TFOS DEWS II pathophysiology report

The effects of facial mask use on ocular surface parameters and tear film cytokine profile in prolonged use

OBJECTIVE

To compare tear fluid levels of matrix metalloproteinase 9 (MMP-9) and IL-1ß cytokines between healthcare workers wearing facial masks and controls with correlations in clinical findings.

METHODS

In a prospective, controlled clinical trial tear fluid was analyzed for MMP-9 and IL-1ß levels using a commercially available test (Invitrogen; Thermo Fisher Scientific Inc. Waltham, Massachusetts, USA). Symptoms and signs of dry eye disease (DED) were evaluated using the ocular surface disease index (OSDI), noninvasive tear break-up time (NIBUT), tear meniscus height (TMH), Oxford corneal staining, meibomiography, and clinical findings of meibomian gland dysfunction (MGD).

RESULTS

In the 38 eyes of healthcare workers and 30 eyes of controls, there was no statistically significant difference between the groups in terms of age and sex (p > 0.05). The mean OSDI score, daily mask wear time, meibomiography degree, and rate of positive clinical findings of MGD were higher in group 1 than in group 2, and the mean NIBUT was higher in group 2. (p > 0.05). The mean values of IL-1ß and MMP-9 were higher in group 1 (p = 0.036 and p = 0.001, respectively). The TMH and Oxford score percentages were similar between the two groups (p > 0.05).

CONCLUSIONS

Elevated levels of IL-1ß and MMP-9 in the basal tear fluid reveal increased ocular inflammation in healthcare professionals. Lower NIBUT values with higher OSDI and meibomian gland loss scores support ocular surface disturbance depending on regular mask use.

Case report: Utilization of a scleral lens to mitigate exposure keratopathy and associated mental health decline

PURPOSE

To report a case of acute exposure keratopathy with comorbid depression and improvement of both conditions with the use of a scleral lens (SL).

OBSERVATIONS

A 72-year-old male with a past ocular history significant for extensive basal cell carcinoma (BCC) excision of the right upper and lower eyelids presented for evaluation of exposure keratitis and consideration of a SL for the right eye. Examination was notable for post-surgical irregular lid margins with lagophthalmos, trichiasis and an Oxford Grade I staining of the central exposed cornea. Medical history was notable for chronic severe depression and anxiety with suicidal ideation. Upon treatment with a SL, the patient noted ocular comfort, and reported significantly improved affect.

CONCLUSION AND IMPORTANCE

Currently, there is no peer reviewed literature reporting on the management of exposure keratopathy in the setting of comorbid affective disorders. This case highlights the improvement in quality of life for a patient with exposure keratitis and severe depression with suicidal ideation and points to the potential utilization of a SL to mitigate the risk of mental health decompensation.

NOV03 for Signs and Symptoms of Dry Eye Disease Associated With Meibomian Gland Dysfunction: The Randomized Phase 3 MOJAVE Study

PURPOSE

To evaluate the efficacy and safety of NOV03 (perfluorohexyloctane) ophthalmic drop for the treatment of signs and symptoms of dry eye disease (DED) associated with meibomian gland dysfunction (MGD).

DESIGN

Randomized, double-masked, controlled trial.

METHODS

Patients ≥18 years of age with a history of DED and signs of MGD were randomly assigned 1:1 to treatment with NOV03 or hypotonic saline (0.6%) 4 times daily for 8 weeks. The primary sign and symptom endpoints were change from baseline to week 8 in total corneal fluorescein staining (tCFS; National Eye Institute scale) and eye dryness score (0-100 visual analog scale), respectively.

RESULTS

A total of 620 patients (NOV03, n = 311; saline, n = 309) were randomized and treated. Least-squares (LS) mean change from baseline to week 8 was statistically significantly greater for NOV03 compared with saline for both tCFS (-2.3 vs -1.1; LS mean treatment difference, -1.2 [95% confidence interval -1.7 to -0.8]; P < .001) and visual analog scale dryness score (-29.4 vs -19.2; LS mean treatment difference, -10.2 [95% CI -14.4 to -6.1]; P < .001), with statistically significant between-group differences observed as early as week 2. The incidence of ocular adverse events was similar for NOV03 (12.9%) and saline (12.3%). There were no serious adverse events and no adverse events leading to treatment discontinuation.

CONCLUSIONS

In this randomized controlled trial of patients with DED associated with MGD, NOV03 significantly reduced both signs and symptoms of DED compared with hypotonic saline control. NOV03 was well tolerated, with an adverse event profile similar to that of saline.

Development and validation of a multiplex electrochemiluminescence immunoassay to evaluate dry eye disease in rat tear fluids

Dry eye disease (DED) is a challenge in ophthalmology. Rat models represent valuable tools to study the pathophysiology and to develop novel treatments. A major challenge in DED research is detecting multiple biomarkers in a low tear volume sample. Multiplex immunoassays for DED rat research are missing. We have developed a multiplex electrochemiluminescence immunoassay (ECLIA) to detect three biomarkers for DED: MMP-9, IL-17 and ICAM-1. Tears, used as matrix, were collected from six healthy Wistar rats. Assays were run based on the U-Plex Meso Scale Diagnostics (MSD) platform, by two independent operators according to the EMA guideline on bioanalytical method validation. Linear mixed, regression models were fit to perform the statistical analysis on the range of concentrations for the chosen analytes. During optimization, it has observed that incubation time, temperature and agitation affected the robustness of the protocol. ECLIA optimum conditions include the use of antibodies at 0.5 µg/ml concentration and 1 h incubation at room temperature with shaking. Precision met the acceptance criteria in the chosen range: 1062-133 pg/ml for ICAM-1, 275-34.4 pg/ml for IL-17, 1750-219 pg/ml for MMP-9. Accuracy and linearity were acceptable for a broader range. This is the first report of a validated ECLIA that allows measurements of three relevant DED biomarkers in rat tear fluids.

Exploring the Cutting Edge of Vision Science: New Developments in Diagnostics and Treatment of Ocular Surface in Dry Eye Disease

The ocular surface refers to the outermost layer of the eye, which includes the cornea, conjunctiva and eyelids [...].

Impact of Exposomes on Ocular Surface Diseases

Ocular surface diseases (OSDs) are significant causes of ocular morbidity, and are often associated with chronic inflammation, redness, irritation, discomfort, and pain. In severe OSDs, loss of vision can result from ocular surface failure, characterised by limbal stem cell deficiencies, corneal vascularisation, corneal opacification, and surface keratinisation. External and internal exposomes are measures of environmental factors that individuals are exposed to, and have been increasingly studied for their impact on ocular surface diseases. External exposomes consist of external environmental factors such as dust, pollution, and stress; internal exposomes consist of the surface microbiome, gut microflora, and oxidative stress. Concerning internal exposomes, alterations in the commensal ocular surface microbiome of patients with OSDs are increasingly reported due to advancements in metagenomics using next-generation sequencing. Changes in the microbiome may be a consequence of the underlying disease processes or may have a role in the pathogenesis of OSDs. Understanding the changes in the ocular surface microbiome and the impact of various other exposomes may also help to establish the causative factors underlying ocular surface inflammation and scarring, the hallmarks of OSDs. This review provides a summary of the current evidence on exposomes in various OSDs.

Inflammation of Dry Eye Syndrome: A Cellular Study of the Epithelial and Macrophagic Involvement of NFAT5 and RAGE

Dry eye inflammation is a key step in a vicious circle and needs to be better understood in order to break it. The goals of this work were to, first, characterize alarmins and cytokines released by ocular surface cells in the hyperosmolar context and, second, study the role of NFAT5 in this process. Finally, we studied the potential action of these alarmins in ocular surface epithelial cells and macrophages via RAGE pathways. HCE and WKD cell lines were cultured in a NaCl-hyperosmolar medium and the expression of alarmins (S100A4, S100A8, S100A9, and HMGB1), cytokines (IL6, IL8, TNFα, and MCP1), and NFAT5 were assessed using RT-qPCR, ELISA and multiplex, Western blot, immunofluorescence, and luciferase assays. In selected experiments, an inhibitor of RAGE (RAP) or NFAT5 siRNAs were added before the hyperosmolar stimulations. HCE and WKD cells or macrophages were treated with recombinant proteins of alarmins (with or without RAP) and analyzed for cytokine expression and chemotaxis, respectively. Hyperosmolarity induced epithelial cell inflammation depending on cell type. NFAT5, but not RAGE or alarmins, participated in triggering epithelial inflammation. Furthermore, the release of alarmins induced macrophage migration through RAGE. These in vitro results suggest that NFAT5 and RAGE have a role in dry eye inflammation.

Relationship Between Human Meibum Lipid Composition and the Severity of Meibomian Gland Dysfunction: A Spectroscopic Analysis

Purpose

Information on the relationship between meibum lipid composition and severity of meibomian gland dysfunction (MGD) is limited. The purpose of this study was to analyze the molecular components of meibum collected from individuals with no MGD, mild-to-moderate MGD, and severe MGD.

Methods

Adults with and without MGD were enrolled in a prospective, multicenter, exploratory clinical trial (ClinicalTrials.gov Identifier: NCT01979887). Molar ratios of cholesteryl ester to wax ester (RCE/WE) and aldehyde to wax ester (Rald/WE) in meibum samples were measured with 1H-NMR spectroscopy. Results were evaluated for participants grouped by MGD disease status and severity (non-MGD, mild-to-moderate MGD, and severe MGD), as defined by maximum meibum quality scores, Schirmer test results, and Subject Ocular Symptom Questionnaire responses.

Results

Sixty-nine meibum samples from 69 individuals were included in the analysis: 24 non-MGD, 24 mild-to-moderate MGD, and 21 severe MGD. Mean RCE/WE was 0.29 in non-MGD, 0.14 in mild-to-moderate MGD (P = 0.038 vs. non-MGD, 51% lower), and 0.07 in severe MGD (P = 0.16 vs. mild-to-moderate MGD, 52% lower; P = 0.002 vs. non-MGD, 76% lower). Mean Rald/WE was 0.00022 in non-MGD, 0.00083 in mild-to-moderate MGD (P = 0.07 vs. non-MGD, 277% higher), and 0.0024 in severe MGD (P = 0.003 vs. mild-to-moderate MGD, 190% higher; P < 0.001 vs. non-MGD, 992% higher).

Conclusions

RCE/WE was lowest and Rald/WE was highest in the severe MGD cohort, suggesting that these meibum constituent molar ratios may result from the pathophysiology associated with MGD and can impact ocular surface lipid and tear film homeostasis. These findings may potentially help identify targets for MGD treatment.

TFOS Lifestyle Report: Impact of environmental conditions on the ocular surface

Environmental risk factors that have an impact on the ocular surface were reviewed and associations with age and sex, race/ethnicity, geographical area, seasonality, prevalence and possible interactions between risk factors are reviewed. Environmental factors can be (a) climate-related: temperature, humidity, wind speed, altitude, dew point, ultraviolet light, and allergen or (b) outdoor and indoor pollution: gases, particulate matter, and other sources of airborne pollutants. Temperature affects ocular surface homeostasis directly and indirectly, precipitating ocular surface diseases and/or symptoms, including trachoma. Humidity is negatively associated with dry eye disease. There is little data on wind speed and dewpoint. High altitude and ultraviolet light exposure are associated with pterygium, ocular surface degenerations and neoplastic disease. Pollution is associated with dry eye disease and conjunctivitis. Primary Sjögren syndrome is associated with exposure to chemical solvents. Living within a potential zone of active volcanic eruption is associated with eye irritation. Indoor pollution, "sick" building or house can also be associated with eye irritation. Most ocular surface conditions are multifactorial, and several environmental factors may contribute to specific diseases. A systematic review was conducted to answer the following research question: "What are the associations between outdoor environment pollution and signs or symptoms of dry eye disease in humans?" Dry eye disease is associated with air pollution (from NO2) and soil pollution (from chromium), but not from air pollution from CO or PM10. Future research should adequately account for confounders, follow up over time, and report results separately for ocular surface findings, including signs and symptoms.

1,5-Dicaffeoylquinic acid from Pseudognaphalium affine ameliorates dry eye disease via suppression of inflammation and protection of the ocular surface

PURPOSE

Pseudognaphalium affine (P. affine), a medicinal plant, has long been used to treat various diseases due to its astringent and vulnerary effects. These therapeutic benefits are largely attributed to high contents of phytochemicals, such as flavonoids and polyphenols, that have anti-inflammatory and tissue-protective activities. Herein, we investigated the potential of dicaffeoylquinic acids (diCQAs), polyphenols from P. affine, as a novel treatment for dry eye disease (DED).

METHODS

We isolated 1,5-, 3,4-, 3,5- and 4,5-diCQAs from the P. affine methanol extract, and tested the effects of diCQA isomers in cultures of human corneal epithelial cells (CECs) under desiccating hyperosmolar stress and in two mouse models for DED: desiccating environmental stress-induced DED and the NOD.B10-H2b mouse model of ocular Sjögren's syndrome.

RESULTS

Initial screening showed that, among the diCQAs, 1,5-diCQA significantly inhibited apoptosis and enhanced viability in cultures of CECs under hyperosmolar stress. Moreover, 1,5-diCQA protected CECs by promoting proliferation and downregulating inflammatory activation. Subsequent studies with two mouse models of DED revealed that topical 1,5-diCQA administration dose-dependently decreased corneal epithelial defects and increased tear production while repressing inflammatory cytokines and T cell infiltration on the ocular surface and in the lacrimal gland. 1,5-diCQA was more effective in alleviating DED, as compared with two commercially-available dry eye treatments, 0.05% cyclosporine and 0.1% sodium hyaluronate eye drops.

CONCLUSIONS

Together, our results demonstrate that 1,5-diCQA isolated from P. affine ameliorates DED through protection of corneal epithelial cells and suppression of inflammation, thus suggesting a novel DED therapeutic strategy based on natural compounds.

TFOS Lifestyle: Impact of nutrition on the ocular surface

Nutrients, required by human bodies to perform life-sustaining functions, are obtained from the diet. They are broadly classified into macronutrients (carbohydrates, lipids, and proteins), micronutrients (vitamins and minerals) and water. All nutrients serve as a source of energy, provide structural support to the body and/or regulate the chemical processes of the body. Food and drinks also consist of non-nutrients that may be beneficial (e.g., antioxidants) or harmful (e.g., dyes or preservatives added to processed foods) to the body and the ocular surface. There is also a complex interplay between systemic disorders and an individual's nutritional status. Changes in the gut microbiome may lead to alterations at the ocular surface. Poor nutrition may exacerbate select systemic conditions. Similarly, certain systemic conditions may affect the uptake, processing and distribution of nutrients by the body. These disorders may lead to deficiencies in micro- and macro-nutrients that are important in maintaining ocular surface health. Medications used to treat these conditions may also cause ocular surface changes. The prevalence of nutrition-related chronic diseases is climbing worldwide. This report sought to review the evidence supporting the impact of nutrition on the ocular surface, either directly or as a consequence of the chronic diseases that result. To address a key question, a systematic review investigated the effects of intentional food restriction on ocular surface health; of the 25 included studies, most investigated Ramadan fasting (56%), followed by bariatric surgery (16%), anorexia nervosa (16%), but none were judged to be of high quality, with no randomized-controlled trials.

Tunneling nanotubes-based intercellular mitochondrial trafficking as a novel therapeutic target in dry eye

Cell-to-cell mitochondria transfer via tunneling nanotubes (TNTs) has recently been revealed as a spontaneous way to protect damaged cells. Previously, we have reported mesenchymal stem cells (MSCs) can rescue retinal ganglion cell and corneal epithelium through intercellular mitochondrial trafficking. Mitochondrial damage and oxidative stress in corneal epithelial cells are vital in dry eye disease (DED). However, whether intercellular mitochondrial transfer is involved in the pathological and repair process of DED is currently unknown. Therefore, in this study, we designed a coculture system to evaluate the role of intercellular mitochondrial transfer between human corneal epithelial cells (CEC) in DED. In addition, we successfully discovered the ROCK inhibitor, Y-27632 as an intensifier to improve the efficiency of intercellular mitochondrial transport. As expected, the enhanced mitochondrial transfer promotes the regeneration of CECs. Moreover, through further exploration of mechanisms, it was demonstrated that F-actin-mediated cell morphological changes and cytoskeletal remodeling may be potential mechanisms for Y-27632 to induce mitochondrial metastasis. In conclusion, we established a new method for cell repair in DED that healthy CEC offered mitochondria to damaged CEC, providing a new insight into the cellular mechanism of corneal epithelium homeostatic regenerative therapeutics in DED.

Dry eye disease and blinking behaviors: A narrative review of methodologies for measuring blink dynamics and inducing blink response

Dry eye disease (DED) is a leading cause of ophthalmology clinical encounters with prevalence ranging from 8.7% to 64% in various populations. Blinking is an endogenous process to refresh the tear film, clear debris and maintain quality vision. Altered blinking behavior is a common feature of DED and is implicated in the pathology of the disease. However, lack of a comprehensive review on the relationship between altered blinking behavior and DED is notable in the literature. Blinking behavior may be an effect of DED due to an unstable tear film sensitizing a motor response or be its cause due to destabilization of the tear film in conditions such as benign essential blepharospasm. In this comprehensive review, we summarize the current models and theories of tear film dynamics and blinking behavior to better understand their connection to DED and introduce contemporary technologies and measurement tools used in the evaluation and induction of blinking behavior. We also describe future directions of research to better understand the relationship between DED and blinking and explore therapies that address the abnormal blinking component of DED.

TFOS Lifestyle: Impact of cosmetics on the ocular surface

In this report the use of eye cosmetic products and procedures and how this represents a lifestyle challenge that may exacerbate or promote the development of ocular surface and adnexal disease is discussed. Multiple aspects of eye cosmetics are addressed, including their history and market value, psychological and social impacts, possible problems associated with cosmetic ingredients, products, and procedures, and regulations for eye cosmetic use. In addition, a systematic review that critically appraises randomized controlled trial evidence concerning the ocular effects of eyelash growth products is included. The findings of this systematic review highlight the evidence gaps and indicate future directions for research to focus on ocular surface outcomes associated with eyelash growth products.

Proteomic analysis of tears in dry eye disease: A prospective, double-blind multicenter study

PURPOSE

To identify specific dry eye disease (DED) tear biomarker(s) using tear proteomic analysis, clinical parameters, and their correlations before and after DED treatment.

METHODS

A prospective, double-blinded, national multicenter clinical study was performed using data from 80 DED patients. The patients were treated with 0.1% cyclosporine (CsA, n = 28), 0.05% CsA (n = 26), or 3% diquafosol (DQS, n = 26) eye drops, and tear proteome changes and clinical outcomes (tear break-up time [TBUT], corneal erosion [Cor-Er], conjunctival erosion [Conj-Er], and symptom assessment in dry eye [SANDE] scores) were observed at 4, 8, and 12 weeks. For all clinical parameters, correlation analysis was performed between the three drug conditions and the differentially expressed proteins (DEPs) from the proteomic analysis.

RESULTS

AFM, ALCAM, CFB, H1-4, PON1, RAP1B, and RBP4 were identified in all treatment groups and were downregulated after treatment. All clinical parameters significantly improved at 12 weeks than at baseline (p-value <0.0001); however, their values were not significantly different among groups, except for Cor-Er (p-value = 0.007). Compared with the DQS group, Cor-Er score significantly improved after treatment with 0.1% and 0.05% CsA. The seven DEPs identified in all groups were not consistently correlated with the clinical parameters (p-value >0.05).

CONCLUSIONS

Despite differences in drug concentration and action mechanisms, the improvement levels of TBUT, Cor-Er, and SANDE scores were clinically adequate. However, useful tear protein biomarkers, clinically acceptable biomarker combinations correlating with clinical parameters, and clinically acceptable levels of specificity and sensitivity were not identified.

Intraobserver Repeatability Assessment of the S390L Firefly WDR Slitlamp in Patients With Dry Eye Disease: Objective, Automated, and Noninvasive Measures

OBJECTIVES

To assess the intraobserver repeatability of automated, objective, and noninvasive measures obtained with the S390L Firefly WDR slitlamp.

METHODS

This cross-sectional study included 50 eyes of patients with dry eye disease with a mean age of 55.06±12.96 years. Three consecutively repeated measures of the following variables were obtained: first noninvasive break-up time (F-NIBUT), average noninvasive break-up time (A-NIBUT), tear meniscus height, tear meniscus area (TMA), nasal ciliary hyperemia (NCIH), temporal ciliary hyperemia (TCIH), nasal conjunctival hyperemia (NCOH), temporal conjunctival hyperemia (TCOH), upper loss area meibomian gland (U-LAMG), lower loss area meibomian gland (L-LAMG), upper meibomian gland dysfunction grade (U-MGD grade), and lower meibomian gland dysfunction grade (L-MGD grade). Intraobserver repeatability was estimated with coefficient of variation (CoV), intrasubject standard deviation (SD) (S w ), and Bland-Altman plots.

RESULTS

All variables showed no statistically significant differences in the repeated-measures analysis except for L-MGD grade ( P =0.045). F-NIBUT and A-NIBUT obtained the highest CoV with an average value of 0.48±0.41 [0.02-1.00] and 0.34±0.25 [0.02-1.00], respectively. The remaining variables showed CoVs between 0.04±0.11 [0.00-0.43] and 0.18±0.16 [0.00-0.75]. A-NIBUT, TMA, NCOH, and L-LAMG obtained an S w of 2.78s, 0.21 mm 2 , <0.001, and 4.11%, respectively. Bland-Altman plots showed a high level of agreement between pairs of repeated measures.

CONCLUSION

The S390L Firefly WDR slitlamp has moderate intraobserver repeatability for F-NIBUT and A-NIBUT, which suggests that F-NIBUT and A-NIBUT are tests with high variability. The remaining variables show satisfactory intraobserver repeatability.

NLRP3 Inflammasome as a Potential Therapeutic Target in Dry Eye Disease

Dry eye disease (DED) is a multifactorial ocular surface disorder arising from numerous interrelated underlying pathologies that trigger a self-perpetuating cycle of instability, hyperosmolarity, and ocular surface damage. Associated ocular discomfort and visual disturbance contribute negatively to quality of life. Ocular surface inflammation has been increasingly recognised as playing a key role in the pathophysiology of chronic DED. Current readily available anti-inflammatory agents successfully relieve symptoms, but often without addressing the underlying pathophysiological mechanism. The NOD-like receptor protein-3 (NLRP3) inflammasome pathway has recently been implicated as a key driver of ocular surface inflammation, as reported in pre-clinical and clinical studies of DED. This review discusses the intimate relationship between DED and inflammation, highlights the involvement of the inflammasome in the development of DED, describes existing anti-inflammatory therapies and their limitations, and evaluates the potential of the inflammasome in the context of the existing anti-inflammatory therapeutic landscape as a therapeutic target for effective treatment of the disease.

In-vivo corneal confocal microscopy: Imaging analysis, biological insights and future directions

In-vivo corneal confocal microscopy is a powerful imaging technique which provides clinicians and researcher with the capabilities to observe microstructures at the ocular surfaces in significant detail. In this Mini Review, the optics and image analysis methods with the use of corneal confocal microscopy are discussed. While novel insights of neuroanatomy and biology of the eyes, particularly the ocular surface, have been provided by corneal confocal microscopy, some debatable elements observed using this technique remain and these are explored in this Mini Review. Potential improvements in imaging methodology and instrumentation are also suggested.

Recent Advances of Ocular Drug Delivery Systems: Prominence of Ocular Implants for Chronic Eye Diseases

Chronic ocular diseases can seriously impact the eyes and could potentially result in blindness or serious vision loss. According to the most recent data from the WHO, there are more than 2 billion visually impaired people in the world. Therefore, it is pivotal to develop more sophisticated, long-acting drug delivery systems/devices to treat chronic eye conditions. This review covers several drug delivery nanocarriers that can control chronic eye disorders non-invasively. However, most of the developed nanocarriers are still in preclinical or clinical stages. Long-acting drug delivery systems, such as inserts and implants, constitute the majority of the clinically used methods for the treatment of chronic eye diseases due to their steady state release, persistent therapeutic activity, and ability to bypass most ocular barriers. However, implants are considered invasive drug delivery technologies, especially those that are nonbiodegradable. Furthermore, in vitro characterization approaches, although useful, are limited in mimicking or truly representing the in vivo environment. This review focuses on long-acting drug delivery systems (LADDS), particularly implantable drug delivery systems (IDDS), their formulation, methods of characterization, and clinical application for the treatment of eye diseases.

Ocular-Surface Regeneration Therapies for Eye Disorders: The State of the Art

The ocular surface is a complex structure that includes cornea, conjunctiva, limbus, and tear film, and is critical for maintaining visual function. When the ocular-surface integrity is altered by a disease, conventional therapies usually rely on topical drops or tissue replacement with more invasive procedures, such as corneal transplants. However, in the last years, regeneration therapies have emerged as a promising approach to repair the damaged ocular surface by stimulating cell proliferation and restoring the eye homeostasis and function. This article reviews the different strategies employed in ocular-surface regeneration, including cell-based therapies, growth-factor-based therapies, and tissue-engineering approaches. Dry eye and neurotrophic keratopathy diseases can be treated with nerve-growth factors to stimulate the limbal stem-cell proliferation and the corneal nerve regeneration, whereas conjunctival autograft or amniotic membrane are used in subjects with corneal limbus dysfunction, such as limbal stem-cell deficiency or pterygium. Further, new therapies are available for patients with corneal endothelium diseases to promote the expansion and migration of cells without the need of corneal keratoplasty. Finally, gene therapy is a promising new frontier of regeneration medicine that can modify the gene expression and, potentially, restore the corneal transparency by reducing fibrosis and neovascularization, as well as by stimulating stem-cell proliferation and tissue regeneration.

Eyes on Topical Ocular Disposition: The Considered Design of a Lead Janus Kinase (JAK) Inhibitor That Utilizes a Unique Azetidin-3-Amino Bridging Scaffold to Attenuate Off-Target Kinase Activity, While Driving Potency and Aqueous Solubility

An unmet medical need remains for patients suffering from dry eye disease (DED). A fast-acting, better-tolerated noncorticosteroid anti-inflammatory eye drop could improve patient outcomes and quality of life. Herein, we describe a small-molecule drug discovery effort to identify novel, potent, and water-soluble JAK inhibitors as immunomodulating agents for topical ocular disposition. A focused library of known 3-(4-(2-(arylamino)pyrimidin-4-yl)-1H-pyrazol-1-yl)propanenitriles was evaluated as a molecular starting point. Structure-activity relationships (SARs) revealed a ligand-efficient (LE) JAK inhibitor series, amenable to aqueous solubility. Subsequent in vitro analysis indicated the potential for off-target toxicity. A KINOMEscan selectivity profile of 5 substantiated the likelihood of widespread series affinity across the human kinome. An sp²-to-sp³ drug design strategy was undertaken to attenuate off-target kinase activity while driving JAK-STAT potency and aqueous solubility. Tactics to reduce aromatic character, increase fraction sp³ (Fsp³), and bolster molecular complexity led to the azetidin-3-amino bridging scaffold in 31.

Chloroquine and Hydroxychloroquine in the Treatment of Dry Eye Disease

The role of chloroquine (CQ) and hydroxychloroquine (HCQ) in the management of dry eye disease is still unclear. This systematic review and meta-analysis investigates the efficacy and feasibility of CQ and HCQ in patients with dry eye disease. In February 2023, PubMed, Embase, Google Scholar, and Web of Science were accessed. Data from 462 patients (mean age 54.4 ± 2.8 years) were collected. Compared to baseline, the tear breakup time (p < 0.0001) and Schirmer I test (p < 0.0001) were significantly increased, and the Ocular Surface Disease Index (OSDI, p < 0.0001) and corneal staining (p < 0.0001) were significantly decreased at the last follow-up in the CQ/HCQ group. At the last follow-up, the OSDI was significantly lower in the CQ/HCQ group compared to the control group (p < 0.0001). Corneal staining was significantly greater in the control group compared to the CQ/HCQ group (p < 0.0001). The Schirmer I test showed no significant difference between the groups (p = 0.2). Altogether, CQ and HCQ improved the symptoms and signs of dry eye disease.

How Can We Best Diagnose Severity Levels of Dry Eye Disease: Current Perspectives

Dry eye disease (DED) is a common ocular condition, but the diagnosis relative to other ocular conditions and the evaluation of severity of the condition has often been difficult. This challenge can be due to clinical signs and symptoms not always correlating with each other. An understanding of the various components which create the condition, as well as the diagnostic measures used to evaluate these components, is useful to the clinician working with DED patients. This review paper will discuss traditional diagnostic options, diagnostic imaging, and Advanced Point of Care testing capabilities to determine the severity level of dry eye disease more adequately.

Current microfluidic platforms for reverse engineering of cornea

According to the World Health Organization, corneal blindness constitutes 5.1% of global blindness population. Surgical outcomes have been improved significantly in the treatment of corneal blindness. However, corneal transplantation is limited by global shortage of donor tissue, prompting researchers to explore alternative therapies such as novel ocular pharmaceutics to delay corneal disease progression. Animal models are commonly adopted for investigating pharmacokinetics of ocular drugs. However, this approach is limited by physiological differences in the eye between animals and human, ethical issues and poor bench-to-bedside translatability. Cornea-on-a-chip (CoC) microfluidic platforms have gained great attention as one of the advanced in vitro strategies for constructing physiologically representative corneal models. With significant improvements in tissue engineering technology, CoC integrates corneal cells with microfluidics to recapitulate human corneal microenvironment for the study of corneal pathophysiological changes and evaluation of ocular drugs. Such model, in complement to animal studies, can potentially accelerate translational research, in particular the pre-clinical screening of ophthalmic medication, driving clinical treatment advancement for corneal diseases. This review provides an overview of engineered CoC platforms with respect to their merits, applications, and technical challenges. Emerging directions in CoC technology are also proposed for further investigations, to accentuate preclinical obstacles in corneal research.

Honey-Related Treatment Strategies in Dry Eye Disease

This systematic review and meta-analysis investigated whether honey-related treatment strategies improve the signs and symptoms of patients with dry eye disease (DED). In March 2023, the following databases were accessed for clinical trials investigating the efficacy of honey-related treatment strategies in DED: PubMed, Web of Science, Google Scholar, and EMBASE. The following data were extracted at baseline and at the last follow-up: Ocular Surface Disease Index, tear breakup time, Schirmer I test, and corneal staining. Data from 323 patients were retrieved (53.3% female, mean age 40.6 ± 18.1 years). The mean follow-up was 7.0 ± 4.2 weeks. All the endpoints of interest significantly improved from baseline to the last follow-up: tear breakup time (p = 0.01), Ocular Surface Disease Index (p < 0.0001), Schirmer I test (p = 0.0001), and corneal staining (p < 0.0001). No difference was found in tear breakup time (p = 0.3), Ocular Surface Disease Index (p = 0.4), Schirmer I test (p = 0.3), and corneal staining (p = 0.3) between the honey-related treatment strategies and the control groups. According to our main results, honey-related treatment strategies are effective and feasible to improve symptoms and signs of DED.

Two Methods for the Isolation and Cultivation of Porcine Primary Corneal Cells

In ophthalmic research, there is a strong need for in vitro corneal cell models. Here, we describe different protocols for the cultivation of primary corneal cells that were isolated from porcine eyes. This primary cell culture can be used to test new therapeutic options for corneal diseases, such as dry eye disease, traumatic injuries, or corneal infections, and to study limbal epithelial stem cell (LESC) expansion. Two different isolation methods were performed: the outgrowth and the collagenase method. To perform the outgrowth protocol, small explants of the corneal limbus were generated and incubated in culture flasks in an incubator for 4-5 weeks. Regarding the collagenase method, to extract corneal cells, porcine corneas were removed, cut into small pieces, and incubated with collagenase. After incubation and centrifugation, the cells were seeded in 6- or 12-well plates and incubated in an incubator for 2-3 weeks. The differences between corneal cell cultivation with fetal bovine serum (FBS) and without it are also discussed. Therefore, the main advantages of the outgrowth method are that it requires fewer porcine eyes, and it takes less time to be performed compared to the collagenase method. On the other hand, with the collagenase method, mature cells are obtained earlier, at about 2 to 3 weeks.

Impact of Plasma Rich in Growth Factors (PRGF) Eye Drops on Ocular Redness and Symptomatology in Patients with Dry Eye Disease

Background and Objectives: Dry eye disease (DED) is a common and very symptomatic pathology that affects normal daily activity. The aim of the study was to evaluate the efficacy of plasma rich in growth factors (PRGF) added to one routine treatment protocol for DED (artificial tears substitutes, lid hygiene, and anti-inflammatory therapy). Materials and Methods: Patients were divided into two groups of treatment: standard treatment group (n = 43 eyes) and PRGF group (n = 59). Patients' symptomatology (inferred from OSDI and SANDE questionnaires), ocular inflammation, tear stability, and ocular surface damage were analyzed at baseline and after 3 months of treatment. Results: OSDI test scores were significantly lower in both groups (p < 0.001). SANDE frequency test scores also improved statistically, with differences between groups (p = 0.0089 SANDE frequency and p < 0.0119 SANDE severity). There was a greater reduction in ocular redness (ocular inflammation) in the PRGF group (p < 0.0001) and fluorescein tear break-up time was significantly improved in the PRGF group (p = 0.0006). No significant changes were found in terms of ocular surface damage. No adverse events were obtained in either group. Conclusions: The addition of PRGF to the standard treatment of DED, according to the results obtained, proved to be safe and produced an improvement in ocular symptomatology and signs of inflammation, particularly in moderate and severe cases, when compared to standard treatment.

Review of Potential Drug-Eluting Contact Lens Technologies

The field of ophthalmology is expanding exponentially, both in terms of diagnostic and therapeutic capabilities, as well as the worldwide increasing incidence of eye-related diseases. Due to an ageing population and climate change, the number of ophthalmic patients will continue to increase, overwhelming healthcare systems and likely leading to under-treatment of chronic eye diseases. Since drops are the mainstay of therapy, clinicians have long emphasised the unmet need for ocular drug delivery. Alternative methods, i.e., with better compliance, stability and longevity of drug delivery, would be preferred. Several approaches and materials are being studied and used to overcome these drawbacks. We believe that drug-loaded contact lenses are among the most promising and are a real step toward dropless ocular therapy, potentially leading to a transformation in clinical ophthalmic practice. In this review, we outline the current role of contact lenses in ocular drug delivery, focusing on materials, drug binding and preparation, concluding with a look at future developments.

Epigenetic Activation of Circadian Clock Genes Elicits Inflammation in Experimental Murine Dry Eye

PURPOSE

To explore whether circadian clock genes contribute to elicit inflammation in experimental dry eye (EDE).

METHODS

RNA sequencing analyzed mRNA expression patterns in EDE model. RT-qPCR and/or Western blot determined the expression of inflammatory factors and circadian genes during EDE. MethylTarget™ assays determined the promoter methylation levels of Per genes in vivo. Per2 or Per3 knockdown assessed their effects on inflammatory factors in vitro.

RESULTS

We utilized an intelligently controlled environmental system (ICES) to establish a mouse EDE model. The significant upregulated genes were enriched for circadian rhythms. Therein lied oscillatory and time-dependent upregulation of PER2 and PER3, as well as their promoter hypomethylation during EDE. Silencing PER2 or PER3 significantly decreased inflammatory factor expression and also reversed such increased inflammatory response in azacitidine (AZA) treatment in vitro model.

CONCLUSIONS

Our findings suggest that DNA methylation mediated the upregulation of PER2 and PER3, leading to inflammatory response in EDE.

Clinical observation of tear film breakup time with a novel smartphone-attachable technology

PURPOSE

To demonstrate the practicability of a portable instrument in assessing tear film breakup time (TFBUT): a lens attachment for smartphones (LAS).

METHODS

By applying LAS in combination with the iPhone 12 pro, and a recordable slit-lamp microscope, we obtained TFBUT videos from 58 volunteers. The comparison between the conventional slit-lamp microscope and LAS by an experienced ophthalmologist. Moreover, we also invited an ophthalmic postgraduate student and an undergraduate student with no clinical experience to assess TFBUT in those videos. The inter-observer reliability was assessed using intraclass correlation coefficients (ICC).

RESULTS

The TFBUT of 116 eyes in total was recorded. Reliability indexes were adequate. The Spearman's correlation analysis and the intraclass correlation coefficient suggested a strong correlation between the 2 modalities (Right eye: Spearman's r = 0.929, 95% confidence interval (CI) = 0.847-0.963, ICC = 0.978, p < 0.001; Left eye: Spearman's r = 0.931, 95% CI = 0.866-0.964, ICC = 0.985, p < 0.001;). Between instruments, the majority of TFBUT measurements showed good agreement on Bland Altman plot. A high concordance was observed in TFBUT, when assessed by an ophthalmologist and an ophthalmic postgraduate student (Left eye: LAS ICC = 0.951, p < 0.001; Left eye: slit-lamp microscope ICC = 0.944, p < 0.001).

CONCLUSIONS

Compared with the conventional slit-lamp microscope, the LAS has sufficient validity for evaluating TFBUT in clinics or at home.

Subconjunctival Sirolimus-Loaded Liposomes for the Treatment of Moderate-to-Severe Dry Eye Disease

Purpose

To determine the effectiveness of subconjunctival application of a novel sirolimus liposomal formulation for the treatment of dry eye.

Methods

A randomized, triple-blind, Phase II clinical trial. Thirty-eight eyes of 19 patients were included. Nine patients (18 eyes) assigned to the sham group (Sham) and 10 patients (20 eyes) to sirolimus-loaded liposomes group (Sirolimus). The treatment group received three doses of subconjunctival liposome-encapsulated sirolimus and the sham group received three doses of liposomal suspension without sirolimus. Subjective (Ocular Surface Disease Index, OSDI) and measured (corrected distance visual acuity, conjunctival hyperemia, tear osmolarity, Schirmer's test, corneal/conjunctival staining and matrix metalloproteinase-9) variables were measured.

Results

Sirolimus-entrapped liposomes-treated group OSDI scores changed from 62.19 (± 6.07) to 37.8 (± 17.81) (p=0.0024), and conjunctival hyperemia from 2.0 (± 0.68) to 0.83 (± 0.61) (p<0.0001); Sham group with OSDI scores from 60.02 (± 14.2) to 36.02 (± 20.70) (p=0.01), and conjunctival hyperemia from 1.33 (± 0.68) to 0.94 (± 0.87) (p=0.048). All the other evaluated outcomes only showed significant differences in the sirolimus group: corneal/conjunctival staining score (p=0.0015), lipid layer interferometry (p=0.006), and inferior meibomian gland dropout (p=0.038). No local or systemic adverse effects regarding the medication itself were reported, and the administration route was well accepted.

Conclusion

Our findings suggest that sub-conjunctival sirolimus-loaded liposomes are effective in reducing both signs and symptoms of dry eye in patients with poorly controlled moderate-to-severe DED, while avoiding other topical administration adverse effects. Further investigation with a larger sample size is required to determine long-term effects.

Association of meibomian gland morphology with orifice plugging and lid margin thickening in meibomian gland dysfunction patients

PURPOSE

We sought to investigate the association of meibomian gland morphology with lid margin abnormalities in patients with meibomian gland dysfunction.

METHODS

This retrospective study included 368 eyes of 184 patients. Meibography was used to evaluate meibomian gland (MG) morphological features, such as dropout, distortion, thickened ratio and thinned ratio. Lid margin photography was used to evaluate lid margin abnormalities including orifice plugging, vascularity, irregularity and thickening. The association between MG morphological features and lid margin abnormalities was analyzed using a mixed linear model.

RESULTS

The study found a positive correlation between plugging of gland orifices grade and MG dropout grade in both the upper lids (B = 0.40, p = 0.007) and the lower lids (B = 0.55, p = 0.001). Plugging of gland orifices grade was also positively correlated to MG distortion grade in the upper lids (B = 0.75, p = 0.006). In the upper lids, MG thickened ratio increased first (B = 0.21, p = 0.003) and then decreased (B = - 0.14, p = 0.010) with a higher lid margin thickening grade. MG thinned ratio was negatively correlated with lid margin thickening (B = - 0.14, p = 0.002, B = - 0.13, p = 0.007). MG distortion grade decreased with lid margin thickening (B = - 0.61, p = 0.012).

CONCLUSION

Orifice plugging was correlated to meibomian gland distortion and dropout. Lid margin thickening was associated with meibomian gland thickened ratio, thinned ratio, and distortion. The study also suggested that distorted and thinned glands may be transitional phases between thickened glands and glands dropout.

Mapping the research on Sjögren's syndrome-related dry eye disease: a bibliometric network analysis of the past 20 years

PURPOSE

Our study aimed to make a bibliometric analysis on Sjögren's syndrome-related dry eye disease (SS-DED), explore its potential research hotspots, and provide critical information for future research interest and undeveloped topics in this field, which can benefit clinicians and researchers.

METHODS

We extracted all publications relating to SS-DED from 2003 to 2022 from the Web of Science Core Collection database. Original articles and reviews in English were included. The contributions of different countries, institutions, journals, and authors were compared, and the research hotspots were visualized for network analysis through GraphPad Prism, CiteSpace, and VOSviewer.

RESULTS

We enrolled a total of 987 publications. The United States contributed the most publications (281, 28.5%), followed by China (157, 15.9%) and Japan (80, 8.11%). Publications from the United States were cited more frequently (13,060 citations), with the highest H-index of 57. China ranked second in the total number of publications, the papers were not cited frequently (3790 citations), and the H-index ranked second (H-index = 31). PLoS One (32, 3.24%) published the most papers, and the University of California system had the highest number of publications (45, 4.56%). Bootsma H from the Netherlands published the most papers. The trend of research hotspots evolved mainly from the basic manifestation to pathogenesis and treatment of SS-DED and paid more attention to distinguishing SS-DED from that dry eye disease without SS.

CONCLUSIONS

Based on the bibliometric, co-citation, and network analyses in this study, we obtained the annual publications and citations, the growth trends of publications, the productivity of countries, organizations, journals, and authors, high-quality publications, and the emerging hotspots of SS-DED, which may open new doors for promising research directions.

Extending the use of biologics to mucous membranes by attachment of a binding domain

Biologics are almost exclusively administered systemically, but localized delivery is preferable as it minimizes off-target exposure and allows more aggressive treatments. Topical application of biologics to epithelia is generally ineffective because most are covered with fluids and biologics are washed out too quickly to have significant therapeutic effects. Here we explore the idea that attaching a binding domain can serve as an "anchor" to extend the residency time of biologics on wet epithelia, allowing their effective use even with infrequent applications. We use topical application to the ocular surface as a challenging test since foreign substances are washed out especially efficiently by tear flow and blinking. Our results demonstrate that conjugation of antibodies to wheat germ agglutinin, which binds GlcNAc and sialic acid that are ubiquitously present in tissues, increases their half-life 350-fold upon application to the ocular surface in a mouse model of dry eye, a common and onerous disease in humans. Importantly, antibodies to IL-17A, IL-23, and IL-1β conjugated to the agglutinin reduces manifestations of dry eye, even when applied just once daily. In contrast, unconjugated antibodies are ineffective. Attaching an anchor to biologics is a simple means to overcome washout and to extend their therapeutic use.

Anti-inflammatory and antioxidative effects of gallic acid on experimental dry eye: in vitro and in vivo studies

BACKGROUND

To investigate the anti-inflammatory and antioxidative effects of gallic acid (GA) on human corneal epithelial cells (HCECs) and RAW264.7 macrophages as well as its therapeutic effects in an experimental dry eye (EDE) mouse model.

METHODS

A cell counting kit-8 (CCK-8) assay was used to test the cytotoxicity of GA. The effect of GA on cell migration was evaluated using a scratch wound healing assay. The anti-inflammatory and antioxidative effects of GA in vitro were tested using a hypertonic model (HCECs) and an inflammatory model (RAW264.7 cells). The in vivo biocompatibility of GA was detected by irritation tests in rabbits, whereas the preventive and therapeutic effect of GA in vivo was evaluated using a mouse model of EDE.

RESULTS

In the range of 0-100 μM, GA showed no cytotoxicity in RAW264.7 cells or HCECs and did not delay the HCECs monolayer wound healing within 24 h. Ocular tolerance to GA in the in vivo irritation test was good after seven days. In terms of antioxidative activity, GA significantly reduced the intracellular reactive oxygen species (ROS) in lipopolysaccharide (LPS) activated RAW264.7 macrophages and HCECs exposed to hyperosmotic stress. Furthermore, after pre-treatment with GA, the expression levels of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NADPH quinone oxidoreductase-1 (NQO-1) were significantly upregulated in RAW264.7 macrophages. GA also exhibits excellent anti-inflammatory properties. This is mainly demonstrated by the ability of GA to effectively downregulate the nuclear transcription factor-κB (NF-κB) pathway in LPS-activated RAW264.7 macrophages and to reduce inflammatory factors, such as nitric oxide (NO), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α). In vivo efficacy testing results in a mouse model of EDE showed that GA can effectively prevent and inhibit the apoptosis of corneal epithelial cells (CECs), reduce inflammatory factors in the cornea and conjunctiva as well as protect goblet cells.

CONCLUSION

In vitro and in vivo results indicate that GA possesses potent anti-inflammatory and antioxidative properties with no apparent cytotoxicity within the range of 0-100 μM. It is a promising eye drop formulation for the effective prevention and treatment of dry eye disease (DED).

The Comparison between the Composition of 100% Autologous Serum and 100% Platelet-Rich Plasma Eye Drops and Their Impact on the Treatment Effectiveness of Dry Eye Disease in Primary Sjogren Syndrome

PURPOSE

The aim of the study was to compare the difference in composition between 100% autologous serum (AS) and 100% platelet-rich plasma (PRP) eye drops and assess their impact on the clinical outcomes after the treatment of severe dry eye (DE) in primary Sjogren Syndrome patients (pSS).

MATERIALS AND METHODS

This is an interventional, non-randomized, comparative, three-month study. 22 patients with severe DE in pSS were treated with 100% AS (22 eyes) and 100% PRP (22 eyes) eye drops 5 times per day in monotherapy mode. The quantifications of growth factors (GFs) such as fibroblast growth factor (FGF), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), nerve growth factor (NGF), transforming growth factor (TGF-b), insulin-like growth factor (IGF), fibronectin, and substance p in hemoderivates were done. The main outcome measures were: Ocular Surface Disease Index (OSDI), Best Corrected Visual Acuity (BCVA), the Schirmer test, tear break-up time (TBUT), corneal and conjunctival staining according to the Oxford scale, conjunctival hyperaemia, and Meibomian gland parameters. The results were compared at baseline, 1 month, and 3 months following the treatment. The clinical results were correlated with the concentration of GFs in the biological tear substitutes.

RESULTS

Significant differences were observed in the concentration of FGF (4.42 ± 0.86 vs. 15.96 ± 7.63, p < 0.0001), EGF (4.98 ± 0.97 vs. 39.06 ± 20.18, p < 0.0001), fibronectin (929.6 ± 111.5 vs. 823.64 ± 98.49, p = 0.0005), VEGF (175.45 ± 65.93 vs. 717.35 ± 488.15, p < 0.0001), PDGF AB (619.6 ± 117.30 vs. 349.66 ± 79.82, p < 0.0001), NGF (85.22 ± 23.49 vs. 8.29 ± 9.06, p < 0.0001), PDGF (935.38 ± 434.26 vs. 126.66 ± 54.41, p < 0.0001), substance p (112.58 ± 27.28 vs. 127.51 ± 26.56, p = 0.0125) in PRP compared to AS. The level of TGF-β was undoubtedly higher in AS than in PRP (1031.37 ± 330.23 vs. 726.03 ± 298.95, p = 0.0004). No significant differences between AS and PRP were observed in the concentration of IGF. Therapy with blood products relieved the signs and symptoms in pSS DE patients. There was a statistically significant improvement in BCVA, the Schirmer test, TBUT, Meibomian gland parameters, and the reduction of the OSDI scores, Oxford staining, and conjunctiva hyperaemia in each of the groups. However, the clinical changes were more significant in the PRP group. There were numerous correlations between the level of GFs and the mean change in clinical outcomes. No adverse events were reported.

CONCLUSIONS

Despite the fact that blood derivatives differ in composition, they seem to be effective and safe in the treatment of severe DE in pSS patients. The signs and symptoms of DE were reduced in both groups, but only the mean change in OSDI was statistically significant. A greater reduction in OSDI scores was observed in the PRP group. The obtained results and the composition of haemoderivates may indicate the superiority of PRP in relieving the symptoms of DE in pSS patients compared to AS.

The Autoimmune Rheumatic Disease Related Dry Eye and Its Association with Retinopathy

Dry eye disease is a chronic disease of the ocular surface characterized by abnormal tear film composition, tear film instability, and ocular surface inflammation, affecting 5% to 50% of the population worldwide. Autoimmune rheumatic diseases (ARDs) are systemic disorders with multi-organ involvement, including the eye, and play a significant role in dry eye. To date, most studies have focused on Sjögren's syndrome (one of the ARDs) since it manifests as two of the most common symptoms-dry eyes and a dry mouth-and attracts physicians to explore the relationship between dry eye and ARDs. Many patients complained of dry eye related symptoms before they were diagnosed with ARDs, and ocular surface malaise is a sensitive indicator of the severity of ARDs. In addition, ARD related dry eye is also associated with some retinal diseases directly or indirectly, which are described in this review. This review also summarizes the incidence, epidemiological characteristics, pathogenesis, and accompanying ocular lesions of ARD's related dry eye, emphasizing the potential role of dry eye in recognition and monitoring among ARDs patients.

Dichotomous versus 5-scale grading system for the interpretation of the point-of-care immunoassay for tear matrix metalloproteinase-9 in dry eye

In this study, we compared the dichotomous and 5-scale grading systems for point-of-care immunoassay of tear matrix metalloproteinase (MMP)-9 in dry eye disease (DED) patients and identified the optimal dichotomous system to correlate with DED parameters. We included 167 DED patients without primary Sjogren's syndrome (pSS) (Non-SS DED) and 70 DED patients with pSS (SS DED). We graded MMP-9 expression in InflammaDry® (Quidel, San Diego, CA, USA) using a 5-scale grading system and dichotomous grading systems with four different cut-off grades (D1 to D4 systems). The only DED parameter that showed a significant correlation with the 5-scale grading method was tear osmolarity (Tosm). In both groups, subjects with positive MMP-9 had lower tear secretion and higher Tosm than those with negative MMP-9 according to the D2 dichotomous system. Tosm determined D2 positivity at cutoffs > 340.5 and > 317.5 mOsm/L in the Non-SS DED and SS DED groups, respectively. Tear secretion < 10.5 mm or tear break-up time < 5.5 s stratified D2 positivity in the Non-SS DED group. In conclusion, the dichotomous grading system of InflammaDry reflects ocular surface indices better than the 5-scale grading system and may be more practical in real clinical circumstances.

Superior limbic keratoconjunctivitis: Update on pathophysiology and management

Superior limbic keratoconjunctivitis (SLK) is an under-recognized condition characterized by a final common pathologic presentation of superior conjunctival and limbal inflammation and staining. Existing literature attributes both microtrauma and local inflammation, frequently in the setting of tear film insufficiency, as the underlying mechanisms that lead to a self-perpetuating pathologic process dependent in on inflammatory cells and signaling. Effective treatments act by targeting inflammation and by mitigating mechanical stressors. This critical review discusses the latest in our understanding of the pathophysiology of SLK and how it guides our treatment strategies.

Cyclosporin A improves the hyperosmotic response in an experimental dry eye model by inhibiting the HMGB1/TLR4/NF-κB signaling pathway

Hyperosmolarity is closely related to dry eye disease (DED), which induces corneal epithelial cell structure and dysfunction leading to ocular surface inflammation. Cyclosporine A (CSA) is a cyclopeptide consisting of 11 deduced amino acids. It has an immunosuppressive effect and shows a vital function in inhibiting the inflammatory response. The mechanism of CSA in DED is still not entirely clear. This experiment aimed to investigate the possible mechanism of CSA in the hyperosmotic DED model. This study found that CSA can inhibit the transcript levels of DED high mobility group protein 1 (HMGB1), Toll-like receptor 4 (TLR4) and nuclear transcription factor κB (NF-κB) in signaling pathways. In addition, the study also found that 550 mOsm/L can induce the formation of DED models in vivo or in vitro. Furthermore, different concentrations of CSA have different effects on the expression of HMGB1 in human corneal epithelial cells under hyperosmotic stimulation, and high concentrations of CSA may increase the expression of HMGB1. In addition, CSA effectively reduced the corneal fluorescence staining score of the DE group and increased the tear volume of mice. Therefore, this experimental investigation might supply new evidence for the mechanism of CSA in DED, provide a potential new therapy for treating DED, and provide a theoretical basis for CSA treatment of DED.

MicroRNAs of extracellular vesicles derived from mesenchymal stromal cells alleviate inflammation in dry eye disease by targeting the IRAK1/TAB2/NF-κB pathway

PURPOSE

To investigate the efficacy and mechanisms of human umbilical cord-derived MSC-derived extracellular vesicles (hucMSC-EVs) in a mouse model of desiccation-induced dry eye disease (DED).

METHODS

hucMSC-EVs were enriched by ultracentrifugation. The DED model was induced by desiccating environment combined with scopolamine administration. The DED mice were divided into the hucMSC-EVs group, fluorometholone (FML) group, PBS group, and blank control group. Tear secretion, corneal fluorescein staining, the cytokine profiles in tears and goblet cells, TUNEL-positive cell, and CD4+ cells were examined to assess therapeutic efficiency. The miRNAs in the hucMSC-EVs were sequenced, and the top 10 were used for miRNA enrichment analysis and annotation. The targeted DED-related signaling pathway was further verified by using RT‒qPCR and western blotting.

RESULTS

Treatment with hucMSC-EVs increased the tear volume and maintained corneal integrity in DED mice. The cytokine profile in the tears of the hucMSC-EVs group presented with a lower level of proinflammatory cytokines than PBS group. Moreover, hucMSC-EVs treatment increased goblet cell density and inhibited cell apoptosis and CD4+ cell infiltration. Functional analysis of the top 10 miRNAs in hucMSC-EVs showed a high correlation with immunity. Among them, miR-125 b, let-7b, and miR-6873 were conserved between humans and mice and were associated with the IRAK1/TAB2/NF-κB pathway that was activated in DED. Furthermore, IRAK1/TAB2/NF-κB pathway activation and the abnormal expression of IL-4, IL-8, IL-10, IL-13, IL-17, and TNF-α were reversed by hucMSC-EVs.

CONCLUSIONS

hucMSCs-EVs alleviate DED signs, suppress inflammation and restore homeostasis of the corneal surface by multitargeting the IRAK1/TAB2/NF-κB pathway via certain miRNAs.

The relationship between sedentary behavior and dry eye disease

PURPOSE

Sedentary behavior (SB) has been linked with low-grade systemic inflammation, which could play a role in the development of dry eye disease (DED). This cross-sectional study aims to investigate the association between SB and DED.

METHODS

We assessed 48,418 participants from the population-based Lifelines cohort (58% female, 18-96 years). Women's Health Study (WHS)-defined DED was the primary outcome. SB was assessed using the Marshall Sitting Questionnaire. The relationship between DED and SB was analyzed using logistic regressions, corrected for age, sex, BMI, smoking status, demographics, and 48 comorbidities. Any potential modifying effect of physical activity (PA) was also assessed, and the analyses were repeated excluding the most computer-intensive domains, investigating SB independent from screen exposure.

RESULTS

WHS-defined DED was present in 9.1% of participants. Greater SB was associated with an increased risk of DED (odds ratio (OR) 1.015 per hour/day, 95%CI 1.005-1.024, P = 0.004). The association between SB and DED was only significant for those with less than WHO-recommended PA (OR 1.022, 95%CI 1.002-1.042, P = 0.027), and not in participants meeting WHO's recommendation (OR 1.011, 95%CI 0.999-1.023, P = 0.076). Lastly, when excluding computer-related sitting, the relationship between SB and DED was attenuated, and no longer significant (OR 1.009, 95%CI 0.996-1.023, P = 0.19).

CONCLUSIONS

Greater sedentary time was tied to an increased risk of DED, especially for those with lower PA levels than WHO recommendations. However, as there was no significant association when computer-intensive sitting time was excluded, screen use could explain the observed relationship and should be noted as a possible key confounder.

TFOS Lifestyle: Impact of the digital environment on the ocular surface

Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred terminology) was defined as "the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing". Digital eye strain prevalence of up to 97% has been reported, due to no previously agreed definition/diagnostic criteria and limitations of current questionnaires which fail to differentiate such symptoms from those arising from non-digital tasks. Objective signs such as blink rate or critical flicker frequency changes are not 'diagnostic' of digital eye strain nor validated as sensitive. The mechanisms attributed to ocular surface disease exacerbation are mainly reduced blink rate and completeness, partial/uncorrected refractive error and/or underlying binocular vision anomalies, together with the cognitive demand of the task and differences in position, size, brightness and glare compared to an equivalent non-digital task. In general, interventions are not well established; patients experiencing digital eye strain should be provided with a full refractive correction for the appropriate working distances. Improving blinking, optimizing the work environment and encouraging regular breaks may help. Based on current, best evidence, blue-light blocking interventions do not appear to be an effective management strategy. More and larger clinical trials are needed to assess artificial tear effectiveness for relieving digital eye strain, particularly comparing different constituents; a systematic review within the report identified use of secretagogues and warm compress/humidity goggles/ambient humidifiers as promising strategies, along with nutritional supplementation (such as omega-3 fatty acid supplementation and berry extracts).

IFN-γ Facilitates Corneal Epithelial Cell Pyroptosis Through the JAK2/STAT1 Pathway in Dry Eye

Purpose

To investigate the effect of gamma interferon (IFN-γ) on corneal epithelial pyroptosis in an experimental dry eye (DE) model and explore the underlying molecular mechanisms.

Methods

Experimental DE was established in adult wild-type (WT) C57BL/6 mice and Ifng-knockout mice on a C57BL/6 background by subcutaneous injection of scopolamine (1.5 mg/0.3 mL, three times per day) and exposure to desiccating stress. An immortalized human corneal epithelial cell line (HCE-T) was treated with IFN-γ under hyperosmolar conditions. Corneal epithelial defects, tear production, and conjunctival goblet cells were detected by fluorescein sodium staining, the phenol red cotton test, and periodic acid-Schiff staining. The mRNA expression was measured by quantitative real-time PCR. Changes in protein expression were analyzed by Western blotting and immunofluorescence staining. Cell Counting Kit-8 and lactate dehydrogenase assays and in situ TUNEL staining were used to assess cell death.

Results

The expression of IFNG and its related genes was increased in the corneas of DE mice, whereas genetic deletion of Ifng ameliorated desiccating stress-induced dry eye symptoms. We further found that IFN-γ activated the JAK2/STAT1 signaling pathway inducing corneal epithelial pyroptosis. Topical application of a STAT1 inhibitor in vivo or siRNA targeting STAT1 in vitro suppressed pyroptosis of corneal epithelial cells. In addition, the production of reactive oxygen species (ROS) was elevated in DE, and a reduction in excessive ROS release prevented pyroptosis.

Conclusions

The increase in IFN-γ participates in the pathogenesis of dry eye and promotes corneal epithelial pyroptosis by activating the JAK2/STAT1 signaling pathway. Oxidative stress might be in downstream of JAK2/STAT1, thereby contributing to pyroptosis.

Evaluation of Celligent® Biomimetic Water Gradient Contact Lens Effects on Ocular Surface and Subjective Symptoms

This study aimed to evaluate the non-invasive and subjective symptoms associated with Lehfilcon A water gradient silicone hydrogel contact lenses with bacterial and lipid resistance technology. A prospective, longitudinal, single-centre, self-controlled study was conducted among silicone hydrogel contact lens wearers. Non-invasive analysis of the pre-lens tear film was performed using the Integrated Clinical Platform (ICP) Ocular Surface Analyzer (OSA), and the meibomian glands were evaluated with the Cobra® HD infrared meibographer. After 30 days of contact lens wear, the subjects were re-evaluated to determine the changes in conjunctival redness, subjective dry eye disease, tear meniscus height, lipid pattern, and non-invasive break-up time. Results showed that the lipid layer thickness decreased significantly from 2.05 ± 1.53 to 0.92 ± 1.09 Guillon patterns, and the tear meniscus height decreased from 0.21 ± 0.04 to 0.14 ± 0.03. The mean pre-lens non-invasive break-up time (NIBUT) significantly increased from 15.19 ± 9.54 to 25.31 ± 15.81 s. The standard Patient Evaluation of Eye Disease (SPEED) score also decreased from 7.39 ± 4.39 to 5.53 ± 4.83. The results suggest that Lehfilcon A significantly reduced lipid and aqueous tear film volume but improved break-up time and subjective dry eye symptoms.

Involvement of endoplasmic reticulum stress in trigeminal ganglion corneal neuron injury in dry eye disease

Dry eye disease (DED) is a multifactorial disease with a high prevalence worldwide. Uncomfortable corneal sensations severely affect daily life in DED patients. Hence, corneal neuron injury is a vital pathogenesis in DED. Notably, endoplasmic reticulum stress (ERS) plays a role in peripheral neuron injury. However, the role of ERS in DED corneal neuron injury is still far from being clear. In this study, we established an environmental DED (eDED) model in vivo and a hyperosmotic DED model in vitro. Subsequently, trigeminal ganglion (TG) corneal neurons were retrograde labeled by WGA-Alexa Fluor 555, and fluorescence-activated cell sorting was used to collect targeted corneal neurons for RNA sequencing in mice. Our results revealed that TG corneal neuron injury but not apoptosis in DED. ERS-related genes and proteins were upregulated in TG corneal neurons of the eDED mice. ERS inhibition alleviated TG corneal neuron's ERS-related injury. Therefore, ERS-induced TG corneal neuron injury may be an important pathomechanism and provide a promising therapeutic approach to DED.

Primary cilia control cellular patterning of Meibomian glands during morphogenesis but not lipid composition

Meibomian glands (MGs) are modified sebaceous glands producing the tear film's lipids. Despite their critical role in maintaining clear vision, the mechanisms underlying MG morphogenesis in development and disease remain obscure. Cilia-mediate signals are critical for the development of skin adnexa, including sebaceous glands. Thus, we investigated the role of cilia in MG morphogenesis during development. Most cells were ciliated during early MG development, followed by cilia disassembly during differentiation. In mature glands, ciliated cells were primarily restricted to the basal layer of the proximal gland central duct. Cilia ablation in keratine14-expressing tissue disrupted the accumulation of proliferative cells at the distal tip but did not affect the overall rate of proliferation or apoptosis. Moreover, impaired cellular patterning during elongation resulted in hypertrophy of mature MGs with increased meibum volume without altering its lipid composition. Thus, cilia signaling networks provide a new platform to design therapeutic treatments for MG dysfunction.

Rodent models for dry eye syndrome: Standardization using benzalkonium chloride and scopolamine hydrobromide

Dry eye disease is a highly prevalent ocular condition that significantly affects the quality of life and presents a major challenge in ophthalmology. Animal models play a crucial role in investigating the pathophysiology and developing effective treatments. The goal of this study was to compare and standardize two dry eye disease rodent models and explore their recovery aspects. We have standardized benzalkonium chloride and scopolamine-induced dry eye disease models which represents two different classes of the dry eye i.e., evaporative dry eye and aqueous deficient dry eye, respectively. After the development of dry eye conditions, a self-recovery period of seven days was granted to assess the reversal of the induced changes. The dry eye condition was assessed by measuring tear volume, corneal slit lamp imaging, and histological examination of the cornea, the lacrimal and the harderian gland. The study indicated the development of chronic inflammation of the cornea and lacrimal gland in the case of benzalkonium after five days of the treatment, while the scopolamine treated group showed chronic inflammation of the lacrimal gland after five days and corneal inflammation after seven days of administration. The recovery study suggested that after discontinuation of inducing agent, the dry eye symptoms were still persistent suggesting the utility of the model in evaluating dry eye treatments. The study highlights the comparative changes in both models along with recovery which can serve as a base for drug discovery and development against dry eye disease.

Correlation Between Air Quality Index and Tear Film Lipid Layer Thickness: Comparison Between Patients with Sjogren's Syndrome and with Meibomian Gland Dysfunction

Purpose: To evaluate the effect of air pollution on the tear film stability by analyzing the correlation between Air Quality Index (AQI) and Lipid Layer thickness (LLT) in Xuzhou.Methods: As a prospective descriptive observational study, 284 patients with meibomian gland dysfunction (MGD), 157 patients with Sjögren's syndrome (SS), and 264 healthy volunteers were included. The tear film lipid layer thickness of the three groups of subjects was measured weekly and compared with the air quality index to analyze the correlation between the two indicators. Logistic regression analysis and linear regression analysis were used to analyze the effect of AQI on the thickness of the tear film lipid layer. The change of LLT with air pollution at different AQI levels was also analyzed.Results: There are obvious seasonal differences in the changes of air pollution index in Xuzhou. Significant differences could be observed in the thickness of the lipid layer of the tear film among the three groups. LLT in the MGD group and SS group decreased with the aggravation of air pollution, while remained unchanged in the control group. There was strong evidence of correlation between LLT of the MGD group (F = 353.494, p < 0.01, adjusted R2 = 0.695) and the SS group (F = 502.404, p < 0.01, adjusted R2 = 0.764) with AQI, while there was minor correlation between LLT with AQI in control group (F = 8.525, p < 0.01, adjusted R2 = 0.046).Conclusions: Air pollution can cause a decrease in the thickness of the tear film lipid layer, thereby affecting tear film stability, leading to the occurrence of dry eye.