Marmamula S, Mitchell W, Zebardast N, Locascio J, Barrenkala NR, Kumbham TR, Modepalli SB, Khanna RC, Friedman DS. Impact of Vision Loss on Visual Function Among Elderly Residents in the "Home for the Aged" in India: The Hyderabad Ocular Morbidity in Elderly Study. Transl Vis Sci Technol 2020;9(13):11.Abstract
Purpose: The purpose of this study was to report the association between visual impairment (VI) and self-reported visual difficulty among the elderly in residential care using the Indian Vision Functioning Questionnaire (IND-VFQ-33) psychometrically validated questionnaire. Methods: Participants aged ≥ 60 years were recruited from 41 homes in Hyderabad in South India. All participants underwent detailed eye examination and interviews. Self-reported visual function was assessed using the IND-VFQ-33 questionnaire. Factor Analysis and Item Response Theory (IRT) models were used for analysis. Multivariable regression models were used to investigate associations between derived global difficulty scores versus severity and causes of VI. Presenting visual acuity worse than 6/18 in the better eye was considered as VI. Results: In total, 867 elderly participants completed the INDVFQ-33. Two latent traits ("daily activities" and "visual symptoms") were identified on factor analysis, each with uniquely loading questions. Participants with VI reported significantly higher daily activities difficulty (6 points higher) and visual symptoms difficulty (1.7 points higher) than those without VI ( < 0.05). Those with cataract reported the highest daily activities and visual symptoms difficulty (7.6 points and 2.2 points higher, respectively, < 0.05). Greater severity of VI was associated with increased self-reported difficulty for both factors, and for all causes of VI. Conclusions: We present a psychometrically validated visual questionnaire particularly suited to older adults in residential homes. We show a significant association between cause/severity of VI and difficulty with daily activities and visual symptoms after adjusting for sociodemographic and medical factors. Translational Relevance: Understanding the impact of vision loss on visual functions in the elderly will help in planning and resource allocation for developing early intervention programs for the elderly.
Marques JP, Pires J, Simão J, Marques M, Gil JQ, Laíns I, Alves D, Nunes S, Cachulo ML, Miller JB, Vavvas DG, Miller JW, Husain D, Silva R. Validation of RetmarkerAMD as a semiautomatic grading software for AMD. Eye (Lond) 2020;34(3):600-602.
Martinez-Carrasco R, Argüeso P, Fini EM. Dynasore protects ocular surface mucosal epithelia subjected to oxidative stress by maintaining UPR and calcium homeostasis. Free Radic Biol Med 2020;160:57-66.Abstract
The mucosal epithelia of the ocular surface protect against external threats to the eye. Using a model of human stratified corneal epithelial cells with mucosal differentiation, we previously demonstrated that a small molecule inhibitor of dynamin GTPases, dynasore, prevents damage to cells and their transcellular barriers when subjected to oxidative stress. Investigating mechanisms, we now report the novel finding that dynasore acts by maintaining Ca homeostasis, thereby inhibiting the PERK branch of the unfolded protein response (UPR) that promotes cell death. Dynasore was found to protect mitochondria by preventing mitochondrial permeability transition pore opening (mPTP), but, unlike reports using other systems, this was not mediated by dynamin family member DRP1. Necrostatin-1, an inhibitor of RIPK1 and lytic forms of programmed cell death, also inhibited mPTP opening and further protected the plasma membrane barrier. Significantly, necrostatin-1 did not protect the mucosal barrier. Oxidative stress increased mRNA for sXBP1, a marker of the IRE1 branch of the UPR, and CHOP, a marker of the PERK branch. It also stimulated phosphorylation of eIF2α, the upstream regulator of CHOP, as well as an increase in intracellular Ca. Dynasore selectively inhibited the increase in PERK branch markers, and also prevented the increase intracellular Ca in response to oxidative stress. The increase in PERK branch markers were also inhibited when cells were treated with the cell permeable Ca chelator, BAPTA-AM. To our knowledge, this is the first time that dynasore has been shown to have an effect on the UPR and suggests therapeutic applications.
Mayro EL, Wang M, Elze T, Pasquale LR. The impact of artificial intelligence in the diagnosis and management of glaucoma. Eye (Lond) 2020;34(1):1-11.Abstract
Deep learning (DL) is a subset of artificial intelligence (AI), which uses multilayer neural networks modelled after the mammalian visual cortex capable of synthesizing images in ways that will transform the field of glaucoma. Autonomous DL algorithms are capable of maximizing information embedded in digital fundus photographs and ocular coherence tomographs to outperform ophthalmologists in disease detection. Other unsupervised algorithms such as principal component analysis (axis learning) and archetypal analysis (corner learning) facilitate visual field interpretation and show great promise to detect functional glaucoma progression and differentiate it from non-glaucomatous changes when compared with conventional software packages. Forecasting tools such as the Kalman filter may revolutionize glaucoma management by accounting for a host of factors to set target intraocular pressure goals that preserve vision. Activation maps generated from DL algorithms that process glaucoma data have the potential to efficiently direct our attention to critical data elements embedded in high throughput data and enhance our understanding of the glaucomatous process. It is hoped that AI will realize more accurate assessment of the copious data encountered in glaucoma management, improving our understanding of the disease, preserving vision, and serving to enhance the deep bonds that patients develop with their treating physicians.
McColgan NM, Feeley MN, Woodward AM, Guindolet D, Argüeso P. The O-GlcNAc modification promotes terminal differentiation of human corneal epithelial cells. Glycobiology 2020;30(11):872-880.Abstract
Dynamic modification of nuclear and cytoplasmic proteins with O-linked β-N-acetylglucosamine (O-GlcNAc) plays an important role in orchestrating the transcriptional activity of eukaryotic cells. Here, we report that the O-GlcNAc modification contributes to maintaining ocular surface epithelial homeostasis by promoting mucin biosynthesis and barrier function. We found that induction of human corneal epithelial cell differentiation stimulated the global transfer of O-GlcNAc to both nuclear and cytosolic proteins. Inflammatory conditions, on the other hand, were associated with a reduction in the expression of O-GlcNAc transferase at the ocular surface epithelia. Loss- and gain-of-function studies using small interfering RNA targeting O-GlcNAc transferase, or Thiamet G, a selective inhibitor of O-GlcNAc hydrolase, respectively, revealed that the presence of O-GlcNAc was necessary to promote glycocalyx barrier function. Moreover, we found that Thiamet G triggered a correlative increase in both surface expression of MUC16 and apical epithelial cell area while reducing paracellular permeability. Collectively, these results identify intracellular protein O-glycosylation as a novel pathway responsible for promoting the terminal differentiation of human corneal epithelial cells.
McKay TB, Hutcheon AEK, Guo X, Zieske JD, Karamichos D. Modeling the cornea in 3-dimensions: Current and future perspectives. Exp Eye Res 2020;197:108127.Abstract
The cornea is an avascular, transparent ocular tissue that serves as a refractive and protective structure for the eye. Over 90% of the cornea is composed of a collagenous-rich extracellular matrix within the stroma with the other 10% composed by the corneal epithelium and endothelium layers and their corresponding supporting collagen layers (e.g., Bowman's and Descemet's membranes) at the anterior and posterior cornea, respectively. Due to its prominent role in corneal structure, tissue engineering approaches to model the human cornea in vitro have focused heavily on the cellular and functional properties of the corneal stroma. In this review, we discuss model development in the context of culture dimensionality (e.g., 2-dimensional versus 3-dimensional) and expand on the optical, biomechanical, and cellular functions promoted by the culture microenvironment. We describe current methods to model the human cornea with focus on organotypic approaches, compressed collagen, bioprinting, and self-assembled stromal models. We also expand on co-culture applications with the inclusion of relevant corneal cell types, such as epithelial, stromal keratocyte or fibroblast, endothelial, and neuronal cells. Further advancements in corneal tissue model development will markedly improve our current understanding of corneal wound healing and regeneration.
McKay TB, Guo X, Hutcheon AEK, Karamichos D, Ciolino JB. Methods for Investigating Corneal Cell Interactions and Extracellular Vesicles In Vitro. Curr Protoc Cell Biol 2020;89(1):e114.Abstract
Science and medicine have become increasingly "human-centric" over the years. A growing shift away from the use of animals in basic research has led to the development of sophisticated in vitro models of various tissues utilizing human-derived cells to study physiology and disease. The human cornea has likewise been modeled in vitro using primary cells derived from corneas obtained from cadavers or post-transplantation. By utilizing a cell's intrinsic ability to maintain its tissue phenotype in a pre-designed microenvironment containing the required growth factors, physiological temperature, and humidity, tissue-engineered corneas can be grown and maintained in culture for relatively long periods of time on the scale of weeks to months. Due to its transparency and avascularity, the cornea is an optimal tissue for studies of extracellular matrix and cell-cell interactions, toxicology and permeability of drugs, and underlying mechanisms of scarring and tissue regeneration. This paper describes methods for the cultivation of corneal keratocytes, fibroblasts, epithelial, and endothelial cells for in vitro applications. We also provide detailed, step-by-step protocols for assembling and culturing 3D constructs of the corneal stroma, epithelial- and endothelial-stromal co-cultures and isolation of extracellular vesicles. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Isolating and culturing human corneal keratocytes and fibroblasts Basic Protocol 2: Isolating and culturing human corneal epithelial cells Basic Protocol 3: Isolating and culturing human corneal endothelial cells Basic Protocol 4: 3D corneal stromal construct assembly Basic Protocol 5: 3D corneal epithelial-stromal construct assembly Basic Protocol 6: 3D corneal endothelial-stromal construct assembly Basic Protocol 7: Isolating extracellular vesicles from corneal cell conditioned medium Support Protocol: Cryopreserving human corneal fibroblasts, corneal epithelial cells, and corneal endothelial cells.
McKay TB, Serjersen H, Hjortdal J, Zieske JD, Karamichos D. Characterization of Tear Immunoglobulins in a Small-Cohort of Keratoconus Patients. Sci Rep 2020;10(1):9426.Abstract
Keratoconus (KC) is classically considered a non-inflammatory condition caused by central corneal thinning that leads to astigmatism and reduced visual acuity. Previous studies have identified increased systemic levels of pro-inflammatory factors, including interleukin-6, tumor necrosis factor-α, and matrix metalloproteinase-9, suggesting that KC may have an inflammatory component in at least a subset of patients. In this study, we evaluated the levels of different immunoglobulins (light and heavy chains) based on Ig α, Ig λ, Ig κ, Ig µ, and Ig heavy chain subunits in non-KC tears (n = 7 control individuals) and KC tears (n = 7 KC patients) using tandem-liquid chromatography mass spectrometry. The most abundant Ig heavy chains detected in both control individuals and KC patients were Ig α-1 and Ig α-2 likely correlating to the higher IgA levels reported in human tears. We identified significant differences in immunoglobulin κ-chain V-II levels in KC patients compared to control individuals with no significant difference in Ig κ/Ig λ ratios or heavy chain levels. Our study supports previous findings suggesting that KC possesses a systemic component that may contribute to the KC pathology. Further studies are required to define causality and establish a role for systemic immune system-dependent factors and pro-inflammatory processes in KC development or progression.
McKay MK, Borkar DS, Sevgi DD, Susarla G, Papaliodis GN, Sobrin L. Comparison of Modified Posterior Sub-Tenon's vs. Trans-Septal Triamcinolone Injection for Non-infectious Uveitis. Ocul Immunol Inflamm 2020;:1-8.Abstract
: To compare the safety and efficacy of trans-septal vs. modified posterior sub-Tenon's (PST) corticosteroid injections for noninfectious uveitis.: Retrospective comparison of periocular triamcinolone injection by modified PST (n = 36) vs. traditional trans-septal (n = 79) techniques. Safety and efficacy outcomes were analyzed with regression models.: There was no significant difference in visual acuity improvement between the groups at 6 months. There were higher rates of vitritis resolution in the modified PST group but this was not statistically significant (85.7% vs 62.9%, = .07). Intraocular pressure (IOP) elevation rate trended higher with the modified PST injection (21.9% vs 9.0%, = .06), with no instances of glaucoma surgery in either group. Two modified PST injection patients with refractory IOP rises had IOP normalization after corticosteroid depot removal. One year cataract surgery rates were similar.: Modified PST injection offers clinical efficacy but with possibly higher IOP response rate which could be managed with corticosteroid removal.
McKay TB, Schlötzer-Schrehardt U, Pal-Ghosh S, Stepp MA. Integrin: Basement membrane adhesion by corneal epithelial and endothelial cells. Exp Eye Res 2020;:108138.Abstract
Integrins mediate adhesion of cells to substrates and maintain tissue integrity by facilitating mechanotransduction between cells, the extracellular matrix, and gene expression in the nucleus. Changes in integrin expression in corneal epithelial cells and corneal endothelial cells impacts their adhesion to the epithelial basement membrane (EpBM) and Descemet's membrane, respectively. Integrins also play roles in assembly of basement membranes by both activating TGFβ1 and other growth factors. Over the past two decades, this knowledge has been translated into methods to grow corneal epithelial and endothelial cells in vitro for transplantation in the clinic thereby transforming clinical practice and quality of life for patients. Current knowledge on the expression and function of the integrins that mediate adhesion to the basement membrane expressed by corneal epithelial and endothelial cells in health and disease is summarized. This is the first review to discuss similarities and differences in the integrins expressed by both cell types.
McKay TB, Hutcheon AEK, Zieske JD. Biology of corneal fibrosis: soluble mediators, integrins, and extracellular vesicles. Eye (Lond) 2020;34(2):271-278.Abstract
Corneal fibrosis develops in response to injury, infection, postsurgical complications, or underlying systemic disease that disrupts the homeostasis of the tissue leading to irregular extracellular matrix deposition within the stroma. The mechanisms that regulate corneal scarring are focused heavily on the canonical transforming growth factor-β pathway and relevant activators, and their role in promoting myofibroblast differentiation. In this paper, we discuss the biochemical pathways involved in corneal fibrosis in the context of different injury models-epithelial debridement, superficial keratectomy, and penetrating incision. We elaborate on the interplay of the major pro-fibrotic factors involved in corneal scar development (e.g., transforming growth factor-β1, thrombospondin-1, and ανβ6), and explore a novel role for extracellular vesicles secreted by the wounded epithelium and the importance of the basement membrane.
Mehta MC, Narayanan R, Thomas Aretz H, Khanna R, Rao GN. The L V Prasad Eye Institute: A comprehensive case study of excellent and equitable eye care. Healthc (Amst) 2020;:100408.Abstract
Global healthcare delivery systems are facing ever-increasing challenges on multiple fronts. The need to study and define successful models of care delivery systems has become increasingly important. The L V Prasad Eye Institute (LVPEI) has a distinctive eye care delivery system offering rich lessons at many operational levels. The system has been developed on the basis of LVPEI's foundational public eye health study, and follows a complexity-driven (dependent on disease complexity) clinical care system forming a five-tier pyramidal model - at the apex is the quaternary care centre at Hyderabad, followed by increasing numbers of tertiary, secondary or community, primary, and rural eye care centres, where the revenue from paying patients covers free-care via an economic cross-subsidy. This has achieved a level of scale, efficiency, social impact, and clinical and scientific innovation rarely seen in a single health system. Building on the foundational principles of this pyramidal care with a robust economic cross-subsidy model, LVPEI has seamlessly established successful professional, academic, and educational systems that combine innovation, scientific discovery, and the development of in-house technologies focused on improving service quality and clinical decision making. In this case study, we show that all elements of the LVPEI model are practical and may be applicable to academic medical centres in diverse healthcare settings; currently, this is being tested in Liberia, West Africa.
Mihailovic A, Varadaraj V, Ramulu PY, Friedman DS. Evaluating Goldmann Applanation Tonometry Intraocular Pressure Measurement Agreement Between Ophthalmic Technicians and Physicians. Am J Ophthalmol 2020;219:170-176.Abstract
PURPOSE: To examine IOP measurement disagreement between technicians and physicians and the impact of an educational intervention on the short and long-term disagreement in IOP measurement using Goldmann applanation tonometry. DESIGN: Prospective study designed to enhance measurement reliability. SETTING: A glaucoma clinic at a university hospital. StudyPopulation: 6 technicians and 2 physicians. INTERVENTION: An educational intervention was implemented for the technicians to improve IOP measurement agreement with physicians. MainOutcomeMeasures: Frequency of IOP measurement disagreement between physicians and technicians, defined as a difference in IOP of >2 or >3 mm Hg and assessed at baseline and immediately and 6 months postintervention. RESULTS: IOP was evaluated for a total of 529 eyes (physician measured mean IOP = 16.4 mm Hg [SD = 5.9]), 30 per technician-physician pair for each data collection period: baseline, immediately postintervention and 6 months postintervention. At baseline, physicians disagreed 17% and 7% of the time when measuring IOP using >2 and >3 mm Hg to define disagreement, respectively, whereas the average disagreement between technicians and physicians was 25% and 13%. Disagreement was greater at IOPs greater than 20 mm Hg. No significant changes were noted in the frequency of disagreement between technicians and physicians immediately or 6 months postintervention. CONCLUSIONS: Two physicians measuring the same patient in the same room disagreed by >2 mm Hg in 17% of patients' eyes, and this amount of disagreement was even higher when comparing physicians to certified technicians. An educational intervention did not improve agreement in IOP measurements between technicians and physicians. This highlights an important limitation of Goldmann tonometry.
Milman T, Jakobiec FA, Lally SE, Shields JA, Shields CL, Eagle RC. Lacrimal Gland Hamartoma (Formerly Termed Dacryoadenoma). Am J Ophthalmol 2020;217:189-197.Abstract
PURPOSE: Since the original description of "dacryadenoma" by Jakobiec and associates, the data on this unusual epibulbar lacrimal gland lesion remain sparse. The aim of this study was to characterize clinically, morphologically, and immunohistochemically this isolated epibulbar lacrimal gland lesion. DESIGN: Retrospective observational case series. METHODS: Institutional pathology records between 2000 and 2019 were searched for all cases of isolated epibulbar lacrimal gland lesions. Tissue from 3 normal lacrimal glands and 1 complex choristoma were included for comparative analysis. Clinical, histopathologic, and immunohistochemical findings were recorded. RESULTS: Four patients with isolated epibulbar lacrimal gland lesions, 2 male and 2 female, with a median age of 18 years (range, 12-57) were identified. All patients presented with recent onset of unilateral pink-to-orange, well-circumscribed subepithelial juxtaforniceal (3/4, 75%), or nasal (1/4, 25%) bulbar conjunctival nodules, which were asymptomatic (3/4, 75%) or associated with foreign body sensation (1/4, 25%). When compared with the normal lacrimal gland and complex choristoma, all isolated epibulbar lacrimal gland lesions were composed predominantly of variably dilated, branching tubular structures with pseudo-apocrine snouts, and either totally absent (2/2, 50%) or rare (2/2, 50%) ducts and rare acinar zymogen granules (3/4, 75%). CONCLUSION: Our study confirms that a subset of isolated epibulbar lacrimal gland lesions differs morphologically and immunohistochemically from normal lacrimal gland tissue and the lacrimal gland in a complex choristoma. These differences range from subtle to overt, suggesting that isolated epibulbar lacrimal gland lesions may have originated from precursor cellular elements indigenous to the conjunctiva (hamartia) and grew into disorganized lacrimal gland tissue.
Minaeva O, Sarangi S, Ledoux DM, Moncaster JA, Parsons DS, Washicosky KJ, Black CA, Weng FJ, Ericsson M, Moir RD, Tripodis Y, Clark JI, Tanzi RE, Hunter DG, Goldstein LE. In Vivo Quasi-Elastic Light Scattering Eye Scanner Detects Molecular Aging in Humans. J Gerontol A Biol Sci Med Sci 2020;75(9):e53-e62.Abstract
The absence of clinical tools to evaluate individual variation in the pace of aging represents a major impediment to understanding aging and maximizing health throughout life. The human lens is an ideal tissue for quantitative assessment of molecular aging in vivo. Long-lived proteins in lens fiber cells are expressed during fetal life, do not undergo turnover, accumulate molecular alterations throughout life, and are optically accessible in vivo. We used quasi-elastic light scattering (QLS) to measure age-dependent signals in lenses of healthy human subjects. Age-dependent QLS signal changes detected in vivo recapitulated time-dependent changes in hydrodynamic radius, protein polydispersity, and supramolecular order of human lens proteins during long-term incubation (~1 year) and in response to sustained oxidation (~2.5 months) in vitro. Our findings demonstrate that QLS analysis of human lens proteins provides a practical technique for noninvasive assessment of molecular aging in vivo.
Mitchell W, Hassall M, Henderson T. Updating the model of eye care for Aboriginal populations in remote Central Australia. Clin Exp Ophthalmol 2020;48(9):1299-1306.Abstract
Eye disease is the third-highest contributor towards health inequality for Aboriginal Australians. Understanding how the Central Australian ophthalmology service addresses complexities of remote eye care is crucial in understanding how expansion can meet current and future needs. The present study analyses findings from the MEDLINE database and Governmental reports, and descriptive information from stakeholders in Central Australia and the Australian Department of Health. We describe the current Central Australian ophthalmology model at three levels; (a) the healthcare service level (specialized primary care, local/outreach optometry and ophthalmology services, and intensive extended surgical weeks), (b) the community level (local community staff, clinics and initiatives, and eye "champions" and mutual support), and (c) the healthcare system level (federal and state government, and private funding). We conclude that building full-time specialist availability, and system-wide approaches to increase patient utilisation, will facilitate overcoming barriers of remoteness, and create enduring improvements in Central Australian eye care and health-inequality.
Mitchell W, Bhatia R, Zebardast N. Retrospective cross-sectional analysis of the changes in marijuana use in the USA, 2005-2018. BMJ Open 2020;10(7):e037905.Abstract
OBJECTIVES: Understanding trends of marijuana use in the USA throughout a period of particularly high adoption of marijuana-legalisation, and understanding demographics most at risk of use, is important in evolving healthcare policy and intervention. This study analyses the demographic-specific changes in the prevalence of marijuana use in the USA between 2005 and 2018. DESIGN, SETTING AND PARTICIPANTS: A 14-year retrospective cross-sectional analysis of the National Health and Nutrition Examination Survey database, a publicly available biennially collected national survey, weighted to represent the entire US population. A total of 35 212 adults between 18 and 69 years old participated in the seven-cycles of surveys analysed (2005-2018). PRIMARY OUTCOME MEASURED: Lifetime use, first use before 18 years old, and past-year use of marijuana. RESULTS: The majority of adults reported ever using marijuana. While the overall prevalence of lifetime marijuana use remained stable (p=0.53), past-year use increased significantly between 2005 and 2018 (p<0.001) with highest rate of past-year use among younger age groups (p<0.001), males (p<0.001) and those with income below poverty level (p<0.001). Past-year use was the most common among non-Hispanic blacks, and less common among Hispanic/Mexican populations (p<0.002). Trends in past-year use increased among all age categories, males/females, all ethnicities, those with high school education/above, and those at all income levels (p<0.01 for all). CONCLUSIONS: While lifetime marijuana use remained stable, past-year use significantly increased between 2005 and 2018. While past-year use remained the most common in younger age groups, males, non-Hispanic blacks and those with lower income; increasing trends in past-year use were significant for all age, sex, race and income categories, and for those with high school education/above. With high adoption of marijuana-legalisation laws during this period, our results suggest an associated increase in past-year marijuana use.An accurate understanding of those most at risk can help to inform decisions of healthcare policy-makers and professionals, and facilitate a safe transition of changing marijuana legalisation and use in the USA.
Miyajima T, Melangath G, Zhu S, Deshpande N, Vasanth S, Mondal B, Kumar V, Chen Y, Price MO, Price FW, Rogan EG, Zahid M, Jurkunas UV. Loss of NQO1 generates genotoxic estrogen-DNA adducts in Fuchs Endothelial Corneal Dystrophy. Free Radic Biol Med 2020;147:69-79.Abstract
Fuchs Endothelial Corneal Dystrophy (FECD) is an age-related genetically complex disease characterized by increased oxidative DNA damage and progressive degeneration of corneal endothelial cells (HCEnCs). FECD has a greater incidence and advanced phenotype in women, suggesting a possible role of hormones in the sex-driven differences seen in the disease pathogenesis. In this study, catechol estrogen (4-OHE), the byproduct of estrogen metabolism, induced genotoxic estrogen-DNA adducts formation, macromolecular DNA damage, and apoptotic cell death in HCEnCs; these findings were potentiated by menadione (MN)-mediated reactive oxygen species (ROS). Expression of NQO1, a key enzyme that neutralizes reactive estrogen metabolites, was downregulated in FECD, indicating HCEnC susceptibility to reactive estrogen metabolism in FECD. NQO1 deficiency in vitro exacerbated the estrogen-DNA adduct formation and loss of cell viability, which was rescued by the supplementation of N-acetylcysteine, a ROS scavenger. Notably, overexpression of NQO1 in HCEnCs treated with MN and 4-OHE quenched the ROS formation, thereby reducing the DNA damage and endothelial cell loss. This study signifies a pivotal role for NQO1 in mitigating the macromolecular oxidative DNA damage arising from the interplay between intracellular ROS and impaired endogenous estrogen metabolism in post-mitotic ocular tissue cells. A dysfunctional Nrf2-NQO1 axis in FECD renders HCEnCs susceptible to catechol estrogens and estrogen-DNA adducts formation. This novel study highlights the potential role of NQO1-mediated estrogen metabolite genotoxicity in explaining the higher incidence of FECD in females.
Modjtahedi BS, Jacobs DS, Fong DS. A new patient-centered approach to ocular surface discomfort. Ocul Surf 2020;18(2):196-198.
Moein H-R, Akhlaq A, Dieckmann G, Abbouda A, Pondelis N, Salem Z, Müller RT, Cruzat A, Cavalcanti BM, Jamali A, Hamrah P. Visualization of micro-neuromas by using in vivo confocal microscopy: An objective biomarker for the diagnosis of neuropathic corneal pain?. Ocul Surf 2020;Abstract
PURPOSE: The diagnosis of neuropathic corneal pain (NCP) is challenging, as it is often difficult to differentiate from conventional dry eye disease (DED). In addition to eye pain, NCP can present with similar signs and symptoms of DED. The purpose of this study is to find an objective diagnostic sign to identify patients with NCP, using in vivo confocal microscopy (IVCM). METHODS: This was a comparative, retrospective, case-control study. Patients with clinical diagnosis of NCP (n = 25), DED (n = 30), and age and sex-matched healthy controls (n = 16), who underwent corneal imaging with IVCM (HRT3/RCM) were included. Central corneal IVCM scans were analyzed by 2 masked observers for nerve density and number, presence of micro-neuromas (terminal enlargements of subbasal corneal nerve) and/or nerve beading (bead-like formation along the nerves), and dendritiform cell (DC) density. RESULTS: There was a decrease in total nerve density in both NCP (14.14 ± 1.03 mm/mm) and DED patients (12.86 ± 1.04 mm/mm), as compared to normal controls (23.90 ± 0.92 mm/mm; p < 0.001). However, total nerve density was not statistically different between NCP and DED patients (p = 0.63). Presence of nerve beading was not significantly different between patients and normal controls (p = 0.15). Interestingly, micro-neuromas were observed in all patients with NCP, while they were not present in any of the patients with DED (sensitivity and specificity of 100%). DC density was increased significantly in both NCP (71.89 ± 16.91 cells/mm) and DED patients (111.5 ± 23.86 cells/mm), as compared to normal controls (24.81 ± 4.48 cells/mm (Colloca et al., 2017) [2]; p < 0.05). However, there was no significant difference in DC density between DED and NCP patients (p = 0.31). CONCLUSION: IVCM may be used as an adjunct diagnostic tool for the diagnosis of NCP in the presence of neuropathic symptoms. Micro-neuromas may serve as a sensitive and specific biomarker for the diagnosis of NCP.