Descemet Stripping Automated Endothelial Keratoplasty Graft Research Articles

Determining Risk Factors for Detachment After Endothelial Keratoplasties: Nine-Year Review of a Single Institution.

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.

Simple Modification of a DSAEK Carrier Enables Graft Insertion by Injection Without Compromising Endothelial Cell Viability.

We evaluate the quality and feasibility of preloading Descemet stripping automated endothelial keratoplasty (DSAEK) grafts into a modified EndoGlide Ultrathin system for graft injection. DSAEK grafts were prepared by experienced processing technicians at 2 separate locations, loaded into a modified EndoGlide Ultrathin, and placed in storage media. Grafts processed at one location were shipped cross-country overnight to the other location and were examined on arrival for positioning within the modified EndoGlide Ultrathin. All grafts were ejected and analyzed for endothelial cell loss (ECL) with calcein acetoxymethyl staining and FIJI segmentation. A subset of grafts was measured by optical coherence tomography for graft thickness 1 hour after cut, 1 hour after loading, and 1 day after loading. No grafts were displaced from the modified carrier over 3 shipping events (n = 9), and all grafts (n = 18) were successfully ejected. Grafts loaded into the modified carrier and ejected exhibited no more cell loss than grafts loaded into the standard carrier and removed by pull-through (14.0% ± 2.8% vs. 12.2% ± 3.4%, respectively, P = 0.24). Carrier modification skills can be successfully transferred as grafts loaded by a processing technician new to carrier modification were within the acceptable limit of 25% ECL for transplant DSAEK grafts. Graft thickness increased significantly (P < 0.05) between the postcut and 1-hour postload measurement and the postcut and 24-hour postload measurement. The EndoGlide Ultrathin can be modified to enable its use for graft injection while not compromising the ability to use the pull-through method for graft delivery. Preloaded DSAEK grafts swell significantly during the 24-hour storage period, and patterns of ECL may be linked to swelling.

Modified Method for Nanothin Descemet Stripping Automated Endothelial Keratoplasty.

The purpose of this study was to describe a method to achieve a high success rate for nanothin (NT, ≤50 μm) Descemet stripping automated endothelial keratoplasty (DSAEK) graft preparation using anterior chamber pressurizer (ACP) with a modified setting and evaluate its postoperative efficacy. A prospective cohort (study group) of 24 patients with corneal endothelial dysfunction was consecutively enrolled and received DSAEK grafts using the modified ACP method from December 2021 to May 2022. The control group included 24 historical patients who received DSAEK grafts using conventional ACP procedure. Central graft thickness (CGT), graft regularity (3-mm and 5-mm diameter zones), best spectacle-corrected visual acuity, and endothelial cell density (ECD) were compared between 2 groups. A 100% ultrathin (UT, ≤100 μm) DSAEK rate and 62.5% NT-DSAEK rate was achieved at 3 months postsurgery in the study group, with a 51.3 ± 14.8 μm CGT, while a 70.8% UT-DSAEK rate and 4.2% NT-DSAEK rate was achieved in the control group, with an 89.0 ± 15.4 μm CGT (P <0.001). At 3-month postoperative follow-up, the regularity of graft thickness was significantly better in the study group (central-to-peripheral thickness difference: P = 0.044 and 0.014 for 3-mm and 5-mm diameter zones, respectively, graft thickness uniformity: P <0.001 and 0.012, respectively). There was no statistical difference in the best spectacle-corrected visual acuity (P = 0.170) or ECD (P = 0.833) between 2 groups at 3-month postoperative follow-up. DSAEK grafts harvested using modified ACP method were thinner and more regular compared with the conventional ACP method.

Clinicopathologic Analyses of Failed Endothelial Keratoplasty (the Clinical Cases)

Purpose: To evaluate the clinicopathologic features of failed endothelial keratoplasty. Methods. In this study 11 patients (11 eyes) with recurrence of bullous keratopathy (BK) were included. Group 1 consisted of 4 patients who underwent repeat Descemet Stripping Automated Endothelial Keratoplasty (DSAEK), group 2 included 7 patients who underwent penetrating keratoplasty (PK) after failed Descemet Membrane Endothelial Keratoplasty (DMEK). Preoperative anterior segment optical coherence tomography (OCT), RTVue-100, Optovue, USA, was performed. Intraoperatively aqueous humour (AqH) samples were collected for multiplex cytokine analysis. During keratoplasty failed grafts/corneal buttons were obtained and then investigated histologically (hematoxylin/eosin staining, primary antibodies to pancytokeratin, vimentin, collagen III). Results. Recurrence of BK in all clinical cases manifests by the increase of inflammatory factors in AqH, corneal edema, neovascularization and remodeling to fibrosis. Glaucoma may induce DMEK/ DSAEK graft failure due to chronic local inflammation. In the clinical cases recurrence of BK was caused by peripheral and central graft detachment, rebubbling, graft upside-down orientation and donor corneal genetic disorders. Conclusions. Chronic local inflammation (including corneal morphological changes) in patients with BK recurrence is an indication for reoperation. The modification of keratoplasty — DMEK/DSAEK/PK — is determined according to slit-lamp and OCT images of the cornea. High-level risk of immune reaction (especially in cases of three and more times repeated keratolasty) is the reason for systemic corticosteroid and, sometimes, cytostatic therapy.

Netarsudil-Associated Reticular Epithelial Edema Directly Influenced by Endothelial Dysfunction in a Post-Endothelial Keratoplasty Patient

Purpose: The purpose of this report was to describe a case in which reticular epithelial edema secondary to topical netarsudil ophthalmic solution 0.2% occurred directly in relation to focal endothelial dysfunction in a post-endothelial keratoplasty eye. Methods: This was a case report. Results: A 76-year-old man with a complex ocular history was diagnosed with pseudophakic bullous keratopathy of the left eye. Topical netarsudil was prescribed to treat his glaucoma and to attempt improvement of his corneal edema. The corneal examination remained stable for many months, but the patient eventually underwent a Descemet stripping automated endothelial keratoplasty (DSAEK) for worsening corneal edema. One week later, the patient was observed to have 360-degree reticular epithelial edema around the periphery of the DSAEK graft. Given the lack of visual significance and need for continued glaucoma treatment, the patient was continued on netarsudil. The reticular epithelial edema later became restricted to areas outside the graft zone as the peripheral DSAEK graft endothelial cell function improved. Two months post-DSAEK, the patient developed a partial inferior endothelial graft rejection related to inadvertent cessation of topical steroid, with keratic precipitates, stromal edema, and new overlying reticular epithelial edema. On treatment and resolution of the DSAEK graft rejection, the overlying reticular epithelial edema also resolved. Conclusions: This case clearly demonstrates that netarsudil-associated reticular epithelial edema is highly likely to be related to endothelial cell dysfunction and that if endothelial cell dysfunction improves, the reticular epithelial edema will also improve, despite the continuation of netarsudil.

Fuchs endothelial corneal dystrophy masking an underlying postrefractive surgery ectasia

Introduction: This article describes a case presenting Fuchs endothelial corneal dystrophy (FECD) masking an underlying postrefractive surgery ectasia. Patient and Clinical Findings: A 69-year-old woman presented in January 2022 with blurriness, halos, and glare in the left eye. Ocular history included a photorefractive keratectomy performed twice in her left eye in 2007 for hyperopic astigmatism. A diagnosis of asymptomatic Fuchs dystrophy was noted in 2010. She had acute decompensation of the cornea in the left eye because of FECD, and the first Descemet-stripping automated endothelial keratoplasty (DSAEK) with cataract surgery was performed in 2018. Diagnosis, Intervention, and Clinical Findings: The patient had a failed DSAEK graft in the left eye. A repeat DSAEK was performed in 2022, and 6 months postoperatively, the patient started showing signs of ectasia in the left eye. The authors believe the ectasia was preexisting but masked by the failed DSAEK graft and FECD and started showing after corneal deturgescence postoperatively. Conclusions: The presence of FECD and corneal ectasia can complicate diagnosis because of overlapping clinical and topographic features. This case highlights the importance of preoperative topography with epithelial/stromal thickness mapping in patients with a history of multiple refractive corneal procedures to consider the possibility of ectasia and prevent unforeseen outcomes and complications. Further research is necessary to determine standardized imaging techniques, particularly in cases of concurrent diseases.

Size and Shape Matter: Cell Viability of Preloaded Descemet Stripping Automated Endothelial Keratoplasty Grafts in Three Different Carriers.

The aim of this study was to examine endothelial cell loss (ECL) associated with preloaded Descemet stripping automated endothelial keratoplasty (DSAEK) grafts loaded into 3 carriers of different size and shape. Thirty-six donor corneas were prepared for DSAEK and loaded into an EndoGlide Ultrathin (control) (2.0 mm × 3.5 mm lumen, 4.5 mm/4.9 mm incision for scleral tunnel/clear corneal insertion), Descemet membrane endothelial keratoplasty EndoGlide (experimental) (1.1 mm × 1.7 mm lumen, 2.65 mm incision), or round glass Jones tube (experimental) (1.8 mm lumen, 3.0 mm incision). Control grafts were stored for 6 days in Optisol-GS and experimental grafts stored for 24 hours in Life4C before analysis using Calcein AM staining. Grafts were imaged and ECL was analyzed by FIJI segmentation. The statistical significance of ECL was determined using 1-way ANOVA and Tukey post hoc analysis. There were no significant differences in donor characteristics for grafts in each cohort. ECL for grafts loaded into the EndoGlide Ultrathin was 10.3% ± 2.3% (graft thickness: 60-189 μm, n = 9). ECL for grafts loaded into the Descemet membrane endothelial keratoplasty EndoGlide was 22.2% ± 7.1% (graft thickness: 38-63 μm, n = 9). ECL for thin grafts (34-60 μm, n = 9) loaded into the Jones tube was 24.0% ± 5.0%. ECL for thick grafts (92-119 μm, n = 9) loaded into the Jones tube was 34.2% ± 6.1% ECL ( P < 0.001). Combined regression analysis revealed that graft thickness is directly correlated to ECL ( P < 0.01). The size and shape of the carrier can influence the cell viability of preloaded DSAEK grafts. Compared with a larger carrier, smaller lumen carriers are associated with greater ECL. In smaller lumen carriers, ECL increases with increasing DSAEK graft thickness.

Association Between Indication for Descemet Stripping Automated Endothelial Keratoplasty and Rural Residency.

Residing in rural locations can be a barrier to health care access. This study investigated the impact of residing in rural and small town (RST) areas on Descemet stripping automated endothelial keratoplasty (DSAEK) indications and outcomes in Atlantic Canada. A retrospective cohort analysis examined consecutive DSAEKs performed in Nova Scotia between 2017 and 2020. Patient rurality was determined by the Statistical Area Classification system developed by Statistics Canada. Univariate and multivariate logistic regression models were used to assess for factors associated with DSAEK indication, including repeat keratoplasty, RST residence status, and travel time. Of 271 DSAEKs during the study period, 87 (32.1%) were performed on the eyes of RST residents. The median postoperative follow-up time was 1.6 years. Undergoing DSAEK for a previous failed keratoplasty was not associated with a higher odds of RST residency (odds ratio [OR], 0.50; 95% confidence interval [CI], 0.19-1.16; P = 0.13) but was associated with travel time (OR, 0.78 for each increasing hour of travel; 95% CI, 0.61-0.99; P = 0.044). RST residency was not associated with the occurrence of graft failure (OR, 0.48; 95% CI, 0.17-1.17; P = 0.13). Residing in a rural area in Atlantic Canada was not associated with DSAEK graft failure. Repeat endothelial keratoplasty was associated with shorter travel time for corneal surgery but not rural residency status. Further research in this field could inform regional health strategies aimed at improving equity and accessibility to ophthalmology subspecialist care.

Donor lamella thickness after ultrathin Descemet stripping automated endothelial keratoplasty and its relation to postoperative visual acuity and pre-operative lamella measures

BackgroundTo accurately measure ultrathin Descemet stripping automated endothelial keratoplasty (DSAEK) donor lamella thickness during the first postoperative year and to correlate this with pre-operative and other postoperative measurements.MethodsDonor lamella thickness in 41 eyes undergoing DSAEK for Fuchs endothelial dystrophy (FED) was measured using the Tomey Casia OCT directly after graft preparation and at 1 week and 1, 3, 6 and 12 months postoperatively. Visual acuity and endothelial cell density were measured as the secondary parameters.ResultsIndividual graft thickness profiles were shown to be fairly regular within the optically relevant area. There was a strong and highly significant correlation between the pre- and postoperative lamellar thicknesses at all time points (p < 0.0001). Compared with the measurements directly after preparation at the cornea bank, the lamella thickness decreased by 12% after 12 months. Between 1 and 12 months postoperatively, the lamella thickness (mean ± SD) changed from 112 ± 27 μm to 101 ± 21 μm. Best spectacle-corrected visual acuity (BSCVA) changed from 0.46 ± 0.30 logMAR pre-operatively through 0.36 ± 0.33 at 1 month to 0.13 ± 0.16 at 1 year postoperatively. The endothelial cell counts were comparable to those reported in previous studies.ConclusionsThickness profiles of individual grafts were fairly regular within the optically relevant area. A strong relationship between pre- and postoperative graft thicknesses was detected, and ultrathin DSAEK grafts prepared using methods similar to that applied in this study are expected to show a deswelling of around 12% during the first postoperative year. No correlation was detected between graft thickness and BSCVA.

The predictability of graft thickness for Descemet’s stripping automated endothelial keratoplasty using a mechanical microkeratome system

Descemet's stripping automated endothelial keratoplasty (DSAEK) is used for treating corneal endothelial dysfunction, and the postoperative visual acuity outcome depends on the thickness of the graft. We created a simple nomogram using factors affecting the cutting thickness during graft preparation via a mechanical microkeratome system for DSAEK. This retrospective study was conducted from May 2018 through October 2022 and included donor eyes cut by automatic methods. We measured the graft thickness, cutting accuracy, and assessed ten variables with donor/cornea-related factors potentially affecting the cutting thickness. Subsequently, we created a simple nomogram. We analyzed 81 donor tissues, and the donor median age was 76 years. The mean central graft thickness was 122.2 μm, with 62% of the grafts that could be cut within the target central graft thickness range. Comparatively, donor corneas from those with cardiac diseases were cut deeper (P = 0.007). The developed nomogram provided a 83% probability of estimating the post-cutting graft thickness within 25 µm. Our nomogram, which considers cause of death, enables reproducible production of graft of a desired thickness. A detailed analysis of donor tissues, including the cause of donor death and the characteristics from pressurization to cutting, will enable more precise DSAEK graft preparation.

Penetrating Keratoplasty Versus Descemet Stripping Automated Endothelial Keratoplasty in Children With Congenital Hereditary Endothelial Dystrophy: Long-Term Results.

The purpose of this study was to compare the outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PKP) in patients with congenital hereditary endothelial dystrophy (CHED). This was a retrospective, comparative study of all the patients with a histopathological diagnosis of CHED who underwent PKP or DSAEK between January 1, 1990, and December 31, 2016. All the cases were included except those patients who had clear grafts but did not complete 2 years of postoperative follow-up. The main outcome measure was graft clarity 2 years after surgery. There were 111 eyes of 63 patients. Seventy-six eyes underwent PKP, and 35 eyes underwent DSAEK. The median age at surgery was 6.8 years in the PKP group and 10.32 years in the DSAEK group. At 2 years postoperatively, clear grafts were noted in 66 of 76 (86.8%) eyes in the PKP group and 30 of 35 (85.7%) eyes in the DSAEK group. At the last follow-up, 80.3% of PKP grafts and 82.8% of DSAEK grafts were clear ( P =0.5). The type and timing of complications differed between the 2 groups. The PKP group had a statistically significant higher rate of graft rejection (19.5%) versus the DSAEK group (0%) ( P =0.01). DSAEK complications were mainly lenticule detachment that developed within one month postoperatively. There was no statistically significant difference in the visual outcomes at the last follow-up between the groups. Endothelial keratoplasty is a safe alternative to conventional PKP in CHED. The visual outcome and survival rates were comparable, but DSAEK had a lower rejection rate and fewer suture-related complications.

Clinical Outcomes of Nanothin Descemet Stripping Automated Endothelial Keratoplasty in Korean Patients with Corneal Endothelial Dysfunction

PurposeTo evaluate the clinical outcomes of nanothin Descemet stripping automated endothelial keratoplasty (DSAEK) in Korean patients with corneal endothelial dysfunction.MethodsWe retrospectively reviewed medical records of the patients who underwent nanothin DSAEK (graft thickness ≤50 μm) due to corneal endothelial dysfunction and followed up more than 1 year. We evaluated best-corrected visual acuity (BCVA), central corneal thickness, and corneal endothelial cell density at preoperative and 1, 3, 6, and 12 months postoperatively.ResultsSixteen eyes of 16 patients with the mean follow-up period of 13.00 ± 0.96 months were included. The mean graft thickness after deswelling was 45.25 ± 4.59 μm (range, 38.0–50.0 μm). The mean logarithm of the minimum angle of resolution BCVA improved from 1.37 ± 0.53 preoperatively to 0.68 ± 0.46, 0.55 ± 0.35, 0.40 ± 0.25, and 0.39 ± 0.25 at 1, 3, 6, and 12 months postoperatively (p = 0.005, p < 0.001, p < 0.001, and p < 0.001), respectively. The mean central corneal thickness improved from 752.00 ± 129.11 to 555.75 ± 54.66 μm at 12 months postoperatively (p = 0.006). The mean graft endothelial cell density decreased from 2,859.62 ± 228.34 to 1,542.25 ± 627.34 cells/mm2 at 12 months postoperatively (p = 0.012). The postoperative complications included increased intraocular pressure (n = 3, 18.75%) and graft dislocation (n = 1, 6.25%), all of which were successfully managed by anterior chamber paracentesis or rebubbling. No other serious complications were encountered.ConclusionsNanothin DSAEK produced significant and stable visual improvements without severe postoperative complications in Korean patients with corneal endothelial dysfunction.

Eye bank versus surgeon prepared Descemet stripping automated endothelial keratoplasty tissues: Influence on adhesion force in a pilot study.

Purpose:To evaluate and compare the biomechanical properties of the eye bank-prepared and surgeon prepared Descemet stripping automated endothelial keratoplasty (DSAEK) tissues.Methods:In this laboratory study, corneal tissues for research were randomly allocated in the following groups: a) surgeon-cut DSAEK and b) eye bank-prepared (pre-cut and pre-loaded) DSAEK. Endothelial cell loss (ECL), immunostaining for tight junction protein ZO-1, elastic modulus, and adhesion force were investigated.Results:ECL was not found to be significantly different between surgeon-cut DSAEK (7.8% ±6.5%), pre-cut DSAEK (8.6% ±2.3%), and pre-loaded DSAEK (11.1% ±4.8%) (P = 0.5910). ZO-1 was expressed equally across all groups. Surgeon-cut DSAEK grafts showed a significantly higher elastic modulus compared to pre-cut and pre-loaded DSAEK groups (P = 0.0047 and P < 0.0001, respectively). Adhesion force was significantly greater in the surgeon-cut DSAEK compared to pre-cut (P < 0.0001) or pre-loaded DSAEK groups (P = 0.0101).Conclusion:The laboratory data on the biomechanics of DSAEK grafts suggests that surgeon-cut DSAEK grafts present higher elastic modulus and adhesion force compared to eye bank-prepared DSAEK grafts.

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

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

Anterior Chamber Characteristics, Endothelial Parameters, and Corneal Densitometry After Descemet Stripping Automated Endothelial Keratoplasty in Patients With Fuchs Dystrophy.

PurposeTo compare anterior segment parameters in patients with Fuchs endothelial dystrophy (FED) who underwent Descemet stripping automated endothelial keratoplasty (DSAEK) in one eye and no corneal surgery in the fellow eye.MethodsThis prospective study was conducted on 28 eyes of 14 patients with FED who underwent DSAEK in one eye at least one year prior (DSAEK group) and no corneal surgery in the fellow eye (control group). Each eye was analyzed with the anterior segment optical coherence tomography, specular microscopy, and Scheimpflug imaging systems. Data were compared between the two groups.ResultsThe mean age of the patients was 76.9 7.0 years. There were no statistically significant differences in the mean central corneal thickness (CCT), central anterior chamber depth, anterior chamber angle parameters, cylinder and keratometry values between two groups (all P-values 0.05). The paracentral corneal thickness, corneal volume, endothelial cell density, and hexagonal cell ratio measurements were statistically significantly higher in the DSAEK group than the control (all P-values < 0.05), and anterior chamber volume in the DSAEK group was significantly less than the control (P = 0.046). While posterior and total corneal densitometry values in the DSAEK group were statistically significantly lower than the control (P < 0.001 and P = 0.011, respectively), there were no statistically significant differences in the anterior or middle corneal densities (P = 0.108 and P = 0.134, respectively).ConclusionWe found that total corneal densitometry value decreased in DSAEK group. Although DSAEK surgery did not affect the anterior chamber angle parameters, it reduced the anterior chamber volume and increased the corneal volume and paracentral corneal thickness due to the addition of the DSAEK graft.

Causes of corneal transplant failure: a multicentric study.

To identify the causes of failure of the different surgical corneal graft techniques: penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK). This multicentric retrospective study enrolled a consecutive cohort of patients who had undergone any type of keratoplasty between 2001 and 2016. The clinical data were obtained from the patient's medical records, following ethical guidelines, permissions and data protection. The main outcome measured in the study was the cause of graft failure, defined as any irreversible loss of graft transparency capable of compromising vision. The main causes of graft failure were classified as follows: (A) primary graft failure (PGF), (B) immunological rejection, (C) non-rejection (which includes endothelial decompensation without rejection, IOP elevation/glaucoma, diseases of the ocular surface, recurrence of the primary disease, wound dehiscence/hypotonia and trauma, among others) and (D) specific causes of lamellar keratoplasty failure. A descriptive study of the obtained data was carried out. The distribution of the causes of failure was evaluated according to the type of corneal transplant. Our research included a cohort of 571 keratoplasty failures, of which 509 met the inclusion criteria. The analysis of the causes of the PK failure showed that immunological allograft rejection represented the main cause, with 28.2% of the failures, followed by surface diseases (17.8%) and endothelial decompensation without rejection (17.3%). For the PK re-grafts group, the main cause of failure was immunological allograft rejection (34.0%), followed by diseases of the ocular surface (18.5%). For the DALK group, the failures mainly occurred due to surface diseases such as limbal stem cell insufficiency, infectious keratitis, keratolysis or persistent epithelial defect (37.8%). However, the main reason for failure in the DSAEK group was endothelial decompensation without rejection (31.9%) while primary graft failure was the main cause of failure in the DMEK group (64.1%). The main reason for failure in PK was immunological allograft rejection, both in primary and secondary transplants. The leading causes for failure were diseases of the ocular surface in the DALK population, endothelial decompensation without rejection in DSAEK and primary graft failure in DMEK.

Random Survival Forests Analysis of Intraoperative Complications as Predictors of Descemet Stripping Automated Endothelial Keratoplasty Graft Failure in the Cornea Preservation Time Study

A new analytic method can evaluate factors of interest associated with graft failure after Descemet stripping automated endothelial keratoplasty (DSAEK) or more generally in any ophthalmic surgical setting with a time-to-event outcome. To reanalyze types of intraoperative complications associated with DSAEK graft failure in the Cornea Preservation Time Study using random survival forests. This cohort study, initially conceived in April 2019, used a prediction model to conduct a post hoc secondary analysis of data collected in a multicenter, double-masked, randomized clinical trial. Forty US clinical sites with 70 surgeons participated, with donor corneas provided by 23 US eye banks. The study included 1090 participants, representing 1330 eyes, undergoing DSAEK for Fuchs dystrophy (1255 eyes [94.4%]) or pseudophakic or aphakic corneal edema (75 eyes [5.6%]). Enrollment occurred between April 16, 2012, and February 20, 2014, and follow-up ended June 5, 2017. Statistical analysis was performed from July 10, 2019, to May 29, 2020. Descemet stripping automated endothelial keratoplasty with random assignment of a donor cornea with preservation time of 7 days or less or 8 to 14 days. Ranked variable importance for intraoperative complications among 50 donor, recipient, and eye bank variables and restricted mean survival time through 47 months (1434 days) after DSAEK were examined. Random survival forests, a nonparametric method (with less restrictive model assumptions) that is far more flexible in its ability to model nonlinear effects and interactions, was used to analyze the data. This study included 1090 participants (663 women [60.8%]; median age, 70 years [range, 42-90 years]), representing 1330 eyes. Random survival forests ranked a DSAEK intraoperative complication as the third most predictive factor of graft failure, after surgeon and eye bank, in the final model with 5 predictors. In the first 47 months after DSAEK, the estimated mean difference in restricted mean survival time for grafts that experienced a DSAEK intraoperative complication vs those that did not was -227 days (99% CI, -352 to -70 days) based on the final RSF model. These findings, while post hoc, support the hypothesis that random survival forests allow for an improved analytic approach for identifying factors predictive of graft failure and for obtaining adjusted graft survival estimates. Random survival forests offer the opportunity to guide the development of future population-based cohort ophthalmic surgical studies, establishing definitive factors for procedural success.

A Simple 60-Second Swelling Technique for More Consistent Ultrathin DSAEK Graft Preparation.

The purpose of this study is to describe a simple but novel 60-second swelling technique for ultrathin Descemet stripping automated endothelial keratoplasty (DSAEK) graft preparation. In addition, we aim to demonstrate the effectiveness of this technique in obtaining thinner DSAEK grafts more consistently without compromising graft quality. We performed a retrospective case-control study comparing standard DSAEK preparation using an ML7 Microkeratome Donor Cornea System (Med-Logics Inc, Athens, TX) with an additional 60 seconds of stromal swelling with a balanced salt solution after the removal of the epithelium but before the microkeratome pass. Thirty cases using this novel swelling technique were compared with controls matched by age, sex, and precut corneal thickness. Donor characteristics and both precut and postcut graft characteristics were analyzed. DSAEK grafts prepared with our simple swelling method were approximately 13 μm thinner on average than those prepared with our conventional ultrathin DSAEK preparation technique (P = 0.001). The frequency of grafts less than 100 μm was much greater with swelling (93.3% vs. 63.3% with conventional technique, P = 0.0052). There were no significant differences in postcut cell counts or decrease in cell counts between the groups. A simple 60-second swelling technique can yield significantly thinner DSAEK tissue in a more consistent range without a significant impact on the endothelial cell count.

Outcome of Descemet membrane endothelial keratoplasty for graft failure after Descemet stripping automated endothelial keratoplasty.

PurposeTo investigate the efficacy and safety of Descemet membrane endothelial keratoplasty (DMEK) for corneal decompensation following primary Descemet stripping automated endothelial keratoplasty (DSAEK).MethodsThis was a retrospective case series of 15 patients that underwent DMEK surgery for corneal decompensation after failed DSAEK. Main outcome parameter was corrected distance visual acuity (CDVA) after DMEK and DSAEK. Secondary outcome measures included central corneal thickness (CCT), endothelial cell density (ECD), rebubbling rate, and primary graft failure after DMEK. Explanted DSAEK grafts were evaluated by light microscopy.ResultsThe mean (±SD) time period between DSAEK and DMEK surgery was 15±8 months (range, 6–31 months). Preoperative CDVA was 1.72±0.62 (logMAR). After DMEK, CDVA improved significantly to 0.78±0.48 at 1 month and to 0.23±0.24 after 12 months (P=0.022). Visual acuity data after DMEK were significantly better compared to preoperative values. The average CCT after DMEK decreased significantly from 869±210 µm (preoperative) to 505±45 µm (1 month postoperative) (P<0.001) and remained stable over 12 months. The ECD decreased from 2,589±209/mm2 (preoperative) to 1,691±589/mm2 (12 months postoperative). Rebubbling DMEK was required in three patients (=20%).ConclusionDMEK represents a feasible and safe procedure in achieving better functional results compared to DSAEK. Visual acuity and optical quality can be effectively reestablished after unsuccessful primary DSAEK surgery even in patients with long-standing corneal decompensation. Further investigations are required to validate the preliminary clinical findings.

Comparison of Artificial Anterior Chamber Internal Pressures and Cutting Systems for Descemet's Stripping Automated Endothelial Keratoplasty.

PurposeTo optimize methods of preparing donor cornea tissue for Descemet's stripping automated endothelial keratoplasty (DSAEK), we compared five experimental conditions with different internal pressures and cutting systems.MethodsThe artificial anterior chamber internal pressure (IP) was set at 100 or 200 mm Hg. The microkeratome cut was performed with or without an artificial chamber pressurizer (ACP), using a CBm turbine (CBm) or one use-plus automated (OUP-A). Thirty human research corneas were divided into five groups, and compared after the cut with donor tissue quality parameters, including cutting depth, graft uniformity, cell evaluation, and smoothness of the stromal surface.ResultsThe smallest variation in mean cut depth was observed in the condition, which had IP of 200 mm Hg used ACP and OUP-A. In experimental groups cut using CBm, significantly more consistent thicknesses were made at an IP of 200 than 100 mm Hg. There were no statistically significant differences among the groups in either endothelial cell density or cell viable assay results after cuts. Using an IP of 200 mm Hg with ACP and CBm produced the roughest stromal surface, and the roughness grading scores showed a positive correlation with the percentage of cut depth.ConclusionsAn IP of 200 mm Hg was the best setting for DSAEK grafts with high predictability of cut depth and uniformity of graft thickness without endothelial cell damage.Translational RelevanceFor successful DSAEK, it is recommended that a set internal pressure of 200 mm Hg be used during microkeratome cutting for donor tissue preparation.