Reticular Bullous Epithelial Corneal Edema after Netarsudil Use for Elevated Intraocular Pressure with Concurrent Fuchs Endothelial Corneal Dystrophy: A Case Report

Introduction

We describe a case of reticular bullous corneal epithelial edema associated with the use of netarsudil ophthalmic solution (0.02%) for elevated intraocular pressure.

Case Presentation

A 74-year-old man with a complex ocular medical history, including Fuchs dystrophy and primary open-angle glaucoma, developed progressively worsening loss of vision 3 weeks following the initiation of topical netarsudil for increased intraocular pressure. Visual acuity in the left eye was counting fingers at 3 feet and intraocular pressure in the left eye was 7 mm Hg. A characteristic "honeycomb" pattern epitheliopathy was seen on ocular examination.

Conclusion

Reticular bullous epithelial corneal edema is an uncommon finding associated with netarsudil use, which can be overlooked in favor of corneal edema associated with Fuchs dystrophy. This is especially relevant given Fuchs dystrophy itself is a predisposing risk factor for netarsudil-induced reticular bullous corneal epithelial edema. Improvement of both the corneal edema and visual acuity should be expected after discontinuing netarsudil and undergoing superficial keratectomy.

Integrative analysis of gene expression datasets in corneal endothelium samples of Fuchs endothelial corneal dystrophy

FECD is an age-related progressive ocular disorder characterized by the gradual loss of corneal endothelial cells. Although the exact pathogenesis of FECD remains incompletely understood, differentially expressed genes in the corneal endothelium of FECD patients compared to controls have been reported in several studies. However, a consensus regarding consistently affected genes in FECD has not been established. To address this issue, we conducted a comprehensive meta-analysis incorporating five studies with data that met our predefined inclusion criteria. The combined dataset included 41 FECD patients and 26 controls. We conducted study-level analyses, followed by a meta-analysis, and subsequent functional enrichment analysis targeting the topmost DEGs. Our findings revealed a total of 1537 consistently dysregulated genes in the corneal endothelium of FECD patients. Notably, only 14.6% (224/1537) of these DEGs had been previously identified as statistically significant in individual datasets. Functional enrichment analysis revealed that the upregulated DEGs were significantly enriched in immune-related signaling pathways, with a particularly high enrichment in "The NLRP3 inflammasome" and "Inflammasomes" pathways. In conclusion, we successfully identify a set of consistently dysregulated genes in FECD, which are associated with both established and novel biological pathways. This study highlights the importance of further investigating the role of inflammasomes in FECD pathogenesis and exploring strategies to modulate inflammasome activation for the management of this debilitating condition.

Systematic review of SLC4A11, ZEB1, LOXHD1, and AGBL1 variants in the development of Fuchs' endothelial corneal dystrophy

Introduction

The pathogenic role of variants in TCF4 and COL8A2 in causing Fuchs' endothelial corneal dystrophy (FECD) is not controversial and has been confirmed by numerous studies. The causal role of other genes, SLC4A11, ZEB1, LOXHD1, and AGBL1, which have been reported to be associated with FECD, is more complicated and less obvious. We performed a systematic review of the variants in the above-mentioned genes in FECD cases, taking into account the currently available population frequency information, transcriptomic data, and the results of functional studies to assess their pathogenicity.

Methods

Search for articles published in 2005-2022 was performed manually between July 2022 and February 2023. We searched for original research articles in peer-reviewed journals, written in English. Variants in the genes of interest identified in patients with FECD were extracted for the analysis. We classified each presented variant by pathogenicity status according to the ACMG criteria implemented in the Varsome tool. Diagnosis, segregation data, presence of affected relatives, functional analysis results, and gene expression in the corneal endothelium were taken into account. Data on the expression of genes of interest in the corneal endothelium were extracted from articles in which transcriptome analysis was performed. The identification of at least one variant in a gene classified as pathogenic or significantly associated with FECD was required to confirm the causal role of the gene in FECD.

Results

The analysis included 34 articles with 102 unique ZEB1 variants, 20 articles with 64 SLC4A11 variants, six articles with 26 LOXHD1 variants, and five articles with four AGBL1 variants. Pathogenic status was confirmed for seven SLC4A11 variants found in FECD. No variants in ZEB1, LOXHD1, and AGBL1 genes were classified as pathogenic for FECD. According to the transcriptome data, AGBL1 and LOXHD1 were not expressed in the corneal endothelium. Functional evidence for the association of LOXHD1, and AGBL1 with FECD was conflicting.

Conclusion

Our analysis confirmed the causal role of SLC4A11 variants in the development of FECD. The causal role of ZEB1, LOXHD1, and AGBL1 variants in FECD has not been confirmed. Further evidence from familial cases and functional analysis is needed to confirm their causal roles in FECD.

DNA methylation changes and increased mRNA expression of coagulation proteins, factor V and thrombomodulin in Fuchs endothelial corneal dystrophy

Late-onset Fuchs endothelial corneal dystrophy (FECD) is a disease affecting the corneal endothelium (CE), associated with a cytosine-thymine-guanine repeat expansion at the CTG18.1 locus in the transcription factor 4 (TCF4) gene. It is unknown whether CTG18.1 expansions affect global methylation including TCF4 gene in CE or whether global CE methylation changes at advanced age. Using genome-wide DNA methylation array, we investigated methylation in CE from FECD patients with CTG18.1 expansions and studied the methylation in healthy CE at different ages. The most revealing DNA methylation findings were analyzed by gene expression and protein analysis. 3488 CpGs had significantly altered methylation pattern in FECD though no substantial changes were found in TCF4. The most hypermethylated site was in a predicted promoter of aquaporin 1 (AQP1) gene, and the most hypomethylated site was in a predicted promoter of coagulation factor V (F5 for gene, FV for protein). In FECD, AQP1 mRNA expression was variable, while F5 gene expression showed a ~ 23-fold increase. FV protein was present in both healthy and affected CE. Further gene expression analysis of coagulation factors interacting with FV revealed a ~ 34-fold increase of thrombomodulin (THBD). THBD protein was detected only in CE from FECD patients. Additionally, we observed an age-dependent hypomethylation in elderly healthy CE.Thus, tissue-specific genome-wide and gene-specific methylation changes associated with altered gene expression were discovered in FECD. TCF4 pathological methylation in FECD because of CTG18.1 expansion was ruled out.

Clinical outcomes of Descemet membrane endothelial keratoplasty performed in eyes with keratoconus and corneal endothelial dysfunction

PURPOSE

To evaluate the clinical outcome of Descemet membrane endothelial keratoplasty (DMEK) performed in eyes with comorbid keratoconus (KCN) and corneal endothelial dysfunction.

METHODS

Twenty-five consecutive eyes of 14 patients with comorbid stable KCN underwent DMEK for corneal endothelial dysfunction; best spectacle corrected visual acuity (BSCVA), maximum corneal curvature (Kmax), maximum corneal power (Pmax), central corneal thickness (CCT), and intra- and postoperative complications were assessed.

RESULTS

Excluding eyes requiring re-transplantation for primary graft failure (n = 3), all eyes showed improvement in BSCVA, reaching ≥ 20/40 (0.5) in 86%, ≥ 20/25 (0.8) in 55%, and ≥ 20/20 (1.0) in 27% by one month postoperatively; 90%, 76%, and 48% by 6 months postoperatively; and 88%, 76%, and 47% by 12 months postoperatively. CCT decreased from 571μm preoperatively to 485μm at 1 month (p < 0.001) and 481μm at 12 months (p < 0.001). Kmax decreased by a median of 1.4 diopters (D) at 1 month (p = 0.003) and 3.1 D at 12 months (p = 0.021), and every eye with a preoperative Kmax ≥ 46 D demonstrated flattening. Pmax decreased by 2.1 D at 1 month (p = 0.001) and 4.0 D at 12 months (p = 0.016).

CONCLUSION

DMEK is technically feasible in eyes with comorbid KCN and may give excellent outcomes visual and refractive outcomes, including significant corneal flattening, which may potentially create a visually significant hyperopic shift in patients with severely ectatic corneas.

Retrospective Study of a Sustained-Release Intracanalicular Dexamethasone Insert for Treatment of Ocular Inflammation After Cataract and Corneal Surgery

PURPOSE

To evaluate the effectiveness and safety of a sustained-release intracanalicular dexamethasone insert (Dextenza, Ocular Therapeutix, Inc.) as an adjunctive therapy in patients undergoing cataract and corneal surgery.

PATIENTS AND METHODS

This retrospective case series contains 18 patients undergoing cataract surgery and 6 patients undergoing corneal surgery. All patients received the Dextenza intracanalicular insert. 6/18 of the patients in the cataract surgery arm were on the standard of care post-surgery topical steroid drop regimen, whereas 11/18 of the patients were on a reduced regimen. 1/18 of the patients was on a drop regimen that deviated from the aforementioned regimens. 2/6 of the patients in the corneal surgery arm were on the standard of care post-surgery topical steroid drop regimen, whereas 3/6 of the patients were on a reduced regimen. 1/6 of the patients were on a drop regimen that deviated from the aforementioned regimens.

RESULTS

The primary outcome measures are intraocular pressure (IOP) levels and anterior chamber inflammation levels across the post-operative recovery period. 1/18 of the patients in the cataract surgery arm and 1/6 of the patients in the corneal surgery arm experienced a clinically significant IOP spike greater than 10 millimeters of mercury (mmHg) above baseline IOP. No patient in either of the study groups had significant inflammation after 1 week post-surgery. 1/18 of the patients in the cataract surgery arm and 1/6 of the patients in the corneal surgery arm experienced a canalicular obstruction.

CONCLUSION

Dextenza with the lower drop protocol showed non-inferiority in terms of inflammation management and safety. As with any steroid delivery mechanism, monitoring IOP is paramount when using Dextenza. One of the patients with a canalicular obstruction had a history of punctal plug implantation, so care should be taken when choosing to implant Dextenza in such a patient.

Culture of corneal endothelial cells obtained by descemetorhexis of corneas with Fuchs endothelial corneal dystrophy

Currently, endothelial keratoplasty is the gold standard for the surgical treatment of Fuchs endothelial corneal dystrophy (FECD). Despite the remarkable success in terms of surgical outcomes, a shortage of corneal donor tissue poses a limitation to performing endothelial keratoplasty in many parts of the world. Cell therapy is a potential alternative strategy to keratoplasty and is currently under investigation. Considering that corneas with FECD may contain relatively healthy endothelial cells, samples obtained by descemetorhexis of eyes undergoing EK for FECD can be used for ex vivo expansion of endothelial cells as an autologous cell culture. In this study, we established corneal endothelial cell cultures derived from 40 patients that underwent endothelial keratoplasty for advanced FECD. Several parameters were evaluated including patient characteristics such as age, gender, and endothelial cell density as well as various processing and cell culture protocols based on different combinations of shipping temperatures, stabilization periods and treatment methods for corneal endothelial cell dissociation. FECD cultures were classified into three groups as: (i) no cells, (ii) cell cultures with endothelial-like morphology or (iii) cell cultures with fibroblast-like features. Our data seem to suggest that some factors can influence FECD cell culture characteristics including young age, high paracentral endothelial cell density, low shipping temperature and short stabilization period prior to cell isolation. Treatment with type 1 collagenase for cell isolation can delay endothelial-to-mesenchymal transition, but does not increase proliferative capacity. Although heterologous corneal endothelial cultures from healthy donors have shown encouraging outcomes, the feasibility of autologous cell therapy as a potential treatment for FECD remains challenging. Low initial cell concentration as well as endothelial to mesenchymal transition are the main obstacles to the application of FECD cultures in the clinical setting.

Update on the Surgical Management of Fuchs Endothelial Corneal Dystrophy

Fuchs endothelial corneal dystrophy (FECD) is the most common posterior corneal dystrophy and the leading indication for corneal transplantation in the United States. FECD is slowly progressive, and patients develop gradual corneal endothelial decompensation, eventually resulting in failure of the endothelium to maintain corneal deturgescence. Medical management consists of topical hyperosmotic agents to facilitate dehydration of the cornea, but surgical intervention is often required to regain corneal clarity. The surgical management of FECD has evolved over the past two decades as corneal transplantation techniques have allowed for more selective keratoplasty and replacement of only the diseased layers of the cornea. Prior surgical management consisted of penetrating keratoplasty (PK) that carried significant intraoperative risks associated with "open sky" as well as postoperative risks of graft rejection, wound dehiscence, postoperative astigmatism, and prolonged visual rehabilitation. In the past 15 years, endothelial keratoplasty (EK) has become the treatment of choice for endothelial disease, significantly reducing the risks associated with the surgical treatment of FECD. Here we discuss the current surgical management of FECD, including the introduction of Descemet stripping only (DSO), and highlight future investigative efforts.

Clinical and genetic investigation of amantadine-associated corneal edema

PURPOSE

Amantadine use has been temporally associated with bilateral corneal edema in a series of cases; however, its pathophysiological mechanisms have yet to be elucidated. We sought to rule out subclinical Fuchs dystrophy as a contributor, characterize its pattern of corneal edema, and describe the long-term outcome of concurrent topical steroids while resuming amantadine.

PATIENT AND METHODS

After a 44-year-old woman presented with new acute onset bilateral corneal edema, amantadine was discontinued, with clinical improvement. However, neurological decompensation required restarting amantadine, which she did concurrently with topical loteprednol. To determine whether subclinical Fuchs dystrophy might be present, triplet-primed polymerase chain reaction was conducted to measure copy number of the CTG18.1 trinucleotide repeat in TCF4. Specular microscopy and Scheimpflug imaging were conducted and followed for 32 months to assess for resolution and stability. Literature review was conducted to assess for consistency of the clinical phenotype.

RESULTS

Corneal edema resolved clinically 4 weeks after discontinuation of amantadine. Serial Scheimpflug imaging demonstrated resolution of posterior and central corneal edema and specular microscopy revealed intracellular opacities with loss of endothelial cell density. Despite resuming amantadine, Scheimpflug imaging and specular microscopy measurements remained stable at 32 months. Triplet-primed PCR of CTG18.1 in TCF4 revealed no trinucleotide repeat expansion.

CONCLUSIONS

Amantadine-associated corneal edema is characteristically posterior and central and appears unlikely to represent early or subclinical decompensation of Fuchs dystrophy. We describe the unique outcome of continued corneal clearance after restarting amantadine concurrently with steroids, a pattern that has persisted over 32 months to date.

A review of the evidence for in vivo corneal endothelial regeneration

Human corneal endothelium has long been thought to be a nonmitotic cell layer with no endogenous reparative potential. Pathologies that damage endothelial function result in corneal decompensation and, if untreated, blindness. The mainstay of treatment involves partial or complete corneal replacement, amounting to 40% of all corneal transplants performed worldwide. We summarize the case reports describing complications postoperatively in the form of (sub)total graft detachment and those resulting in postoperative bare stroma. Complications during cataract and glaucoma surgeries leading to an uncovered posterior cornea are also included. We discuss the newer treatment strategies that are alternatives for current Descemet membrane endothelial keratoplasty and Descemet stripping automated endothelial keratoplasty, including partial grafts and stripping of the diseased cell layer. In more than half of the cases reviewed, corneal transparency returned despite incomplete or no corneal endothelial cell transplantation. We question the existing paradigm concerning corneal endothelial wound healing in vivo. The data support further clinical study to determine the safety of simple descemethorexis in central endothelial pathologies, such as Fuchs endothelial corneal dystrophy, where presence of healthy peripheral cells may allow successful corneal recompensation without the need for donor cells.

Combined Cataract/DSEK/DMEK: Changing Expectations

Endothelial keratoplasty (EK) has revolutionized corneal transplant surgery by providing rapid visual recovery and improved visual outcomes. In parts of the world with Fuchs endothelial dystrophy, many patients may present with both cataracts and corneal degeneration requiring surgery. Other forms of endothelial decompensation may also present with cataracts. The staging or combination of transplant surgery and cataract surgery depend on both the abilities of the surgeon and the surgical techniques being considered. We currently use phacoemulsification to remove cataracts and routinely perform both cataract surgery and EK with topical anesthesia. The decision to perform either combined or staged cataract and transplant surgery depends upon the examination of the eye including assessment of the anterior chamber depth and the status of the anterior surface of the cornea, which affects the ability to reliably assess keratometry. Additional considerations include the type of lens implant to use, the desired refractive outcome, and the patient's preference about whether to undergo 1 or 2 surgical procedures per eye.

In Vitro Topographical Model of Fuchs Dystrophy for Evaluation of Corneal Endothelial Cell Monolayer Formation

A common indication for corneal transplantation, which is the most transplanted tissue, is a dysfunctional corneal endothelium due to Fuchs' endothelial dystrophy (FED). FED is diagnosed by the presence of in vivo pathological microtopography on the Descemet membrane, which is called corneal guttata. Minimally invasive corneal endothelial cell regenerative procedures such as endothelial cell injection therapy and Rho kinase inhibitor pharmacotherapy have been proposed as alternatives to conventional corneal transplantation for FED patients. However, the effect of guttata on monolayer reformation following such therapies is unknown and there is no equivalent in vitro or animal model to study monolayer reformation. Using a synthetic guttata FED disease model, the formation of the monolayer is investigated to evaluate the efficacy of both therapies. Results obtained suggest that guttata dimensions, density, and spacing greatly affect the fate of corneal endothelial cells in terms of migratory behavior and monolayer reformation. Densely packed synthetic guttata mimicking late-stage FED hinders monolayer reformation, while synthetic guttata of lower height and density show improved monolayer formation. These results suggest that severity of the FED, as determined by height and density of existing guttata, can potentially attenuate corneal endothelial monolayer formation of corneal cell injection therapy and pharmacotherapy.

Initial experience with Descemet stripping automated endothelial keratoplasty in Saudi Arabia

Purpose:

To analyze the visual results of Descemet stripping automated endothelial keratoplasty (DSAEK) in the first consecutive 10 cases.

Materials and Methods:

Retrospective, non-randomized, non-comparative interventional case series. Ten eyes of 10 patients with endothelial dysfunctions of different etiology, scheduled for DSEAK, were included in this study. Indications, operative problems, and postoperative complications were noted. Best-corrected visual acuity, refractive and keratometric astigmatism, and central corneal thickness were analyzed for each patient after a minimum follow-up of 10 months.

Results:

In a median follow-up of 12 months (range 10–16 months), visual outcomes were satisfactory. Preoperative diagnosis included five eyes of psuedophakic bullous keratopathy and two eyes of repeated failed corneal grafts and one bullous keratopathy secondary to anterior chamber phakic IOL implantation. Two eyes with Fuchs dystrophy and cataract had combined DSAEK and phacoemulsification and IOL implantation. One patient had known glaucomatous optic nerve precluding vision better than 20/150. Of the remaining nine patients, four eyes had BSCVA of 20/40 or better by postoperative 6 months (3 by 3 months). The average pachymetry was 646.9 μm. One patient had total graft dislocation and one needed trabeculectomy. None of the patients developed graft rejection or graft failure. None of patients needed to convert to penetrating keratoplasty.

Conclusion:

DSAEK is safe and effective procedure in patients with endothelial dysfunctions with encouraging surgical and visual outcomes.