Outcomes and Complications of Limbal Stem Cell Allograft Transplantation: A Report by the American Academy of Ophthalmology.

PURPOSE: To review the published literature on the safety and outcomes of keratolimbal allograft (KLAL) transplantation and living-related conjunctival limbal allograft (lr-CLAL) transplantation for bilateral severe/total limbal stem cell deficiency (LSCD). METHODS: Literature searches were last conducted in the PubMed database in February 2023 and were limited to the English language. They yielded 523 citations; 76 were reviewed in full text, and 21 met the inclusion criteria. Two studies were rated level II, and the remaining 19 studies were rated level III. There were no level I studies. RESULTS: After KLAL surgery, best-corrected visual acuity (BCVA) improved in 42% to 92% of eyes at final follow-up (range, 12-95 months). The BCVA was unchanged in 17% to 39% of eyes and decreased in 8% to 29% of eyes. Two of 14 studies that evaluated the results of KLAL reported a notable decline in visual acuity over time postoperatively. Survival of KLAL was variable, ranging from 21% to 90% at last follow-up (range, 12-95 months) and decreased over time. For patients undergoing lr-CLAL surgery, BCVA improved in 31% to 100% of eyes at final follow-up (range, 16-49 months). Of the 9 studies evaluating lr-CLAL, 4 reported BCVA unchanged in 30% to 39% of patients, and 3 reported a decline in BCVA in 8% to 10% of patients. The survival rate of lr-CLAL ranged from 50% to 100% at final follow-up (range, 16-49 months). The most common complications were postoperative elevation of intraocular pressure, persistent epithelial defects, and acute allograft immune rejections. CONCLUSIONS: Given limited options for patients with bilateral LSCD, both KLAL and lr-CLAL are viable choices that may provide improvement of vision and ocular surface findings. The studies trend toward a lower rejection rate and graft failure with lr-CLAL. However, the level and duration of immunosuppression vary widely between the studies and may impact allograft rejections and long-term graft survival. Complications related to immunosuppression are minimal. Repeat surgery may be needed to maintain a viable ocular surface. Reasonable long-term success can be achieved with both KLAL and lr-CLAL with appropriate systemic immunosuppression. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Rat Model of Type 2 Diabetes Mellitus Recapitulates Human Disease in the Anterior Segment of the Eye.

Changes in the anterior segment of the eye due to type 2 diabetes mellitus (T2DM) are not well-characterized, in part due to the lack of a reliable animal model. This study evaluates changes in the anterior segment, including crystalline lens health, corneal endothelial cell density, aqueous humor metabolites, and ciliary body vasculature, in a rat model of T2DM compared with human eyes. Male Sprague-Dawley rats were fed a high-fat diet (45% fat) or normal diet, and rats fed the high-fat diet were injected with streptozotocin i.p. to generate a model of T2DM. Cataract formation and corneal endothelial cell density were assessed using microscopic analysis. Diabetes-related rat aqueous humor alterations were assessed using metabolomics screening. Transmission electron microscopy was used to assess qualitative ultrastructural changes ciliary process microvessels at the site of aqueous formation in the eyes of diabetic rats and humans. Eyes from the diabetic rats demonstrated cataracts, lower corneal endothelial cell densities, altered aqueous metabolites, and ciliary body ultrastructural changes, including vascular endothelial cell activation, pericyte degeneration, perivascular edema, and basement membrane reduplication. These findings recapitulated diabetic changes in human eyes. These results support the use of this model for studying ocular manifestations of T2DM and support a hypothesis postulating blood-aqueous barrier breakdown and vascular leakage at the ciliary body as a mechanism for diabetic anterior segment pathology.

Squishy matters - Corneal mechanobiology in health and disease.

The cornea, as a dynamic and responsive tissue, constantly interacts with mechanical forces in order to maintain its structural integrity, barrier function, transparency and refractive power. Cells within the cornea sense and respond to various mechanical forces that fundamentally regulate their morphology and fate in development, homeostasis and pathophysiology. Corneal cells also dynamically regulate their extracellular matrix (ECM) with ensuing cell-ECM crosstalk as the matrix serves as a dynamic signaling reservoir providing biophysical and biochemical cues to corneal cells. Here we provide an overview of mechanotransduction signaling pathways then delve into the recent advances in corneal mechanobiology, focusing on the interplay between mechanical forces and responses of the corneal epithelial, stromal, and endothelial cells. We also identify species-specific differences in corneal biomechanics and mechanotransduction to facilitate identification of optimal animal models to study corneal wound healing, disease, and novel therapeutic interventions. Finally, we identify key knowledge gaps and therapeutic opportunities in corneal mechanobiology that are pressing for the research community to address especially pertinent within the domains of limbal stem cell deficiency, keratoconus and Fuchs' endothelial corneal dystrophy. By furthering our understanding corneal mechanobiology, we can contextualize discoveries regarding corneal diseases as well as innovative treatments for them.

Advanced Corneal Imaging in Keratoconus: A Report by the American Academy of Ophthalmology.

PURPOSE: To review the published literature on the diagnostic capabilities of the newest generation of corneal imaging devices for the identification of keratoconus. METHODS: Corneal imaging devices studied included tomographic platforms (Scheimpflug photography, OCT) and functional biomechanical devices (imaging an air impulse on the cornea). A literature search in the PubMed database for English language studies was last conducted in February 2023. The search yielded 469 citations, which were reviewed in abstract form. Of these, 147 were relevant to the assessment objectives and underwent full-text review. Forty-five articles met the criteria for inclusion and were assigned a level of evidence rating by the panel methodologist. Twenty-six articles were rated level II, and 19 articles were rated level III. There were no level I evidence studies of corneal imaging for the diagnosis of keratoconus found in the literature. To provide a common cross-study outcome measure, diagnostic sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were extracted. (A perfect diagnostic test that identifies all cases properly has an AUC of 1.0.) RESULTS: For the detection of keratoconus, sensitivities for all devices and parameters (e.g., anterior or posterior corneal curvature, corneal thickness) ranged from 65% to 100%. The majority of studies and parameters had sensitivities greater than 90%. The AUCs ranged from 0.82 to 1.00, with the majority greater than 0.90. Combined indices that integrated multiple parameters had an AUC in the mid-0.90 range. Keratoconus suspect detection performance was lower with AUCs ranging from 0.66 to 0.99, but most devices and parameters had sensitivities less than 90%. CONCLUSIONS: Modern corneal imaging devices provide improved characterization of the cornea and are accurate in detecting keratoconus with high AUCs ranging from 0.82 to 1.00. The detection of keratoconus suspects is less accurate with AUCs ranging from 0.66 to 0.99. Parameters based on single anatomic locations had a wide range of AUCs. Studies with combined indices using more data and parameters consistently reported high AUCs. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Risk Factors for Fibrous Ingrowth in Eyes Requiring Primary Keratoplasty.

PURPOSE: The aim of this study was to define risks for corneal transplantation associated with fibrous ingrowth among first-time transplant recipients. METHODS: We performed a retrospective case-control study of patients with a histopathologic diagnosis of fibrous ingrowth between 2002 and 2019. Patients with fibrous ingrowth from a first corneal specimen were included. Those with incomplete records were excluded. A 1:2 case-control ratio was used. Controls were matched using surgical indication, surgery year, transplantation method, sex, and age. RESULTS: Seventy-eight eyes (76 patients) were included and matched with 160 control eyes. The incidence of fibrous ingrowth found on a first corneal transplant was 0.6% per year. The most common keratoplasty indications were pseudophakic corneal edema (n = 25, 32%) and aphakic corneal edema (n = 15, 19%). Cases were more likely to have a history of ocular trauma (odds ratio [OR], 2.94; 95% CI, 1.30-6.30; P = 0.007), uveitis (OR, 2.73; 95% CI, 1.12-6.63; P = 0.022), retinal detachment or previous retinal surgery (OR, 2.40; 95% CI, 1.34-4.30; P = 0.003), glaucoma tube-shunt surgery (OR, 2.70; 95% CI, 1.29-5.65; P = 0.007), aphakia (OR, 3.02; 95% CI, 1.61-5.67; P = 0.0004), or iris derangement (OR, 10.52; 95% CI, 5.45-20.30; P <0.0001). A multivariate logistic regression model using iris derangement, history of ocular trauma, history of uveitis, and history of cataract surgery demonstrated 81% sensitivity and 66% specificity in predicting presence of fibrous ingrowth. CONCLUSIONS: A history of ocular trauma, uveitis, retinal detachment or previous retinal surgery, glaucoma tube-shunt surgery, aphakia, and iris derangement are risks for detecting fibrous ingrowth among first-time keratoplasty recipients. Patients with these conditions should be monitored closely for corneal decompensation.

Type II Diabetes Mellitus Causes Extracellular Matrix Alterations in the Posterior Cornea That Increase Graft Thickness and Rigidity.

Purpose: There is a pressing need to investigate the impact of type II diabetes mellitus on the posterior cornea in donor tissues given its increasing prevalence and potential impact on endothelial keratoplasty surgical outcomes. Methods: Immortalized human cultured corneal endothelial cells (CECs; HCEC-B4G12) were grown in hyperglycemic media for 2 weeks. Extracellular matrix (ECM) adhesive glycoprotein expression and advanced glycation end products (AGEs) in cultured cells and corneoscleral donor tissues, as well as the elastic modulus for the Descemet membrane (DMs) and CECs of diabetic and nondiabetic donor corneas, were measured. Results: In CEC cultures, increasing hyperglycemia resulted in increased transforming growth factor beta-induced (TGFBI) protein expression and colocalization with AGEs in the ECM. In donor corneas, the thicknesses of the DM and the interfacial matrix (IFM) between the DM and stroma both increased from 8.42 ± 1.35 µm and 0.504 ± 0.13 µm in normal corneas, respectively, to 11.13 ± 2.91 µm (DM) and 0.681 ± 0.24 µm (IFM) in non-advanced diabetes (P = 0.013 and P = 0.075, respectively) and 11.31 ± 1.76 µm (DM) and 0.744 ± 0.18 µm (IFM) in advanced diabetes (AD; P = 0.0002 and P = 0.003, respectively). Immunofluorescence in AD tissues versus controls showed increased AGEs (P < 0.001) and markedly increased labeling intensity for adhesive glycoproteins, including TGFBI, that colocalized with AGEs. The elastic modulus significantly increased between AD and control tissues for the DMs (P < 0.0001) and CECs (P < 0.0001). Conclusions: Diabetes and hyperglycemia alter human CEC ECM structure and composition, likely contributing to previously documented complications of endothelial keratoplasty using diabetic donor tissue, including tearing during graft preparation and reduced graft survival. AGE accumulation in the DM and IFM may be a useful biomarker for determining diabetic impact on posterior corneal tissue.

Mice Deficient in TAZ (Wwtr1) Demonstrate Clinical Features of Late-Onset Fuchs' Endothelial Corneal Dystrophy.

Purpose: We sought to define the role of Wwtr1 in murine ocular structure and function and determine the role of mechanotransduction in Fuchs' endothelial corneal dystrophy (FECD), with emphasis on interactions between corneal endothelial cells (CEnCs) and Descemet's membrane (DM). Methods: A Wwtr1 deficient mouse colony was established, and advanced ocular imaging, atomic force microscope (AFM), and histology/immunofluorescence were performed. Corneal endothelial wound healing was assessed using cryoinjury and phototherapeutic keratectomy in Wwtr1 deficient mice. Expression of WWTR1/TAZ was determined in the corneal endothelium from normal and FECD-affected patients; WWTR1 was screened for coding sequence variants in this FECD cohort. Results: Mice deficient in Wwtr1 had reduced CEnC density, abnormal CEnC morphology, softer DM, and thinner corneas versus wildtype controls by 2 months of age. Additionally, CEnCs had altered expression and localization of Na/K-ATPase and ZO-1. Further, Wwtr1 deficient mice had impaired CEnC wound healing. The WWTR1 transcript was highly expressed in healthy human CEnCs comparable to other genes implicated in FECD pathogenesis. Although WWTR1 mRNA expression was comparable between healthy and FECD-affected patients, WWTR1/TAZ protein concentrations were higher and localized to the nucleus surrounding guttae. No genetic associations were found in WWTR1 and FECD in a patient cohort compared to controls. Conclusions: There are common phenotypic abnormalities seen between Wwtr1 deficient and FECD-affected patients, suggesting that Wwtr1 deficient mice could function as a murine model of late-onset FECD. Despite the lack of a genetic association between FECD and WWTR1, aberrant WWTR1/TAZ protein subcellular localization and degradation may play critical roles in the pathogenesis of FECD.

Disease Endotypes Predict the Severity of Mucous Membrane Pemphigoid.

Mucous membrane pemphigoid is an autoimmune disease with variable clinical presentation and multiple autoantigens. To determine whether disease endotypes could be identified on the basis of the pattern of serum reactivity, the clinical and diagnostic information of 70 patients with mucous membrane pemphigoid was collected, and reactivity to dermal or epidermal antigens, using indirect immunofluorescence, and specific reactivity to bullous pemphigoid (BP) autoantigens BP180 and BP230, collagen VII, and laminin 332 were evaluated. Most patients had lesions at multiple mucosae, with the most prevalent being oropharyngeal (mouth, gingiva, pharynx; 98.6%), followed by ocular (38.6%), nasal (32.9%), genital or anal (31.4%), laryngeal (20%), and esophageal (2.9%) sites and skin (45.7%). Autoantigen profiling identified BP180 (71%) as the most common autoantigen, followed by laminin 332 (21.7%), collagen VII (13%), and BP230 IgG (11.6%). Reactivity to dermal antigens predicted a more severe disease characterized by a higher number of total sites involved, especially high-risk sites, and a decreased response to rituximab. In most cases, identification of dermal indirect immunofluorescence reactivity is an accurate predictor of disease course; however, confirmation of laminin 332 reactivity is important, with dermal indirect immunofluorescence positivity because of an increased risk of solid tumors. In addition, the ocular mucosae should be monitored in patients with IgA on direct immunofluorescence.

Metabolic and proteomic indications of diabetes progression in human aqueous humor.

Diabetes mellitus is a multiorgan systemic disease impacting numerous ocular structures that results in significant ocular morbidity and often results in more frequent corneal and glaucoma surgeries for affected individuals. We hypothesize that the systemic metabolic and proteomic derangement observed in the progression of diabetes influences the composition of the aqueous humor (AH), which ultimately impacts the anterior segment health of the eye. To identify changes associated with diabetes progression, we mapped the metabolite profile and proteome of AH samples from patients with varying severities of type II diabetes (T2DM). Patients were classified as nondiabetic (ND or control), non-insulin-dependent diabetic without advanced features of disease (NAD-ni), insulin-dependent diabetic without advanced features (NAD-i), or diabetic with advanced features (AD). AH samples collected from the anterior chamber during elective ophthalmic surgery were evaluated for metabolite and protein expression changes associated with diabetic severity via gas chromatography/mass spectrometry and ultra-high performance liquid chromatography tandem mass spectrometry, respectively. Metabolic and proteomic pathway analyses were conducted utilizing MetaboAnalyst 4.0 and Ingenuity Pathway Analysis. A total of 14 control, 12 NAD-ni, 4 NAD-I, and 14 AD samples were included for analysis. Elevated levels of several branched amino acids (e.g., valine, leucine, isoleucine), and lipid metabolites (e.g., palmitate) were found only with increasing diabetic severity (i.e., the AD group). Similar proteomic trends were noted in amino acid and fatty acid metabolism and the unfolded protein/stress response. These results represent the first report of both metabolomic and proteomic evaluation of aqueous humor. Diabetes results in metabolic and proteomic perturbations detectable in the AH, and unique changes become manifest as T2DM severity worsens. Changes in AH composition may serve as an indicator of disease severity, risk assessment of anterior segment cells and structures, and potential future therapies.

Risk factors, management, and outcomes of Acanthamoeba keratitis: A retrospective analysis of 110 cases.

PURPOSE: To evaluate the risk factors, medical and surgical management, and visual outcomes of patients affected by Acanthamoeba keratitis (AK) over a 16-year period. OBSERVATIONS: Records were reviewed retrospectively for all AK patients treated at University of Iowa between 2002 and 2017. Main outcomes measured were risk factors, time to diagnosis, coinfection types, initial and final visual acuities, and treatment outcomes, with failure of medical therapy defined as need for therapeutic keratoplasty (TK). Effects of steroid use on these outcomes were determined. Among all AK cases occurring during the study period (N = 110), the median age of the AK cohort was 31 years (range 8-80 years), and 49.1% were men. Contact lens wear was the primary risk factor for AK (95/100, 86.4%), and the median time to diagnosis was 0.70 (0.23-1.23) months. Forty-four AK patients (40%) failed medical therapy. Vision outcomes were better for AK patients with successful medical therapy compared to those requiring TK (LogMAR 0.00 v. 0.30; p < 0.0001). Corticosteroid use was associated with increased time to diagnosis (1.00 v. 0.50 months; p = 0.002), decreased final vision (LogMAR 0.10 v. 0.00; p < 0.05) and increased need for TK (40/77 v. 4/33; p < 0.001). CONCLUSIONS AND IMPORTANCE: Acanthamoeba keratitis cases have increased over the past two decades at our institution. In this large retrospective study, AK was commonly misdiagnosed with delayed diagnosis and high rates of failed medical therapy. Corticosteroid use before AK diagnosis led to poorer outcomes. Our findings underscore the need for ophthalmologists to suspect Acanthamoeba in the setting of contact lens-associated keratitis before topical steroids are initiated.

Solubilized ubiquinol for preserving corneal function.

Defective cellular metabolism, impaired mitochondrial function, and increased cell death are major problems that adversely affect donor tissues during hypothermic preservation prior to transplantation. These problems are thought to arise from accumulated reactive oxygen species (ROS) inside cells. Oxidative stress acting on the cells of organs and tissues preserved in hypothermic conditions before surgery, as is the case for cornea transplantation, is thought to be a major reason behind cell death prior to surgery and decreased graft survival after transplantation. We have recently discovered that ubiquinol - the reduced and active form of coenzyme Q10 and a powerful antioxidant - significantly enhances mitochondrial function and reduces apoptosis in human donor corneal endothelial cells. However, ubiquinol is highly lipophilic, underscoring the need for an aqueous-based formulation of this molecule. Herein, we report a highly dispersible and stable formulation comprising a complex of ubiquinol and gamma cyclodextrin (γ-CD) for use in aqueous-phase ophthalmic products. Docking studies showed that γ-CD has the strongest binding affinity with ubiquinol compared to α- or ß-CD. Complexed ubiquinol showed significantly higher stability compared to free ubiquinol in different aqueous ophthalmic products including Optisol-GS® corneal storage medium, balanced salt solution for intraocular irrigation, and topical Refresh® artificial tear eye drops. Greater ROS scavenging activity was noted in a cell model with high basal metabolism and ROS generation (A549) and in HCEC-B4G12 human corneal endothelial cells after treatment with ubiquinol/γ-CD compared to free ubiquinol. Furthermore, complexed ubiquinol was more effective at lowering ROS, and at far lower concentrations, compared to free ubiquinol. Complexed ubiquinol inhibited lipid peroxidation and protected HCEC-B4G12 cells against erastin-induced ferroptosis. No evidence of cellular toxicity was detected in HCEC-B4G12 cells after treatment with complexed ubiquinol. Using a vertical diffusion system, a topically applied inclusion complex of γ-CD and a lipophilic dye (coumarin-6) demonstrated transcorneal penetrance in porcine corneas and the capacity for the γ-CD vehicle to deliver drug to the corneal endothelium. Using the same model, topically applied ubiquinol/γ-CD complex penetrated the entire thickness of human donor corneas with markedly greater ubiquinol retention in the endothelium compared to free ubiquinol. Lastly, the penetrance of ubiquinol/γ-CD complex was assayed using human donor corneas preserved for 7 days in Optisol-GS® per standard industry practices, and demonstrated higher amounts of ubiquinol retained in the corneal endothelium compared to free ubiquinol. In summary, ubiquinol complexed with γ-CD is a highly stable composition that can be incorporated into a variety of aqueous-phase products for ophthalmic use including donor corneal storage media and topical eye drops to scavenge ROS and protect corneal endothelial cells against oxidative damage.

Cell-Matrix Interactions in the Eye: From Cornea to Choroid.

The extracellular matrix (ECM) plays a crucial role in all parts of the eye, from maintaining clarity and hydration of the cornea and vitreous to regulating angiogenesis, intraocular pressure maintenance, and vascular signaling. This review focuses on the interactions of the ECM for homeostasis of normal physiologic functions of the cornea, vitreous, retina, retinal pigment epithelium, Bruch's membrane, and choroid as well as trabecular meshwork, optic nerve, conjunctiva and tenon's layer as it relates to glaucoma. A variety of pathways and key factors related to ECM in the eye are discussed, including but not limited to those related to transforming growth factor-ß, vascular endothelial growth factor, basic-fibroblastic growth factor, connective tissue growth factor, matrix metalloproteinases (including MMP-2 and MMP-9, and MMP-14), collagen IV, fibronectin, elastin, canonical signaling, integrins, and endothelial morphogenesis consistent of cellular activation-tubulogenesis and cellular differentiation-stabilization. Alterations contributing to disease states such as wound healing, diabetes-related complications, Fuchs endothelial corneal dystrophy, angiogenesis, fibrosis, age-related macular degeneration, retinal detachment, and posteriorly inserted vitreous base are also reviewed.

Mitophagy: An Emerging Target in Ocular Pathology.

Mitochondrial function is essential for the viability of aerobic eukaryotic cells, as mitochondria provide energy through the generation of adenosine triphosphate (ATP), regulate cellular metabolism, provide redox balancing, participate in immune signaling, and can initiate apoptosis. Mitochondria are dynamic organelles that participate in a cyclical and ongoing process of regeneration and autophagy (clearance), termed mitophagy specifically for mitochondrial (macro)autophagy. An imbalance in mitochondrial function toward mitochondrial dysfunction can be catastrophic for cells and has been characterized in several common ophthalmic diseases. In this article, we review mitochondrial homeostasis in detail, focusing on the balance of mitochondrial dynamics including the processes of fission and fusion, and provide a description of the mechanisms involved in mitophagy. Furthermore, this article reviews investigations of ocular diseases with impaired mitophagy, including Fuchs endothelial corneal dystrophy, primary open-angle glaucoma, diabetic retinopathy, and age-related macular degeneration, as well as several primary mitochondrial diseases with ocular phenotypes that display impaired mitophagy, including mitochondrial encephalopathy lactic acidosis stroke, Leber hereditary optic neuropathy, and chronic progressive external ophthalmoplegia. The results of various studies using cell culture, animal, and human tissue models are presented and reflect a growing awareness of mitophagy impairment as an important feature of ophthalmic disease pathology. As this review indicates, it is imperative that mitophagy be investigated as a targetable mechanism in developing therapies for ocular diseases characterized by oxidative stress and mitochondrial dysfunction.

Optimizing Visualization of Descemet Membrane Endothelial Keratoplasty Tissue: Assessing the Impact of Trypan Blue Exposure on Stain Duration and Corneal Endothelial Cell Function.

PURPOSE: To assess how trypan blue staining affects Descemet membrane endothelial keratoplasty (DMEK) graft visibility and corneal endothelial cell (CEC) mitochondrial respiration. METHODS: DMEK grafts (n = 20) were stained with trypan blue 0.06% for 1, 3, 5, or 10 minutes. Each graft was injected into an artificial anterior chamber. Surgery was simulated with tapping and sweeping motions on the corneal surface and injections of balanced salt solution (BSS). Graft visibility was assessed at 5, 10, 20, and 30 minutes. Effects of trypan blue on mitochondrial respiration were assessed using primary CECs cultured from donor corneas (n = 43). Treatment wells exposed to trypan blue 0.06% (1, 5, or 30 minutes) and donor-matched control wells to methylene blue 1% (1 minute) or BSS (1, 5, or 30 minutes) were assayed for key respiration parameters. RESULTS: After 5 minutes of surgical manipulation, grafts stained for 5 minutes were significantly more visible than grafts stained for 1 or 3 minutes; there was no added benefit of staining for 10 minutes. After 10 minutes of surgical manipulation, grafts stained for 3 minutes were more visible than grafts stained for 1 minute, without additional benefits of staining ≥5 minutes. No visibility differences were observed after ≥20 minutes of surgical manipulation. CEC mitochondrial respiration did not change significantly following trypan blue exposure for all intervals tested compared to BSS. CONCLUSIONS: Staining DMEK grafts with trypan blue for 3 to 5 minutes optimizes visibility during surgical manipulation without mitochondrial impairment. Corneal surgeons learning DMEK will benefit from optimizing this critical step.

Indications for Wear, Visual Outcomes, and Complications of Custom Imprint 3D Scanned Scleral Contact Lens Use.

PURPOSE: To report indications for wear, visual outcomes, and complications of EyePrintPRO (EPP) scleral contact lens (SCL) use. METHODS: A retrospective review identified all patients fitted with this device between December 2013 and March 2018. Baseline demographics, wear indication, and contact lens history were determined. Habitual-corrected visual acuity was measured at baseline and follow-up. Adverse wear symptoms and signs, reprinting, and device cessation were tracked. RESULTS: Ninety-five eyes from 69 patients were followed for a median of 12.1 months (interquartile range 4.4-19.6). Indications for wear included vision improvement and/or ocular surface stabilization in the setting of irregular corneal shape (n = 68 eyes, 72%), ocular surface disease (n = 17, 18%), exposure keratopathy (n = 7, 7%), neurotrophic keratitis (n = 5, 5%), and extracorneal topographical abnormalities preventing noncustom lens fitting such as glaucoma drainage devices (n = 8, 8%). Median habitual-corrected visual acuity improved from 0.67 to 0.08 (P = 0.0003). One-third of eyes (33.1%) developed adverse wear symptoms. Fifteen of 95 eyes (16%) developed adverse wear signs. Device cessation occurred in 10 eyes (10.5%) and reprinting occurred in 14 eyes (14.7%) unrelated to prior lens wear or indication (P = 0.67 and 0.15, respectively). In eyes that previously failed SCLs (n = 56), 12 eyes required reprinting and 49 eyes continued use. CONCLUSIONS: Indications for EPP wear include irregular corneal shape, ocular surface disease, and extracorneal topographic abnormalities. Visual acuity improves with the use of EPP. Clinicians and patients should be aware of potential adverse wear symptoms/signs and device cessation that may occur with EPP use. EPP is a viable salvage therapy in eyes that previously failed SCLs.

Potential Functional Restoration of Corneal Endothelial Cells in Fuchs Endothelial Corneal Dystrophy by ROCK Inhibitor (Ripasudil).

PURPOSE: Rho-associated kinase (ROCK) inhibitors have been successfully used as a rescue strategy in eyes that failed to clear after descemetorhexis without endothelial graft for treatment of Fuchs endothelial corneal dystrophy (FECD). The functional mechanisms by which ROCK inhibitors modulate corneal endothelial cell regeneration in FECD patients have, however, not been clarified. Here, we analyzed the effect of the ROCK inhibitor ripasudil on corneal endothelial cells of FECD patients and normal donors using ex vivo tissue and in vitro cellular models. DESIGN: Experimental study: laboratory investigation. METHODS: This institutional study used endothelial cell-Descemet membrane lamellae from FECD patients (n = 450) undergoing Descemet membrane endothelial keratoplasty (FECD ex vivo model), normal research-grade donor corneas (n = 30) after scraping off central endothelial cells (ex vivo wound healing model), normal donor corneas (n = 20) without endothelial injury, and immortalized cell lines (n = 3) generated from FECD patients (FECD in vitro model). Descemet membrane lamellae were dissected into halves and incubated for 24-72 hours in storage medium with or without a single dose of 30 µM ripasudil. The effects of ripasudil on expression of genes and proteins related to endothelial cell proliferation, migration, functionality, and endothelial-to-mesenchymal transition were analyzed and complemented by functional assays on FECD cell lines. RESULTS: A single dose of ripasudil induced significant upregulation of genes and proteins related to cell cycle progression, cell-matrix adhesion and migration, as well as endothelial barrier and pump function up to 72 hours, whereas classical markers of endothelial-to-mesenchymal transition were downregulated in both FECD and normal specimens compared to unstimulated controls ex vivo. In addition to stimulation of proliferation and migration, ripasudil-induced changes in expression of functional signature genes could be also verified in FECD cell lines in vitro. CONCLUSIONS: These data support the concept that inhibition of ROCK signaling represents a potent tool in regenerative therapies in FECD patients through reactivation of cell proliferation and migration as well as restoration of endothelial pump and barrier function without inducing adverse phenotypic changes.

Ubiquinol Supplementation of Donor Tissue Enhances Corneal Endothelial Cell Mitochondrial Respiration.

PURPOSE: To determine whether ubiquinol improves mitochondrial function and cell viability in human donor corneal endothelial cells during hypothermic corneal tissue storage. METHODS: Endothelial cell Descemet membrane tissues were treated with 10 µM ubiquinol, the reduced form of the antioxidant coenzyme Q10, for 5 days in Optisol-GS storage media before assaying for mitochondrial activity using extracellular flux analysis of oxygen consumption. In addition, endothelial cell Descemet membrane tissues were analyzed for cell viability using apoptosis and necrosis assays. Control tissues from mate corneas were treated with diluent only, and comparisons were analyzed for differences. RESULTS: A total of 13 donor corneal tissues with a mean (SEM) preservation time of 11.8 days (0.4) were included for the analysis. Treatment with 10 µM ubiquinol increased spare respiratory capacity by 174% (P = 0.001), maximal respiration by 93% (P = 0.003), and proton leak by 80% (P = 0.047) compared with controls. Cells treated with ubiquinol had no significant change in cell necrosis or apoptosis. CONCLUSIONS: Preliminary testing in donor corneal tissue at specified doses indicates that ubiquinol may be a useful biocompatible additive to hypothermic corneal storage media that increases corneal endothelial cell mitochondrial function. Additional investigations are indicated to further study and optimize the dose and formulation of ubiquinol for use in preserving donor corneal tissue function during hypothermic storage.

Intraoperative fibrin formation during Descemet membrane endothelial keratoplasty.

PURPOSE: To describe Descemet membrane endothelial keratoplasty (DMEK) cases complicated by spontaneous intraoperative fibrin formation. METHODS: DMEK surgeries performed at two centers using a standardized technique were reviewed retrospectively for the occurrence of intraoperative fibrin formation. Cases were assessed for recipient medical history, donor age, best spectacle-corrected visual acuity (BSCVA), intraoperative unscrolling time, 6-month endothelial cell loss (ECL), and the course of the mate donor cornea. RESULTS: In this review of 868 cases of standardized DMEK surgery with surgical peripheral iridotomy, 32 eyes of 29 patients (3.7%) were complicated by the formation of intraoperative fibrin formation, including 3 patients that developed fibrin in both eyes. Three of the 32 grafts failed (9.4%). None of the mate corneas transplanted (n = 27) developed complications related to fibrin. The donor age ranged from 51 to 75 years and recipient age ranged from 49 to 82 years (median, 66 years). Unscrolling time ranged from 1 to 105 min (median, 15 min). Nine eyes required one rebubble procedure. No eyes had vision-limiting comorbidities, and the 6-month BSCVA was ≥20/40 in all eyes. Six-month ECL ranged from 19% to 73% (median, 44%). CONCLUSIONS: We conclude that fibrin formation during DMEK surgery is an uncommon but important complication that can make graft manipulation more difficult, and may have deleterious effects on endothelial cell density and graft survival.

Transcorneal Cryotherapy and Descemet Membrane Endothelial Keratoplasty to Treat Epithelial Downgrowth and Corneal Decompensation After Cataract Surgery.

PURPOSE: Epithelial downgrowth is a vision-threatening complication of intraocular surgery or penetrating ocular trauma, and although various therapeutic interventions have been performed to treat this disease, success has been limited. We present a case of corneal decompensation secondary to epithelial downgrowth after uncomplicated clear corneal cataract surgery in the left eye, treated successfully with sequential transcorneal cryotherapy to destroy epithelial cell nests followed by Descemet membrane endothelial keratoplasty (DMEK) to restore corneal clarity and vision. METHODS: We applied a transcorneal cryotherapy probe using a double freeze-thaw technique at -80°C to the entire cornea, with care taken to spare the limbus except at the superior temporal quadrant overlying the clear corneal incision where treatment was applied intentionally. The same procedure was performed 2 weeks later to ensure complete ablation of epithelial nest cells. Uncomplicated DMEK surgery using standard technique was performed 1 week later to restore corneal clarity. RESULTS: Visual acuity at presentation was 20/40. Endothelial cell densities were 2138 cells/mm (22% loss) and 1720 cells/mm (37% loss) at 3- and 12-months after DMEK, respectively. Two years after surgery, the best-corrected visual acuity remained 20/20 and the patient had no evidence of recurrence or limbal stem cell deficiency. CONCLUSIONS: The use of sequential cryotherapy as a targeted intervention to destroy invasive corneal epithelial cells followed by staged DMEK surgery to replace damaged corneal endothelium was, in this case, an effective treatment for endothelial decompensation secondary to epithelial downgrowth and may be a potential alternative for the management of this disease.