Endothelial Keratoplasty Surgery Research Articles

Accuracy of formulas for intraocular lens power for eyes undergoing descemet stripping automated endothelial keratoplasty and cataract surgery.

To compare accuracy in intraocular lens (IOL) power calculation in eyes undergoing combined cataract and Descemet stripping and automated endothelial keratoplasty (C-DSAEK) surgery of the following formulas: Barrett Universal II, EVO, Haigis, Hoffer Q, Holladay 2, Kane and SRK/T. 72 eyes from 72 patients (38 males, (53%)) with a mean age 68.08 ± 8.69 years (from 44 to 88 years old) underwent combined C-DSAEK were included. The IOL powers to implant were calculated with Barrett Universal II formula targeting -1 D refraction. Preoperative and postoperative data were used to obtain the median of absolute prediction errors (MAE) targeting emmetropia with every tested formula. Means of MAE calculated were +1.45 D for Barrett Universal II, +1.37 D for EVO, +1.48 D for Haigis, +1.38 D for Hoffer Q, +1.37 D for Holladay 2, +1.39 D for Kane and +1.31 D for SRK/T. SRK/T MAE showed major significant (p < 0.01) differences compared to the other formulas. Even if tested formulas are not able to accurately target emmetropia, SRK/T seems to be able to provide closer results in eyes undergoing C-DSAEK.

Machine learning based endothelial cell image analysis of patients undergoing descemet membrane endothelial keratoplasty surgery.

In this study, we developed a machine learning approach for postoperative corneal endothelial cell images of patients who underwent Descemet's membrane keratoplasty (DMEK). An AlexNet model is proposed and validated throughout the study for endothelial cell segmentation and cell location determination. The 506 images of postoperative corneal endothelial cells were analyzed. Endothelial cell detection, segmentation, and determining of its polygonal structure were identified. The proposed model is based on the training of an R-CNN to locate endothelial cells. Next, by determining the ridges separating adjacent cells, the density and hexagonality rates of DMEK patients are calculated. The proposed method reached accuracy and F1 score rates of 86.15 % and 0.857, respectively, which indicates that it can reliably replace the manual detection of cellsin vivoconfocal microscopy (IVCM). The AUC score of 0.764 from the proposed segmentation method suggests a satisfactory outcome. A model focused on segmenting endothelial cells can be employed to assess the health of the endothelium in DMEK patients.

Chinese expert consensus on corneal endothelial transplantation (2024)

Endothelial keratoplasty (EK) is an effective therapy for corneal endothelial diseases and mainly includes Descemet stripping endothelial keratoplasty and Descemet membrane endothelial keratoplasty. Compared with penetrating keratoplasty, EK has better vision rehabilitation and a lower rate of allograft rejection after surgery. However, EK poses a series of technical challenges, and varied complications may occur intraoperatively and postoperatively. A successful EK surgery depends on the standardized technical manipulations and the management of surgical complications. In order to standardize the surgical procedure of EK in China, the Cornea Group of Ophthalmology Branch of Chinese Medical Association has made a comprehensive discussion about indications of surgery, preoperative evaluation, surgical manipulations, and the management of complications based on the literature available thus far and clinical practice in China, and eventually established this consensus, which may guide corneal surgeons in performing the EK surgery.

Long-Term Follow-Up of Descemet Stripping Only: Data Up to 7 Years Postoperatively.

The aim of this study was to report long-term follow-up of eyes undergoing Descemet stripping only (DSO). This was a retrospective study including 26 eyes of 20 patients undergoing DSO between December 2015 and November 2022. Eligibility criteria included peripheral endothelial cell count (ECC) >1000 cells/mm2 and symptoms caused by central guttata. Patients underwent a central circular 4-mm descemetorhexis using a reverse Sinskey hook and a pair of descemetorhexis forceps using a peeling technique. Three parameters were measured before surgery and at last follow-up: best-corrected visual acuity (BCVA), central corneal thickness (CCT), and ECC measured centrally and at the periphery. The mean age was 73 ± 9 years [52-90 years]. The average follow-up period was 23.7 ± 24.8 months [3-84]. Twenty-two eyes responded to DSO with 20 female eyes (91%) and 2 male eyes (9%). The mean postoperative BCVA improved from 0.3 ± 0.17 logMAR to 0.09 ± 0.13 logMAR (P value <0.05). The mean postoperative CCT decreased from 588 ± 41 μm to 546 ± 50 μm (P-value <0.05). The mean postoperative central ECC was 780 ± 257 cells/mm2 [484-1500]. Peripheral ECC decreased postoperatively (1837 ± 407 cells/mm2 preoperatively to 864 ± 340 cells/mm2 postoperatively, P value >0.05). Peripheral endothelial cell polymegathism was stable (average of 26.8% ± 6.8% preoperatively and 30.2% ± 14% postoperatively). Average peripheral endothelial cells polymorphism decreased postoperatively (63.1 ± 20.5% preoperatively to 33% ± 25% postoperatively, P value >0.05). Four eyes did not show improvement after DSO and underwent Descemet membrane endothelial keratoplasty surgery. There were 3 men (75%) and 1 women (25%). The preoperative trend was for nonresponders to have lower BCVA, higher CCT, more abnormal peripheral polymorphism, and polymegathism. The results of this study, with up to 7 years follow up, demonstrate the durability of DSO.

Successful YAG Laser Treatment for Epithelial Ingrowth in Descemet Stripping Endothelial Keratoplasty Interface

Purpose: To present a case of epithelial ingrowth in the graft–host interface after Descemet stripping endothelial keratoplasty (DSEK) surgery that was successfully treated with an Nd:YAG Laser. Methods: A 79-year-old Caucasian female underwent a repeat DSEK 9 months after a prior DSEK graft rejection and subsequent failure. At her regularly scheduled 1-month follow-up visit, an asymptomatic dense white interface opacity was observed within the stromal interface, with an appearance consistent with epithelial ingrowth. The depth and location was confirmed by anterior segment optical coherence tomography. After initial observation, the opacity was noted to be growing over 2 months. The epithelial ingrowth cells were then treated with an Nd:YAG Laser. Results: The patient remained stable 12 months post laser treatment with no recurrence of epithelial ingrowth. Focal stromal pits were noted at the site of Nd:YAG Laser treatment within the DSEK graft stromal interface, but were not visually significant. Conclusions: Nd:YAG laser treatment is a safe and effective way to treat early-stage epithelial ingrowth in the interface after DSEK surgery.

Challenges of DMEK Technique with Young Corneal Donors' Grafts: Surgical Keys for Success-A Pilot Study.

To report on the surgical maneuvers recommended for a successful unfolding of very young donors in order to accomplish an uneventful Descemet Membrane Endothelial Keratoplasty (DMEK) surgery. Five patients (three females and two males, mean age 71.2 ± 6.7 years) with Fuchs endothelial cell dystrophy who underwent DMEK with very young donors (between 20 and 30 years old) were included. The following demographic data were assessed: donor's age, donor's endothelial cell density (ECD), preservation time, recipient's age and sex and unfolding surgical time. Best-corrected visual acuity (BCVA; decimal system), ECD and corneal central thickness (CCT) were assessed preoperatively and at 6-month follow-up. Donors' mean age was 23.6 ± 3.6 years (range 21 to 30) and the mean ECD was 2748.6 ± 162.6 cells/mm2. All of them underwent an uneventful DMEK as a single procedure performed by one experienced surgeon (MAG) with a mean unfolding time of 7.2 ± 4.9 min (range 4 to 15). The essential steps, including patient preparation as well as DMEK graft implantation, orientation, unrolling and centering are detailed. At 6 months, BCVA was 0.6 ± 0.2, ECD was 1945.0 ± 455.5 cells/mm2 and CCT was 497.0 ± 19.7 microns. We hereby present the keys to overcome tightly scrolled grafts of very young donors, which prove perfectly suitable for DMEK surgery. The graft shape tends towards a double-roll and specific maneuvers are strongly recommended.

Persistent Localized Descemet Membrane Endothelial Keratoplasty Detachments Secondary to Corneal Ink Stain Marks.

The aim of this study was to describe 2 cases of persistent endothelial graft detachments secondary to corneal gentian violet ink stain marks. This study included a case review of hospital records of 2 eyes with localized Descemet's membrane detachments after Descemet membrane endothelial keratoplasty (DMEK) surgery. Two patients underwent consecutive uncomplicated DMEK surgery for Fuchs endothelial dystrophy with identical techniques. The grafts were marked with an ink marker through a stromal window to ensure correct orientation during donor graft preparation. Both patients had localized detachments around the ink mark on day 1, week 1, and up to 1 month at postoperative review. The persistent detachment was believed to be due to the gentian violet marker used which had a higher concentration of isopropyl alcohol solvent than the standard marking pen routinely used. Ink markers with higher concentrations of isopropyl solvent may result in higher DMEK detachment rates and caution is advised when using these markers.

Optical quality of the cornea after Descemet membrane endothelial keratoplasty surgery: early results from Türkiye.

Descemet membrane endothelial keratoplasty (DMEK) is increasingly favored in the treatment of endothelial dysfunction due to its benefits, which include swift visual rehabilitation and recovery, a relatively low rejection rate, and superior refractive stability. In this study, we examined alterations in corneal clarity among patients who underwent DMEK and correlated these densitometry findings with other optical parameters of corneal topography. The study incorporated 35 eyes from 35 patients who had previously undergone DMEK surgery for pseudophakic bullous keratopathy at Ankara Bilkent City Hospital. The results from these patients were compared with those from a healthy control group. The preoperative and postoperative optical parameters of the patients were assessed using Pentacam Scheimpflug topography (Oculus). We observed significant decreases in corneal densitometry in the 0-2 mm and 2-6 mm zones of the anterior, posterior, central, and total layers at the sixth month postoperatively compared to the preoperative period (P<0.05). The corneal densitometry values at postoperative month 6 were elevated in all layers and zones relative to the healthy group (P<0.05). The root mean square of higher-order aberrations in postoperative period was elevated significantly (P<0.001). Six months after operation, the optical quality of the cornea following DMEK surgery did not achieve the level of a healthy cornea.

Impact of topographic hot spots on the refractive outcomes of combined DMEK and cataract surgery.

To compare the refractive results of combined Descemet membrane endothelial keratoplasty (DMEK) and cataract surgery in eyes with Fuchs endothelial corneal dystrophy (FECD) with and without topographic hot spots. "Villa Igea" Hospital, Forlì, Italy. Interventional case series. 57 eyes of 52 patients with FECD undergoing combined DMEK, cataract surgery, and monofocal intraocular lens (IOL) implantation were included in this single-center study. Patients were classified based on the presence or absence of topographic hot spots on the preoperative axial power map. Prediction error (PE) was calculated as the postoperative manifest spherical equivalent (SE) refraction minus the SE predicted refraction. 6 months postoperatively, mean PE was +0.79 ± 1.12 diopters (D). In eyes with hot spots, mean keratometry (K), K flat, and K steep significantly decreased after surgery (all P < .05), whereas no significant changes were observed in eyes without hot spots (all P > .05). Eyes with hot spots showed a significantly more hyperopic PE than eyes without hot spots (+1.13 ± 1.23 vs +0.40 ± 0.86 D; P = .013). Combined DMEK and cataract surgery can result in a hyperopic refractive surprise. The presence of topographic hot spots before surgery is associated with a higher hyperopic shift.

The Influence of Glaucoma as a Comorbidity on Cytokine Expression in Aqueous Humor of Patients with Fuchs Endothelial Corneal Dystrophy and Bullous Keratopathy

Purpose: to evaluate the effect of primary open-angle glaucoma (POAG) as a comorbidity on cytokine expression in aqueous humor (AqH) of patients with Fuchs endothelial corneal dystrophy (FECD) and bullous keratopathy (BK).Patients and methods. In this prospective consecutive case study 58 patients (58 eyes) were divided into 2 main groups. Group 1 (22 patients with FECD) included 11 patients with coexisting POAG II–IIIA (group 1a) and 11 patients without ocular comorbidity (group 1b). Group 2 (28 patients with BK) consisted of 19 patients with coexisting POAG II–IIIA (group 2a) and 9 patients without ocular comorbidity (group 2b). Group 3 (control) included 8 patients with cataract. The patients of groups 1 and 2 underwent endothelial keratoplasty. Intraoperatively obtained recipients’ Descemet’s membranes (DMs) were investigated histologically (hematoxylin/eosin staining). A total of 58 AqH samples were collected from consecutive patients who underwent endothelial keratoplasty (groups 1a, 1b, 2a, 2b) or cataract surgery (controls). The AqH levels of cytokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p70), IL-13, IL-17, G-CSF, GM-CSF, IFN-γ, MCP-1, MIP-1β and TNF-α) were compared among the groups.Results. Clinical diagnoses of FECD (group 1) and BK (group 2) were confirmed by the results of morphologic study. The levels of IL-8, MCP-1, IFN-γ were significantly higher in AqH samples from FECD and BK groups (regardless of the presence or absence of POAG) compared with the controls. IL-6 level was significantly elevated in FECD with coexisting POAG (group 1a) and BK (groups 2a and 2b) than in the controls. The influence of POAG on the local inflammation in FECD and BK is confirmed by the increased level of MIP-1β and the low concentration of GM-CSF compared with the controls. Among BK eyes (groups 2a and 2b), POAG as a comorbidity (group 2a) was associated with decreased level of IL-12. FECD with coexisting POAG was characterized with lower level of IL-13 in AqH than in the controls.Conclusions. POAG as a comorbid pathology in patients with FECD leads to high immune response mediated by cytokines expression. BK regardless of coexisting POAG is associated with severe local immune inflammation.

Cost-effectiveness of the ADVISE trial: An intraoperative OCT protocol in DMEK surgery.

The intraoperative optical coherence tomography (iOCT) is recently introduced in Descemet membrane endothelial keratoplasty (DMEK) surgery, which aims to increase clinical performance and surgery safety. However, the acquisition of this modality is a substantial investment. The objective of this paper is to report on the cost-effectiveness of an iOCT-protocol in DMEK surgery with the Advanced Visualization in Corneal Surgery Evaluation (ADVISE) trial. This cost-effectiveness analysis uses data 6 months postoperatively from the multicentre prospective randomized clinical ADVISE trial. Sixty-five patients were randomized to usual care (n = 33) or the iOCT-protocol (n = 32). Quality-Adjusted Life Years (EQ-5D-5L), Vision-related Quality of Life (NEI-VFQ-25) and self-administered resources questionnaires were administered. Main outcome is the incremental cost-effectiveness ratio (ICER) and sensitivity analyses. The iOCT protocol reports no statistical difference in ICER. For the usual care group compared with the iOCT protocol, respectively, the mean societal costs are €5027 compared with €4920 (Δ€107). The sensitivity analyses report the highest variability on time variables. This economic evaluation learned that there is no added value in quality of life or cost-effectiveness in using the iOCT protocol in DMEK surgery. The variability of cost variables depends on the characteristics of an eye clinic. The added value of iOCT could gain incrementally by increasing surgical efficiency, and aiding in surgical decision-making.

Innate Immune Cytokine Levels in Eyes With Late Endothelial Keratoplasty Failure.

The aim of this study was to compare aqueous humor cytokine levels in eyes with an initial endothelial keratoplasty (EK) that cleared and later decompensated versus control eyes. In this prospective case-control study, aqueous humor samples were collected under sterile conditions at the start of planned cataract or EK surgery in normal controls (n = 10), Fuchs dystrophy controls with no previous surgery (n = 10) or previous cataract surgery only (n = 10), eyes with Descemet membrane EK (DMEK) endothelial decompensation (n = 5), and eyes with Descemet stripping EK (DSEK) endothelial decompensation (n = 9). Cytokine levels were quantified with the LUNARIS Human 11-Plex Cytokine Kit and compared using the Kruskal-Wallis nonparametric test and post hoc Wilcoxon pairwise 2-sided multiple comparison test. Levels of granulocyte-macrophage colony-stimulating factor, interferon gamma, interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-10, IL-12p70, and tumor necrosis factorα did not differ significantly between groups. However, IL-6 was significantly increased in DSEK regraft eyes versus controls without previous ocular surgery. IL-8 was significantly increased in eyes with previous cataract or EK surgery versus eyes without previous surgery, and IL-8 was significantly increased in DSEK regraft eyes versus eyes with previous cataract surgery. The levels of innate immune cytokines IL-6 and IL-8 were elevated in the aqueous humor of eyes with failed DSEK, but not with failed DMEK. The differences between DSEK and DMEK may be related to the lower inherent immunogenicity of DMEK grafts and/or the more advanced stage of some of the DSEK graft failures at the time of diagnosis and treatment.

Role of Direct Supervision in the Learning Curve of Descemet Membrane Endothelial Keratoplasty Surgery.

The aim of this study was to compare complication rates of Descemet membrane endothelial keratoplasty (DMEK) performed by directly supervised and nondirectly supervised corneal fellows. This study was a retrospective, comparative case series of DMEK surgeries performed by novice surgeons (less than 15 DMEK cases) with or without direct direct expert supervision. Patients who underwent surgery for Fuchs endothelial dystrophy or pseudophakic bullous keratopathy with a minimum follow-up of 12 weeks were included. Data on patients' demographics, surgical details, surgeon level, intraoperative and postoperative complications, and rate of rebubbling were collected. In this study, 41 nondirectly supervised and 48 directly supervised DMEK surgeries were included. At 6 months, 67.4% of eyes achieved a best-corrected visual acuity of ≤0.3 logMAR with no significant difference between groups ( P = 0.95). Intraoperative complications occurred in 22% of cases in the nondirect supervision group and 4.2% in the direct supervision group ( P = 0.02). Postoperative complications occurred in 9.8% of cases in the nondirect supervision group and 6.2% of cases in the direct supervision group ( P = 0.7). The rebubbling rate was comparable in the 2 groups (34.1% vs. 33.3%, P = 1.0). Five cases (12.2%), all from the nondirect supervision group, required secondary keratoplasty ( P = 0.02). The overall complication rate was significantly higher in the nondirect supervision group (31.7% vs. 10.4%, P = 0.03). Functional success can be achieved in directly supervised or nondirectly supervised DMEK surgery. However, nondirectly supervised DMEK surgery may associate with higher rates of complications.

Deep Learning Model for the Detection of Corneal Edema Before Descemet Membrane Endothelial Keratoplasty on Optical Coherence Tomography Images.

Descemet membrane endothelial keratoplasty (DMEK) is the preferred method for treating corneal endothelial dysfunction, such as Fuchs endothelial corneal dystrophy (FECD). The surgical indication is based on the patients' symptoms and the presence of corneal edema. We developed an automated tool based on deep learning to detect edema in corneal optical coherence tomography images. This study aimed to evaluate this approach in edema detection before Descemet membrane endothelial keratoplasty surgery, for patients with or without FECD. We used our previously described model allowing to classify each pixel in the corneal optical coherence tomography images as "normal" or "edema." We included 1992 images of normal and preoperative edematous corneas. We calculated the edema fraction (EF), defined as the ratio between the number of pixels labeled as "edema," and those representing the cornea for each patient. Differential central corneal thickness (DCCT), defined as the difference in central corneal thickness before and 6 months after surgery, was used to quantify preoperative edema. AUC of EF for the edema detection was calculated for Several DCCT thresholds and a value of 20 µm was selected to define significant edema as it provided the highest area under the curve value. The area under the curve of the receiver operating characteristic curve for EF for the detection of 20 µm of DCCT was 0.97 for all patients, 0.96 for Fuchs and normal only and 0.99 for non-FECD and normal patients. The optimal EF threshold was 0.143 for all patients and patients with FECD. Our model is capable of objectively detecting minimal corneal edema before Descemet membrane endothelial keratoplasty surgery. Deep learning can help to interpret optical coherence tomography scans and aid the surgeon in decision-making.

Surgical goniolens for tag identification and removal in DMEK surgery.

We describe a novel technique for identifying endothelial Descemet membrane (DM) tags remaining after descemetorhexis in patients undergoing Descemet membrane endothelial keratoplasty (DMEK) surgery. 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. A detailed visualization of the peripheral inner corneal layer is possible using goniolens, without using any staining in the anterior chamber. 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.

Video Grading of Descemet Membrane Endothelial Keratoplasty Surgery to Identify Surgeon Risk Factors for Graft Detachment and Rebubbling: A Post Hoc Observational Analysis of the Advanced Visualization In Corneal Surgery Evaluation Trial.

The aim of this study was to explore video-graded intraoperative risk factors for graft detachment (GD) and rebubbling in Descemet membrane endothelial keratoplasty surgery. A post hoc analysis of 65 eyes of 65 pseudophakic subjects with Fuchs endothelial dystrophy that underwent Descemet membrane endothelial keratoplasty surgery as part of the Advanced Visualization In Corneal Surgery Evaluation trial. All surgical recordings were assessed by 2 graders using a structured assessment form. A multinominal regression was performed to estimate the independent effect of video-graded intraoperative factors on the incidence of GD and rebubbling. Secondary outcomes are corrected distance visual acuity and endothelial cell density. In total, 33 GDs were recorded, of which 17 required rebubbling. No significant predictors for GD or rebubbling were identified. However, the results revealed 2 clinically relevant patterns. An unfavorable graft configuration (ie, wrinkled, tight scroll, or taco-shaped) and a gas-bubble size smaller than the graft diameter were associated with an increased risk of GD [odds ratio (OR) 2.5 and OR 2.26, respectively] and rebubbling (OR 2.0 and OR 2.60, respectively). Inversely, a larger gas-bubble size was associated with a reduced risk of GD (OR 0.37) and rebubbling (OR 0.36). At 3 and 6 months postoperatively, corrected distance visual acuity was poorer in subjects requiring a rebubbling and endothelial cell density loss was higher in subjects with a partial GD. Our analysis revealed that the gas-bubble size and graft shape/geometry seem to be relevant clinical factors for GD and rebubbling, whereas descemetorhexis difficulty, degree of graft manipulation, graft overlap, and surgical iridectomy were not associated with an increased risk.

Effects of Systemic Diseases on Graft Preparation in Descemet Membrane Endothelial Keratoplasty.

To evaluate the effects of the systemic diseases and drugs of the donor on Descemet membrane (DM) graft preparation. Seventy-eight corneas of 58 donors, of whom the DM grafts were used in Descemet membrane endothelial keratoplasty (DMEK) surgery, between January 2018 and January 2020, were enrolled in this retrospective study. The hospital records of the donors were analyzed. Age, sex, blood type, systemic diseases, and drugs; complete blood count; biochemistry panel for liver and kidney functions in the past 48 hours; and the drugs used in the hospital, if any, in the past 24 hours were recorded. The grafts with tears that occurred while preparation were included in group 1, and the successful grafts with no tears were included in group 2. There were no statistically significant differences in the characteristics of the donors between groups. However, breast cancer and the use of sevelamer were found to be significantly higher in group 1 ( P =0.010, P =0.033, respectively). No statistically significant difference in the use of other drugs was found between groups. Although diabetic donors have been reported to be inappropriate candidates for the preparation of DM grafts for DMEK, most of the donors with several systemic diseases including diabetes can be used in DMEK surgery, with the right technique in DM graft preparation.

Rate of Endothelial Cell Loss and Graft Survival in Descemet Membrane Endothelial Keratoplasty in Eyes Requiring a Rebubble.

We aimed to compare the rate of 6-month endothelial cell loss (ECL) and 6-month graft survival in eyes that did not require a postoperative rebubble with eyes that did require a postoperative rebubble after Descemet membrane endothelial keratoplasty (DMEK) surgery. A consecutive series of DMEK surgeries performed from September 2013 to March 2020 was retrospectively analyzed. Eyes that did not require a rebubble for graft detachment were compared with eyes with 1 rebubble and eyes with 2 or more rebubbles for 6-month ECL and graft survival. A subanalysis of the rebubble rate for different indications for transplantation was also performed. One thousand two hundred ninety-eight eyes were included in this study. The 6-month ECL for eyes with no rebubbles, 1 rebubble, and ≥2 rebubbles was 29.3% ± 16.2% (n = 793), 36.4% ± 18.6% (n = 97, P = 0.001), and 50.1% ± 19.6% (n = 28, P < 0.001), respectively. The 6-month graft survival rate for eyes with no rebubbles, 1 rebubble, and ≥2 rebubbles was 99.5%, 97.8% ( P = 0.035), and 81.8% ( P < 0.001), respectively. When compared to the rebubble rate for DMEK for Fuchs dystrophy (156/1165 eyes = 13.4%), the rebubble rates were statistically higher for DMEK for failed penetrating keratoplasty (28.5%, P = 0.021) and pseudophakic bullous keratopathy (28.0%, P = 0.036). Eyes undergoing any rebubble procedure in the postoperative period after DMEK have an increased risk of endothelial cell loss and graft failure at 6 months postoperative. DMEK in eyes for failed penetrating keratoplasty and failed DMEK had the highest rebubble rate, with the former reaching statistical significance.

Descemet Membrane Endothelial Keratoplasty (DMEK) for Severe Verrucous Posterior Polymorphous Corneal Dystrophy with Uncommon Clinical and Ultrastructural Findings.

To report a case of severe verrucous posterior polymorphous corneal dystrophy (PPCD) and cataract, which was treated with Descemet membrane endothelial keratoplasty (DMEK) and simultaneous cataract surgery as a triple procedure (Triple-DMEK). A 62-year-old female patient presented to our department for co-evaluation of advanced PPCD with cataract and progressive light sensitivity in both eyes. The clinical examination demonstrated unusual clinical findings with prominent verrucous lesions on the posterior surface of the cornea without corneal decompensation. We performed a Triple-DMEK in case of simultaneous cataract. The corneal tissue was examined by light and transmission electron microscopy. Intraoperatively, it was difficult to remove the verrucous structures completely after classical descemetorhexis. Light microscopic examination demonstrated epithelium-like transformation of the corneal endothelium by immunostaining (cytokeratin AE1/3 staining). Transmission electron microscopy revealed thickening of Descemet's membrane (18.5 to 30.0 µm). The anterior banded layer had a normal structure and was slightly thickened (3.5 to 5.5 µm). A normal posterior non-banded layer (PNBL) was observed but thinned (2.5 to 4.0 µm) or missing. It was followed by an altered PNBL with abnormal fibrillary inclusions, which was strongly and variably thickened (11.0 to 24.5 µm). The corneal endothelium was degenerated, partially absent, and epithelial-like altered. The nodular lesions were found to consist of a few degenerated cells that were embedded in an amorphous extracellular matrix interspersed with collagen fibers, which were not arranged in regular lamellae, forming the corneal stroma. The occurrence of pigment granules among the cellular debris suggested that the cells were endothelial cells. The corrected distance visual acuity improved from 20/50 to 20/30 in the right eye (+ 0.00/- 1.75/157°) and from 20/60 to 20/30 in the left eye (+ 0.00/- 1.75/33°), with significant improvement in light sensitivity. The clinical and ultrastructural findings seem to be an unusual variant of the typical characteristic appearance of a PPCD. This case demonstrates that Triple-DMEK is feasible even in very advanced dystrophic changes of the posterior corneal surface, with good morphological and functional results.

3D Visualization System in Descemet Membrane Endothelial Keratoplasty (DMEK): A Six-Month Comparison with Conventional Microscope.

Background: To compare the efficacy and safety of Descemet membrane endothelial keratoplasty (DMEK) surgery using the three-dimensional (3D) display system NGENUITY to DMEK surgery performed with the traditional microscope (TM) in patients affected by Fuchs Endothelial Corneal Disease (FECD). Methods: Retrospective comparative study of 40 pseudophakic eyes of 40 patients affected by FECD who underwent DMEK surgery. Twenty patients (3D group) were operated on using the 3D display system and 20 patients (TM group) were operated on using the traditional microscope. Best spectacle corrected visual acuity (BSCVA), central corneal thickness (CCT), endothelial cell density (ECD) and corneal densitometry (CD) values were documented before and at 1, 3 and 6 months after DMEK. Intra- and postoperative complications were recorded. Results: The baseline assessments did not differ between the two groups (p > 0.05). Global surgical time and time to perform descemetorhexis were significantly lower in the TM group (p = 0.04 and p = 0.02, respectively). BSCVA, CCT, ECD and CD values did not differ significantly in the two groups at all follow-ups (p > 0.05). Complication rate was similar between the two groups. Conclusion: Three-dimensional display systems can be securely employed in DMEK surgery considering the satisfactory clinical outcomes, including Scheimpflug CD. Nevertheless, the slightly longer surgical time of the 3D DMEKs may lead to surgeons’ hesitancy. The main advantages of the heads-up approach may be the improved ergonomic comfort during surgery and the utility of assistants in surgical training.