Fuchs Endothelial Corneal Dystrophy Research Articles

Characterization of a Novel Mouse Model for Fuchs Endothelial Corneal Dystrophy.

Fuchs endothelial corneal dystrophy (FECD) is a progressive blinding disorder, characterized by increased corneal endothelial excrescences (guttae), corneal endothelial cell loss, and edema. These symptoms are hypothesized to be caused by changes in the extracellular matrix (ECM) and mitochondrial dysfunction in the corneal endothelium. Despite this clinical and biological relevance, a comprehensive animal model that recapitulates all the major disease characteristics is currently unavailable. In this study, we develop such a model to improve our understanding of the signaling pathways involved in the FECD progression and develop strategies for early intervention. To generate a comprehensive FECD model, we generated a double mutant mouse bearing tamoxifen-inducible knockdown of Slc4a11 and the Col8a2 (Q455K) mutation. We performed optical coherence tomography (OCT) and in vivo confocal microscopy using the Heidelberg Retinal Tomography 3 - Rostock Cornea module (HRT3-RCM) on the mice at 5 weeks of age before tamoxifen feeding to establish baseline values for corneal thickness, endothelial cell density, and test for the presence of guttae. We measured these parameters again post-tamoxifen treatment at 16 weeks of age. We collected corneas at 16 weeks to perform histopathology, immunofluorescence staining for tight junctions, adherens junctions, and oxidative stress. We evaluated endothelial pump function using a lactate assay. The double mutant tamoxifen-fed animals showed the presence of guttae, and displayed increased corneal thickness and decreased endothelial cell density. Endothelial cells showed altered morphology with disrupted adherens junctions and elevated reactive oxygen species (ROS). Finally, we found that stromal lactate concentrations were elevated in the double mutant mice, indicative of compromised endothelial pump function. Overall, this mouse model recapitulates all the important phenotypic features associated with FECD.

Deep learning for detection of Fuchs endothelial dystrophy from widefield specular microscopy imaging: a pilotstudy

BackgroundTo describe the diagnostic performance of a deep learning (DL) algorithm in detecting Fuchs endothelial corneal dystrophy (FECD) based on specular microscopy (SM) and to reliably detect widefield peripheral SM images with an endothelial cell density (ECD) > 1000 cells/mm2.MethodsFive hundred and forty-seven subjects had SM imaging performed for the central cornea endothelium. One hundred and seventy-three images had FECD, while 602 images had other diagnoses. Using fivefold cross-validation on the dataset containing 775 central SM images combined with ECD, coefficient of variation (CV) and hexagonal endothelial cell ratio (HEX), the first DL model was trained to discriminate FECD from other images and was further tested on an external set of 180 images. In eyes with FECD, a separate DL model was trained with 753 central/paracentral SM images to detect SM with ECD > 1000 cells/mm2 and tested on 557 peripheral SM images. Area under curve (AUC), sensitivity and specificity were evaluated.ResultsThe first model achieved an AUC of 0.96 with 0.91 sensitivity and 0.91 specificity in detecting FECD from other images. With an external validation set, the model achieved an AUC of 0.77, with a sensitivity of 0.69 and specificity of 0.68 in differentiating FECD from other diagnoses. The second model achieved an AUC of 0.88 with 0.79 sensitivity and 0.78 specificity in detecting peripheral SM images with ECD > 1000 cells/mm2.ConclusionsOur pilot study developed a DL model that could reliably detect FECD from other SM images and identify widefield SM images with ECD > 1000 cells/mm2 in eyes with FECD. This could be the foundation for future DL models to track progression of eyes with FECD and identify candidates suitable for therapies such as Descemet stripping only.

Applications of Imaging Technologies in Fuchs Endothelial Corneal Dystrophy: A Narrative Literature Review.

Fuchs endothelial corneal dystrophy (FECD) is a complex genetic disorder characterized by the slow and progressive degeneration of corneal endothelial cells. Thus, it may result in corneal endothelial decompensation and irreversible corneal edema. Moreover, FECD is associated with alterations in all corneal layers, such as thickening of the Descemet membrane, stromal scarring, subepithelial fibrosis, and the formation of epithelial bullae. Hence, anterior segment imaging devices that enable precise measurement of functional and anatomical changes in the cornea are essential for the management of FECD. In this review, the authors will introduce studies on the application of various imaging modalities, such as anterior segment optical coherence tomography, Scheimpflug corneal tomography, specular microscopy, in vitro confocal microscopy, and retroillumination photography, in the diagnosis and monitoring of FECD and discuss the results of these studies. The application of novel technologies, including image processing technology and artificial intelligence, that are expected to further enhance the accuracy, precision, and speed of the imaging technologies will also be discussed.

Comparative Analysis of Tomographic Indicators Forecasting Decompensation in Fuchs Endothelial Corneal Dystrophy.

To compare the performance of 3 commercially available tomographers (the Pentacam Scheimpflug camera, the swept-source optical coherence tomography Casia, and the blue light slit-scanning tomographer Precisio) in the identification of patterns associated with Fuchs endothelial corneal dystrophy (FECD) decompensation. This was a clinic-based cross-sectional imaging study. Pachymetry maps and posterior surface elevation maps were acquired with the 3 devices from 61 eyes affected by FECD. The maps were graded according to the evidence of tomographic patterns predictive of FECD decompensation (loss of parallel isopachs, displacement of the thinnest point, and focal posterior depression) by 2 blind cornea specialists. The loss of parallel isopachs was significantly less frequently evident in Pentacam pachymetry maps [8%, 95% confidence interval (CI) (3%, 18%)] compared with both the Casia [31%, 95% CI (20%, 44%), P = 0.01] and Precisio devices [24%, 95% CI (15%, 37%), P = 0.05]. The displacement of the thinnest point was graded as most evident in a significantly higher proportion of Precisio pachymetry maps [43%, 95% CI (31%, 55%)] compared with both the Pentacam [13%, 95% CI (6%, 24%), P = 0.001] and Casia devices [21%, 95% CI (12%, 33%), P = 0.03]. There were no significant differences in the identification of focal posterior depression on posterior elevation maps across the 3 devices. Identification of patterns predictive of FECD prognosis on pachymetry and posterior elevation maps is possible with different devices. However, their evidence varies across tomographers, and the results from different devices are not interchangeable.

Differences in Guttae Ultramorphology in Relation to Visual Function in Fuchs Endothelial Corneal Dystrophy.

The purpose of this study was to investigate the differences in guttae ultramorphology and their relation to visual function in eyes with Fuchs endothelial corneal dystrophy (FECD). Thirty FECD eyes without ocular comorbidities were included. Visual functional parameters (best-corrected visual acuity with high-contrast and low-contrast letters and contrast sensitivity/LogCS) and corneal morphology measured with Scheimpflug tomography (Pentacam) were assessed. The surgically removed Descemet membranes were examined by light and transmission electron microscopy. Preoperative mean best-corrected visual acuity (logarithm of the minimum angle of resolution) was 0.52 ± 0.18, LogCS 0.96 ± 0.21 and central corneal thickness 640 ± 55 μm. All eyes had signs of subclinical corneal edema in Scheimpflug tomography; clinically visible corneal edema was present in 40% of eyes. Histological findings included a posterior fibrillar zone (PFZ) in 10 specimens (33%) and abnormal collagen depositions in Descemet membranes in 14 specimens (47%). Guttae buried within the PFZ were present only in eyes with clinically visible edema (n = 4, 13%). There was no difference in visual function results and tomography parameters between eyes with and without PFZ or between protruding guttae and guttae embedded in a PFZ, respectively. Guttae morphology and density were not correlated with visual functional parameters. Guttae buried in a PFZ occurred only in eyes with clinically manifest edema, and thereby, they are an ultramorphological sign for advanced FECD. Subclinical edema was present in all eyes and might be more relevant for quality of vision than guttae ultramorphology.

Absence of the Klotho Function Causes Cornea Degeneration with Specific Features Resembling Fuchs Endothelial Corneal Dystrophy and Bullous Keratopathy.

The Klotho loss-of-function mutation is known to cause accelerated senescence in many organs, but its effects on the cornea have not been published. The present study aims to investigate the effects of the Klotho null mutation on cornea degeneration and to characterize the pathological features. Mouse corneas of Klotho homozygous, heterozygous, and wild-type mice at 8 weeks of age for both genders were subject to pathological and immunohistological examinations. The results show an irregular topography on the corneal surface with a Klotho null mutation. Histological examinations revealed a reduced corneal epithelial cell density, endothelial cell-shedding, and decreased cornea stromal layer thickness in the absence of the Klotho function. Furthermore, guttae formation and the desquamation of wing cells were significantly increased, which was comparable to the characteristics of Fuchs endothelial corneal dystrophy and bullous keratopathy. The mechanism analysis showed multi-fold abnormalities, including oxidative stress-induced cornea epithelium apoptosis and inflammation, extracellular matrix remodeling in the stroma, and a disruption of epithelial repair, presumably through the epithelial-mesenchymal transition. In conclusion, cornea degeneration was observed in the Klotho loss-of-function mutant mice. These pathological features support the use of Klotho mutant mice for investigating age-related cornea anomalies, including Fuchs endothelial corneal dystrophy, bullous keratopathy, and dry eye diseases.

Long noncoding RNA ZFAS1: A novel anti-apoptotic target in Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD) is the leading cause of endothelial keratoplasty without efficacious drug treatment. Recent studies have emphasized the involvement of epigenetic regulation in FECD development. Long non-coding RNAs (lncRNAs) are recognized as crucial epigenetic regulators in diverse cellular processes and ocular diseases. In this study, we revealed the expression patterns of lncRNAs using high-throughput sequencing technology in FECD mouse model, and identified 979 significantly dysregulated lncRNAs. By comparing the data from FECD human cell model, we obtained a series of homologous lncRNAs with similar expression patterns, and revealed that these homologous lncRNAs were enriched in FECD related biological functions, with apoptosis (mmu04210) showing the highest enrichment score. In addition, we investigated the role of lncRNA zinc finger antisense 1 (ZFAS1) in apoptotic process. This study would broaden our understanding of epigenetic regulation in FECD development, and provide potential anti-apoptotic targets for FECD therapy.

Fuchs endothelial corneal dystrophy: an updated review.

The present review will summarize FECD-associated genes and pathophysiology, diagnosis, current therapeutic approaches, and future treatment perspectives. Literature review. Fuchs' endothelial corneal dystrophy (FECD) is the most common bilateral corneal dystrophy and accounts for one-third of all corneal transplants performed in the US. FECD is caused by a combination of genetic and non-heritable factors, and there are two types: early-onset FECD, which affects individuals from an early age and is usually more severe, and late-onset FECD, which is more common and typically manifests around the age of 40. The hallmark findings of FECD include progressive loss of corneal endothelial cells and the formation of focal excrescences (guttae) on the Descemet membrane. These pathophysiological changes result in progressive endothelial dysfunction, leading to a decrease in visual acuity and blindness in later stages. The present review will summarize FECD-associated genes and pathophysiology, diagnosis, current therapeutic approaches, and future treatment perspectives. With the characterization and understanding of FECD-related genes and ongoing research into regenerative therapies for corneal endothelium, we can hope to see more significant improvements in the future in the management and care of the disease.

Enhanced Monofocal Intraocular Lenses in Fuchs' Endothelial Dystrophy Patients: Results from Triple Descemet Membrane Endothelial Keratoplasty Procedure.

Descemet membrane endothelial keratoplasty (DMEK) is currently regarded as the most effective surgical procedure for addressing Fuchs Endothelial Corneal Dystrophy (FECD), frequently performed in conjunction with cataract surgery. In this retrospective study, we present a comparison of visual performance, clinical outcomes, and optical quality between two types of monofocal Intraocular Lenses (IOLs): one standard and one enhanced intermediate vision model, implanted in patients who underwent combined phacoemulsification and DMEK surgery. This single center comparative retrospective study was conducted at the Eye Clinic of the University of Florence (Italy) and included a total of 48 eyes of 48 patients affected by FECD and cataract. All patients underwent combined DMEK with phacoemulsification procedures. The patients' data were analyzed and divided into two groups: one group (standard group) consisted of 24 eyes that underwent phaco-DMEK with implantation of a monofocal IOL, and the second group (enhanced monofocal group) included 24 eyes that underwent phaco-DMEK with implantation of an enhanced monofocal IOL. In both groups, the following monocular visual outcomes were evaluated 6 months after surgery: Uncorrected Distance Visual Acuity (UDVA) and Best-Corrected Distance Visual Acuity (BCDVA) at 4 mts; Uncorrected Intermediate Visual Acuity (UIVA), Distance-Corrected Intermediate Visual Acuity (DCIVA) at 66 cm; Uncorrected Near Visual Acuity (UNVA) and Best Corrected Near Visual Acuity (BCNVA). Monocular defocus curves were also assessed. Furthermore, optical quality in terms of Contrast Sensitivity (CS) in photopic conditions, Higher-Order Aberrations (HOAs) at a pupil size of 5 mm. Modulation Transfer Function (MTF), Objective Scatter Index (OSI), and Strehl ratio, were also analyzed. A Patient-Reported Spectacle Independence Questionnaire was revised to evaluate spectacle independence outcomes. the two groups did not exhibit statistically significant differences in terms of UDVA, BCDVA, UNVA and BCNVA, photopic CS, HOAs, OSI, Strehl ratio, and MTF. However, in the phaco-DMEK enhanced monofocal IOL group, significantly better results were observed in terms of UIVA and DCIVA as well as a different defocus curve profile at 1.50 D, providing better defocus results at intermediate distance compared with the ZCB00 IOL. In our study, we found that enhanced monofocal lens performed favorable visual outcomes, even in cases of FECD, compared to standard monofocal IOLs. Comparable optical quality observed in the Eyhance group could allow surgeons to consider these lenses as a viable option for selected patients with FECD.

Fuch's Endothelial Corneal Dystrophy in Cataract Patients Is Associated with Elevated Levels of Inflammatory Chemokines, but Not Growth Factors, in the Aqueous Humor.

The study investigated a profile of chemokines and growth factors in the aqueous humor (AH) of eyes with Fuch's endothelial corneal dystrophy (FECD) and cataracts in comparison with cataract patients as a control group. A total of 52 AH samples (26 FECD + cataract and 26 cataract/control) were collected before cataract surgery. None of the patients had any clinically apparent inflammation at the time of AH collection. The AH levels of MCP-1 (CCL2), MIP-1α (CCL3), MIP-1β(CCL4), RANTES (CCL5), eotaxin (CCL11), IP-10 (CXCL10), FGF basic, G-CSF, GM-CSF, PDGF-bb, and VEGF were compared between the groups. The analyses were performed using the Bio-Plex 200 System from Bio-Rad. Among the studied parameters, the AH levels of RANTES, eotaxin, and IP-10 significantly increased in the FECD + cataract eyes, compared with the cataract controls (p < 0.05). Elevated levels of the RANTES, Eotaxin, and IP-10 indicate more intense inflammation in the eyes of patients in the FECD + cataract group. Moreover, these factors exhibit potential as predictive biomarkers for early detection of FECD in cataract patients. The discovery of elevated concentrations of biochemical markers in a patient, who has not yet received a clinical diagnosis, may suggest the need for heightened observation of the other eye to monitor the potential development of FECD.

Predicting Long-Term Endothelial Cell Loss after Preloaded Descemet Membrane Endothelial Keratoplasty in Fuchs’ Endothelial Corneal Dystrophy: A Mathematical Model

(1) Background: This study offers a biexponential model to estimate corneal endothelial cell decay (ECD) following preloaded “endothelium-in” Descemet membrane endothelial keratoplasty (DMEK) in Fuchs’ endothelial corneal dystrophy (FECD) patients; (2) Methods: A total of 65 eyes undergoing DMEK alone or combined with cataract surgery were evaluated. The follow-up period was divided into an early phase (first 6 months) and a late phase (up to 36 months). Endothelial cell count (ECC) and endothelial cell loss (ECL) were analyzed; (3) Results: The half time of the ECD was 3.03 months for the early phase and 131.50 months for the late phase. The predicted time-lapse interval to reach 500 cells/mm2 was 218 months (18.17 years), while the time-lapse interval to reach 250 cells/mm2 was 349 months (29.08 years). There was no statistically significant difference between the ECL in DMEK combined with cataract extraction and DMEK alone at 24 months (p ≥ 0.20). At the late phase, long-term ECL prediction revealed a lower ECC half time in patients undergoing DMEK combined with cataract surgery (98.05 months) than DMEK alone (250.32 months); (4) Conclusions: Based on the mathematical modeling, a predicted average half-life of a DMEK graft could reach 18 years in FECD. Moreover, combining cataract extraction with DMEK could result in excessive ECL in the long term.

Comparison of Scheimpflug and Anterior Segment Optical Coherence Tomography Imaging Parameters for Japanese Patients With Fuchs Endothelial Corneal Dystrophy With and Without TCF4 Repeat Expansions.

The aim of this study was to investigate the association between cytosine-thymine-guanine trinucleotide repeat (TNR) expansion in TCF4 and the clinical phenotypes of corneal densitometry or anterior segment morphology in Fuchs endothelial corneal dystrophy. This retrospective cross-sectional study included 150 eyes from 75 Japanese consecutive patients with Fuchs endothelial corneal dystrophy. Cytosine-thymine-guanine repeat expansion of leukocyte-derived genomic DNA was analyzed through fragment analysis using polymerase chain reaction and triplet repeat primed polymerase chain reaction. Scheimpflug-based densitometry and anterior segment optical coherence tomography were applied. Corneal densitometry, and corneal and anterior segment morphology parameters were compared between patients with and without TNR expansion of 50 or more (expansion and nonexpansion groups, respectively) using a mixed model. The average age of the patients was 66.8 ± 13.0 years, and the modified Krachmer grading scale was 1, 2, 3, 4, 5, and 6 for 7, 32, 28, 51, 6, and 18 eyes, respectively. Sixteen patients (21%) exhibited ≥50 TNR expansion. No significant differences in sex, age, history of keratoplasty, modified Krachmer grade, and corneal densitometry in either diameter or depth were observed between the 2 groups. No significant differences in anterior segment morphology, including the anterior chamber depth and anterior chamber angle width parameters, were observed using a univariate mixed model, except for central corneal thickness (P = 0.047). However, according to the multivariate mixed model, repeat expansion was not significantly associated with central corneal thickness (P = 0.27). No significant differences in clinical phenotypes were found between Japanese patients having Fuchs endothelial corneal dystrophy with and without TNR expansion.

Comparison of Pre- and Post-DMEK Keratometry and Total Keratometry Values for IOL Power Calculations in Eyes Undergoing Triple DMEK

Purpose To evaluate prediction accuracy of pre- and post-DMEK keratometry (K) and total keratometry (TK) values for IOL power calculations in Fuchs endothelial corneal dystrophy (FECD) eyes undergoing DMEK with cataract surgery (triple DMEK). Methods Retrospective cross-sectional multicenter study of 55 FECD eyes (44 patients) that underwent triple DMEK between 2019 and 2022 between two centers in USA and Europe. Swept-source optical coherence tomography biometry (IOLMaster 700) was used for pre- and post-DMEK measurements. K and TK values were used for power calculations with ten formulae (Barrett Universal II (BUII), Castrop, Cooke K6, EVO 2.0, Haigis, Hoffer Q, Hoffer QST, Holladay I, Kane, and SRK/T). Mean error, mean absolute error (MAE), standard deviation, and percentage of eyes within ±0.50/±1.00 diopters (D) were calculated. Studied formulae were additionally adjusted using a method published previously (IOLup1D Method), which increases the IOL power by 1D. While both eyes from the same patient were considered for descriptive statistics, we restricted to one eye per individual (44 eyes for statistical comparisons. Results MAEs for all formulae were lower for post-DMEK K and TK than pre-DMEK K and TK by an average of 0.24 and 0.47 D, respectively. The lowest MAE was 0.49 D for Kane using post-DMEK TK, and the highest MAE was 1.05 D for BUII using pre-DMEK TK. Most IOLup1D formulae had lower MAEs than pre-DMEK K and TK formulae. Conclusions The IOLup1D Method should be used instead of pre-DMEK K and TK values for triple DMEK in FECD eyes. Using post-DMEK TK values for cataract surgery after DMEK provides better refractive accuracy than any of the three studied methods used for triple DMEK procedures.

Smoking, diabetes mellitus and obesity as risk factors for the degree of fuchs endothelial corneal dystrophy (FECD)

Aims/Purpose: To detect environmental factors, which may be possible risk factors in the disease course of Fuchs endothelial corneal dystrophy (FECD).Methods: Evaluation of patients with FECD registered in the FECD genetics database of the Center for Ophthalmology, University Hospital Cologne, from 2018 to 2019. For the evaluation, disease onset, central corneal thickness (CCT), best corrected visual acuity (BSCVA, logMAR), and age‐related Krachmer grading were correlated with the presence of diabetes mellitus (DM), body mass index (BMI), and smoking behaviour. Depending on the variables studied, differences between groups were examined by Mann–Whitney U test and chi‐square test. The significance level was 5%. Krachmer Grading was age‐corrected by using ordinal regression in the mediation analysis. For the mediation analysis the Kenny and Barron 4 Step Analysis was used.Results: 403 patients with FECD were included in the analysis. The mean age at diagnosis was 63.1 (±13.2) years. The female‐to‐male ratio was 1.46:1. Patients with a BMI of 30.0–34.9 kg/m2 developed FECD significantly earlier than patients with a BMI &lt; 30 kg/m2 (p = 0.001). Patients with DM showed significantly more often an age corrected Krachmer grade of 5 compared to patients without DM (p = 0.015). Using the mediation analysis, the presence of DM correlated with age‐corrected Krachmer Grade 5 (p = 0.015), and the presence of DM correlated with BMI of 30.0–34.9 kg/m2 (p = 0.012). BMI of 30.0–34.9 kg/m2 exerts a significant effect on age‐corrected Krachmer grading grade 5 with p = 0.005. The effect of DM on age‐corrected Krachmer Grading 5 is significantly mediated by BMI‐ Group 4 using Kenny and Barron 4 Step Analysis, p = 0.013.Conclusions: Our study shows for the first time that obese individuals develop FECD significantly earlier than non‐obese individuals. Oestrogen secretion in premenopausal women occurs mainly in the ovaries, whereas postmenopausal oestrogens are produced in adipose tissue. Together with gender as a risk factor, this may indicate that oestrogens have a relevant influence on disease progression. Initial laboratory work has shown that oestrogen metabolites have genotoxic and apoptotic effects on corneal endothelial cells.

Therapeutic future of Fuchs endothelial corneal dystrophy: An ongoing way to explore

Abstract: Fuchs endothelial corneal dystrophy (FECD) is one of the most common corneal diseases that causes loss of visual acuity in the world. FECD is a genetically and pathogenetically heterogeneous disease that results in the failure of corneal endothelial cells to maintain fluid balance and functional homeostasis of the cornea. Corneal edema, central guttae formation, and bullae development are common corneal pathologies. Currently, the mainstay of FECD treatment is surgery. However, limited sources of corneal graft and postsurgical complications remain problematic. In recent years, with advances in medical science and technology, there have been a few promising trials of new treatment modalities for FECD. In addition to new surgical methods, novel modalities can be classified into pharmacological-associated treatment, cell therapy-associated treatment, and gene therapy-associated treatment. In this article, our primary focus is on the most recent clinical trials related to FECD, and we present a stepwise approach to enhance FECD management and ultimately improve patient outcomes. We thoroughly searched for FECD clinical trials and reviewed the study designs, methodologies, and outcomes of each trial conducted within the past decade. It is imperative for physicians to stay up-to-date with these cutting-edge treatment approaches.

Advancing in vivo modelling and delivery systems for triplet repeat expansion‐mediated corneal endothelial dystrophy: Implications in Anti‐miR therapy

Aims/Purpose: Triplet repeat expansion‐mediated endothelial corneal dystrophy, including Fuchs endothelial corneal dystrophy (FECD), is characterized by abnormal expansions of trinucleotide repeats, resulting in corneal endothelium dysfunction [1,2]. This study aims to characterize a reliable in vivo model, that it lacks, and explore the therapeutic potential of anti‐miRs, which have shown efficacy in other disorders involving triplet repeat expansions [3,4,5]. Current invasive delivery methods for eye‐based treatments present challenges, so our focus is on optimizing non‐invasive delivery methods for anti‐miR‐based therapy.Methods: A transgenic mouse model with a significant CTG repeat expansion (&gt;1000), established in DM1, was investigated as an in vivo model for corneal endothelial dystrophy. The Fuchs‐like phenotype of the disease was characterized using immunohistochemistry and FISH techniques. Delivery methods were explored to enhance the targeting of corneal endothelial cells (CEC). Delivery efficacy and marker expression were assessed using fluorescence, RT‐qPCR, PCR, western blotting, and immunocytochemistry techniques. FECD cell cultures were established to evaluate the challenging FECD‐specific delivery systems.Results: A novel in vivo model has been characterized for studying corneal endothelial dystrophy caused by triplet repeat expansion, exhibiting similarities to the Fuchs‐like phenotype. Enhanced delivery methods have been identified to improve transfection efficiency in endothelial (HUVEC) and CEC. Successful establishment of FECD cell cultures has allowed the evaluation of these enhanced delivery systems.Conclusions: The first successful characterization of an in vivo model for triplet repeat expansion‐mediated corneal endothelial dystrophy has been achieved. This model shows potential for assessing the reversal of these phenotypes in the ocular region. Moreover, the successful delivery of new systems across CEC suggests the possibility of non‐invasive administration of anti‐miR directly into the eye. This breakthrough opens the door for future research on anti‐miRs in other diseases caused by triplet repeat expansion, such as FECD.ReferenceIn PMID: [1] 28886202, [2] 34130750, [3] 29946070, [4] 32805487, [5] 22764244.

Segmentation of the fibrillar layer in advanced fuchs endothelial corneal dystrophy: Inter‐oberserver‐reliability and intra‐observer‐repeatability analysis of corneal densitometry images

Aims: Our previous studies state that a central subendothelial collagen‐rich fibrillar layer (FL) is present in about 80% of advanced Fuchs endothelial corneal dystrophy (FECD) corneas which correlates with decreased corneal endothelial cell density and focal oedema formation. In this study, we investigated the previously unknown inter‐observer reliability and intra‐observer reproducibility of FL segmentation on Scheimpflug corneal densitometry images in patients with advanced FECD.Methods: Preoperative Scheimpflug images of patients receiving DMEK or triple DMEK for advanced FECD were retrospectively analysed. FL‐negative cases were excluded. Images were manually segmented with the open‐source software MITK by two experienced graders. A MATLAB‐based code calculated the region of interest (ROI) area, maximum calliper length, maximum horizontal and vertical dimension, and Dice similarity coefficient for FL‐areas. The intraclass correlation coefficient (ICC) was calculated by IBM SPSS (two‐way mixed, average measures). The FL localization on corneal densitometry were visualized by spatial heatmaps by MATLAB.Results: Among 308 eyes, 248 were FL‐positive (80.5%) and 60 FL‐negative (19.5%). The average Dice similarity coefficient of FL areas segmented by two graders was calculated at 0.85. Calculations on the segmentations of Grader 1 vs. Grader 2 include: ROI 7.91mm2 ± 4.8 vs. 9.29 mm2 ± 5.0, Calliper length 4.07 mm ± 1.1 vs. 4.21 mm ± 1.0, maximum horizontal dimension 3.85 mm ± 1.1 vs. 3.95 mm ± 1.0, maximum vertical dimension 3.17 mm ± 1.0 vs. 3.3 mm ± 1.0. The ICC was calculated at 0.938 vs. 0.957 vs. 0.930 for ROI (0.955 vs. 0.960 vs. 0.944 calliper length, 0.958 vs. 0.959 vs. 0.946 maximum horizontal dimension, 0.952 vs. 0.941 vs. 0.945 maximum vertical dimension) and 0.85 vs. 0.86 vs. 0.89 for the Dice similarity coefficient (inter‐observer vs. intra‐observer Grader 1 vs. intra‐observer Grader 2). Spatial heatmap analysis demonstrated primarily inferotemporal localization of increased densitometry areas in FL‐positive eyes.Conclusions: FL segmentation on corneal densitometry images exhibit high inter‐observer reliability and intra‐observer reproducibility scores. We provide evidence for corneal densitometry images as a valid tool to detect FL in advanced FECD and confirm the inferotemporal corneal projection of FL.

Trends in keratoplasty from central and Northern India. Part I: Indications for keratoplasty.

To report the indications for keratoplasty and analyze trends in two decades in India. This was a retrospective review of eye bank registries of six tertiary eye care centers located in central and northern India from 2005 to 2021. The patterns of corneal pathology and changes in trends were analyzed. Between 2005 and 2021, 13223 corneal grafts were performed in the six collaborating tertiary eye care centers. The most common indication for keratoplasty in both decades was corneal ulcer (41.1%), followed by corneal scar (25.5%), failed graft (12.0%), post-cataract surgery corneal edema (11.7%), corneal dystrophies (3.1%), corneal ectasia (1.8%), corneal trauma (0.3%), congenital corneal opacity (0.3%), and others (4.1%). An increasing trend was seen in corneal ulcers, failed grafts, and keratoconus. A reducing trend was seen in corneal scar and aphakic bullous keratopathy. There was no change in pseudophakic bullous keratopathy and Fuchs endothelial corneal dystrophy. Corneal ulcers, corneal scars, failed grafts, and post-cataract surgery corneal edema remained the foremost indications for keratoplasty in two decades in India. An increasing trend was seen in corneal ulcers and failed grafts which are of concern as these indications carry a poorer outcome. Capacity building in lamellar keratoplasty techniques is the need of the hour as pseudophakic bullous keratopathy was an important indication, and an increasing trend was noticed in keratoconus.

Five-year clinical outcomes of 107 consecutive DMEK surgeries.

The long-term clinical outcomes, postoperative complications, and graft survival of Descemet-membrane endothelial keratoplasty (DMEK) remain poorly understood. We retrospectively assessed these variables in all consecutive eyes that underwent DMEK for any indication in 2014-2018. The findings were compared to the long-term DMEK studies of five other groups (3-10-year follow-up). Patients underwent ophthalmological tests preoperatively, at 1, 3, 6, and 12 postoperative months, and then annually. Five-year graft survival was determined by Kaplan-Meier estimator. Change in best-corrected visual acuity (BCVA), endothelial-cell density (ECD), and central-corneal thickness (CCT) at each timepoint was determined. 107 eyes (80 patients; 72 years old; 67% female) underwent first-time DMEK for uncomplicated Fuchs endothelial corneal dystrophy (94% of eyes), pseudophakic bullous keratopathy (3%), and regraft after previous keratoplasty (3%). The most common complication was graft detachment requiring rebubbling (18%). Thirteen grafts (12%) failed at ≤15 months. Cumulative 5-year graft-survival probability was 88% (95% confidence intervals = 79-94%). BCVA improved from 0.6 logMAR preoperatively to 0.05 logMAR at 1 year (p<0.0001) and then remained stable. Donor ECD dropped by 47% at 6 postoperative months and then continued to decrease by 4.0%/year. Five-year endothelial-cell loss was 65% (from 2550 to 900 cells/mm2). CCT dropped from 618 to 551 μm at 5 years (p<0.0001). These findings are generally consistent with previous long-term DMEK studies. DMEK has low complication and high graft-survival rates and excellent clinical outcomes that persist up to 5 years post-surgery. DMEK seems to be a safe and effective treatment in the long term.

Transcriptomic meta-analysis reveals ERRα-mediated oxidative phosphorylation is downregulated in Fuchs' endothelial corneal dystrophy.

Late-onset Fuchs' endothelial corneal dystrophy (FECD) is a degenerative disease of cornea and the leading indication for corneal transplantation. Genetically, FECD patients can be categorized as with (RE+) or without (RE-) the CTG trinucleotide repeat expansion in the transcription factor 4 gene. The molecular mechanisms underlying FECD remain unclear, though there are plausible pathogenic models proposed for RE+ FECD. In this study, we performed a meta-analysis on RNA sequencing datasets of FECD corneal endothelium including 3 RE+ datasets and 2 RE- datasets, aiming to compare the transcriptomic profiles of RE+ and RE- FECD. Gene differential expression analysis, co-expression networks analysis, and pathway analysis were conducted. There was a striking similarity between RE+ and RE- transcriptomes. There were 1,184 genes significantly upregulated and 1,018 genes significantly downregulated in both RE+ and RE- cases. Pathway analysis identified multiple biological processes significantly enriched in both-mitochondrial functions, energy-related processes, ER-nucleus signaling pathway, demethylation, and RNA splicing were negatively enriched, whereas small GTPase mediated signaling, actin-filament processes, extracellular matrix organization, stem cell differentiation, and neutrophil mediated immunity were positively enriched. The translational initiation process was downregulated in the RE+ transcriptomes. Gene co-expression analysis identified modules with relatively distinct biological processes enriched including downregulation of mitochondrial respiratory chain complex assembly. The majority of oxidative phosphorylation (OXPHOS) subunit genes, as well as their upstream regulator gene estrogen-related receptor alpha (ESRRA), encoding ERRα, were downregulated in both RE+ and RE- cases, and the expression level of ESRRA was correlated with that of OXPHOS subunit genes. Meta-analysis increased the power of detecting differentially expressed genes. Integrating differential expression analysis with co-expression analysis helped understand the underlying molecular mechanisms. FECD RE+ and RE- transcriptomic profiles are much alike with the hallmark of downregulation of genes in pathways related to ERRα-mediated OXPHOS.