Distribution of aqueous-deficient and evaporative dry eye in a clinic-based patient cohort: a retrospective study

Long-Term Safety and Efficacy of Perfluorohexyloctane Ophthalmic Solution for the Treatment of Patients With Dry Eye Disease: The KALAHARI Study

PURPOSE

The aim of this study was to assess the long-term safety and efficacy of perfluorohexyloctane (PFHO) ophthalmic drop (formerly NOV03) for treatment of dry eye disease (DED).

METHODS

KALAHARI was a phase 3, multicenter, single-arm, open-label extension study in patients aged 18 years or older with DED associated with Meibomian gland dysfunction who completed the randomized, double-masked, hypotonic saline-controlled GOBI study. Patients instilled 1 drop of PFHO (MIEBO, Bausch + Lomb) 4 times daily in both eyes for 52 weeks. Safety assessments included adverse events, best-corrected visual acuity, slit-lamp biomicroscopy, intraocular pressure, and dilated fundoscopy. Efficacy end points included change from GOBI study baseline in total corneal fluorescein staining and eye dryness score (0-100 visual analog scale).

RESULTS

Overall, 208 patients from GOBI (PFHO [n = 97]; saline [n = 111]) were rolled over into KALAHARI. Twenty-nine patients (13.9%) had ≥1 ocular adverse event, with most being mild or moderate in severity; the most common ocular adverse events were vitreous detachment (1.9%), allergic conjunctivitis (1.4%), blurred vision (1.4%), and increased lacrimation (1.4%). Other safety end points were unremarkable. For patients continuing PFHO from GOBI, improvements in total corneal fluorescein staining and visual analog scale dryness scores observed in GOBI were maintained throughout KALAHARI. Patients treated with saline in GOBI and switched to PFHO in KALAHARI showed improvements in total corneal fluorescein staining and visual analog scale scores by week 4 that were maintained for the rest of the study.

CONCLUSIONS

PFHO was safe and well tolerated and maintained efficacy for improving signs and symptoms of DED in this year-long study of patients with DED associated with Meibomian gland dysfunction.

Changes in Human Meibum Lipid Composition Related to the Presence and Severity of Meibomian Gland Dysfunction

Purpose: Changes in meibum composition and quantity in meibomian gland dysfunction (MGD) result in tear film instability and dry eye. This exploratory study aimed to identify changes in (O-acyl)-ω-hydroxy fatty acid (OAHFA) and hydrocarbon chain (HC) unsaturation levels in meibum related to the presence and severity of MGD. Methods: Meibum samples were collected from 3 cohorts of adults with no MGD, mild-to-moderate MGD, and severe MGD in a noninterventional clinical trial (NCT01979887). OAHFAs, cholesterol esters (CE), HC unsaturation, and HC length in the meibum samples were quantified with 1H-nuclear magnetic resonance spectroscopy using 2 methods of normalization. Results: Meibum samples from 62 subjects were analyzed: 21 non-MGD, 21 mild-to-moderate MGD, and 20 severe MGD. Meibum OAHFA and CE levels and HC unsaturation were reduced with increasing severity of MGD, with most pairwise comparisons significant (P < 0.05, t-tests), following the order non-MGD > mild-to-moderate MGD > severe MGD. Regardless of the resonances used for normalization, each pairwise comparison of OAHFA, CE, and HC unsaturation levels in MGD (combined severities) versus non-MGD samples was significant (P < 0.01, t-test). Analysis using various normalization equations showed reductions of 20%-22% for OAHFAs, 51%-57% for CE, and 36%-66% for HC unsaturation in MGD (combined severities) compared with non-MGD. HC length was not altered in MGD (combined severities) compared with non-MGD samples (t-test). Conclusions: Meibum OAHFA, CE, and HC unsaturation levels were reduced in MGD and were lowest in the severe MGD cohort. These findings may contribute to the understanding of the pathophysiology of MGD.

Clinical Efficacy of 2% Rebamipide in Patients With Video Display Terminal-Associated Dry Eye Disease: A Prospective, Randomized, Double-Blinded Study

PURPOSE

To compare the effects of 2% rebamipide clear solution and 0.1% sodium hyaluronate eye drops in patients with visual display terminal (VDT)-related dry eye disease (DED).

DESIGN

Prospective, randomized, double-blinded Study.

METHODS

This was a prospective, double-blind, and randomized controlled study. Patients with VDT-related DED were randomly allocated to a 2% rebamipide (REB) group or a 0.1% sodium hyaluronate (HYA) group (4 times/day for 4 weeks). The ocular surface disease index (OSDI), dry eye questionnaire-5 (DEQ-5), Placido disk-tear film analyzer, fluorescein-stained tear break-up time (FBUT), ocular surface staining score, and Schirmer 1 test were examined before and after the instillation of drug.

RESULTS

A total of 56 eyes of 28 patients (28 eyes of 14 patients in each group) were included. There were no significant differences in the baseline data. The OSDI, DEQ-5, FBUT, and conjunctival erosion scores improved significantly in both groups after treatment. In the REB group, corneal staining and bulbar nasal redness scores also improved significantly after treatment ( P <0.001 and 0.036, respectively), whereas no significant differences were found in these parameters in the HYA group ( P =0.326 and 0.118, respectively). The REB group showed a significantly larger decrease in the corneal staining score than the HYA group ( P =0.016). No adverse reactions were observed.

CONCLUSIONS

A 2% rebamipide clear solution effectively improved the symptoms and signs in patients with VDT-related DED and was superior to 0.1% sodium hyaluronate ophthalmic solution in improving corneal epithelial damage, making it a safe and effective treatment option for VDT-related DED.

Confocal Microscopy of the Cornea in Aqueous-Deficient Dry Eye Disease-A Literature Review

BACKGROUND

In vivo confocal microscopy (IVCM) is a vital tool in studying dry eye disease (DED), providing insights into morphological changes at ocular surface unit levels. This review presents the main differences in corneal structure between aqueous-deficient dry eye disease (AD-DED) and normal eyes.

METHODS

A comprehensive search of PubMed, Web of Science, Embase, and MEDLINE databases from January 2000 to December 2023 was conducted. The study selection process, as well as data selection and examination, were independently performed by two members of the review team.

RESULTS

The review reveals a consistent decrease in corneal surface epithelial cell density in AD-DED cases compared to a control group, but conflicting data on basal epithelial cell density. Notably, the abnormal hyperreflectivity of keratocytes in patients with Sjogren's syndrome was recorded, and there was a significant keratocyte density in AD-DED subjects compared to evaporative DED and control groups. Studies also found a decrease in sub-basal nerve density, increased tortuosity, and the fragmentation of nerve fibers. Dendritic cell density and dendritic cell dendrites increase in AD-DED patients compared to healthy subjects.

CONCLUSIONS

IVCM is a powerful tool for enhancing our understanding of the pathophysiological mechanisms underlying DED. However, the review underscores the urgent need to standardize the terminology, analysis, and units used for accurate interpretation, a crucial step in advancing our knowledge of DED.

Classification of dry eye disease subtypes

PURPOSE

The current subclassifications of dry eye disease (DED) are aqueous deficient (ADDE) and evaporative (EDE) forms, but there lacks consistency in the clinical characteristics used to define each of these. This study used clinical data to inform cut-off values for the subclassification of ADDE and EDE, to allow more consistent study of the epidemiology of both DED subtypes.

METHODS

The study enrolled 261 residents from the UK, extracted from a cohort with demographics representing the population (mean 42.4 ± 18.7 years, 56 % females). The TFOS DEWS II diagnostic criteria were used to identify those with DED. Meibomian gland loss/drop-out (from meibography), lipid layer thickness (LLT - from interferometry graded on the Guillon-Keeler scale), and tear meniscus height (TMH - Keratograph 5M) along with tear evaporation (Delfin Vapometer) were used to characterise the subclassification. The Dry Eye Risk Factor Survey was used to assess risk factors associated with each DED subtype.

RESULTS

Compared to individuals who were not diagnosed with DED, EDE was characterized by signs of meibomian gland loss of > 28 %, LLT grade < 3 and tear evaporation > 46 g/m2/h. In contrast, ADDE was best characterized by a reduced TMH < 0.2 mm. Based on these criteria, the prevalence of ADDE was 6.2 %, EDE was 64.2 %, and 11.1 % exhibited features of both ADDE and EDE, with 18.5 % unclassified despite having a DED diagnosis. Contact lens wear and computer use were risk factors for ADDE (p < 0.05), whereas age was a positive risk factor for EDE (p < 0.01). Meibomian gland loss (occurring in 27.9 %) was the most commonly observed sign in EDE.

CONCLUSIONS

Data driven-classification of DED confirms that the evaporative form is most prevalent and identified that in a generalisable UK population, ADDE alone occurs only in approximately 1 in 16 cases of DED.

Re-Esterified Triglyceride ω-3 Fatty Acids in Dry Eye Disease With Meibomian Gland Dysfunction: A Randomized Clinical Trial

Importance

Taking ω-3 supplements has been associated with a reduction in symptoms of dry eye disease (DED) associated with meibomian gland dysfunction (MGD). However, a recent relatively large clinical trial concluded that treating DED with ω-3 consumption was ineffective, potentially warranting additional investigations.

Objectives

To investigate the effect of re-esterified triglyceride (rTG) ω-3 fatty acid supplementation on DED associated with MGD.

Design, Setting, and Participants

This double-masked, parallel-group, randomized clinical trial was conducted at 7 institutions from September 2020 to January 2023. Patients with DED associated with MGD were included and randomly assigned to the ω-3 group (received 1680 mg of eicosapentaenoic acid and 560 mg of docosahexaenoic acid), whereas those in the grape-seed group received 3000 mg of grape-seed oil daily.

Interventions

rTG ω-3 Fatty acid supplementation vs grape-seed oil.

Main Outcome Measures

The primary end point was the Ocular Surface Disease Index (OSDI) from baseline to 6 and 12 weeks. The safety parameters were visual acuity and intraocular pressure change.

Results

A total of 132 patients (mean [SD] age, 50.6 [13.8] years; 103 female [78.0%]) were included in this study. The mean (SD) baseline OSDI scores of the ω-3 and grape-seed groups were 43.5 (16.5) and 44.1 (16.6), respectively. A total of 58 patients (87.9%) and 57 patients (86.4%) in the ω-3 and grape-seed groups, respectively, completed 12 weeks of follow-up. There were no differences in compliance with the dietary supplement intake between groups (ω-3, 95.8% and grape-seed, 95.4%). The OSDI (SD) change from baseline to 6 and 12 weeks was -20.5 (16.0) and -22.7 (15.7), respectively, in the ω-3 group and -15.1 (20.2) and -18.8 (21.7), respectively, in the grape-seed control group (difference at 6 weeks = -5.4; 95% CI, -12.15 to 1.33; P = .12 and at 12 weeks = -3.9; 95% CI, -10.90 to 3.13; P = .28). There were no changes in safety parameters or adverse events related to taking the dietary supplement in either group.

Conclusions and Relevance

This randomized clinical trial did not show a benefit of the rTG form of ω-3 for ameliorating symptoms of DED associated with MGD, although fewer than 60 participants were evaluated in each group. Any secondary outcomes from this study should be considered for hypothesis generation of future evaluations of the effect of the rTG form of ω-3 on DED associated with MGD.

Trial Registration

CRIS Identifier: KCT0004927.

Prevalence of meibomian gland dysfunction at a tertiary centre in Taiwan

CLINICAL RELEVANCE

Meibomian gland dysfunction and dry eye disease are closely related conditions that often coexist and can contribute to the development of each other. Understanding the similarities and differences between these diseases can assist clinicians in implementing effective treatments for both conditions in a clinical setting.

BACKGROUND

Dry eye disease is a multifactorial disease of the tears and ocular surface. This study aimed to evaluate the demographic characteristics of patients with meibomian gland dysfunction in Taiwan, investigate the association between meibomian gland dysfunction and dry eye parameters, and estimate the prevalence of meibomian gland dysfunction among patients with dry eye symptoms at a tertiary referral centre.

METHODS

This cross-sectional study enrolled patients aged ≥20 years who complained of dry eye symptoms and visited a tertiary centre between September 2019 and March 2020. The patients completed the Ocular Surface Disease Index and Standard Patient Evaluation of Eye Dryness questionnaires before undergoing ocular examination. The lipid layer thickness and meiboscale scores were recorded. In addition, the study measured tear film break-up time, examined corneal staining, and evaluated the number of meibomian glands yielding liquid secretions using a slit lamp.

RESULTS

The study evaluated 202 eyes of 202 patients with a mean age of 58.05 ± 13.34 years. The prevalence of meibomian gland dysfunction was 93%. Mean meiboscale score and age were negatively associated, and tear film break-up time was positively associated with the mean number of meibomian glands yielding liquid secretions. Hyperlipidaemia and smoking were the main risk factors for Meibomian gland dysfunction.

CONCLUSIONS

The prevalence of meibomian gland dysfunction among patients with dry eye symptoms was extremely high at the tertiary centre, highlighting the strong relationship between Meibomian gland dysfunction and dry eye disease. Clinicians should consider meibomian gland dysfunction as a possible cause of dry eye.

Comparing meibomian gland visibility on optical coherence tomography and Keratograph 5M images using objective and subjective grading methods

PURPOSE

To investigate if there is a visible difference in meibomian gland (MG) length between images captured with the Visante optical coherence tomography (OCT; wavelength = 1,310 nm) and the OCULUS Keratograph 5M (K5M; wavelength = 880 nm).

METHODS

Adults between 18 and 40 years were recruited. Baseline dry eye disease was evaluated with the Standard Patient Evaluation of Eye Dryness (SPEED) and tear meniscus height and tear breakup time with the K5M. Right upper and lower eyelid MGs were imaged with the K5M and Visante OCT. Each image was graded with the 0 to 3 meiboscore scale. The central 5 MGs were evaluated with ImageJ for percent gland length visibility.

RESULTS

Thirty participants were analyzed with a median (interquartile range [IQR]) age of 23.0 (5.0) years (53.3 % female). Overall, participants were asymptomatic and had normal tear films. Meiboscores based on K5M and Visante OCT was significantly different for the lower eyelid (0[1] vs 1[2]; p = 0.007) but not the upper eyelid (0[1] vs 0[1]; p = 1.00). The mean percent gland visibility of the upper eyelid (82.7[9.6] vs 75.2[13.5]; p < 0.001) and the lower eyelid (81.2[12.7] vs 64.1[17.6]; p < 0.001) were significantly greater on the Visante OCT than the K5M images, respectively.

CONCLUSION

OCT images had significantly greater percent visible MG lengths than the K5M images. This suggests viable segments of the MGs may be missed with typical imaging, which may explain how it is possible that studies have found less post-treatment MG atrophy.

Topical glaucoma medications - Possible implications on the meibomian glands

One of the most common causes of blindness on a global scale is glaucoma. There is a strong association between glaucoma and increased intraocular pressure (IOP). Because of this, adequate IOP-lowering is the most important treatment strategy, mostly through topical eyedrops. Well-functioning meibomian glands are paramount for maintaining a stable tear film, and their dysfunction is the most common cause of dry eye disease. There is a growing concern that both topical glaucoma medications themselves and their added preservatives damage the meibomian glands, and consequently, the ocular surface. Preserved topical glaucoma medications appear to cause dysfunction and atrophy of the meibomian glands. Upon comparison, preserved formulations caused more symptoms of dry eye, tear film instability, inflammatory changes and meibomian gland dropout than the preservative-free counterpart. However, although seemingly less detrimental, unpreserved alternatives may diminish glandular efficacy, and, depending on the active ingredient, lead to glandular death. This negatively impacts quality of life, adherence to treatment regimens and prognosis. In this review, we explore the available evidence regarding the effects of IOP-lowering eye drops on the meibomian glands.

Improved Signs and Symptoms of Dry Eye Disease for Restasis® Patients Following a Single Tearcare® Treatment: Phase 2 of the SAHARA Study

Purpose

To evaluate dry eye disease (DED) signs and symptoms six months after a single treatment with Localized Heat Therapy (LHT) (TearCare, Sight Sciences) for patients previously treated for six months with cyclosporine (0.05%) ophthalmic emulsion (CsA) BID (Restasis, Allergan).

Setting

Nineteen ophthalmic and optometric practices in 11 US states.

Design

Multicenter, cross-over, six month extension to the SAHARA randomized, controlled trial (RCT). Included patients were those randomized to CsA in Phase 1 of the SAHARA RCT.

Methods

This was the second phase of the SAHARA RCT in which, following the 6-month endpoint, all patients that had been randomized to CsA discontinued CsA and were treated with LHT and subsequently followed for an additional six months. Outcome measures at 12 months for CsA patients crossed over to LHT included TBUT, OSDI and MGSS.

Results

One hundred and sixty-one patients (322 eyes) were analyzed. Mean (SD) baseline TBUT prior to CsA was 4.4 (1.2) seconds, 5.6 (2.6) at 6 months which improved to 6.6 (3.2) and 6.1 (2.8) seconds (both P < 0.001) at 9 and 12 months (3, 6 months post LHT). Mean (SD) OSDI was 50.0 (14.9) at baseline and 34.2 (21.5) after CsA. With LHT at 6 months, this improved to 30.0 (20.6) and 31.0 (19.5) at 9 and 12 months (P = 0.162 vs month 6, P < 0.0001 vs baseline). MGSS was 7.1 (3.2) at baseline, 13.3 (8.2) at the end of CsA treatment which improved to 17.4 (8.8) and 16.1 (9.0) at 9 and 12 months; both P <0.001.

Conclusion

SAHARA showed 6-month superiority of LHT to CsA in clinical signs and non-inferiority in symptom scores. This extension shows that patients treated with CsA for 6 months can achieve meaningful additional improvement in signs and symptoms lasting for as long as 6 months following a single LHT treatment without the need for topical prescription therapy.

Engaging Stakeholders to Develop a Roadmap for Dry Eye and MGD PCORI-Funded Research

Introduction

Although affecting an estimated 35% of the population, Dry Eye is not well understood by patients and the medical community. As a result, both in research and clinical settings, diagnostic and treatment protocols tend to be non-specific, ad hoc, and inadequate, with a narrow industry-driven focus. The purpose of this convening was to propose a research roadmap that orients Dry Eye researchers toward a comprehensive patient-centered approach to diagnosing and treating Dry Eye, Meibomian gland dysfunction (MGD), and related comorbidities with a goal of improving clinical outcomes for Dry Eye/MGD patients.

Methods

Sixteen participants, including Dry Eye/MGD patients, caregivers, and patient advocates together with a group of experts in Dry Eye, MGD and other fields identified gaps in research on Dry Eye and MGD diagnostic and treatment approaches (age range 20-80; male to female ratio of 7:11; patients: 7). During a 2-day virtual convening, participants were assigned to topic-specific focus-group sessions to discuss and develop research questions pertaining to Dry Eye and MGD. The research questions were compiled into a proposed patient-centered roadmap for Dry Eye and MGD research. Two additional participants contributed to the proposed roadmap following the convening.

Results

The focus groups identified over 80 patient-centered research questions important to patients and other stakeholders and compiled these into a proposed research roadmap.

Conclusion

The convened stakeholders aim to establish a cohesive and comprehensive patient-centered approach to treating Dry Eye, Meibomian Gland Dysfunction, and comorbidities. The research roadmap will serve as a reference for researchers, educational institutions, clinicians, and others evaluating diagnostic and treatment protocols in Dry Eye and MGD.

Sex Differences in the Prevalence of Meibomian Gland Dysfunction: A Mini Review

PURPOSE

In this review, we aimed to investigate the literature on sex-specific prevalence of meibomian gland dysfunction (MGD) and to determine whether women or men are more at risk for MGD.

METHODS

A search was conducted on PubMed using the terms: (Sex OR Gender OR prevalence) AND (Meibomian gland).

RESULTS

Twenty-four relevant studies on MGD prevalence were identified, including 10 population-based and 14 hospital-based studies. Among the population-based studies, five studies reported higher rates among men, three studies found no differences, and one study observed higher rates among women. In the hospital-based studies, 10 studies reported no difference, two found higher rates among men, and one found higher among women. In the reviewed literature, there was a considerable variation between studies in terms of quality, sample size, age ranges, diagnostic criteria.

CONCLUSIONS

While most of the population-based studies suggest a higher prevalence among men, the majority of clinic-based studies show no significant difference. Further research with larger samples and standardized criteria is needed to determine whether men are indeed more susceptible to MGD.

Red filter meibography by smartphones in patients with meibomian gland dysfunction: a validity and reliability study

OBJECTIVE

The objective of this study is to determine the validity and reliability of the red filter meibography by smartphone compared with infrared in assessing meibomian gland drop-out.

METHODS AND ANALYSIS

An analytical cross-sectional study was done with a total of 35 subjects (68 eyes) with suspected MGD based on symptoms and lid morphological abnormalities. Meibomian glands were photographed using two smartphones (Samsung S9 and iPhone XR) on a slit-lamp with added red filter. Images were assessed subjectively using meiboscore by the two raters and drop-out percentages were assessed by ImageJ.

RESULTS

There was no agreement in meiboscore and a minimal level of agreement in drop-out percentages between red filter meibography and infrared. Inter-rater reliability showed no agreement between two raters. Intra-rater reliability demonstrated weak agreement in rater 1 and no agreement in rater 2.

CONCLUSION

Validity of the red filter meibography technique by smartphones is not yet satisfactory in evaluating drop-out. Further improvement on qualities of images must be done and research on subjective assessment was deemed necessary due to poor results of intrarater and inter-rater reliability.

Achieving net-zero in the dry eye disease care pathway

Climate change is a threat to human health and wellbeing across the world. In recent years, there has been a surge in awareness of this crisis, leading to many countries and organisations setting "net-zero" targets. This entails minimising carbon emissions and neutralising remaining emissions by removing carbon from the atmosphere. At the 2022 United Nations Climate Change Conference (COP27), commitments to transition away from fossil fuels and augment climate targets were underwhelming. It is therefore imperative for public and private sector organisations to demonstrate successful implementation of net-zero and set a precedent for the global political consensus. As a top 10 world employer, the United Kingdom National Health Service (NHS) has pledged to reach net-zero by 2045. The NHS has already taken positive steps forward, but its scale and complexity as a health system means stakeholders in each of its services must highlight the specifications for further progress. Dry eye disease is a chronic illness with an estimated global prevalence of 29.5% and an environmentally damaging care pathway. Moreover, environmental damage is a known aggravator of dry eye disease. Worldwide management of this illness generates copious amounts of non-recyclable waste, utilises inefficient supply chains and involves recurrent follow-up appointments and prescriptions. By mapping the dry eye disease care pathway to environmental impact, in this review we will highlight seven key areas in which reduced emissions and pollution could be targeted. Examining these approaches for improved environmental sustainability is critical in driving the transformation needed to preserve our health and wellbeing.

Impact of Clinician Subjectivity on the Assessment of Dry Eye Disease Prevalence in a UK Public Health Care Patient Population

Purpose

To understand the impact of subjectivity on diagnosis rates of dry eye disease (DED) in an unbiased population.

Patients and Methods

A multicenter study enrolled 818 subjects with complete report forms (465 females, 67.1 ± 16.7 years, 353 males, 65.0 ± 15.9 years). Subjects were evaluated for staining, TBUT, tear osmolarity, meibomian gland disease, and OSDI.

Results

Physicians diagnosed 48.7% of subjects as having DED, ranging from 42.9% to 62.3% between sites. Positivity rates for staining (≥ grade 1) ranged from 41.3% to 84.1% (mean = 0.8 ± 0.9 grade), TBUT (<10s) ranged from 39.1% to 61.6% (mean = 10.4 ± 6.6 seconds), osmolarity (>308 mOsm/L) ranged from 63.7% to 72.4% (mean = 319.7 ± 20.8), MGD grading ranged from 28.9% to 51.3% (mean = 0.5 ± 0.7), and symptoms measured by OSDI ranged from 57.6% to 71.0% (mean = 23.5 ± 20.5) between sites. Tear osmolarity was the most consistent between sites (max/min positivity = 114%), followed by OSDI (123%), TBUT (158%), MGD (178%), and staining (204%). DED markers were uncorrelated (average r2 = 0.05 ± 0.07). A substantial number of subjects (N = 110) exhibited positive symptoms (OSDI = 32.4 ± 15.7) and hyperosmolarity (338.1 ± 20.1 mOsm/L) but no other obvious signs of DED (MGD grade = 0.2 ± 0.4, TBUT = 13.5 ± 7.0 seconds, staining grade = 0.4 ± 0.5).

Conclusion

Subjective signs of DED varied considerably, whereas objective measurements of OSDI and osmolarity were the most consistent between sites. A large proportion of subjects exhibited high symptoms and hyperosmolarity but no other obvious signs of dry eye disease, most of whom were undiagnosed by clinical assessment without access to the osmolarity measurement.

Dry Eye Disease in the Middle East and Northern Africa: A Position Paper on the Current State and Unmet Needs

In the Middle East and Northern Africa (MENA), dry eye disease (DED) is often misdiagnosed or overlooked. This review summarizes a series of conversations with ophthalmologists in the region around a variety of climatic, lifestyle, and iatrogenic factors that contribute to specific features of DED in the MENA region. These considerations are further classified by patient lifestyle and surgical choices. All statements are based on discussions and formal voting to achieve consensus over three meetings. Overall, a deeper understanding of the disease characteristics of DED specific to MENA can better guide local eyecare practitioners on appropriate management and follow-up care. Additionally, population-based studies and patient and physician education on ocular surface diseases, together with the use of culturally appropriate and language-specific questionnaires can help ease the public health burden of DED in this region.

Modeling dry eye with an air-liquid interface in corneal epithelium-on-a-chip

Dry eye syndrome (DES) is a complex ocular condition characterized by an unstable tear film and inadequate tear production, leading to tissue damage. Despite its common occurrence, there is currently no comprehensive in vitro model that accurately reproduce the cellular characteristics of DES. Here we modified a corneal epithelium-on-a-chip (CEpOC) model to recapitulate DES by subjecting HCE-T human corneal epithelial cells to an air-liquid (AL) interface stimulus. We then assessed the effects of AL stimulation both in the presence and absence of diclofenac (DCF), non-steroidal anti-inflammatory drug. Transcriptomic analysis revealed distinct gene expression changes in response to AL and AL_DCF, affecting pathways related to development, epithelial structure, inflammation, and extracellular matrix remodeling. Both treatments upregulated PIEZO2, linked to corneal damage signaling, while downregulating OCLN, involved in cell-cell junctions. They increased the expression of inflammatory genes (e.g., IL-6) and reduced mucin production genes (e.g., MUC16), reflecting dry eye characteristics. Metabolomic analysis showed increased secretion of metabolites associated with cell damage and inflammation (e.g., methyl-2-oxovaleric acid, 3-methyl-2-oxobutanoic acid, lauroyl-carnitine) in response to AL and even more with AL_DCF, indicating a shift in cellular metabolism. This study showcases the potential use of AL stimulus within the CEpOC to induce cellular characteristics relevant to DES.

Uveitis and Dry Eye Disease in Children: A Cross-Sectional Comparative Study

PURPOSE

This study aims to evaluate the ocular surface characteristics in children diagnosed with uveitis and explore the association between uveitis and dry eye disease (DED).

METHODS

We included 84 children, 42 with uveitis and 42 healthy children. We performed the OSDI questionnaire and several ocular surface tests, including osmolarity, NITBUT, Schirmer test, and vital staining. We used Fisher's exact test and Mann-Whitney to compare variables and a binomial logistic regression to determine the factors associated with DED.

RESULTS

The difference in the prevalence of DED between uveitis (54.8%) and healthy (31%) groups was statistically significant (p < 0.05). Most patients with uveitis had mixed DED, and none of the healthy subjects had a severe form of the disease. There were no statistically significant differences in most of the tear film tests. However, all parameters tended to worsen in the uveitis group, and lipid layer thickness was thinner (p < 0.036). The uveitis group exhibited significantly more symptoms (p < 0.05). In the multivariate logistic regression, uveitis was associated with an odds ratio (OR) of 3.0 (95% CI: 1.07-8.42, p < 0.05) for DED.

CONCLUSIONS

Our findings demonstrate a significantly higher prevalence of DED in children with uveitis compared to their healthy counterparts. Furthermore, our analysis indicates that the risk of DED in pediatric patients with uveitis is threefold higher than in healthy children. Therefore, it is crucial for clinicians to vigilantly monitor the development of DED in pediatric patients with uveitis and consider the implementation of preventive treatments.

New advances in medical management of dry eye: optimizing treatment strategies for enhanced relief

PURPOSE

Dry eye disease (DED) is a prevalent ocular surface disease that is conventionally characterized by tear film hyperosmolarity and instability. This review presents a summarized classification of DED, followed by a comprehensive discussion of the most recent topical and systemic medications and clinical recommendations for selecting the most appropriate option for each patient.

METHODS

An extensive literature search was conducted on electronic databases, such as PubMed, Scopus, and Web of Science, using keywords including "dry eye syndrome," "ocular surface disease," "medical management," "artificial tears," "topical immunomodulators," and "meibomian gland dysfunction."

RESULTS

The underlying reasons for DED can range from insufficient aqueous tear production to increased tear evaporation. Recent literature has provided a more in-depth understanding of the pathophysiology of DED by examining the tear film's lipid, aqueous, and mucin layers. However, despite these advancements, medical management of patients with symptomatic DED has not fully reflected this modernized knowledge of its pathophysiology.

CONCLUSION

To develop a rationalized strategy for treating DED, it is crucial to have updated knowledge of therapeutic options, their mechanisms of actions, and indications based on the DED type and underlying causes.

LipiFlow for the treatment of dry eye disease

BACKGROUND

Meibomian gland dysfunction (MGD) is the most common underlying cause of dry eye disease (DED). MGD leads to pathological alteration of the composition or quantity of meibum, or both, which subsequently results in tear evaporation and the typical signs and symptoms associated with DED. The LipiFlow Thermal Pulsation System (LipiFlow) is a medical device used to treat MGD in office; however, it is unclear if LipiFlow can outperform other DED treatments.

OBJECTIVES

To evaluate the effectiveness of LipiFlow for treating DED signs and symptoms and the safety of LipiFlow compared with sham or other available treatments for MGD in adults.

SEARCH METHODS

The Cochrane Eyes and Vision Information Specialist searched the electronic databases for randomized controlled trials. There were no restrictions on language or date of publication. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, including the Cochrane Eyes and Vision Trials Register; 2022, Issue 6), MEDLINE Ovid, Embase.com, PubMed, LILACS (Latin American and Caribbean Health Science Information database), ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) electronic databases. We also examined the reference lists of identified trials, review articles, and guidelines for information about relevant trials that may not have been identified by our search strategy. We contacted investigators regarding ongoing trials. The last database search was performed on 24 October 2022.

SELECTION CRITERIA

We included studies conducted in adults (over 18 years of age) with DED or MGD as defined by the primary trial investigators. We imposed no restrictions on race, ethnicity, or sex. We considered trials involving contact lens wearers if they were equally represented between groups.

DATA COLLECTION AND ANALYSIS

We applied standard Cochrane methodology.

MAIN RESULTS

We included 13 trials that randomized a total of 1155 participants (28 to 236 participants randomized per study). Six trials were conducted in the USA, three in China, two in Thailand, one in France, and one in Italy. Eight trials were of single-center design, while four trials were of multicenter design; one trial did not report the number of participating centers. Study characteristics The study population of the included trials was 66% female (range 48% to 80%), with an age range of 19 to 86 years. LipiFlow, used as a stand-alone intervention, was compared with basic warm compresses in five studies, thermostatic device in five studies, oral intervention in one trial, and topical dry eye medications in one trial. LipiFlow was also evaluated together with eyelid hygiene product versus eyelid hygiene products alone in one trial. Findings Five trials compared LipiFlow with a basic warm compress applied for varying durations and frequencies during the trial period; only one of these trials combined a warm compress with eyelid massage. Analyzing symptom scores by different questionnaires (Ocular Surface Disease Index [OSDI] and Standard Patient Evaluation of Eye Dryness [SPEED]) yielded conflicting evidence of a difference in symptoms between LipiFlow and basic warm compresses after four weeks. There was no evidence of a difference in meibomian gland expression, meibum quality, or tear breakup time when comparing LipiFlow with basic warm compresses. Another five trials compared LipiFlow with thermostatic devices. Analysis of symptom scores at four weeks showed that thermostatic devices had reduced OSDI scores by a mean difference (MD) of 4.59 (95% confidence interval [CI] 1.23 to 7.95; I2 = 0, P = 0.007; 553 participants; very low certainty evidence) as compared with LipiFlow. When we compared LipiFlow plus eyelid hygiene with eyelid hygiene alone, there was no evidence of difference in signs or symptoms at any time point evaluated. Only one trial compared LipiFlow with a topical DED medication (lifitegrast 5%). The single-trial estimate suggested that 5% lifitegrast may increase meibomian gland expression scores compared with LipiFlow at day 42 (MD -1.21, 95% CI -2.37 to -0.05; 50 participants; low certainty evidence) by using a meibomian gland expression scale of 0 to 8. One trial compared LipiFlow with an oral intervention (doxycycline), finding that LipiFlow may result in significantly better SPEED scores than doxycycline at three months (MD -4.00, 95% CI -7.33 to -0.67; 24 participants; very low certainty evidence). No other significant differences in signs or symptoms were found between LipiFlow and doxycycline at three months. We did not find any other statistically significant differences in symptoms or signs for any other analysis performed in this review at the one- to four-week time point. Adverse events No trial reported any intervention-related, vision-threatening adverse events.

AUTHORS' CONCLUSIONS

LipiFlow performs similarly to other commonly used DED treatments with regard to DED signs and symptoms. The best available evidence was deemed to have a high level of bias, leading to low or very low certainty evidence. Additional research with adequate masking, a standardized testing methodology, and a sample representative of the MGD population is therefore needed before any firm conclusions can be drawn regarding comparative benefits and harms.

Regional Conjunctival Differences in Glycocalyx Mucin Expression in Dry Eye and Normal Subjects

Purpose

To compare regional conjunctival expression of membrane-associated mucins (MAMs) MUC1, MUC4, and MUC16 in normal and dry eye (DE) subjects.

Methods

Adults with and without signs and symptoms of DE were recruited. Impression cytology was performed to collect MAMs from four bulbar and upper eyelid palpebral conjunctival regions of both eyes. After protein extraction, samples from both eyes of a single subject were pooled by region, and expression was analyzed using a capillary electrophoresis nano-immunoassay system. The chemiluminescence intensity of each antigen binding signal was calculated after normalization to the total protein amount. Statistical analyses were conducted using GraphPad Prime 9.

Results

Samples from thirteen to sixteen DE and seven to eleven normal subjects were analyzed. In normal samples, MUC1 expression from the nasal bulbar conjunctiva was significantly greater than superior (P = 0.004) and inferior (P = 0.005). In DE samples, MUC1 expression was highest superiorly. Significant differences in MUC4 and MUC16 expression were not seen in normal samples. MUC4 and MUC16 expression was upregulated superiorly (P < 0.0001) and inferiorly (P < 0.0001) in DE compared with those regions in normal samples.

Conclusions

Although MAMs form a hydrophilic barrier called the glycocalyx, each mucin may have unique functions that are currently unexplored. All MAMs were expressed in the upper palpebral conjunctiva. Increased MUC1 expression nasally in healthy subjects suggests a functional need for increased protection. When comparing DE with normal eyes, upregulation of MUC1 superiorly, and in both MUC4 and MUC16 both superiorly and inferiorly, may indicate a need to decrease eyelid friction during blinking, especially in DE.

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.

Dry eye disease in the young: A narrative review

Dry eye disease (DED), a multifactorial ocular disease that significantly impacts quality of life, is most commonly reported in adults. This review describes the prevalence, risk factors, diagnosis and management of DED in children. A literature search, conducted from January 2000-December 2022, identified 54 relevant publications. Using similar diagnostic criteria to those reported in adults, namely standardized questionnaires and evaluation of tear film homeostatic signs, the prevalence of DED in children ranged from 5.5% to 23.1 %. There was limited evidence for the influence of ethnicity in children, however some studies reported an effect of sex in older children. Factors independently associated with DED included digital device use, duration of digital device use, outdoor time and urban living, Rates of DED were higher in children with ocular allergy and underlying systemic diseases. Compared with similar studies in adults, the prevalence of a prior DED diagnosis or a diagnosis based on signs and symptoms was lower in children, but symptoms were commonly reported. Treatment options were similar to those in adults, including lifestyle modifications, blinking, management of lid disease and unpreserved lubricants in mild disease with escalating treatment with severity. Management requires careful exploration of symptoms, medical history and the diagnosis and management of ocular comorbidities such as allergy and anterior blepharitis. Appropriately powered population-based studies are required to understand the prevalence of and risk factors for DED in children. Development of age-appropriate thresholds for signs and symptoms of DED would support better diagnosis of disease and understanding of natural history.

Quality of life improvement in dry eye patients after intense pulsed light therapy compared to punctal plugs

PURPOSE

The purpose of the study was to evaluate the quality of life (QOL) improvement in evaporative dry eye patients after treatment with intense pulsed light (IPL) therapy compared to punctal plug insertion.

METHODS

A prospective comparative interventional study included 30 patients with moderate-to-severe evaporative dry eye. Patients' QOL affection before and after treatment was assessed by the Ocular Surface Disease Index (OSDI) questionnaire. Fifteen patients were treated with IPL therapy (Group 1). The other 15 patients were treated with silicone punctal plug insertion (Group 2).

RESULTS

Improvement of patients' QOL was noticed in all patients of Group 1, with significant improvement of OSDI score from a mean value of 56.9 to 22.9 (P = 0.001). Improvement was noticed in 80% of Group 2 patients (mean OSDI score pretreatment: 53.8 and posttreatment: 31.7, P = 0.017). The tear breakup time (TBUT) in Group 1 significantly improved from a mean of 3.2 s to 5.9 s (P = 0.001), whereas it showed no significant changes in Group 2 (mean TBUT pretreatment: 3.6 s and posttreatment: 3.9 s, P = 0.654). Complications occurred in 13.3% in Group 2, including punctal granuloma and proximal canalicular obstruction. No adverse effects were recorded in Group 1.

CONCLUSION

IPL therapy had better results with more improvement of patients' QOL compared to punctal plugs. It also showed a better safety profile with no reported complications.

Evaluation of Main Lacrimal Gland through Shear-wave Ultrasound Elastography in Patients with Low Schirmer Value

OBJECTIVE

To compare main lacrimal gland values through shear-wave elastography (SWE) in patients with low Schirmer value and unspecified Sjögren's syndrome (SS) with healthy controls.

MATERIAL AND METHOD

Admitted to the ophthalmology department with Schirmer value <10 mm, randomly selected 46 eyes of 46 patients evaluated for Sjögren's syndrome (SS) in the rheumatology department between December 2022 and April 2023 were classified as low Schirmer group (LSG). Randomly selected 48 eyes of 48 patients at a similar age with Schirmer value >10 mm were included as controls. Main lacrimal gland SWE measurements in LSG and control groups were recorded and compared as meter/second (m/sec).

RESULTS

Mean SWE values of the main lacrimal gland were measured as 2.78 ± 0.66 m/sec and 2.26 ± 0.29 m/sec in LSG and controls. SWE measurements were significantly higher in LSG patients than in controls (p<0.001). No significant correlation was found in the analysis between the Schirmer and the main lacrimal gland SWE values in LSG patients (p=0.702, r=0.058). No significant correlation was also detected between the Schirmer and main lacrimal gland SWE values in controls (p=0.097, r=0.242). No significant relationship was also found between age, gender, body mass index (BMI), and SWE values (p=0.351, p=0.493, p=0.328, respectively).

CONCLUSION

Mean SWE value of the main lacrimal gland was determined as significantly higher in patients with aqueous lacrimal insufficiency without SS than in controls. We consider that SWE measurements may be an imaging method to support the diagnosis of aqueous lacrimal insufficiency and used in follow-ups of those with dry eye syndrome (DES) in the future.

A Randomized, Controlled Trial Comparing Tearcare® and Cyclosporine Ophthalmic Emulsion for the Treatment of Dry Eye Disease (SAHARA)

Purpose

We compare outcomes in eyes with dry eye disease (DED) treated with TearCare (TC) or topical cyclosporine 0.05% (RESTASIS; CsA).

Setting

Nineteen ophthalmic and optometric practices in 11 US states.

Design

Multicenter, randomized, assessor-masked, controlled IRB-approved trial. Eligible subjects: ≥22 years of age, dry eye symptoms within 3-6 months, Tear Break-up Time (TBUT) ≥1 to ≤7 s, Meibomian Gland Secretion Score (MGSS) ≤12, Ocular Surface Disease Index (OSDI) of 23-79. Randomized (1:1) to TC or CsA. TC subjects treated at baseline and month 5; CsA was twice daily for 6 months.

Methods

Follow-up visits were scheduled for Day 1, Week 1, Months 1, 3, and 6 with primary inference at Month 6. Primary outcomes: TBUT and OSDI; secondary outcomes: MGSS, conjunctival and corneal staining, eye dryness score (EDS), symptoms assessment in dry eye (SANDE) score, and Schirmer tear score (STS). Safety assessments included adverse events, best corrected visual acuity, intraocular pressure, and slit-lamp findings.

Results

Overall, 345 subjects, 172 TC and 173 CsA. TBUT improved at all time points in both groups (p<0.0001), with statistically greater improvement for TC versus CsA (p=0.0006). OSDI improved significantly at all time points in both groups (p<0.0001) with no significant differences between treatments. MGSS and other measures of meibomian gland function improved significantly more with TC eyes versus CsA; other secondary outcomes showed significant improvements in both groups with no difference between groups. Treatment-related adverse events were uncommon (10 total, 8 in the CsA group consistent with prior CsA studies); most (9/10) mild.

Conclusion

TC provides statistically superior and sustained improvement in TBUT and multiple measures of meibomian gland secretion, and non-inferior improvement in OSDI, corneal and conjunctival staining, SANDE, EDS, and STS versus CsA. TC should be a preferred treatment for DED associated with MGD.

Poloxamer sols endowed with in-situ gelability and mucoadhesion by adding hypromellose and hyaluronan for prolonging corneal retention and drug delivery

The purpose of this study was to develop poloxamer (P407)-based in-situ thermogellable hydrogels with reducing concentration of P407 by adding hypromellose (HPMC) and with enhancing mucoadhesion of resulting hydrogels by adding hyaluronic acid (HA) for prolonging ocular delivery of hydroxypropyl-β-cyclodextrin (HPβCD)-solubilized testosterone (TES). Results demonstrated that 0.5% TES solution was successfully solubilized with adding 10% HPβCD. Non-gellable 13% P407 sol became in-situ gellable with adding 2.0-2.5% HPMC and mucoadhesibility was further imporved with adding 0.3% HA-L (low MW) or HA-H (high MW). Optimized 0.5% HPβCD-solubilized TES P407-based thermogellable hydrogels with enhancement of mucoadhesion for prolonging ocular delivery comprised 13% P407, 2.5% HPMC, and 0.3% HA-L or HA-H. Furthermore, rheological measurements under simulated eye blinking confirmed that non-thixotropic properties of optimized hydrogels could be spreaded evenly and retain a greater amount of drug-loaded hydrogels on the ocular surface for a longer period to prolong drug delivery. Compared with conventional eye drops, the prolonged residence time of optimized hydrogels from ex vivo and in vivo studies were observed, indicating relationships between rheological properties and in vivo performances. It was concluded that P407-based thermosensitive hydrogels with reducing concentration of P407 and enhancing mucoadhesion was successfully formulated by adding 2.5% HPMC and 0.3% HA in 13% P407 for potentially accomplishing effective clinical treatment of DED.

PM2.5 exposure increases dry eye disease risks through corneal epithelial inflammation and mitochondrial dysfunctions

Dry eye disease (DED) is the most common disease affecting vision and quality of life. PM2.5 was a potential risk of DED. Herein, we conducted animal exposure and cell-based studies to evaluate the pathogenic effect of PM2.5 exposure on the ocular surface and DED etiological mechanisms. C57 mice were exposed to filtered air and PM2.5 aerosol. We assessed health conditions and inflammation of the ocular surface by corneal fluorescein staining and immunohistochemistry. In parallel, cultured human corneal epithelial cells (HCETs) were treated with PM2.5, followed by characterization of cell viability, intracellular ATP level, mitochondrial activities, and expression level of DED relevant mRNA and proteins. In mice, PM2.5 exposure induced severe superficial punctate keratopathy and inflammation in their cornea. In HCETs, cell proliferation and ROS generation followed dose-response and time-dependent manner; meanwhile, mitochondrial ROS (mtROS) level increased and mitochondrial membrane potential (MMP) level decreased. Inflammation cascade was triggered even after short-term exposure. The reduction of ATP production was alleviated with Nrf2 overexpression, NF-κB P65 knockdown, or ROS clearance. Nrf2 overexpression and P65 knockdown reduced inflammatory reaction through decreasing expression of P65 and increasing of Nrf2, respectively. They partly alleviated changes of ROS/mtROS/MMP. This research proved that PM2.5 would cause DED-related inflammation reaction on corneal epithelial cells and further explored its mechanism: ROS from mitochondrial dysfunctions of corneal epithelial cells after PM2.5 exposure partly inhibited the expression of anti-inflammatory protein Nrf2 led the activation of inflammatory protein P65 and its downstream molecules, which finally caused inflammation reaction.

Evaluation of aqueous-deficient and evaporative dry eye cases with confocal microscopy

INTRODUCTION

Dry eye disease (DED) is an important health problem affecting hundreds of millions of people worldwide. In vivo confocal microscopy (IVCM) is a non-invasive imaging tool that can visualize ocular surface diseases. In this study, we aimed to evaluate corneal structures and inflammatory cells with IVCM in DED patients.

MATERIAL AND METHODS

The patients were divided into three subgroups: group 1, consisting of 22 patients with aqueous tear insufficiency; group 2, consisting of 21 patients with evaporative type DED; and group 3, consisting of 20 healthy patients. Imaging was performed with IVCM. The corneal epithelium, nerves, stroma, endothelial and inflammatory cells were compared between groups.

RESULTS

There was a significant decrease in corneal epithelial cell density in cases with DED, and there was a significant increase in corneal basal epithelial cell density in the aqueous-deficient type. Keratocyte density was significantly increased in the aqueous-deficient type. A significant decrease in the number and density of sub-basal nerves was found in aqueous-deficient cases, and an increase was found in neural pilling and folding. Dendritic cell density, size, number and area were significantly increased in the aqueous-deficient type. There was also decreased corneal endothelial cell density in DED.

CONCLUSION

We evaluated pathological changes in DED on the corneal surface by IVCM. This methodology is valuable in terms of objectively evaluating how the corneal surface is affected in accordance with disease severity and in predicting poor response to treatment.

Thermal Pulsation in the Management of Meibomian Gland Dysfunction and Dry Eye: A Report by the American Academy of Ophthalmology

PURPOSE

To review the literature to determine the efficacy and safety of thermal pulsation technologies in improving signs or symptoms of meibomian gland dysfunction (MGD) and dry eye compared with no therapy or with conventional warm compress therapy or eyelid hygiene.

METHODS

A literature search was conducted in the PubMed database in June 2022 and again in March 2023 to identify all studies in the English language on the use of thermal pulsation to treat MGD or dry eye. The search yielded 59 citations, and 11 articles met all of the inclusion criteria. The panel methodologist then assigned a level of evidence rating for each study; 8 studies were rated level I evidence and 3 studies were rated level II evidence.

RESULTS

All included studies evaluated a single 12-minute session using the LipiFlow automated thermal pulsation system (TearScience, Inc, or Johnson & Johnson). Improvements were detected in subjective and objective metrics of MGD or dry eye in patients within 1 to 12 months of thermal pulsation treatment compared with nontreatment. Most of the studies (9/11) reported greater efficacy with thermal pulsation than with standard warm compress therapy and eyelid hygiene. Four of these studies showed relevant industry conflicts of interest. Two of the 4 level I studies without direct industry participation concluded that thermal pulsation treatment was not significantly different from conventional hygiene or warm compress therapy control treatments (in symptoms in one of the studies and in objective findings in the second study). No serious adverse events were reported in any of the 11 studies.

CONCLUSIONS

According to the current literature, a single thermal pulsation session may improve subjective or objective parameters of MGD and dry eye safely. However, industry support and participation were present in 4 of the 8 level I studies. The durability beyond several months and cost efficacy remain uncertain. Because the inclusion parameters of this assessment captured only the LipiFlow system, the conclusions are limited to that product. High-quality independent studies are needed to assess the long-term benefits of this intervention.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Tear film lipid layer and corneal oxygenation: a new function?

The classic model of tear film is composed of mucin layer, aqueous layer and the outermost tear film lipid layer (TFLL). The complex mixture of different classes of lipids, mainly secreted by meibomian glands, gives the TFLL unique physicochemical properties. Based on these properties, several functions of TFLL have been found and/or proposed such as the resistance to evaporation and facilitating the formation of a thin film. However, the role of TFLL in the oxygenation of the cornea, a transparent avascular tissue, has never been discussed in the literature. The continuous metabolic activity of the corneal surface and the replenishment of atmospheric gas creates an O2 gradient in the tear film. The molecules of O2 must therefore be transferred from the gas phase to the liquid phase through the TFLL. This process is a function of the diffusion and solubility of the lipid layer as well as interface transfer, which is influenced by alterations in the physical state and lipid composition. In the absence of research on TFLL, the present paper aims to bring the topic into the spotlight for the first time based on existing knowledge on O2 permeability of the lipid membranes and evaporation resistance of the lipid layers. The oxidative stress generated in perturbed lipid layers and the consequent adverse effects are also covered. The function of the TFLL proposed here intends to encourage future research in both basic and clinical sciences, e.g., opening new avenues for the diagnosis and treatment of ocular surface conditions.

Ocular dryness in intensive care: proposal for a new nursing diagnosis

OBJECTIVE

to analyze the concept associated with diagnostic proposition Ocular dryness in adult patients hospitalized in an Intensive Care Unit, identifying its attributes, antecedents and consequences.

METHODS

a methodological study carried out through concept analysis, operationalized by scoping review.

RESULTS

the analysis of 180 studies allowed the identification of two attributes, 32 antecedents and 12 consequences. The attributes were tear film deficiency and ocular signs and/or symptoms. The prevalent antecedents were incomplete eyelid closure (lagophthalmos) and blinking mechanism decrease. Major consequences included conjunctival hyperemia and decreased tear volume.

CONCLUSIONS

this study allowed constructing nursing diagnosis Ocular dryness, part of domain 11, class 2, with 12 defining characteristics, 12 related factors, seven populations at risk and 13 associated conditions. This problem-focused proposal may provide targeted care by promoting early detection and implementing interventions that reduce the risk of ocular damage.

Prevalence of Meibomian Gland Atrophy in Patients Undergoing Cataract Surgery

PURPOSE

The aim of this study was to determine the prevalence of meibomian gland (MG) atrophy in a US-based population of patients presenting for cataract surgery.

METHODS

In this retrospective study, case records of 391 patients aged 50 years or older, who had undergone a preoperative cataract surgery workup with meibography, were included. The amount of atrophy in the lower eyelid was graded as described by Arita et al (grade 0 = no atrophy, grade 1 = 1%-33% atrophy, grade 2 = 34%-66% atrophy, and grade 3 = >66% atrophy), and the prevalence of MG atrophy was determined. Associations between MG atrophy and demography, comorbidities, and risk factors were evaluated.

RESULTS

Overall, 95.1% of patients (372/391) had MG atrophy ≥grade 1, with 50.4% (197/391) having grade 1, 25.8% (101/391) grade 2, and 18.9% (74/391) grade 3. MG atrophy had a statistically significant correlation with MG expressibility (R = 0.22; P = 0.001), but not with meibum grade (R = 0.103; P = 0.123) and telangiectasia (R = 0.014; P = 0.787). The prevalence of MG atrophy (≥grade 1) was comparable among patients who had previously been diagnosed with dry eye disease (DED) versus those who had not; however, the severity of MG atrophy was higher in patients with previous DED diagnosis (grade 2/3: 59% vs. 30.9%). Among patients with no previous history of DED, 18% (35/194) had moderate and 13% (25/194) had severe MG atrophy.

CONCLUSIONS

MG atrophy is common in patients presenting for cataract surgery evaluation, indicating potential underdiagnosis. Routine use of meibography during preoperative screening in cataract surgery patients may facilitate more timely and effective diagnosis and treatment.

Evaluation of dry eye and meibomian gland function in pregnancy

PURPOSE

To evaluate the signs and symptoms of dry eye in healthy pregnant women and investigate the effect of pregnancy on meibomian gland loss using non-contact meibography.

METHODS

Healthy pregnant women and age-matched healthy non-pregnant women were included in the study. Subjective symptoms were assessed using the Ocular Surface Disease Index (OSDI). The first and average non-invasive break-up times (first-NIBUT and avg-NIBUT, respectively) were determined, and the Schirmer test was applied. Non-contact meibography was performed.

RESULTS

The study included a total of 62 women, 30 pregnant (study group) and 32 non-pregnant (control group). There was no significant difference between the groups in terms of OSDI score and the Schirmer test (p > 0.05). The mean first-NIBUT and avg-NIBUT values of the study group (13.1 ± 5.3 and 13.7 ± 4.5 s) were significantly lower than the control group (16.0 ± 2.4 and 16.4 ± 1.5 s) (p: 0.015 and p: 0.040, respectively). The mean meibomian gland losses in the upper and lower eyelids were significantly higher in the study group (16.9 ± 8.2% and 11.6 ± 10.2%) compared to the control group (9.7 ± 6.2% and 5.6 ± 4.7%) (p < 0.001 and p: 0.011, respectively).

CONCLUSIONS

It is considered that loss of the meibomian glands may occur during pregnancy, and this may predispose pregnant women to evaporative dry eye. Although dry eye does not cause significant ocular surface symptoms in pregnancy, NIBUT and non-contact meibography can be considered as effective diagnostic methods for the detection of dry eye in pregnant women.

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.

Cationic nanoemulsion vs. 0.15% sodium hyaluronate artificial tears in the healing process following modern surface keratorefractive surgery

PURPOSE

The aim of this study was to investigate the influence of artificial tears containing either cationic nanoemulsion (CCN) or sodium hyaluronate artificial tears (SH) on early postoperative healing after modern surface refractive surgery.

MATERIALS AND METHODS

In this multicenter, prospective, double-masked, parallel-group (1:1), comparative study, 129 patients (n = 255 eyes) were randomized to receive CCN (n = 128) or SH (n = 127) as an adjuvant treatment after either transepithelial photorefractive keratectomy (transPRK) or Epi-Bowman keratectomy (EBK). The patients' perspectives were gathered using the Ocular Surface Disease Index (OSDI) questionnaire, and uncorrected (UCVA), and corrected (BCVA) visual acuity were assessed before and one week and one month after the procedure. In addition, corneal epithelization and subjective assessment of visual blur and eye irritation on drop instillation were assessed at one week postoperatively.

RESULTS

No statistically significant differences were found between two groups in age, spherical equivalent refractive error, UCVA, BCVA or OSDI scores before the procedure. There was also no difference between groups in UCVA one week and one month after the procedure. However, statistically significantly lower OSDI scores were found one week and one month after the procedure in the CCN group. Moreover, blurred vision after use of the eye drops was observed less frequently in the CCN group than in the SH group.

CONCLUSIONS

The CCN and SH groups had similar postoperative UCVA. However the significantly lower OSDI scores and less frequently blurred vision after application of the eye drops in the CCN group suggest better subjective outcomes in this group.

Early-Stage Development of an Anti-Evaporative Liposomal Formulation for the Potential Treatment of Dry Eyes

Dry eye disease (DED), the most common ocular disorder, reduces the quality of life for hundreds of millions of people annually. In healthy eyes, the tear film lipid layer (TFLL) stabilizes the tear film and moderates the evaporation rate of tear fluid. In >80% of DED cases, these central features are compromised leading to tear film instability and excessive evaporation of tear fluid. Herein we assess the potential of liposomal formulations featuring phosphatidylcholines and tailored lipid species from the wax ester and O-acyl-ω-hydroxy fatty acid categories in targeting this defect. The developed lead formulation displays good evaporation-resistant properties and respreadability over compression-expansion cycles in our Langmuir model system and a promising safety and efficacy profile in vitro. Preclinical in vivo studies will in the future be required to further assess and validate the potential of this concept in the treatment of DED.

Hyperprolactinemia modifies extracellular matrix components associated with collagen fibrillogenesis in harderian glands of non- and pregnant female mice

The harderian gland (HG) is a gland located at the base of the nictating membrane and fills the inferomedial aspect of the orbit in rodents. It is under the influence of the hypothalamic-pituitary-gonadal axis and, because of its hormone receptors, it is a target tissue for prolactin (PRL) and sex steroid hormones (estrogen and progesterone). In humans and murine, the anterior surface of the eyes is protected by a tear film synthesized by glands associated with the eye. In order to understand the endocrine changes caused by hyperprolactinemia in the glands responsible for the formation of the tear film, we used an animal model with metoclopramide-induced hyperprolactinemia (HPRL). Given the evidences that HPRL can lead to a process of cell death and tissue fibrosis, the protein expression of small leucine-rich proteoglycans (SLRPs) was analyzed through immunohistochemistry in the HG of the non- and the pregnant female mice with hyperprolactinemia. The SRLPs are related to collagen fibrillogenesis and they participate in pro-apoptotic signals. Our data revealed that high prolactin levels and changes in steroid hormones (estrogen and progesterone) can lead to an alteration in the amount of collagen, and in the structure of type I and III collagen fibers through changes in the amounts of lumican and decorin, which are responsible for collagen fibrillogenesis. This fact can lead to the impaired functioning of the HG by excessive apoptosis in the HG of the non- and the pregnant female mice with HPRL and especially in the HG of pregnancy-associated hyperprolactinemia.

Recent advances in age-related meibomian gland dysfunction (ARMGD)

Meibomian glands (MGs), located within the tarsal plate of the eyelid, secrete meibum which is the lipid-rich secretion necessary for stabilizing the tear film and preventing tear evaporation. Changes in the quality and quantity of meibum produced causes MG dysfunction (MGD), the leading cause of evaporative dry eye disease (EDED). MGD is an underdiagnosed disease and it is estimated that, in the US, approximately 70 % of the population over 60 have MGD. Three forms of MGD occur based on their meibum secretion: hyposecretory, obstructive, and hypersecretory MGD. The pathophysiology of MGD remains poorly understood, however aging is the primary risk factor. With age, MGs undergo various age-related changes, including decreased acinar basal cell proliferation, hyperkeratinization, MG atrophy, and eventual MG drop-out, leading to age-related MGD (ARMGD). Additionally, studies have suggested that MGs can suffer inflammatory cell infiltration and changes innervation patterns with aging, which could also contribute towards ARMGD. This review focuses on how the aging process affects the MG, and more importantly, how age-related changes to the MG can lead to MG atrophy and MG drop-out, ultimately leading to ARMGD. This review also highlights the most recent developments in potential therapeutic interventions for ARMGD.

3-month post-procedural evaluation of a combined intense pulsed light and photo-biomodulation system in the treatment of meibomian gland dysfunction

PURPOSE

Meibomian gland dysfunction (MGD) is the leading cause of dry eye syndrome. It is a frequent and underdiagnosed condition with a significant socioeconomic impact. We propose here the evaluation of a platform combining intense pulsed light and photo-biomodulation in the treatment of Meibomian gland dysfunction.

METHODS

We conducted a retrospective study at Brest University Hospital analyzing a cohort of 74 eyes (37 patients) at 1 month and 3 months after a protocol of 3 Eye-Light® (Espansione Group, Italy) sessions 14 days apart between January 2019 and April 2020. The primary outcome was the change in OSDI quality of life score. Secondary outcomes were the SPEED questionnaire score; tear break-up time (BUT), Oxford score, non-invasive break-up time (NIBUT), lipid layer thickness, lacrimal meniscus height and Meibomian gland atrophy rate. Tolerance of the treatment was also evaluated.

RESULTS

We found a significant improvement in OSDI scores at 1 month (-17.32; 95% CI (-25.84; -8.79), P<0.0001) and 3 months (-16.95; 95% CI (-25.26; -8.64), P<0.0001). The SPEED score, BUT, Oxford score, Meibomian gland atrophy and NIBUT were also statistically significantly improved. Tolerance to treatment was very good despite two cases of herpetic keratitis, which resolved on treatment.

CONCLUSION

Treatment with the Eye-Light® in three sessions every two weeks significantly reduced symptoms and ocular surface damage in patients with MGD. This data suggests that the use of Eye-Light® may represent a good option for patients with MGD.

Morphological and functional assessment of the tear film and meibomian glands in keratoconus

PURPOSE

To evaluate morphological and functional state of the meibomian glands (MG) in keratoconus patients.

METHODS

One hundred eyes of 100 keratoconus patients and 100 eyes of 100 age-matched control subjects were included into this study. Ocular Surface Disease Index (OSDI) scores, non-invasive break up time (NIBUT), findings of meibography, staining with fluorescein of the ocular surface, tear film break-up time (TBUT), and Schirmer I test were documented in all patients' eyes and control eyes and were compared between the groups .

RESULTS

The mean TBUT and NIBUT were significantly lower, corneal staining and OSDI scores were statistically greater in the keratoconus group (p < 0.05). The mean meiboscore, partial gland, gland dropout and gland thickening scores for upper/lower eyelids were significantly greater in keratoconus patients than controls (p < 0.05). The NIBUT measurements significantly correlated with MG loss in upper/lower eyelids (p < 0.05). The severity of keratoconus seemed to correlate with meiboscore, partial gland, gland thickening scores in upper/lower eyelids.

CONCLUSION

Our data suggests that corneal ectasia in keratoconus is related with alterations in ocular surface, tear film function and MG morphology. Early screening and treatment of MG dysfunction may improve ocular surface quality and allow better disease management in keratoconus patients.

Localized Heat Treatment for Meibomian Gland Dysfunction: A Single-Center Retrospective Analysis of Efficacy over Time

SIGNIFICANCE

Meibomian gland dysfunction (MGD) can produce a myriad of symptoms. The effective treatment of MGD can reduce the burden of this condition. Although several studies have indicated that TearCare (Sight Sciences, Menlo Park, CA) is an effective treatment for MGD, no studies currently provide information regarding the duration of efficacy.

PURPOSE

The purpose of this analysis was to determine the duration of efficacy of symptom relief and improvement of signs (as measured by gland function) for a treatment consisting of controlled heating of the meibomian glands using SmartLids (Sight Sciences) combined with manual expression of the liquefied meibum by a physician.

METHODS

This study involved retrospective analysis of data gathered from a single-center ophthalmology/optometry practice. Symptoms were assessed using the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire, and the signs were assessed using the meibomian gland expression (MGE) scores before and at several time points (8 weeks, 6 months, 12 months, and 18 months). Further analysis evaluating the efficacy in subgroups based on age, race, and sex was performed.

RESULTS

There were 78 patients included in this study. The mean baseline SPEED score decreased from 14 to 7.9 at 8 weeks. The mean SPEED scores at 6 and 12 months were maintained at 7.7 and 7.9, respectively, and at 18 months went to 8.9. At baseline, the mean MGE was 4.9 in the right eye and 4.8 in the left eye. In both eyes, the mean MGE increased to 9.0 in both eyes at 8 weeks. At 6 months, the mean MGE score was maintained at 8.6 in the right and 8.2 in the left and remained consistent at 12 months with 7.8 in the right and 7.8 in the left. At 18 months, the MGE score went to 6.8 in the right eye and 7.0 in the left eye.

CONCLUSIONS

A single TearCare treatment effectively reduced both the symptoms and signs of MGD and maintained its effects for 12 months.

Application of optical coherence tomography and keratograph in the measurements of lower lid margin thickness

PURPOSE

This study aims to investigate the applicability of lower lid margin thickness (LLMT) measurements in adults with and without meibomian gland dysfunction (MGD) by optical coherence tomography (OCT) and keratograph.

METHODS

This is a cross-sectional, observational study. A hundred and eight volunteers aged 20 to 79, including 68 MGD patients and 40 normal subjects, were recruited. Using OCT and keratograph to measure the LLMT from the posterior lash line to anterior edge or outer edge of the tear meniscus was separately performed two times by the same person.

RESULTS

The mean age of normal and MGD subjects was 50.5 ± 14.2 years and 55.8 ± 15.5 years, respectively. The LLMT with OCT and keratograph in MGD patients was significantly greater than that in normal subjects (1.06 ± 0.27 and 1.03 ± 0.25 mm vs. 0.90 ± 0.20 and 0.86 ± 0.16 mm, respectively). In both normal and MGD subjects, the tear meniscus height and LLMT with OCT were both greater than that with keratograph (P < 0.05), and intraclass correlation coefficient (ICC) demonstrated a good agreement in the LLMT measurements between two devices (ICC = 0.83 and 0.79, respectively). Additionally, the LLMT in MGD patients was appeared to be positively correlated with meiboscore (rs = 0.37, P = 0.002).

CONCLUSIONS

The OCT and keratograph were two reliable tools in the LLMT measurements, which may have potential applications for diagnosis and evaluation of MGD. Furthermore, we found that the LLMT measured by OCT was greater than that measured by keratograph.

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.

Efficacy and safety of AZR-MD-001 selenium sulfide ophthalmic ointment in adults with meibomian gland dysfunction: A vehicle-controlled, randomized clinical trial

PURPOSE

Meibomian gland dysfunction (MGD) is a chronic progressive disease with downstream effects on ocular signs and symptoms. AZR-MD-001 is a selenium sulfide ophthalmic ointment that was investigated as a potential treatment option for patients with MGD.

METHODS

A Phase 2, multi-center, double-masked, parallel group study was conducted across 29 sites, with 245 patients randomized 1:1:1 to AZR-MD-001 0.5%, AZR-MD-001 1.0% or vehicle applied to the lower eyelid, twice weekly. Patients were eligible for the trial if they presented with signs and symptoms of MGD. Co-primary efficacy endpoints were the changes from baseline in number of open glands (Meibomian Glands Yielding Liquid Secretion [MGYLS] score) and patient-reported ocular surface symptoms (Ocular Surface Disease Index [OSDI] total score) at Month 3. Efficacy outcomes were captured at Day 14, Month 1.5 and Month 3. Safety and tolerability were assessed for treatment-emergent adverse events (TEAEs).

RESULTS

AZR-MD-001 0.5% (n = 82 patients) treatment resulted in significant improvements in MGYLS score, with patients experiencing an average increase from baseline of 4.2 and 2.4 open glands secreting meibum for the drug and vehicle, respectively (p < 0.001) and from baseline a mean OSDI total score improvement of 7.3 and 3.8 for the drug and vehicle, respectively (p < 0.05). Most TEAEs were mild and transient, with 3 serious adverse events (SAEs) reported with AZR-MD-001 (none related to study drug).

CONCLUSIONS

Co-primary endpoints were met for AZR-MD-001 0.5% at Month 3, with a statistically significant improvement in the signs and symptoms of MGD. AZR-MD-001 was safe and well tolerated.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03652051, ANZCTR Registration Number: AZ201801.

Prevalence and Associated Risk Factors of Dry Eye Disease Among Children and Adults in Saudi Arabia: A Cross-Sectional Study

BACKGROUND

Dry eye disease (DED) is characterized by loss of homeostasis of the tear film or failure to produce sufficient amounts of tears to moisturize the eyes. The condition has been associated with several preventable risk factors.  Objective: The objective of this study is to calculate the prevalence of dry eye and determine the associated risk factors among adults and children in Saudi Arabia.  Methods: This is a cross-sectional study targeting all Saudi populations, including all the regions of Saudi Arabia. The Ocular Surface Disease Index (OSDI) and the five-item Dry Eye Questionnaire (DEQ-5) were used for data collection. Data were collected using an online form that was distributed through social media.  Results: A total of 541 responses were analyzed. The OSDI scores showed that females represented 70.9%, and the age group of 20-40 years represented 59.7%. The prevalence of DED, including all severity levels, was 74.9%. The distribution across levels was as follows: mild cases at 26.2%, moderate cases at 18.2%, and severe at 30.4%. On the other hand, DEQ-5 has shown a prevalence of 37% among the pediatric age group. Several risk factors have been significantly associated with adults' dry eye, including low humidity (P-value=0.002), reading, driving, or watching electronic screens for extended durations (P-value=0.019), autoimmune diseases (P-value=0.033), and undergoing eye procedures (P-value-0.013).  Conclusion: The current study reports a high prevalence rate of dry eyes among the Saudi population. Reading, driving, and using electronic screens for an extended period were found to be associated with the severity of DED. Prospective studies should focus on the epidemiology of the disease, which will provide evidence for better preventive and therapeutic measures.

Intense pulsed-light treatment improves objective optical quality in patients with meibomian gland dysfunction

BACKGROUND

To evaluate changes in objective optical quality following intense pulsed light (IPL) treatment combined with meibomian gland (MG) expression (MGX) in patients with MG dysfunction (MGD).

METHODS

This retrospective cross-sectional study included MGD-related dry eye disease (DED) patients who received IPL treatment between March and December 2021 at Kim's Eye Hospital, Seoul, Republic of Korea. Each patient underwent four sessions of IPL treatment using Lumenis M22 (Lumenis Ltd., Yokneam, Israel) and MGX at three-week intervals.

RESULTS

This study included 90 eyes from 45 patients with MGD. The mean age was 52.3 ± 16.1 years (range, 20-75 years), and 53.3% (24/45) of patients were female. Compared with the baseline, all clinical symptoms and signs significantly improved after IPL treatment combined with MGX. All optical quality parameters obtained with an optical quality analysis system (OQAS: Visiometrics, Castelldefels, Spain) have improved significantly over the baseline (p < 0.001).

CONCLUSIONS

In patients with MGD, IPL treatment combined with MGX improved the objective optical quality and clinical signs and symptoms of DED.

Differential characteristics among asymptomatic and symptomatic meibomian gland dysfunction and those with dry eye

PURPOSE

To identify the characteristics of asymptomatic meibomian gland dysfunction (MGD), symptomatic MGD, and MGD coexisting with dry eye disease (DED).

METHODS

This cross sectional study enrolled a total of 153 eyes of 87 MGD patients. Participants filled in ocular surface disease index (OSDI) questionnaires. Age, gender, Schirmer's test, meibomian gland (MG) related parameters, lipid layer thickness (LLT) and blinking were compared among patients with asymptomatic MGD, symptomatic MGD, and MGD with DED. Multivariate regression was used to analyze the significant factor of DED in MGD. Spearman's rank correlation analysis was used to evaluate the association between the significant factors and MG function.

RESULTS

There was no difference in age, Schirmer's test, lid changes, MG secretion, and MG morphology among three groups. The OSDI of asymptomatic MGD, symptomatic MGD and MGD coexisting with DED were 8.5 ± 2.9, 28.5 ± 12.8 and 27.9 ± 10.5, respectively. Patients with MGD coexisting with DED exhibited more frequent eye blinking than that of patients with asymptomatic MGD (8.1 ± 4.1 vs. 6.1 ± 3.5 blinks/20 sec, P = 0.022), and reduced LLT than that of patients with asymptomatic MGD (68.6 ± 17.2 vs. 77.6 ± 14.5 nm, P = 0.010) and symptomatic MGD (78.0 ± 17.1 nm, P = 0.015). Multivariate analysis identified LLT (per nm, OR = 0.96, 95% CI = 0.93-0.99, P = 0.002) as a significant factor associated with DED development in MGD. The number of expressible MG was positively correlated with LLT (Spearman's correlation coefficient = 0.299, P = 0.016) but negatively correlated with the number of blinking (Spearman's correlation coefficient = -0.298, P = 0.016) in MGD patients with DED, and these findings were not identified in those without DED.

CONCLUSIONS

Asymptomatic MGD, symptomatic MGD, and MGD coexisting with DED share similar characteristics, including meibum secretion and morphology, but MGD patients coexisting with DED exhibited significantly reduced LLT.

Features and influences on the normal tear evaporation rate

Tear evaporation is a normal physiological phenomenon that has an important role in regulating blink activity and tear production. An altered tear evaporation rate (TER) is a defining characteristic of evaporative dry eye disease (DED), and the measurement of tear evaporation is a useful clinical test for diagnosis. Reported values for a normal TER cover a broad range, which may be due to the influence of ocular, environmental, and systemic factors. For improved disease diagnosis, a fuller understanding of the normal TER range is essential. This paper reports on a literature review of the current knowledge of these normal influences on TER.