy of the donor corneas used for optical PK was 2685.7 ± 377.6 cells/mm2 (range, 2028–3448 cells/mm2) and for EK was 2731.7 ± 189.1 cells/mm2 (range, 2380–3194 cells/mm2). The overall primary graft failure rate was 5.1%. All grafts except 1, cleared in the PK group. In the EK group (6 DMEK and 16 DSAEK), 1 patient had a complete graft detachment and another 1 had a primary graft failure after DMEK.Conclusion:The donor corneas retrieved from chronic kidney disease patients are safe and suitable for optical keratoplasty provided they meet the criteria for transplantation.

To investigate in a retrospective review the histological and ultrastructural findings after failed primary and early Descemet membrane endothelial keratoplasty (DMEK), propose possible pathomechanisms of graft failure and give clinical implications. The explanted grafts underwent light- and electromicroscopical investigations in eight failed DMEK cases. Haematoxylin - Eosin, periodic acid Schiff and Alcian blue stainings were performed. Special note was given to any residual stromal remnants, absence of endothelial cells, lamellar structure and 'activation' of keratocytes. Of the eight cases, six were re-DMEKs and two penetrating keratoplasties. Partial graft separation was seen in six and no graft separation in two of the cases. The average time-interval to the re-DMEK or penetrating keratoplasty was 4.6 months. Light and electron microscopy of the two explanted stromal specimens showed varying degrees of keratocyte activation. Endothelial cell loss was observed in essentially all explants with varying degrees and positive correlation with intraoperative difficulty. Assumed upside-down situations showed large areas of intact endothelial cells. In addition, a new layer, situated between the endothelial cell layer and the posterior nonbanded layer, was observed with loose intercellular structure. A loss of the endothelial cell layer of varying degrees and positive correlation with intraoperative difficulty are the prominent feature of primary and early DMEK graft failure. Of note is the upside-down situation, in which in some cases, the endothelial cell layer not only remains intact but also demonstrates metabolical activity in forming a novel cellular layer.

To evaluate Descemet membrane endothelial keratoplasty (DMEK) in the setting of failed penetrating keratoplasty (PKP) and to identify factors associated with DMEK success and failure after PKP. A retrospective chart review of patients who underwent DMEK for failed PKP at Toronto Western Hospital, Canada, between 2014 and 2017 was performed. Demographic characteristics, number of previous transplants, intraoperative and postoperative complications, best spectacle-corrected visual acuity (BSCVA), and endothelial cell density were analyzed. Twenty-eight eyes were included in the study. Rebubbling intervention was performed in 12 eyes (43%) within the first postoperative weeks. Five eyes (18%) developed graft rejection episodes. Twelve eyes (43%) had to be regrafted after DMEK surgery and were deemed failures (because of persistent Descemet membrane detachment, rejection episode that led to secondary failure, and infection). BSCVA before DMEK was significantly worse in the eyes that failed than those that did not [1.97 ± 0.85 and 1.2 ± 0.56 logMAR, respectively, (P = 0.01)]. Rebubbling was required in 75% of eyes in the failure group compared with 19% in the success group (P = 0.002). Six of the 16 eyes (37.5%) in the success group underwent femtosecond laser-enabled DMEK, whereas this technique was not used in any of the eyes in the failure group (P = 0.017). DMEK is a viable option for cases of failed PKP. DMEK failure after PKP might be associated with lower visual acuity before DMEK surgery, higher number of rebubble interventions, and manual descemetorhexis rather than femtosecond laser-enabled DMEK.

Corneal endothelial transplantation has become the gold standard for the treatment of corneal endothelial dysfunctions, replacing full thickness transplantation, known as penetrating keratoplasty. Corneal endothelial transplantation has been described using two different techniques: Descemet's membrane endothelial keratoplasty (DMEK) and Descemet's stripping automated endothelial keratoplasty (DSAEK). Both are still performed worldwide. To compare the effectiveness and safety of Descemet's membrane endothelial keratoplasty (DMEK) versus Descemet's stripping automated endothelial keratoplasty (DSAEK) for the treatment of corneal endothelial failure in people with Fuch's endothelial dystropy (FED) and pseudophakic bullous keratopathy (PBK). We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2017, Issue 7); MEDLINE Ovid; Embase Ovid; LILACS BIREME; the ISRCTN registry; ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). The date of the search was 11 August 2017. We included randomised controlled trials (RCTs) and non-randomised paired, contralateral-eye studies in any setting where DMEK was compared with DSAEK to treat people with corneal endothelial failure. Two review authors independently screened the search results, assessed trial quality and extracted data using the standard methodological procedures expected by Cochrane. Our primary outcome was best corrected visual acuity (BCVA) measured in logarithm of the Minimum Angle of Resolution (logMAR). Secondary outcomes were endothelial cell count, graft rejection, primary graft failure and graft dislocation. We graded the risk of bias of non-randomised studies (NRSs) using ROBINS-I. We did not identify any RCTs but found four non-randomised studies (NRSs) including 72 participants (144 eyes), who had received DSAEK in the first eye followed by DMEK in the fellow eye. All the studies included adult participants where there was evidence of FED and endothelial failure requiring a corneal transplant for the treatment of visual impairment. We did not find any studies that included PBK. The trials were published between 2011 and 2015, and we assessed them as high risk of bias due to potential unknown confounding factors since DSAEK preceded DMEK in all participants. Two studies reported results at 12 months, one at 6 months, and one between 6 and 24 months. At one year, using DMEK in cases of endothelial failure may result in better BCVA compared with DSAEK (mean difference (MD) -0.14, 95% confidence interval (CI) -0.18 to -0.10 logMAR, 4 studies, 140 eyes, low-certainty evidence). None of the participants had severe visual loss (BCVA of 1.0 logMAR or more; very low-certainty evidence). Regarding endothelial cell count data (4 studies, 134 eyes) it is hard to draw any conclusions since two studies suggested no difference and the other two reported that DMEK provides a higher cell density at one year (very low-certainty evidence). No primary graft failure and only one graft rejection were recorded over four studies (144 eyes) (very low-certainty evidence). The most common complications reported were graft dislocations, which were recorded in one or two out of 100 participants with DSAEK but were more common using DMEK, although this difference could not be precisely estimated (risk ratio (RR) 5.40, 95% CI 1.51 to 19.3; 4 studies, 144 eyes, very low-certainty evidence). This review included studies conducted on people with corneal endothelium failure due to FED for whom both DMEK and DSAEK can be considered, and found low-certainty evidence that DMEK provides some advantage in terms of final BCVA, at the cost of more graft dislocations needing 're-bubbling' (very low-certainty of evidence).

Corneal Higher-Order Aberrations after Descemet's Membrane Endothelial Keratoplasty

Purpose To review the risk factors and pathogenesis of endothelial decompensation after penetrating keratoplasty (PKP) and its novel therapeutic strategies. Methods Literature review. Results As the major cause of graft failure in PKP, endothelial decompensation of corneal allograft is considered an irreversible decrease in endothelial cell density and endothelial dysfunction. Various risk factors, including donor status and operative and recipient factors, have been found to be associated with this pathological process. Operative factors like graft size and recipient factors such as indications, glaucoma, or glaucoma surgery history are highly associated with the occurrence of endothelial decompensation, while others are still under investigation. Although the mechanism of these risk factors remains unclear, pathogenesis can be summarized as an acute and chronic loss of endothelium, and cell exchange between donor and recipient is at the core of chronic cell loss. Endothelial keratoplasty has been a useful alternative to repeat standard PKP in eyes with failed grafts. Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet's membrane endothelial keratoplasty (DMEK) following failed PKP provide more rapid visual recovery and achieve better rates of graft survival than those of a second PKP. Conclusions Any direct or indirect damage to the endothelium could cause the loss, morphological changes, and dysfunction of endothelial cells. Graft size, indications, and recipient glaucoma or glaucoma surgery history are risk factors for endothelial decompensation. DSAEK and DMEK are novel therapeutic strategies for failed PKP grafts and have potential superiorities compared with repeat PKP.

This Issue At A Glance

In Vivo Laser Confocal Microscopy after Descemet's Membrane Endothelial Keratoplasty

Recent advances in the field of endothelial transplantation, including increasing acceptance of Descemet's membrane endothelial keratoplasty, may alter the indications for Descemet's stripping automated endothelial keratoplasty, to a procedure reserved for complex endothelial disorders. Recent literature demonstrates that Descemet's membrane endothelial keratoplasty provides better and faster visual outcomes and decreased immunologic rejection compared to Descemet's stripping automated endothelial keratoplasty. However, Descemet's membrane endothelial keratoplasty may be more challenging in the management of a number of more complex endothelial disorders. While the literature on complex Descemet's membrane endothelial keratoplasty is limited, the utility of Descemet's stripping automated endothelial keratoplasty has been validated in the management of endothelial dysfunction in the setting of a number of comorbid conditions including prior penetrating keratoplasty, prior glaucoma surgery, iridocorneal endothelial syndrome, aniridia, aphakia, and anterior chamber intraocular lenses, among others. The increasing adoption of Descemet's membrane endothelial keratoplast is changing the practice of endothelial keratoplasty. However, limitations of the Descemet's membrane endothelial keratoplasty procedure have also served to crystallize the essential role of Descemet's stripping automated endothelial keratoplasty in many complex endothelial keratoplasty scenarios. This article will review indications for endothelial keratoplasty, along with the current evidence for Descemet's stripping automated endothelial keratoplasty and Descemet's membrane endothelial keratoplasty in their management.

Descemet's Membrane Endothelial Keratoplasty: Prospective Study of 1-Year Visual Outcomes, Graft Survival, and Endothelial Cell Loss

Posterior lamellar keratoplasty is increasingly applied in patients with endothelial decompensation after penetrating keratoplasty (PK). The aim of this study was to compare the results of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK) after PK. In this retrospective study, clinical data of 30 patients who received DMEK (n = 19) or DSAEK (n = 11) for endothelial decompensation after PK were evaluated. All lamellar keratoplasties were performed at the Department of Ophthalmology at University Hospital Mainz, Germany. Primary end point included best-corrected visual acuity, and secondary end points included endothelial cell density, rebubbling, and rejection rates, all at 6 and 12 months. After 6 months and 12 months, 89% of DMEK and 73% of DSAEK grafts and 63% of DMEK and 64% of DSAEK grafts provided sufficient corneal deturgescence, respectively, represented by improvement in best-corrected visual acuity. DMEK group median preoperative Logarithm of the Minimum Angle of Resolution visual acuity of 1 increased to 0.5 after 6 and 12 months. DSAEK group median Logarithm of the Minimum Angle of Resolution visual acuity increased from 3 to 2 and 1.3 after 6 and 12 months. After 12 months, graft endothelial cell density had decreased by 58% in the DMEK group and by 59% in the DSAEK group. The proportion of patients requiring a rebubbling were 63% in the DMEK and 64% in the DSAEK group. No lamellar graft rejection occurred in either trial arm. Both DMEK and DSAEK significantly improved visual acuity in patients after PK. Lamellar graft survival, loss of endothelial cells, and mean rebubbling rates were similar in both groups.

To analyze the outcomes and identify the risk factors of failure in Descemet's membrane endothelial keratoplasty (DMEK) for graft failure after penetrating keratoplasty (PKP). Medical records and surgical videos of patients who underwent DMEK for graft failure after PKP were reviewed in this retrospective study. Demographic data, the indication for PKP, number of previous PKPs, duration between the last PKP and graft failure, graft diameter at the last PKP, best-corrected visual acuity (logMAR) before and after DMEK, preoperative additional ocular diseases, and intraoperative and postoperative complications were recorded. Descemet's membrane (DM) attachment was examined on the first day and the first month, postoperatively, and at the last follow-up visit. The patients were divided into two groups according to DM attachment at the last visit (group 1, patients with attached DM; group 2, patients with DM detachment). Twenty eyes of 20 patients were included in this study. At the last follow-up visit, DM was attached in 13 (65%) patients (Group 1) and detached in 7 (35%) cases (Group 2). The BCVA was improved significantly after DMEK in all patients (2.10 ± 0.4, preoperatively; 1.09 ± 0.8, postoperatively; p = 0.005). There were no significant differences between groups, in terms of age, the number and indication for PKP, the time between the last PKP and DMEK, or history of glaucoma. PKP was performed in all patients in group 2. DMEK is a feasible option with fast visual recovery and a low risk of complications in patients with graft failure after PKP. We found no risk factors for the DM graft detachment, so larger studies are needed to analyze intraoperative or donor-related factors as well.

Descemet's Membrane Endothelial Keratoplasty: Prospective Multicenter Study of Visual and Refractive Outcomes and Endothelial Survival

To report the outcomes of Descemet membrane endothelial keratoplasty (DMEK) and Descemet membrane automated endothelial keratoplasty (DMAEK) for failed penetrating keratoplasties (PKs). Retrospective chart review of patients with a failed PK who were managed with DMEK or DMAEK surgery. Surgical technique, clinical findings, visual outcomes, and complications were documented and reported. Six patients (mean age, 62 years; mean follow-up, 10 months) underwent DMEK (4 patients) or DMAEK (2 patients) under a failed PK. The graft diameter of the failed PK was 8 mm in all patients. In 3 patients, a 9-mm donor graft (DMAEK, 2; DMEK, 1) was used, whereas in the remaining patients, an 8-mm donor graft was chosen. Descemet membrane was stripped in 3 eyes because of the presence of Descemetic scarring. Four of the 6 eyes had a triple procedure. Two patients had preexisting open-angle glaucoma, whereas 1 patient developed postoperative steroid-response glaucoma. The median preoperative best-corrected visual acuity was 20/70, and postoperatively at 1, 3, and 6 months, 20/50, 20/40, and 20/30, respectively. The median donor endothelial cell density was 2801 cells per square millimeter, and at 3 and 6 months postoperatively, 1906 and 1880 cells per square millimeter, respectively. Three of the 4 DMEK eyes had peripheral graft detachment that attached successfully with 1 air injection. There was 1 primary failure that was managed with Descemet stripping endothelial keratoplasty. DMEK or DMAEK can be considered to treat failed PKs. However, prior experience in performing these techniques in virgin eyes is recommended before use with a failed PK, which can present an additional challenge.

Risk of Corneal Transplant Rejection Significantly Reduced with Descemet's Membrane Endothelial Keratoplasty