Recurrent DMEK Failures Related to Intraocular Tutoplast.

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 determine roles of patient history, donor tissue characteristics, tissue preparation methods, and surgeon technique for graft detachment requiring rebubbling after Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) procedures. Retrospective analysis of all eyes undergoing first-time DSAEK or DMEK at the study institution between 2013 and 2022. Data were collected regarding recipients' history, donors' medical history, tissue preparation methods, intraoperative details, and postoperative clinical outcomes. Multivariate statistical analysis was conducted to identify risk factors for graft detachment necessitating rebubbling. Of 1240 eyes meeting inclusion criteria, 746 (60.2%) underwent DSAEK, and 494 (39.8%) underwent DMEK. DSAEK procedures had 12.5% rebubbling rate, whereas DMEK procedures had 18.4% rebubbling rate ( P = 0.005). Sub50-DSAEK (<50 μm) grafts had 16.0% rebubble rate, whereas sub100-DSAEK (51-99 μm) and >100 μm DSAEKs had rebubble rate of 9.9% and 9.5%, respectively ( P = 0.006). Significant risk factors for DSAEK graft detachment included history of retinal surgery (OR = 2.59), preloaded tissue (OR = 2.70), forceps insertion (OR = 2.33), use of sub50-DSAEK lenticules versus sub100-DSAEK (OR = 2.44) and >100 μm DSAEK (OR = 2.38) lenticules, and donor history of noninsulin-dependent diabetes mellitus (OR = 4.18). DMEK risk factors included recipient history of cancer (OR = 2.51) and use of higher SF6 gas concentration (OR = 1.09). Although rebubbled DMEK eyes had comparable refractive outcomes to nonrebubbled eyes ( P >0.05), rebubbled DSAEK eyes had worse refractive outcomes at all time points ( P < 0.05). Graft detachments in DSAEK and DMEK are influenced by various factors, including donor tissue characteristics, tissue preparation, and surgical technique. Identifying and understanding these factors can potentially improve postoperative outcomes.

Posterior lamellar keratoplasty, in the form of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK), has become a standard procedure for therapy of endothelial diseases of the cornea. The aim of this article is to describe strategies to prevent and manage complications in DMEK and DSAEK surgery. The article is based on a PubMed literature search and own clinical data. Key words used were "DMEK", "DSAEK", "Descemet membrane endothelial keratoplasty" and "Descemet stripping automated endothelial keratoplasty". The DMEK and DSAEK procedures are safe surgical strategies for treating endothelial corneal diseases if the indications are made correctly. The DMEK procedure is the standard procedure for improvement of visual acuity especially for younger patients with Fuchs' dystrophy and DSAEK is particularly suitable for eyes with complicated anterior chamber situations.

Purpose: To determine roles of patient history, donor tissue characteristics, tissue preparation methods, and surgeon technique for graft detachment requiring rebubbling after Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) procedures. Methods: Retrospective analysis of all eyes undergoing first-time DSAEK or DMEK at the study institution between 2013 and 2022. Data were collected regarding recipients' history, donors' medical history, tissue preparation methods, intraoperative details, and postoperative clinical outcomes. Multivariate statistical analysis was conducted to identify risk factors for graft detachment necessitating rebubbling. Results: Of 1240 eyes meeting inclusion criteria, 746 (60.2%) underwent DSAEK, and 494 (39.8%) underwent DMEK. DSAEK procedures had 12.5% rebubbling rate, whereas DMEK procedures had 18.4% rebubbling rate (P = 0.005). Sub50-DSAEK (<50 μm) grafts had 16.0% rebubble rate, whereas sub100-DSAEK (51-99 μm) and >100 μm DSAEKs had rebubble rate of 9.9% and 9.5%, respectively (P = 0.006). Significant risk factors for DSAEK graft detachment included history of retinal surgery (OR = 2.59), preloaded tissue (OR = 2.70), forceps insertion (OR = 2.33), use of sub50-DSAEK lenticules versus sub100-DSAEK (OR = 2.44) and >100 μm DSAEK (OR = 2.38) lenticules, and donor history of noninsulin-dependent diabetes mellitus (OR = 4.18). DMEK risk factors included recipient history of cancer (OR = 2.51) and use of higher SF6 gas concentration (OR = 1.09). Although rebubbled DMEK eyes had comparable refractive outcomes to nonrebubbled eyes (P >0.05), rebubbled DSAEK eyes had worse refractive outcomes at all time points (P < 0.05).

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).

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). 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. 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). 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.

Split Cornea Transplantation for 2 Recipients: A New Strategy to Reduce Corneal Tissue Cost and Shortage

To describe a new wet lab model of Descemet membrane endothelial keratoplasty (DMEK) using human corneas mounted on an artificial anterior chamber with an artificial iris and to compare the performance time and scores between beginners and experienced anterior segment surgeons. Corneas were mounted on an artificial chamber. To simulate an anterior chamber and to avoid loosing the graft into the tubing, a 3D printed iris was added. Each DMEK procedure required only one cornea for graft preparation, insertion, orientation, unfolding and centration. Ten human research corneas were used for training purposes. Intraoperative OCT was only used to validate the different steps of the procedure. Operators were divided into two groups, two beginners and three experienced DMEK surgeons. All DMEK procedures were successfully performed. Descemet's tears were frequent but harvesting was successful in all procedures. All combinations of graft unfolding techniques were possible. Experienced surgeons performed statistically better then beginners with faster harvesting (12.8 versus 28.2min; p=0.02) and insertion (13.5 versus 20.8min; p=0.05) times and better performance score (94 versus 52; p=0.03). This DMEK wet lab model offers a close to reality, feasible, resource-sparing and valid teaching technique that permits to perform all DMEK surgical steps. It also offers the possibility of varying the surgical difficulty by changing the anterior chamber depth.

Purpose. to report malignant glaucoma and infectious crystalline keratopathy as complications after an uneventful Descemet Membrane Endothelial Keratoplasty (DMEK), and corneal clearance despite graft detachment after the surgery in a patient with pseudophakic bullous keratopathy. Method. A 81-year-old patient with high Intraocular Pressure (IOP) and flat anterior chamber with patent iridotomies after DMEK was diagnosed of malignant glaucoma. The medical approach being insufficient, the patient required a pars-plana vitrectomy, capsulo-hyaloidectomy, and surgical iridectomy. Results. The IOP was reduced and anterior chamber was repositioned after surgical management. Corneal clearance was observed despite graft detachment. The patient developed an infectious crystalline keratopathy after the resolution of malignant glaucoma. Conclusions. malignant glaucoma is a rare complication following DMEK. Corneal clearance can be attained despite graft detachment after DMEK probably due to an unintentional Descemet Membrane Endothelial Transfer (DMET). However, in low dosage, steroid treatment remains a risk factor for developing ICK. Abbreviations: PBK = Pseudophakic Bullous Keratopathy, DMEK = Descemet Membrane Endothelial Keratoplasty, DMET = Descemet Membrane Endothelial Transfer, IOP = Intraocular Pressure, BCVA = Best Corrected Visual Acuity, AC = Anterior Chamber, MG = Malignant Glaucoma, ICK = Infectious Crystalline Keratopathy

PurposeTo compare clinical outcome and complications of Descemet stripping automated keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK).MethodsThis is a retrospective study of the first consecutive cases of DSAEK and DMEK performed by a single surgeon at a tertiary referral centre. Best-corrected visual acuity (BCVA), postoperative complications, rate of rebubbling and regraft were the main outcome measures.ResultsThe study included 241 eyes, 116 subjected to DSAEK and 125 to DMEK. Fuchs endothelial dystrophy (FED) was the predominant diagnosis in both groups. Mean BCVA at all follow-ups up to 2 years was in favour of DMEK. Median BCVA (decimal) at 1 year was 0.4 (0.13–0.60; interquartile range) for the DSAEK and 0.8 (0.6–1.0) for the DMEK group, p<0.001. Preoperative BCVA in the DSAEK group was lower than in DMEK. There was no significant difference in visual improvement between groups at 1 year postoperatively. The most common postoperative complication in both groups was a pupillary block with high intraocular pressure, 27% and 34% respectively. This was not affected by the presence of an iridectomy/iridotomy. In the DMEK group, gas provided significantly better adherence than air (p=0.020). Rebubbling for partial/total detachment was performed in 7% (DSAEK) and 11% (DMEK) of cases, p=0.361. Regraft within 2 years was performed in 13% of eyes in the DSAEK and 17% in the DMEK group, p=0.450. No case of graft rejection occurred.ConclusionBoth DSAEK and DMEK provide overall satisfying outcome and the two techniques do not differ significantly in postoperative pupillary block, detachment rate, early graft failure or graft rejection. However, differences at baseline may have influenced or obscured potential differences. In DMEK procedures, gas seems to facilitate early graft adherence.

Purpose: The aim of this article is to report an unusual case of postoperative graft loss into the vitreous cavity after Descemet membrane endothelial keratoplasty (DMEK) in a patient with an unstable iris-lens diaphragm (scleral-fixated intraocular lens [sf-IOL]) and its successful retrieval with a favourable outcome. Methods: This is a retrospective case report. Results: DMEK procedure was performed in a vitrectomized eye of an 80-year-old woman with pre-existing sf-IOL due to pseudophakic bullous keratopathy. In the setting of an inadvertently created oversized Ando iridectomy and unstable iris-lens diaphragm due to sf-IOL, repeated loss of an anterior chamber gas tamponade occurred. At the 3rd postoperative day, the patient noticed a change in visual perception, and we could detect a loss of the graft into the vitreous via B-scan ultrasound. A 23-G vitrectomy was performed promptly to recover the graft using a bimanual hand-over-hand technique. Six months after DMEK, the patient had a clear cornea without dehiscences with a central corneal thickness of 533 µm and endothelial cell count of 1,219 cells/mm². Conclusions: This case demonstrates the possibility of graft recovery from the vitreous after DMEK and subsequent corneal clearing despite unstable iris-lens diaphragm and vitrectomized eye.

To evaluate whether lens status influences clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) in patients who underwent DMEK in phakia, pseudophakia, or combined with cataract surgery (triple). A retrospective review of 139 eyes (107 patients) with symptomatic Fuchs' dystrophy or secondary corneal edema was performed. Patients were divided into 3 groups: 1) DMEK + cataract surgery, 2) DMEK in pseudophakia, and 3) DMEK in phakia. Of 139 DMEK surgeries, 61 were DMEK triple (43.9%), 55 pseudophakic DMEK (39.6%), and 23 phakic DMEK (16.5%) procedures. Rebubble occurred in 31 of 134 eyes (23.1%), of which 17 were in eyes after DMEK triple (28.3%), 10 after pseudophakic DMEK (19.6%), and 4 after phakic DMEK (17.4%). There was no statistically significant difference in rebubble rates depending on lens status (P = 0.548). There was no statistically significant difference in best corrected visual acuity (BCVA) between eyes that underwent rebubble versus not (P = 0.854). BCVA in patients post-DMEK was 20/25 or better in 81% of cases, and mean BCVA was 20/23. Donor age (P = 0.889), graft cell count (P = 0.525), and graft preparation technique (P = 0.769) were not predictive of rebubbling. Our study demonstrates no difference in DMEK outcome with regard to rebubble rate whether the procedure is performed in combination with cataract surgery, in pseudophakia, or in phakia. Furthermore, donor age, initial graft cell count, and graft preparation technique did not impact rebubble rate. BCVA was also not affected by the need for rebubbling.

To compare the incidence of visually significant postoperative cystoid macular edema (CME) in pseudophakic eyes after Descemet membrane endothelial keratoplasty (DMEK) performed after recent versus remote cataract surgery. A retrospective chart review was performed of all consecutive eyes that underwent DMEK without concurrent cataract surgery at the University of Iowa between October 2012 and December 2014. The DMEK procedures were classified as staged if performed between 2 weeks and 6 months after cataract surgery and solitary if performed more than 6 months after cataract surgery. Possible confounders, including a history of diabetes in the recipient, were tracked. Macular optical coherence tomography was performed to detect CME 1 month after DMEK if the best-corrected visual acuity was ≤20/30 with a clear cornea with no other reason for visual compromise. A total of 173 eyes from 140 patients were included in the statistical analysis. Staged DMEK was performed in 88 eyes (50.8%) and solitary DMEK in 85 eyes (49.2%). The incidence of CME was 8.0% (7 of 88 eyes) in the staged DMEK group and 7.1% (6 of 85 eyes) in the solitary DMEK group (P = 0.823). The incidence of CME did not differ significantly between the staged and solitary DMEK groups regardless of the recipient diabetic status. All cases of CME resolved within 6 months on topical therapy. The incidence of postoperative CME after DMEK is similar in the setting of recent or remote cataract surgery.

The aim of this study was to describe a surgical method that can be easily and safely performed during Descemet membrane endothelial keratoplasty in patients who had previously undergone pars plana vitrectomy with transscleral fixation of the intraocular lens. This report reviewed 2 Descemet membrane endothelial keratoplasty procedures performed in patients with vitrectomized unicameral eyes. The proposed technique is characterized by the temporary suture of the pupillary aperture to block the forward flow of vitreous humor and prevent the abrupt loss of air tamponade due to backward movement of the air bubble into the vitreous cavity. At the same time, another air bubble is injected behind the scleral-fixated intraocular lens to induce forward movement of the iris-intraocular lens diaphragm through buoyancy. Thus, the depth of the anterior chamber is reduced, allowing easier unscrolling of the Descemet membrane endothelial keratoplasty lenticule. Pupil closure and buoyancy of the air bubble allow the anterior chamber to be separated from the inflow of vitreous cavity fluid and maintained adequately shallow. During the keratoplasty, the graft is then easily unscrolled without the support of the capsular diaphragm. Postoperatively, the air bubble is maintained in the anterior chamber for a sufficient period. Nd:YAG laser suture lysis is performed after complete absorption of the air bubble during outpatient follow-up. Temporary pupil occlusion and retrolenticular air bubble injection provide a stable surgical approach in challenging cases of postvitrectomized unicameral eyes.

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