Meibomian gland dysfunction is the primary determinant of dry eye symptoms: Analysis of 2346 patients

Neuropathic corneal pain following refractive surgery: risk factors, clinical manifestations, imaging and proteomic characteristics

BACKGROUND/AIMS

To identify the risk factors for neuropathic corneal pain (NCP) following corneal refractive surgery and to report its clinical manifestations, imaging and proteomic characteristics.

METHODS

This 1 year prospective cohort study included 100 eyes that underwent small incision lenticule extraction (SMILE) or laser-assisted in situ keratomileusis (LASIK). Ocular surface assessments, in-vivo confocal microscopy scans, tear neuromediators and proteomics analyses were performed. NCP was assessed using the ocular pain assessment survey. Univariate and multivariate analyses were conducted to identify the risk factors associated with postoperative NCP.

RESULTS

The incidence of NCP was 13.3% and 10.5% after SMILE and LASIK, respectively (p=0.70). In SMILE, preoperative manifest refractive spherical equivalent (MRSE) and spherical power (both p=0.02) were significantly higher in the NCP compared with the non-NCP group. In LASIK, NCP eyes had a significantly lower corneal nerve fibre length (CNFL) (p=0.02), lower nerve fractal dimension (p=0.003), higher nerve fibre width (p=0.04) and larger neuroma area (p=0.04) than non-NCP eyes. In SMILE, higher preoperative MRSE was a significant risk factor for postoperative NCP (95% CI: 0.48-1.96, p=0.04). An MRSE greater than -8.0 diopter was 9.57 times more likely to develop postoperative NCP (OR=9.57, p=0.002). In LASIK, lower preoperative corneal nerve fibre density (95% CI:0.13-1.11, p=0.05) and CNFL (95% CI:0.09-1.25, p=0.05) were significant risk factors for postoperative NCP. Significant increases in tear nerve growth factor, calcitonin gene-related peptide, Frizzled class receptor 7 and nucleoside-diphosphate kinase three were observed in postoperative NCP.

CONCLUSIONS

The reported characteristics and risk factors would identify patients susceptible to NCP after corneal refractive surgery.

The Application of Terahertz Technology in Corneas and Corneal Diseases: A Systematic Review

Terahertz (THz) waves reside in the electromagnetic spectrum between the microwave and infrared bands. In recent decades, THz technology has demonstrated its potential for biomedical applications. With the highly unique characteristics of THz waves, such as the high sensitivity to water and optimal spatial resolution coupled with the characteristics of the human cornea, such as its high water content, THz technology has been explored as a potential modality to assess corneas and corneal diseases. This systematic review provides an overview of the characteristics of THz waves, the safety profile of THz technology in the field of ophthalmology, and its clinical applications, including the objective evaluation of the corneal hydration, tear film, dry eye disease, corneal endothelium, corneal elasticity, and scarring. The paper also presents our viewpoint on the present challenges and future directions of THz technology prior to its broader integration into clinical practice.

Is Thermal Pulsation Therapy Effective for Dry Eyes Before and After Cataract Surgery? A Systematic Review and Meta-Analysis

Background

Meibomian gland dysfunction (MGD) is a primary cause of evaporative dry eye disease (DED), which is often exacerbated by cataract surgery due to surgical trauma and inflammation. Thermal pulsation therapy (TPT) aims to enhance meibomian gland function and relieve dry eye symptoms. We conducted a systematic review and meta-analysis to evaluate the effectiveness of TPT in managing dry eye symptoms associated with cataract surgery.

Methods

A systematic search was performed in December 2024 across PubMed, ScienceDirect, CINAHL, and the Cochrane Central Register of Controlled Trials to identify original research on the efficacy of TPT in addressing cataract surgery-related dry eye symptoms. The quality of the included studies was evaluated using the Risk of Bias in Non-Randomized Studies of Interventions tool, with results visualized through the Robvis 2.0 tool developed by the Cochrane Collaboration.

Results

The search yielded 365 records, of which seven studies met the inclusion criteria for this meta-analysis. Key outcomes analyzed included the meibomian gland yielding liquid secretion (MGYLS) score, tear break-up time (TBUT), ocular surface disease index (OSDI) score, and lipid layer thickness (LLT). The meta-analysis revealed a moderate effect of TPT, with a small but clinically significant improvement observed in MGYLS scores (Cohen's d = 0.29, p = 0.033) and TBUT (Cohen's d = 0.15, p = 0.029). However, the effects on OSDI scores and LLT were not statistically significant. Study heterogeneity varied, with some outcomes exhibiting considerable variability.

Conclusion

TPT provides moderate and clinically meaningful improvements in MGYLS scores and TBUT for patients experiencing dry eye symptoms after cataract surgery, although improvements in OSDI scores and LLT did not achieve statistical significance. The variability in study quality and heterogeneity highlights the need for well-designed, high-quality research to confirm these findings and evaluate the durability of TPT's therapeutic effects both before and after cataract surgery.

A review of the application of in-vivo confocal microscopy on conjunctival diseases

Over the past few decades, the expanded applications of in-vivo confocal microscopy (IVCM) have greatly enhanced the knowledge of a variety of conjunctival diseases. IVCM allows non-invasively detailed observation of tarsal, palpebral and bulbar conjunctiva, from the superficial to the substantia propria at the cellular level. IVCM has been shown as a powerful tool for the assessment of morphological changes in both physiological and pathological conditions. High-resolution images of different cellular phenotypes, together with quantifiable results, open new insights into understanding the mechanisms of conjunctival diseases, as well as provide valuable and longitudinal information for the diagnosis and therapeutic evaluation. This review aims to provide an overview of the current knowledge on the applications of IVCM on conjunctival disorders, including aging changes, dry eye-related morphological changes, glaucoma and glaucoma surgery-related morphological changes, conjunctival neoplasm, pterygium, allergic conjunctivitis, trachomatous scarring, and the conjunctiva-associated lymphoid tissue (CALT) changes. In this review, we highlight the key findings of previous studies and discusses the current limitations and challenges of IVCM in assessing the structural characteristics of the conjunctiva. Furthermore, we consider possible future directions for unlocking the full potential of IVCM applications. The insights presented here will contribute to a more comprehensive understanding of the applications of IVCM in conjunctival diseases.

Neuropathic Corneal Pain: Tear Proteomic and Neuromediator Profiles, Imaging Features, and Clinical Manifestations

PURPOSE

To investigate the tear proteomic and neuromediator profiles, in vivo confocal microscopy (IVCM) imaging features, and clinical manifestations in neuropathic corneal pain (NCP) patients.

DESIGN

Cross-sectional study.

METHODS

A total of 20 NCP patients and 20 age-matched controls were recruited. All subjects were evaluated by corneal sensitivity, Schirmer test, tear break-up time, and corneal and ocular surface staining, Ocular Surface Disease Index and Ocular Pain Assessment Survey questionnaires were administered, as well as IVCM examinations for corneal nerves, microneruomas, and epithelial and dendritic cells. Tears were collected for neuromediator and proteomic analysis using enzyme-linked immunosorbent assay and data-independent acquisition mass spectrometry.

RESULTS

Burning and sensitivity to light were the 2 most common symptoms in NCP. A total of 188 significantly dysregulated proteins, such as elevated metallothionein-2, creatine kinases B-type, vesicle-associated membrane protein 2, neurofilament light polypeptide, and myelin basic protein, were identified in the NCP patients. The top 10 dysregulated biological pathways in NCP include neurotoxicity, axonal signaling, wound healing, neutrophil degradation, apoptosis, thrombin signaling mitochondrial dysfunction, and RHOGDI and P70S6K signaling pathways. Compared to controls, the NCP cohort presented with significantly decreased corneal sensitivity (P < .001), decreased corneal nerve fiber length (P = .003), corneal nerve fiber density (P = .006), and nerve fiber fractal dimension (P = .033), as well as increased corneal nerve fiber width (P = .002), increased length, total area and perimeter of microneuromas (P < .001, P < .001, P = .019), smaller corneal epithelial size (P = .017), and higher nerve growth factor level in tears (P = .006).

CONCLUSIONS

These clinical manifestations, imaging features, and molecular characterizations would contribute to the diagnostics and potential therapeutic targets for NCP.

Potential therapeutic effects of peroxisome proliferator-activated receptors on corneal diseases

The cornea is an avascular tissue in the eye that has multiple functions in the eye to maintain clear vision which can significantly impair one's vision when subjected to damage. Peroxisome proliferator-activated receptors (PPARs), a family of nuclear receptor proteins comprising three different peroxisome proliferator-activated receptor (PPAR) isoforms, namely, PPAR alpha (α), PPAR gamma (γ), and PPAR delta (δ), have emerged as potential therapeutic targets for treating corneal diseases. In this review, we summarised the current literature on the therapeutic effects of PPAR agents on corneal diseases. We discussed the role of PPARs in the modulation of corneal wound healing, suppression of corneal inflammation, neovascularisation, fibrosis, stimulation of corneal nerve regeneration, and amelioration of dry eye by inhibiting oxidative stress within the cornea. We also discussed the underlying mechanisms of these therapeutic effects. Future clinical trials are warranted to further attest to the clinical therapeutic efficacy.

Topical and oral peroxisome proliferator-activated receptor-α agonist ameliorates diabetic corneal neuropathy

Diabetic corneal neuropathy (DCN) is a common diabetic ocular complication with limited treatment options. In this study, we investigated the effects of topical and oral fenofibrate, a peroxisome proliferator-activated receptor-α agonist, on the amelioration of DCN using diabetic mice (n = 120). Ocular surface assessments, corneal nerve and cell imaging analysis, tear proteomics and its associated biological pathways, immuno-histochemistry and western blot on PPARα expression, were studied before and 12 weeks after treatment. At 12 weeks, PPARα expression markedly restored after topical and oral fenofibrate. Topical fenofibrate significantly improved corneal nerve fibre density (CNFD) and tortuosity coefficient. Likewise, oral fenofibrate significantly improved CNFD. Both topical and oral forms significantly improved corneal sensitivity. Additionally, topical and oral fenofibrate significantly alleviated diabetic keratopathy, with fenofibrate eye drops demonstrating earlier therapeutic effects. Both topical and oral fenofibrate significantly increased corneal β-III tubulin expression. Topical fenofibrate reduced neuroinflammation by significantly increasing the levels of nerve growth factor and substance P. It also significantly increased β-III-tubulin and reduced CDC42 mRNA expression in trigeminal ganglions. Proteomic analysis showed that neurotrophin signalling and anti-inflammation reactions were significantly up-regulated after fenofibrate treatment, whether applied topically or orally. This study concluded that both topical and oral fenofibrate ameliorate DCN, while topical fenofibrate significantly reduces neuroinflammation.

Enhancing Meibography Image Analysis Through Artificial Intelligence-Driven Quantification and Standardization for Dry Eye Research

Purpose

This study enhances Meibomian gland (MG) infrared image analysis in dry eye (DE) research through artificial intelligence (AI). It is comprised of two main stages: automated eyelid detection and tarsal plate segmentation to standardize meibography image analysis. The goal is to address limitations of existing assessment methods, bridge the curated and real-world dataset gap, and standardize MG image analysis.

Methods

The approach involves a two-stage process: automated eyelid detection and tarsal plate segmentation. In the first stage, an AI model trained on curated data identifies relevant eyelid areas in non-curated datasets. The second stage refines the eyelid area in meibography images, enabling precise comparisons between normal and DE subjects. This approach also includes specular reflection removal and tarsal plate mask refinement.

Results

The methodology achieved a promising instance-wise accuracy of 80.8% for distinguishing meibography images from 399 DE and 235 non-DE subjects. By integrating diverse datasets and refining the area of interest, this approach enhances meibography feature extraction accuracy. Dimension reduction through Uniform Manifold Approximation and Projection (UMAP) allows feature visualization, revealing distinct clusters for DE and non-DE phenotypes.

Conclusions

The AI-driven methodology presented here quantifies and classifies meibography image features and standardizes the analysis process. By bootstrapping the model from curated datasets, this methodology addresses real-world dataset challenges to enhance the accuracy of meibography image feature extraction.

Translational Relevance

The study presents a standardized method for meibography image analysis. This method could serve as a valuable tool in facilitating more targeted investigations into MG characteristics.

Impact of Age on the Characteristics of Corneal Nerves and Corneal Epithelial Cells in Healthy Adults

PURPOSE

The aim of this study was to investigate age-related changes in corneal nerves and corneal epithelial cell parameters and to establish age-adjusted reference values.

METHODS

A total of 7025 corneal nerve images and 4215 corneal epithelial images obtained using in vivo confocal microscopy from 281 eyes of 143 healthy participants were included. Seven corneal nerve parameters and 3 corneal epithelial cell parameters were quantified using 2 automatic analytic software and analyzed across 6 age groups ranging from 21 to 80 years.

RESULTS

There was a declining trend in all 7 nerve parameters with advancing age. In particular, corneal nerve fiber length and corneal nerve fiber density demonstrated a significant decrease in subjects aged 65 years or older compared with subjects younger than 65 years (10.8 ± 2.6 mm/mm 2 vs. 9.9 ± 2.0 mm/mm 2 , P = 0.011 in corneal nerve fiber length; 15.8 ± 5.2 fibers/mm 2 vs. 14.4 ± 4.3 fibers/mm 2 , P = 0.046 in corneal nerve fiber density), whereas corneal nerve fractal dimension demonstrated a borderline significant decrease ( P = 0.057). Similarly, there was a general declining trend in all epithelial cell parameters with advancing age. Corneal epithelial cell circularity was significantly lower in subjects aged 65 years and older as compared to subjects younger than 65 years (0.722 ± 0.021 μm 2 vs. 0.714 ± 0.021 μm 2 ; P = 0.011).

CONCLUSIONS

Advancing age results in reduced corneal nerve metrics and alteration of corneal cell morphology. Aging effects should be considered when evaluating patients with corneal neuropathy.

Urban Particulate Matter Triggers Meibomian Gland Dysfunction

Purpose

The meibomian gland (MG), as the largest modified sebaceous gland, is potentially damaged by urban particulate matter (UPM) based on epidemiological evidence, but the specific experimental mechanisms remain unknown. This study investigated the effects of UPM on MG dysfunction (MGD) in rodent models.

Methods

Female C57BL/6J mice received eye drops containing UPM suspension or PBS for 14 days. The proliferative capacity and progenitor of MG were evaluated by immunofluorescence. Cell apoptosis was confirmed by TUNEL assay, along with the analysis of caspase family expression. Lipid accumulation was visualized by Oil Red O staining and LipidTox staining. Ductal hyperkeratinization, neutrophil infiltration, and pyroptosis activation were detected through immunostaining. The relative gene expression and signaling pathway activation were determined by Western blot analysis.

Results

Administration of UPM caused MGD-like clinical signs, manifested as distinct corneal epithelial erosion, increased MG orifice occlusion, and glandular dropout. UPM exposure significantly induced progenitor loss, cellular apoptosis, and lipogenic disorder in MG, by reducing P63/Lrig1 expression and increasing cleaved caspase-8, -9, and -3 and meibum lipogenic protein (HMGCR/SREBP-1) expression. UPM-treated mice exhibited ductal hyperkeratinization and neutrophil recruitment. Simultaneously, pyroptosis was motivated, as indicated by the heightened expression of NLRP3 and the cleavage of caspase-1 and -4 and gasdermin D, as well as the increase in IL-1β and IL-18 downstream. The underlying pathological mechanisms of UPM involve the phosphorylation of mitogen-activated protein kinase and nuclear factor-κB.

Conclusions

These results provided direct evidence for the toxicity of UPM in MG. UPM-induced activation of pyroptosis and mitogen-activated protein kinase/nuclear factor-κB signaling pathway might account for the inflammatory MGD.

Review of clinical outcomes of a cationic emulsion tear substitute in patients with dry eye disease

First-line options for the treatment of dry eye disease (DED) rely on artificial tears (ATs), among which cationic emulsion (CE)-based ATs have been developed in order to mimic the healthy tear film for an improved restoration of the ocular surface homeostasis. In this review, we describe the outcomes reported in several studies, assessing the mode of action, ocular tolerance and clinical performance of a CE-based AT. Pilot studies have revealed that CE-based ATs can increase the volume and stability of the tear film while limiting its evaporation rate. Larger studies have demonstrated that CE-based ATs play a significant role in the improvement of both objective and subjective DED parameters, including superior efficacy on DED symptoms compared to several other available AT formulation types. Concomitantly, CE-based ATs have been shown to help patients to prevent or recover from corneal defects associated with refractive surgery. These positive outcomes on ocular surface epithelia are likely due to the combination of unique rheological behaviour and intrinsic anti-inflammatory properties. Based on all clinical findings, CE-based ATs represent a valuable treatment option for patients with various etiologies of DED including evaporative forms and would deserve evaluation of benefits in other surgical intervention types triggering DED.

Relationship between dry eye symptoms and quality of life: associations and mediation analysis

PURPOSE

(1) To determine the independent association of dry eye symptoms with health-related quality of life (HRQoL) in the Singapore population and (2) to further investigate which factors mediate this association.

METHODS

In this cross-sectional study, 7707 participants were included. The presence of dry eye symptoms was defined as experiencing at least one out of the six symptoms either 'often' or 'all the time'. The EuroQoL-5 dimensions (EQ-5D) utility instrument (raw scores converted to UK time trade-off (TTO) values) was used to assess generic HRQoL and the overall score from the Visual Functioning Questionnaire for visual functioning. The association between dry eye symptoms and EQ-5D was investigated using multivariable linear regression, adjusting for demographic and socioeconomic information, comorbidities, systemic and ocular examinations results. Mediation analysis was used to determine whether certain factors mediated this association.

RESULTS

After adjusting for relevant factors, those with dry eye symptoms had significantly lower HRQoL (difference in EQ-5D TTO: -0.062 (95% CI -0.073 to -0.050)), with the inability to open eyes affected the most (-0.101 (95% CI -0.161 to -0.042)), followed by a sandy sensation (-0.089 (95% CI -0.121 to -0.058)), a burning sensation (-0.070 (95% CI -0.105 to -0.036)), red eyes (-0.059 (95% CI -0.082 to -0.036)), a dry sensation (-0.058 (95% CI -0.072 to -0.044)) and crusting of eyelids (-0.040 (95% CI -0.071 to -0.008)). Visual functioning and the presence of recent falls accounted for 8.63% (4.98%-14.5%) and 2.93% (0.04%-5.68%) of the indirect relationship between dry eye and HRQoL, respectively.

CONCLUSION

Dry eye symptoms were independently associated with poor HRQoL. Moreover, this was partly mediated by reduced visual functioning and experiencing recent falls. Our results suggest that efforts to reduce severity of dry eye symptoms are essential to optimise patients' overall functioning and well-being.

Evaluation of the Tear Meniscus Using Optical Coherence Tomography in Meibomian Gland Dysfunction

INTRODUCTION

This study aimed to evaluate tear meniscus parameters in meibomian gland dysfunction (MGD) using optical coherence tomography and ImageJ software.

METHODS

We enrolled 66 eyes of 66 participants and measured tear meniscus parameters, including height, depth, turbidity, and percentage area occupied by particles (PAOP) in the meniscus in the MGD and control groups.

RESULTS

Tear meniscus turbidity and PAOP were significantly higher in the MGD group, but tear meniscus height (TMH) and depth (TMD) did not differ significantly between groups. Tear meniscus turbidity and PAOP were positively correlated with each other and ocular surface parameters, including OSDI and ocular surface staining scores.

CONCLUSION

Tear meniscus turbidity and PAOP were higher in the MGD group than in the control group; therefore, they can be used as significant non-invasive parameters in the prediction of MGD. TMH and TMD did not differ significantly between groups.

Symptoms of dry eye related to the relative humidity of living places

PURPOSE

To investigate the impact of relative humidity (RH) and climate variables of the place of residence on symptoms of dry eye disease (DED) in primary eye care practice.

METHODS

A cross-sectional analysis of the Ocular Surface Disease Index (OSDI) dry eye classification of 1.033 patients [classified as non-DED (OSDI ≤22) and DED (OSDI >22)] was conducted in a multicentre study in Spain. Participants were classified according to the 5-year RH value (data from the Spanish Climate Agency -www.aemet.es) into two groups: those who lived in low RH (<70%) places and those who lived in high RH (≥70%) places. Additionally, differences in daily climate records (EU Copernicus Climate Change Service) were assessed.

RESULTS

The prevalence of DED symptoms was 15.5% (95% CI 13.2%-17.6%). Participants who lived in places with <70% RH showed a higher prevalence of DED (17.7%; 95% CI 14.5%-21.1%; P < 0.01 adjusted for age and sex) than those who lived in places with ≥70% RH (13.6%; 95% CI 11.1%-16.7%) and a closer, but not statistically significant, risk for DED (OR = 1.34, 95% CI 0.96 to 1.89; P = 0.09) than previously described DED risk factors [age older than 50 years (OR = 1.51, 95% CI 1.06 to 2.16; P = 0.02) and female sex (OR = 1.99, 95% CI 1.36 to 2.90; P < 0.01)]. Some climate data showed statistically significant differences (P < 0.05) between participants with DED and non-DED (mean wind gusts; atmospheric pressure; mean and minimum relative humidity); these variables did not significantly increase DED risk (OR close to 1.0 and P > 0.05).

CONCLUSION

This study is the first to describe the impact of climate data on dryness symptomatology in Spain, confirming that participants who live in locations with RH <70% have a higher prevalence (corrected for age and sex) of DED. These findings support the use of climate databases in DED research.

Low-Level Light Therapy Versus Intense Pulsed Light for the Treatment of Meibomian Gland Dysfunction: Preliminary Results From a Prospective Randomized Comparative Study

PURPOSE

The purpose of this study was to evaluate and compare the safety and efficacy of low-level light therapy (LLLT) and intense pulsed light (IPL) for the treatment of meibomian gland dysfunction (MGD).

METHODS

Forty eyes of 40 patients with MGD were randomized to receive either LLLT or IPL. Four weekly sessions of LLLT (MY MASK-E, Espansione Marketing S.p.A., Bologna, Italy) and IPL (Eye-light device, Espansione Marketing S.p.A., Bologna, Italy) were performed. The following parameters were evaluated before and 2 weeks after the last session for each treatment: Standard Patient Evaluation of Eye Dryness questionnaire, noninvasive break-up time, tear meniscus height, redness score, meiboscore, and meibomian gland loss.

RESULTS

All patients completed regularly all the scheduled sessions, and no adverse events were reported in any of the groups. The Standard Patient Evaluation of Eye Dryness score significantly decreased after both LLLT and IPL (P < 0.001) although the improvement was significantly greater in the LLLT compared with the IPL group (-9.9 ± 3.2 vs. -6.75 ± 4.5; P = 0.014). Patients in the LLLT group showed a significantly higher increase in tear meniscus height compared with those in the IPL group (0.06 ± 0.10 mm vs. -0.01 ± 0.014; P = 0.040). In both groups, the noninvasive break-up time, redness score, meiboscore, and meibomian gland loss did not vary significantly after treatment (all P > 0.05).

CONCLUSIONS

Both LLLT and IPL were safe and effective in improving ocular discomfort symptoms in patients with MGD; however, the former determined a greater improvement in symptoms and an improvement of tear volume.

Predicting demographics from meibography using deep learning

This study introduces a deep learning approach to predicting demographic features from meibography images. A total of 689 meibography images with corresponding subject demographic data were used to develop a deep learning model for predicting gland morphology and demographics from images. The model achieved on average 77%, 76%, and 86% accuracies for predicting Meibomian gland morphological features, subject age, and ethnicity, respectively. The model was further analyzed to identify the most highly weighted gland morphological features used by the algorithm to predict demographic characteristics. The two most important gland morphological features for predicting age were the percent area of gland atrophy and the percentage of ghost glands. The two most important morphological features for predicting ethnicity were gland density and the percentage of ghost glands. The approach offers an alternative to traditional associative modeling to identify relationships between Meibomian gland morphological features and subject demographic characteristics. This deep learning methodology can currently predict demographic features from de-identified meibography images with better than 75% accuracy, a number which is highly likely to improve in future models using larger training datasets, which has significant implications for patient privacy in biomedical imaging.

Exploratory Search for Characteristic Symptoms to Distinguish Meibomian Gland Dysfunction from Dry Eye in a Population-Based Study in Japan

Symptom overlap between meibomian gland dysfunction (MGD) and dry eye (DE) makes it difficult to distinguish between these two conditions on the basis of symptoms alone. We searched for characteristic symptoms that might help to distinguish MGD from DE on the basis of a population-based study. Subjects comprised 311 residents of Takushima island (18 to 96 years), including 117 individuals with MGD and 114 with DE. Responses to a symptom-related questionnaire (19 items) were subjected to factor analysis, and univariate regression analysis was performed to identify ocular surface parameters associated with characteristic symptoms of MGD. Factor analysis revealed aggregation of symptoms according to three factors: Factor 1 related to Symptom Score, Factor 2 to DE, and Factor 3 to MGD. Symptoms associated with DE included 11 items, whereas the only item related to MGD was tearing sensation. Pearson’s correlation analysis revealed that tearing sensation was associated with tear meniscus height (TMH), noninvasive tear-film breakup time, fluorescein staining score, meiboscore, meibum grade, and Schirmer value. Subjects with MGD experienced significantly more tearing and had a larger TMH than did those without MGD (p = 0.0334). Tearing sensation may thus be a characteristic symptom of MGD. Physicians should suspect MGD who complain of tearing sensation.

Artificial Tears: Biological Role of Their Ingredients in the Management of Dry Eye Disease

Dry eye disease (DED) is the most common ocular surface disease, characterized by insufficient production and/or instability of the tear film. Tear substitutes are usually the first line of treatment for patients with DED. Despite the large variety of tear substitutes available on the market, few studies have been performed to compare their performance. There is a need to better understand the specific mechanical and pharmacological roles of each ingredient composing the different formulations. In this review, we describe the main categories of ingredients composing tear substitutes (e.g., viscosity-enhancing agents, electrolytes, osmo-protectants, antioxidants, lipids, surfactants and preservatives) as well as their effects on the ocular surface, and we provide insight into how certain components of tear substitutes may promote corneal wound healing, and/or counteract inflammation. Based on these considerations, we propose an approach to select the most appropriate tear substitute formulations according to the predominant etiological causes of DED.

The Effect of Past Cataract Surgery within the Medium to Long-Term Period on Patients with Dry Eye Disease

This study investigates the effects of cataract surgery on dry eye parameters of patients with dry eye disease (DED) in the medium- to long-term post-surgical period (6 months to 5 years). A cross-sectional study was conducted on 438 eyes on first visit to a tertiary clinic (219 eyes with cataract surgery within timeframe, i.e., pseudophakic dry eye group, 219 comparison eyes without such history, i.e., comparison dry eye group). Parameters evaluated include Ocular Surface Disease Index (OSDI) and standard examination for DED. A significantly greater proportion of pseudophakic dry eye group (50%) experienced frequent blurred vision (≥1 episode per week) compared to dry eye control group (38%) (OR = 1.66, 95%CI 1.13, 2.44). Those with ocular discomfort before surgery were more likely to experience blurring at least once a day. However, a significantly greater proportion of the pseudophakic dry eye group (34%) had Schirmer’s I >8mm compared to the comparison group (25%) (OR = 0.605, 95% CI 0.398, 0.921), though the difference was not clinically significant (7.51 mm versus 6.51 mm, p > 0.05). Other DED signs (e.g., overall OSDI score, Tear Break-up Time) were not found to be worse among pseudophakic dry eye group. Pre-operative counselling and preventative measures should be undertaken, especially those with suggestive symptoms pre-operatively.

Dry Eye Disease Symptoms and Its Association with Daily Beverage Intake Among Adults in Saudi Arabia

Purpose

To evaluate the association between dry eye disease (DED) symptoms and daily beverage intake among adults in Saudi Arabia.

Patients and Methods

In this cross-sectional, questionnaire-based study, we distributed an online questionnaire to men and women older than 18 years living in Saudi Arabia. The questionnaire consisted of items related to the sociodemographic characteristics of the participants and two validated indices: the Ocular Surface Disease Index (OSDI) and the brief 15-item Beverage Intake Questionnaire (BEVQ-15). Participants were excluded if they were aged less than 18 years; wore contact lenses; had existing eye disease (excluding refractive errors), history of eye surgery (including corrective eye surgeries), or autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, Sjogren’s syndrome); or were currently taking specific medications including antidepressants, antihistamines, and diuretics.

Results

After applying the study exclusion criteria, a total of 615 participants were included in the statistical analysis. The majority of participants were 18–34 years old (450, 73.2%), and men (381, 62%) exceeded women (234, 38%) by approximately 1.5-fold. OSDI scores showed that 344 participants (55.9%) had DED symptoms, 145 (23.6%) had mild dry eyes; and 106 (17.2%) and 93 (15.1%) had moderate and severe dry eyes, respectively. There was a significant association between sex and DED symptoms (p = 0.012); the frequency of DED symptoms in women exceeded that in men. However, no significant differences were observed with other demographic data such as age and location of residence. Although beverage intake was moderately correlated to OSDI score (R = 0.27), we found no significant association between beverage intake and DED symptoms.

Conclusion

This is the first study to highlight the association between DED symptoms and daily beverage intake. We found a significant association between DED symptoms and female sex. However, no significant association was found between DED symptoms and other demographic characteristics or beverage intake.

Effect of a Novel Thermostatic Device on Meibomian Gland Dysfunction: A Randomized Controlled Trial in Chinese Patients

Introduction

Meibomian gland dysfunction (MGD) is a common eye condition that causes excessive evaporation of tears by changing the tear film composition. Current treatments often fail to produce satisfactory results, which is mostly due to poor patient adherence. This study aimed to evaluate the effectiveness and safety of the MiBoFlo Thermoflo® on both subjective symptoms and objective signs in Chinese patients with MGD.

Methods

This prospective, randomized, controlled clinical trial included 108 eyes of 54 patients with MGD who were recruited in Beijing Tongren Hospital and randomized 1:1 to MiBoFlo (n = 54 eyes) or LipiFlow® (n = 54 eyes) treatment group. In the MiBoFlo group, patients received three 10-min treatments, each spaced 2 weeks apart, and the treatment was followed by eyelid compression each time. Patients in the LipiFlow group received a single 12-min treatment. The primary parameters measured included changes in Ocular Surface Disease Index (OSDI) score, Meibomian Glands Yielding Liquid Secretion (MGYLS) score, and Meibomian Glands Secretion (MGS) score from baseline to 2 months. The secondary parameters included tear meniscus height (TMH), non-invasive keratograph break-up time (NIKBUT), corneal fluorescein staining (CFS), and meibomian glands (MG) loss from baseline to 2 months. Safety parameters include visual acuity (VA), intraocular pressure (IOP), anterior segment, and facial skin.

Results

The OSDI, MGYLS, and MGS scores all improved from baseline to 1 month in both MiBoFlo and LipiFlow groups, and these improvements were maintained at 2 months. CFS score, NIKBUT, and MG loss showed no significant change in both groups.

Conclusion

As a portable and comfortable device, MiBoFlo can improve the treatment of MGD and achieve a sustained improvement in both symptoms and meibomian gland function lasting at least 2 months.

Assessment and Management of Dry Eye Disease and Meibomian Gland Dysfunction: Providing a Singapore Framework

ABSTRACT

The purpose of this article is to provide a framework for general ophthalmologists in Singapore to manage dry eye. This framework considers the evidence in the literature as well as recommendations from expert panels such as the Tear Film & Ocular Surface Society Dry Eye Workshop II and the Asia Cornea Society Workgroup.This article covers the assessment of patient medical history and ask triage questions to identify local and systemic causes of dry eye disease (DED), excluding other possible causes, as well as the risk factors for DED and ocular surface inflammation. Evaluation of clinical signs to establish the diagnosis of DED and differentiation from other causes of irritable, red eyes are described. Tests for understanding the underlying disease processes and severity of DED are also presented.Management of dry eye should involve patient education and engagement. Information about the natural history and chronic nature of DED should be provided to improve long-term management of the disease and enhance compliance. Aggravating factors should be removed or lessened.We provide a guide to determine the most appropriate treatment (or combination of treatments) based on the severity and cause(s) of the disease, as well as the patient's needs and preferences. The aim of the management is to relieve ocular discomfort and prevent worsening of symptoms and signs, as well as to optimize visual function and minimize structural ocular damage. We also discuss the systematic follow-up and assessment of treatment response, as well as monitoring side effects of treatment, bearing in mind continuous support and reassurance to patients.

Comparison of tear proteomic and neuromediator profiles changes between small incision lenticule extraction (SMILE) and femtosecond laser-assisted in-situ keratomileusis (LASIK)

Introduction

The tear proteomics and neuromediators are associated with clinical dry eye parameters following refractive surgery.

Purpose

To investigate and compare the tear proteomic and neuromediator profiles following small incision lenticule extraction (SMILE) versus laser-assisted in-situ keratomileusis (LASIK).

Methods

In this randomized controlled trial with paired-eye design, 70 patients were randomized to receive SMILE in one eye and LASIK in the other eye. Tear samples were collected preoperatively, and 1 week, 1, 3, 6 and 12 months postoperatively, and were examined for protein concentration changes using sequential window acquisition of all theoretical fragment ion mass spectrometry (SWATH-MS). The data were analyzed with DAVID Bioinformatics Resources for enriched gene ontology terms and over-represented pathways. Tear neuromediators levels were correlated with clinical parameters.

Results

Post-SMILE eyes had significantly better Oxford staining scores and tear break-up time (TBUT) than post-LASIK eyes at 1 and 3 months, respectively. Tear substance P and nerve growth factor levels were significantly higher in the LASIK group for 3 months and 1 year, respectively. SMILE and LASIK shared some similar biological responses postoperatively, but there was significant up-regulation in leukocyte migration and wound healing at 1 week, humoral immune response and apoptosis at 1 month, negative regulation of endopeptidase activity at 3 to 6 months, and extracellular structure organization at 1 year in the post-LASIK eyes. Tear mucin-like protein 1 and substance P levels were significantly correlated with TBUT (r = -0.47, r = -0.49, respectively).

Conclusion

Significant differences in the tear neuromediators and proteomics were observed between SMILE and LASIK, even though clinical dry eye signs have subsided and became comparable between 2 procedures.

Prevalence and Risk Factors of Severe Dry Eye in Bangladesh-Based Factory Garment Workers

This study sought to evaluate the prevalence of dry eye and meibomian gland dysfunction (MGD) and the associated factors of severe dry eye symptoms (SDES) among garments worker of Gazipur, Bangladesh. We prospectively collected cross-sectional data for 1050 garments workers of a factory (70% response). All participants had an evaluation of the Ocular Surface Disease Index (OSDI), and a detailed ophthalmic examination including tear breakup time (TBUT), ocular surface fluorescein staining, and Schirmer’s I test. MGD grading was based on the viscosity/color and ease of manual expression of meibum. Mean age of participants was 35.5 ± 12.1 years; 53.8% were women. The prevalence of dry eye (OSDI > 12) was 64.2% (95% CI 61.2–67.1%). OSDI was not significantly different between sex or age-groups but associated with increasing MGD grade (p < 0.001), reduced TBUT (<5 s) [p < 0.001], and reduced Schirmer’s test (<5 mm) [p < 0.001]. Thirty-five percent had SDES (OSDI > 32). Using univariate logistic regressions, SDES was associated with older age (Odds Ratio (OR) 1.01, 95% Confidence Interval [1.005–1.03] per year increase) and male sex (OR 1.76, 95% CI: 1.36–2.27). When adjusted for age and sex, SDES were strongly associated with increase in MGD severity grading (OR 188, 95% CI: 91–390). However, in multivariate regression, TBUT, but not MGD severity, became the only significant determinant of SDES (OR 13.0, 95% CI: 6.3–27.0, for every 1 s decrease in TBUT). MGD is common in garments workers, contributing to dry eye symptoms in addition to other tear parameters. Reduced tear stability is associated with SDES.