Latest evidences on meibomian gland dysfunction diagnosis and management

Comprehensive dry eye therapy: overcoming ocular surface barrier and combating inflammation, oxidation, and mitochondrial damage

BACKGROUND

Dry Eye Disease (DED) is a prevalent multifactorial ocular disease characterized by a vicious cycle of inflammation, oxidative stress, and mitochondrial dysfunction on the ocular surface, all of which lead to DED deterioration and impair the patients' quality of life and social functioning. Currently, anti-inflammatory drugs have shown promising efficacy in treating DED; however, such drugs are associated with side effects. The bioavailability of ocular drugs is less than 5% owing to factors such as rapid tear turnover and the presence of the corneal barrier. This calls for investigations to overcome these challenges associated with ocular drug administration.

RESULTS

A novel hierarchical action liposome nanosystem (PHP-DPS@INS) was developed in this study. In terms of delivery, PHP-DPS@INS nanoparticles (NPs) overcame the ocular surface transport barrier by adopting the strategy of "ocular surface electrostatic adhesion-lysosomal site-directed escape". In terms of therapy, PHP-DPS@INS achieved mitochondrial targeting and antioxidant effects through SS-31 peptide, and exerted an anti-inflammatory effect by loading insulin to reduce mitochondrial inflammatory metabolites. Ultimately, the synergistic action of "anti-inflammation-antioxidation-mitochondrial function restoration" breaks the vicious cycle associated with DED. The PHP-DPS@INS demonstrated remarkable cellular uptake, lysosomal escape, and mitochondrial targeting in vitro. Targeted metabolomics analysis revealed that PHP-DPS@INS effectively normalized the elevated level of mitochondrial proinflammatory metabolite fumarate in an in vitro hypertonic model of DED, thereby reducing the levels of key inflammatory factors (IL-1β, IL-6, and TNF-α). Additionally, PHP-DPS@INS strongly inhibited reactive oxygen species (ROS) production and facilitated mitochondrial structural repair. In vivo, the PHP-DPS@INS treatment significantly enhanced the adhesion duration and corneal permeability of the ocular surface in DED mice, thereby improving insulin bioavailability. It also restored tear secretion, suppressed ocular surface damage, and reduced inflammation in DED mice. Moreover, it demonstrated favorable safety profiles both in vitro and in vivo.

CONCLUSION

In summary, this study successfully developed a comprehensive DED management nanosystem that overcame the ocular surface transmission barrier and disrupted the vicious cycle that lead to dry eye pathogenesis. Additionally, it pioneered the regulation of mitochondrial metabolites as an anti-inflammatory treatment for ocular conditions, presenting a safe, efficient, and innovative therapeutic strategy for DED and other inflammatory diseases.

Safety and Efficacy of Topical Vitamin D in the Management of Dry Eye Disease Associated With Meibomian Gland Dysfunction: A Placebo-Controlled Double-Blind Randomized Controlled Trial

PURPOSE

The aim of this study was to investigate the safety and efficacy of topical vitamin D in the management of dry eye disease associated with meibomian gland dysfunction (MGD).

METHODS

In this randomized controlled trial, patients with symptomatic MGD were divided into 2 groups to receive topical vitamin D drops or placebo in their randomized eyes. The exclusion criteria consisted of patients with vitamin D deficiency, previous ocular surgery, and patients with ocular diseases affecting the tear film. Patients and researchers were masked to the study groups. The outcomes included the score of Dry Eye Questionnaire (DEQ) 5 and Ocular Surface Disease Index (OSDI), corneal and conjunctival staining score, tear breakup time (TBUT), Schirmer, and MG expressibility score evaluated at baseline and weeks 4 and 8.

RESULTS

Twenty-eight eyes of 28 patients were recruited in each group. In addition to the improvement of subjective parameters in both groups, there was a statistically significantly greater improvement in the vitamin D group compared with control for average scores of OSDI (13.38 ± 7.32 vs. 27.94 ± 7.49) and DEQ5 (9.67 ± 1.86 vs. 14.14 ± 2.45) at week 8 (Ps <0.001). In addition, a significant improvement in TBUT and Schirmer test was observed in both groups in weeks 4 and 8 ( P value <0.05). There was a significant difference between the treatment and control groups after 8 weeks for OSDI, DEQ5, Schirmer, TBUT, corneal fluorescein staining, and MG expressibility score ( P value <0.05).

CONCLUSIONS

The preliminary results of this randomized controlled trial suggested that use of topical vitamin D drops with a lipid vehicle could be safe and might significantly improve the symptoms and signs of dry eye associated with MGD.

Quantitative evaluation of morphological and functional changes in meibomian glands and lipid layer thickness in patients with and without keratoconus

PURPOSE

To quantitatively evaluate the morphological parameters of meibomian glands (MGs) and lipid layer thickness (LLT) in patients with keratoconus (KC).

METHODS

In this prospective, cross-sectional study, 164 eyes of 164 keratoconus patients and 64 eyes of 64 age-matched control subjects were included. An advanced automatic MG analyzer was used to quantitatively measure the morphological and functional parameters of MGs. Morphological and functional parameters of MGs, LLT, and other ocular surface parameters were compared between the control and KC groups.

RESULTS

The mean meibomian gland diameter, length, square, and gland area ratio (GA) were all significantly decreased in the KC group (all P < 0.05), while no significant difference was observed in the gland tortuosity index (TI) and gland signal index (SI) between the KC and control groups (all P > 0.05). There was no significant difference in the number of total and incomplete blinking among patients with different stages of keratoconus (all P > 0.05). The gland diameter, square, and TI were all negatively associated with KC severity (all P < 0.05), while no significant difference was observed among all stages of KC in gland length, GA, and SI (all P > 0.05). Moreover, the LLTs were positively correlated with the gland diameter, square, GA, and TI and negatively correlated with anterior corneal curvature or KC severity (all P < 0.05).

CONCLUSIONS

Atrophic morphological changes in the meibomian glands were closely correlated with the severity of keratoconus. Gland diameter may be a sensitive functional morphology metric of meibomian glands in patients with keratoconus.

Effectiveness of a New Active Tear Substitute Containing 0.2% Hyaluronic Acid and 0.001% Hydrocortisone on Signs and Symptoms of Dry Eye Disease by Means of Low- and High-Tech Assessments

INTRODUCTION

An innovative eye drops formulation containing 0.2% hyaluronic acid and a low concentration of hydrocortisone (0.001%; hereafter HALH) has been recently placed on the market (Idroflog®, Alfa Intes, Italy) to manage the dysregulated parainflammation in patients with dry eye disease (DED). In the present paper, the effectiveness of HALH on the signs and symptoms of DED was retrospectively evaluated and compared with that one obtained using standard tear substitutes (STS) by means of low- and high-tech (Keratograph®) assessments.

METHODS

This was a multicenter retrospective study carried out between February and April 2023, involving adult patients with DED diagnosis owing to post-cataract surgery, meibomian gland dysfunction, allergy, or glaucoma medications. The primary aim was to compare the changes induced by different therapies on Keratograph® parameters (noninvasive Keratograph tear breakup time [NIKBUT], tear meniscus height [TMH], eyelid meibography, conjunctival hyperemia, and conjunctivochalasis) or collected by traditional low-tech measures (tear breakup time [TBUT], Schirmer test, Efron score, and epithelial alterations) and the Ocular Surface Disease Index score.

RESULTS

Data from 155 patients were analyzed. The effectiveness of HALH and STS was reported by both high- and low-tech measures. NIKBUT-first showed a significant improvement in the HALH group versus the STS one at 15 days (6.4 ± 3.6 vs 5.4 ± 3.7 s, p = 0.02), whereas this difference was latent with low-tech TBUT until 45 days (6.8 ± 2.6 vs 5.6 ± 2.3 s, p = 0.03). Patients with DED occurring after cataract surgery reported an enhanced activity of HALH versus STS, particularly for NIKBUT-first, TMH, Schirmer test, and hyperemia stage.

CONCLUSION

These findings highlighted the effectiveness of HALH in all DED subtypes, especially in patients with post-cataract surgery, as well as its superiority versus STS in terms of tear film stability improvement. We recommend longer observation (i.e., 3-6 months) to fully ascertain whether the early improvement detected by high-tech measures will be confirmed in subsequent time points even using low-tech tests.

Efficacy of vector thermal pulsation treatment in reducing postcataract surgery dry eye disease in patients affected by meibomian gland dysfunction

PURPOSE

To evaluate the effect of a single LipiFlow vector thermal pulsation treatment performed before cataract surgery in reducing signs and symptoms of postoperative dry eye disease (DED) in patients with mild-moderate meibomian gland dysfunction (MGD).

SETTING

Eye Clinic, Careggi Hospital, University of Florence, Florence, Italy.

DESIGN

Prospective unmasked randomized controlled clinical trial.

METHODS

This study included patients affected by age-related cataract and mild-moderate MGD, who were randomized into 2 groups: (1) a single LipiFlow treatment performed at 5 preoperative weeks and (2) warm compresses and eyelid massages twice a day for 1 preoperative month (control group). Noninvasive break-up time (NI-BUT), Schirmer test, Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire, and MG functionality parameters were evaluated at visit 0 (5 preoperative weeks), visit 1 (1 preoperative week), and visit 2 (1 postoperative month). Confocal microscopy of the MG of lower eyelids was performed at visit 0 and visit 2.

RESULTS

A total of 46 patients (46 eyes) were enrolled. In the LipiFlow group (n = 23), NI-BUT, SPEED questionnaire, and MG functionality parameters significantly improved at visit 1 ( P < .05) and visit 2 ( P < .05) compared with baseline and remained stable postoperatively. In the control group (n = 23), they did not significantly improve after treatment, while worsened postoperatively. Moreover, the changes in all parameters from baseline were significantly different between the 2 groups. Confocal microscopy imaging highlighted lower postoperative MG alterations in the LipiFlow group.

CONCLUSIONS

A single preoperative LipiFlow treatment was effective in preventing postcataract surgery DED in patients with mild-moderate MGD. Postoperatively, treated patients displayed a better ocular surface status compared with warm compresses.

Intense pulsed light-based treatment for the improvement of symptoms in glaucoma patients treated with hypotensive eye drops

Background

Ocular surface disease in glaucoma patients is a significant ocular co-morbidity that can affect 40% to 59% of these patients worldwide. The current study was aimed at evaluating the potential clinical benefit of an intense pulsed light (IPL)-based treatment in glaucomatous patients with ocular surface disease due to prolonged hypotensive eyedrop treatments. To our knowledge, this is the first series analyzing the therapeutic effect of this treatment option in this type of patients.

Methods

This non-comparative prospective case series study enrolled a total of 30 glaucoma patients ranging in age from 57 to 94 years old and treated with hypotensive eyedrops for years with dry eye symptomatology. All patients received four sessions of IPL treatment using the Optima IPL system (Lumenis, Yokneam, Israel) adjusted to the official optimized Lumenis setting. Changes in symptomatology, corneal staining, conjunctival hyperemia, non-invasive break-up time (NIBUT), tear osmolarity, tear meniscus height (TMH), meiboscore and meibomian gland expressibility was analyzed after treatment.

Results

Statistically significant reductions were observed after IPL treatment in the symptomatology scores measured with different questionnaires [ocular surface disease index (OSDI), standard patient evaluation of eye dryness (SPEED) and symptom assessment questionnaire in dry eye (SANDE)] as well as with the visual analogue scale (P < 0.001). Mean change in OSDI was − 15.0 ± 11.3. A significant reduction was found after treatment in the corneal staining score (P < 0.001). A significant reduction was found in tear film meniscus height (P = 0.012), as well as in tear film osmolarity (P = 0.001). A significant reduction was also found in meibomian gland expressibility (P = 0.003), changing the percentage of grade 3 eyes from 44.4% before IPL to 17.2% after treatment.

Conclusions

IPL therapy combined with meibomian gland expression (MGX) seems to be an effective option to improve symptomatology in glaucomatous patients with ocular surface disease due to prolonged hypotensive eyedrop treatments, with an additional improvement in clinical signs, such as tear osmolarity and corneal staining.

Automatic identification of meibomian gland dysfunction with meibography images using deep learning

BACKGROUND

Artificial intelligence is developing rapidly, bringing increasing numbers of intelligent products into daily life. However, it has little progress in dry eye, which is a common disease and associated with meibomian gland dysfunction (MGD). Noninvasive infrared meibography, known as an effective diagnostic tool of MGD, allows for objective observation of meibomian glands. Thus, we discuss a deep learning method to measure and assess meibomian glands of meibography.

METHODS

We used Mask R-CNN deep learning (DL) framework. A total of 1878 meibography images were collected and manually annotated by two licensed eyelid specialists with two classes: conjunctiva and meibomian glands. The annotated pictures were used to establish a DL model. An independent test dataset that contained 58 images was used to compare the accuracy and efficiency of the deep learning model with specialists.

RESULTS

The DL model calculated the ratio of meibomian gland loss with precise values by achieving high accuracy in the identification of conjunctiva (validation loss < 0.35, mAP > 0.976) and meibomian glands (validation loss < 1.0, mAP > 0.92). The comparison between specialists' annotation and the DL model evaluation showed that there is little difference between the gold standard and the model. Each image takes 480 ms for the model to evaluate, almost 21 times faster than specialists.

CONCLUSIONS

The DL model can improve the accuracy of meibography image evaluation, help specialists to grade the meibomian glands and save their time to some extent.

Analysis of Demodex infection rate and risk factors in patients with meibomian gland dysfunction

PURPOSE

In the present study, we aimed to investigate the positive rate of Demodex infection in patients with meibomian gland dysfunction (MGD) and to analyze its risk factors.

METHODS

A total of 178 MGD patients admitted to the Jinan Second People's Hospital from April 2020 to February 2021 were enrolled in the present study. All patients were examined for Demodex infection, and their medical history was collected. The positive rate of Demodex infection was calculated after the examination. The medical history, including age, eating habits, pet ownership, and so on, was collected. First, a univariate analysis was conducted to identify the factors associated with positive Demodex infection, and then, a multivariate comprehensive analysis was carried out to identify the main risk factors for positive Demodex infection.

RESULTS

In the present study, the positive rate of Demodex infection in 178 MGD patients was 73.60%. The risk factors of Demodex infection in MGD patients were gender, pet ownership, toiletry sharing, and diabetes (all P ≤ 0.15). Age was one of the risk factors for infection [B = 0.105, OR 1.111 (95%CI 1.069-1.155), P = 0.000], and toiletry sharing was more likely to cause positive Demodex mite infection [B = 0.891, OR 2.439 (95%CI 1.066-5.577), P = 0.035]. The Demodex infection was not statistically associated with gender (P = 0.234), pet ownership (P = 1.141), and diabetes (P = 0.295).

CONCLUSIONS

The positive rate of Demodex infection was higher in MGD patients. The main risk factors affecting the positive rate of Demodex infection included age and toiletry sharing.

Automation of dry eye disease quantitative assessment: A review

Dry eye disease (DED) is a common eye condition worldwide and a primary reason for visits to the ophthalmologist. DED diagnosis is performed through a combination of tests, some of which are unfortunately invasive, non‐reproducible and lack accuracy. The following review describes methods that diagnose and measure the extent of eye dryness, enabling clinicians to quantify its severity. Our aim with this paper is to review classical methods as well as those that incorporate automation. For only four ways of quantifying DED, we take a deeper look into what main elements can benefit from automation and the different ways studies have incorporated it. Like numerous medical fields, Artificial Intelligence (AI) appears to be the path towards quality DED diagnosis. This review categorises diagnostic methods into the following: classical, semi‐automated and promising AI‐based automated methods.

2D Short-Time Fourier Transform for local morphological analysis of meibomian gland images

Meibography is becoming an integral part of dry eye diagnosis. Being objective and repeatable this imaging technique is used to guide treatment decisions and determine the disease status. Especially desirable is the possibility of automatic (or semi-automatic) analysis of a meibomian image for quantification of a particular gland’s feature. Recent reports suggest that in addition to the measure of gland atrophy (quantified by the well-established “drop-out area” parameter), the gland’s morphological changes may carry equally clinically useful information. Here we demonstrate the novel image analysis method providing detailed information on local deformation of meibomian gland pattern. The developed approach extracts from every Meibomian image a set of six morphometric color-coded maps, each visualizing spatial behavior of different morphometric parameter. A more detailed analysis of those maps was used to perform automatic classification of Meibomian glands images. The method for isolating individual morphometric components from the original meibomian image can be helpful in the diagnostic process. It may help clinicians to see in which part of the eyelid the disturbance is taking place and also to quantify it with a numerical value providing essential insight into Meibomian gland dysfunction pathophysiology.

Latest developments in meibography: A review

Meibography is a visualisation technique that has been used for over 40 years. There have been significant improvements in image quality, examination technique and image interpretation over this period. Although meibography has received sporadic reviews in the past, an updated review is timely due to the rapid recent rise of relevant technology and advances in both image processing and artificial intelligence. The primary aim of this paper is to review recent research into Meibomian gland imaging and update the community about the most relevant technologies and approaches used in the field.

Latest developments on meibomian gland dysfunction: Diagnosis, treatment and management

Background: Meibomian gland dysfunction (MGD) is one of the leading causes of evaporative dry eye disease and one of the most common ophthalmic conditions found in clinical practice. Meibomian gland dysfunction tends to be overlooked because its signs and symptoms do not cause blindness. Meibomian gland dysfunction is characterised by the obstruction of the meibomian gland terminal ducts resulting in tear film instability.Aim: The purpose of this article was to provide an update on MGD’s diagnosis and treatment.Method: A literature review was conducted using search engines such as Google Scholar, Medline and ScienceDirect databases. Keywords such as MGD diagnosis and management and treatment of MGD were used to search the databases.Results: A total of 44 relevant papers were reviewed. These papers were then curated to include only those concerning diagnosis of meibomian gland dysfunction, treatment of meibomian gland dysfunction and management options of meibomian gland dysfunction. The references of individual papers from the curated results were checked to yield a further 13 papers.Conclusion: Meibomian gland dysfunction is not a single entity but is multifactorial in origin; however, our understanding of the condition is evolving rapidly because of newer imaging technology. There is no gold standard treatment option for MGD, but many options are available that include medications and other procedures. 

Combination treatment with intense pulsed light, thermal pulsation (LipiFlow), and meibomian gland expression for refractory meibomian gland dysfunction

PURPOSE

To evaluate the clinical efficacy and safety of combination treatment with intense pulsed light (IPL), LipiFlow thermal pulsation, and manual meibomian gland expression (MGX) for patients with refractory meibomian gland dysfunction (MGD).

METHODS

A total of 23 eyes from 23 patients who underwent combination treatment with IPL, LipiFlow, and MGX for refractory MGD were included in the study. All patients were followed up for 12 months after the first treatment. All patients were examined prior to treatment and underwent three sessions of IPL, LipiFlow, and MGX, a subsequent three sessions of IPL and MGX, and six subsequent sessions of MGX. Patients were examined 10 weeks, 6 months, and 12 months after the first treatment. The ophthalmologic examination included ocular surface disease index (OSDI), non-invasive tearfilm break-up time (NIBUT), lipid layer thickness (LLT), meibomian gland expressibility (MGE), meibomian gland morphology (meiboscore), and tear meniscus height (TMH).

RESULTS

OSDI, NIBUT, LLT, and MGE significantly improved with treatment, which was maintained during the follow-up period. TMH and meiboscore remained unchanged throughout follow-up. No serious adverse events occurred during follow-up.

CONCLUSIONS

Combination therapy with IPL, LipiFlow, and MGX was clinically effective and safe for the treatment of refractory MGD. Combination treatment could be considered for patients with insufficient improvement despite conventional MGD treatments, including IPL treatment with MGX.

Meibomian Glands and Tear Film Findings in Type 2 Diabetic Patients: A Cross-Sectional Study

Background

The characteristics of the meibomian gland and tear film in patients with type 2 diabetes (T2D) with different glycemic control levels and diabetic durations remain largely unexplored. This study aimed to identify the association of dry eye and meibomian gland dysfunction (MGD) in T2D.

Materials and Methods

Ninety-nine patients with type 2 diabetes mellitus (DM group), 33 dry eye patients without diabetes mellitus (DE group), and 40 normal subjects (NC group) were recruited for this study. Participants were evaluated with an Ocular Surface Disease Index (OSDI) questionnaire, tear film breakup time (BUT), the Schirmer I test (SIT), corneal fluorescein staining (FL), lipid layer thickness (LLT), and MGD parameters. Glycosylated hemoglobin (HbA_1c) and duration of diabetes were recorded.

Results

The SIT value in the DM group was higher than that of the DE group (p < 0.05). The BUT and LLT were lower, and MGD parameters were higher in the DM group than those of the DE and NC groups (p < 0.05). In the DM group, 47 patients were diagnosed with dry eye (DM + DE group), whereas 40 patients without dry eye were categorized as the DM − DE group. The SIT, BUT, and LLT values in the DM − DE group were higher (p < 0.01), and MGD parameters were lower (p < 0.01) in the DM − DE group than those of the DM + DE group. The MGD parameters were higher in the DM − DE group than those in the NC group (p < 0.05). The HbA_1c levels were correlated with OSDI, BUT, LLT, FL, and MGD parameters (p < 0.001) in the DM group. However, in patients with low HbA_1c, normal SIT value, and low OSDI, the MGD parameters were higher than those in the NC group (p < 0.05). The duration of diabetes positively correlated with MGD parameters (p < 0.001).

Conclusion

Asymptomatic MGD may be an early sign of dry eye and ocular discomfort in T2D. The MGD parameters were associated with the HbA_1c level and diabetic duration.

Performance of a Translucent Activator for LipiFlow Vectored Thermal Pulse (VTP) Treatment of Meibomian Gland Dysfunction

Purpose

Investigator feedback was used to assess the clinical use of the LipiFlow^® System with the new translucent Activator Clear to successfully complete LipiFlow^® treatments.

Patients and Methods

This was a prospective, open-label clinical investigation. A total of 88 eyes (44 subjects) were treated using the LipiFlow^® System with the new Activator Clear. Subjects diagnosed with bilateral meibomian gland dysfunction (MGD) were enrolled in the study. Each investigator performed a complete LipiFlow^® treatment with the translucent Activator on both eyes of each subject. Investigators completed a questionnaire assessing the clinical use of the Activator Clear on a 5-point scale (1 – very difficult or strongly disagree, 3 – neutral, 5 – very easy or strongly agree).

Results

The new translucent Activator provided successful LipiFlow^® treatments in 100% of cases, with 95% confidence interval of (96%, 100%). Additionally, the investigators agreed or strongly agreed that the translucent components of the Activator Clear made it easy to access and position the activator with confidence on the subject’s eye.

Conclusion

The overall investigators’ impressions on usage and functionality of LipiFlow^® System with the translucent Activator were very positive. The Activator Clear enables doctors with efficient and confident positioning around patient eyelids to ensure successful LipiFlow^® treatment when used as indicated.

Compliance with Lid Hygiene in Patients with Meibomian Gland Dysfunction

Purpose

To evaluate the level and predictor of compliance with lid hygiene of the patients with meibomian gland dysfunction (MGD) by a specially designed and validated questionnaire.

Patients and Methods

A cross-sectional, descriptive study was conducted among patients with symptomatic meibomian gland dysfunction visiting at Ramathibodi Hospital from April 2019 to December 2020. Dry eye symptom, fluorescein tear breakup time (TBUT), ocular surface staining, lid morphology, meibum quality, and meibum expressibility were evaluated. All patients were instructed to perform lid hygiene two times daily. Eight weeks after receiving the instruction, the patients were asked to complete a newly developed seven-item questionnaire to assess compliance. The associated factors limiting treatment adherence were evaluated. Proper statistical analyses were used to determine the relationships between compliance and non-compliance and a group of relevant baseline variables. P < 0.05 was considered to be statistically significant.

Results

A total of 77 patients were recruited into the study. Sixty-three patients (81.8%) were female. The mean age was 66.71 ± 8.17 years old (42–87 years). Good compliance with lid hygiene was reported by 42 patients (54.6%). Patient demographic factors or the number of concurrent systemic or ophthalmic drugs were not significantly different between the compliance and non-compliance groups. Some clinical signs, including the higher scores of meibomian gland expressibility and moderate to severe ocular surface staining, were significantly positively associated with lid hygiene compliance (χ² = 10.13, P = 0.001 and χ² = 10.48, P = 0.001, respectively). A lack of time was the most notable reason for non-compliance.

Conclusion

Approximately half of the patients with symptomatic MGD had good compliance with lid hygiene by the specific questionnaire. Appropriate patient education and optimization methods of lid hygiene may promote patient compliance.

Morphological and Functional Changes of Meibomian Glands in Pediatric and Adult Patients with Allergic Conjunctivitis

Allergic conjunctivitis (AC) is one of the most common ocular disorders in clinical practice and is associated with meibomian gland dysfunction. This study aimed to explore the morphological and functional changes of meibomian glands (MGs) in pediatric and adult patients with AC and to analyze their potential predictors. In our prospective, observational cohort study, a total of 59 patients with AC were enrolled, with 30 patients aged ≤16 years in the pediatric group and 29 patients in the adult group. All patients underwent examinations at baseline and last visit when the complete resolution of conjunctival papillae was identified. An automatic MG analyzer was used to measure the morphological and functional parameters of MGs, including their area ratio (GA), tortuosity index (TI), and signal index (SI). Two groups were comparable at baseline in terms of characteristics and MG parameters (p > 0.05). The morphological (length, square, and GA) and functional MG parameters (SI) of AC patients significantly improved in the pediatric group after treatment (all p < 0.05), but not in the adult group. The change in the GA correlated with age, sex, GA, TI, and SI at baseline (all p < 0.05). Age (p = 0.001) and GA (p < 0.001) at baseline were predictors of an improvement in the GA of MGs. The findings showed that the structure and function of MGs in pediatric patients with AC seem to improve after the conjunctival papillae disappear, but not in adult patients.

Development of a Novel Tear Lipid Test Strip

PURPOSE

The unifying characteristic of dry eye is the loss of tear film homeostasis, and the tear lipid layer is a key component for maintaining film stability. The detection of tear lipid is of great significance for the diagnosis of dry eye. In this study, we explored a new test strip for the detection of tear lipid.

METHODS

The tear lipid test strip was prepared by coating the strip material with hydrophobic nano-silica. We tested its physical properties with iodine vapor chromogenic and cobalt chloride test methods. Its biosafety was evaluated by an ocular irritation test in rabbits. Finally, we established a rabbit meibomian gland dysfunction model and measured both eyes with the tear lipid test strip at the first, third, seventh, 14th, 16th, and 21st day after surgery.

RESULTS

The tear lipid test strip had fine lipophilicity and hydrophobicity. It can extract lipid from tear, and the tear lipid can be quantified by measuring the length of lipid infiltration. In the ocular irritation test, the test strip had no obvious eye irritation. The length of lipid infiltration between experimental and control rabbit eyes began to show statistical difference since the third day after surgery.

CONCLUSIONS

The novel tear lipid test strip has great lipophilicity, hydrophobicity, and biological safety. It might be effectively applied in diagnosis of dry eye.

Artificial intelligence in dry eye disease

Dry eye disease (DED) has a prevalence of between 5 and 50%, depending on the diagnostic criteria used and population under study. However, it remains one of the most underdiagnosed and undertreated conditions in ophthalmology. Many tests used in the diagnosis of DED rely on an experienced observer for image interpretation, which may be considered subjective and result in variation in diagnosis. Since artificial intelligence (AI) systems are capable of advanced problem solving, use of such techniques could lead to more objective diagnosis. Although the term 'AI' is commonly used, recent success in its applications to medicine is mainly due to advancements in the sub-field of machine learning, which has been used to automatically classify images and predict medical outcomes. Powerful machine learning techniques have been harnessed to understand nuances in patient data and medical images, aiming for consistent diagnosis and stratification of disease severity. This is the first literature review on the use of AI in DED. We provide a brief introduction to AI, report its current use in DED research and its potential for application in the clinic. Our review found that AI has been employed in a wide range of DED clinical tests and research applications, primarily for interpretation of interferometry, slit-lamp and meibography images. While initial results are promising, much work is still needed on model development, clinical testing and standardisation.

Experimental Models, Induction Protocols, and Measured Parameters in Dry Eye Disease: Focusing on Practical Implications for Experimental Research

Dry eye disease (DED) is one of the major ophthalmological healthcare challenges worldwide. DED is a multifactorial disease characterized by a loss of homeostasis of the tear film, and its main pathogenesis is chronic ocular surface inflammation related with various cellular and molecular signaling cascades. The animal model is a reliable and effective tool for understanding the various pathological mechanisms and molecular cascades in DED. Considerable experimental research has focused on developing new strategies for the prevention and treatment of DED. Several experimental models of DED have been developed, and different animal species such as rats, mice, rabbits, dogs, and primates have been used for these models. Although the basic mechanisms of DED in animals are nearly identical to those in humans, proper knowledge about the induction of animal models is necessary to obtain better and more reliable results. Various experimental models (in vitro and in vivo DED models) were briefly discussed in this review, along with pathologic features, analytical approaches, and common measurements, which will help investigators to use the appropriate cell lines, animal, methods, and evaluation parameters depending on their study design.

Comparative of meibomian gland morphology in patients with evaporative dry eye disease versus non-dry eye disease

Many recent studies have showed that morphological changes are one of the key signs of meibomian gland disease (MGD). These changes can be seen even before symptom onset, potentially underestimating the prevalence of MGD; however, until now, there is no conclusive information about the impact of meibomian gland (MG) morphology in tear film physiology and disease. This study aimed to investigate the prevalence of anatomical and morphological MG alterations between patients with evaporative dry eye disease (DED) and healthy controls. Retrospective chart review of seventy-five patients with evaporative DED and healthy individuals who had dry eye assessments included Ocular Surface Disease Index questionnaire, meibum quality, meibum expressibility, lid margin abnormality, ocular staining, non-invasive tear film break-up time, and meibography. We did not find significant differences in MG alterations in the upper lid between healthy and DED subjects. Patients with evaporative DED presented MG alterations in the lower lid more frequently than healthy subjects (54.8 vs. 30.3%; p = 0.03). The presence of shortened glands was the only MG alteration that was more prevalent in the lower lid in dry-eye patients than in healthy subjects (p < 0.05). Subjects with evaporative DED presented more alterations in the lower lid than healthy subjects.

Quantitative analysis of morphological and functional features in Meibography for Meibomian Gland Dysfunction: Diagnosis and Grading

BACKGROUND

To explore the performance of quantitative morphological and functional analysis in meibography images by an automatic meibomian glands (MGs) analyser in diagnosis and grading Meibomian Gland Dysfunction (MGD).

METHODS

A cross-sectional study collected 256 subjects with symptoms related to dry eye and 56 healthy volunteers who underwent complete ocular surface examination was conducted between January 1, 2019, and December 31, 2020. The 256 symptomatic subjects were classified into MGD group (n = 195) and symptomatic non-MGD group (n = 61). An automatic MGs analyser was used to obtained multi-parametric measurements in meibography images including the MGs area ratio (GA), MGs diameter deformation index (DI), MGs tortuosity index (TI), and MGs signal index (SI). Adjusted odds ratios (ORs) of the multi-parametric measurements of MGs for MGD, and the area under the receiver operating characteristic (AUC-ROC) curves of multi-parametric measurements for MGD diagnosing and grading were conducted.

FINDINGS

When consider age, sex, ocular surface condition together, the estimated ORs for DI was 1.62 (95% CI, 1.29-2.56), low-level SI was 24.34 (95% CI, 2.73-217.3), TI was 0.76(95% CI, 0.54-0.90), and GA was 0.86 (95% CI, 0.74-0.92) for MGD. The combination of DI-TI-GA-SI showed an AUC = 0.82 (P < 0.001) for discriminating MGD from symptomatic subjects. The DI had a higher AUC in identifying early-stage MGD (grade 1-2), while TI and GA had higher AUCs in moderate and advanced stages (grade 3-5). Merging DI-TI-GA showed the highest AUCs in distinguish MGD severities.

INTERPRETATION

The MGs area ratio, diameter deformation, tortuosity and signal intensity could be considered promising biomarkers for MGD diagnosis and objective grading.

FUNDING

This work was supported by the Key-Area Research and Development Program of Guangdong Province (No. 2019B010152001), the National Natural Science Foundation of China under Grant (81901788) and Guangzhou Science and Technology Program (202002030412).

Efficacy and safety of a vectored thermal pulsation system (Lipiflow®) in the treatment of meibomian gland dysfunction: a systematic review and meta-analysis

PURPOSE

To investigate the efficacy and safety of a vectored thermal pulsation system (Lipiflow®) in the treatment of dry eye disease resulting from meibomian gland dysfunction (MGD).

METHODS

We searched for randomized clinical trials (RCTs) in Embase, MEDLINE, the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Web of Science, and ClinicalTrials.gov up to 4 January 2021. The subjective symptoms, objective tests of dry eye, meibomian gland function, and the incidence of adverse events were evaluated.

RESULTS

Ten qualified RCTs incorporating 761 patients were analyzed. In the comparison of Lipiflow® treatment and lid hygiene, the subgroup with inconsistent units of randomization and analysis showed that the Lipiflow® treatment brought slight improvement in corneal fluorescein staining (mean difference (MD), - 0.42; 95% CI, - 0.75 to - 0.1), significant improvements in ocular surface disease index (OSDI) score (MD, - 7.4; 95% CI, - 11.06 to - 3.74), Standard Patient Evaluation of Eye Dryness (SPEED) score (MD, - 2.7; 95% CI, - 3.95 to - 1.45), meibomian glands yielding liquid secretion (MGYLS) (MD, 1.3; 95% CI, 0.78 to 1.82), and meibomian glands yielding secretion score (MGYSS) (MD, 4.09; 95% CI, 1.18 to 6.99). Meanwhile, significant improvements were detected in OSDI score, SPEED score, MGYLS, and MGYSS with patients who received Lipiflow® treatment compared with those who received nontreatment. The adverse events were comparable in the two control groups.

CONCLUSIONS

Lipiflow® treatment can improve the subjective and objective outcomes of MGD and does not increase the incidence of adverse events. The improper choice of units of analysis may be the leading cause of heterogeneity, which should be noted in the design of future ophthalmology research. Additional well-designed, large-scale RCTs are required to reach a firmer conclusion.

The effects of a steam warming eye mask on the ocular surface and mental health

PURPOSE

The continuous use of warming eye masks improves tear function. In this double-blind randomized controlled trial, we aimed to analyze the effects of warming eye mask use on the ocular surface and mental health.

METHODS

We enrolled 86 participants (age range: 23-89 years) from affiliated institutions who were divided into two groups: the warm group that used warming eye masks that generate moist heat at 40 °C for 10 min and the control group that used non-warming eye masks. The participants used the masks for 10 min once daily for 2 weeks. Before and after the intervention, in 79 participants (warm group 39, control group 40), we analyzed the tear break up time (TBUT) and corneal and conjunctival fluorescein staining results in the right eye and Hospital Anxiety and Depression Score (Anxiety: HADS-A, Depression: HADS-D), and Subjective Happiness Scale (SHS) questionnaires. The parameters before and after the intervention were compared via paired-t tests.

RESULTS

The following variables changed after the intervention: TBUT (warm group: 1.4 ± 2.1 s vs. control group: -0.01 ± 2.38 s), fluorescein staining score (-0.7 ± 1.1 vs.-0.2 ± 1.1), HADS-A (-0.8 ± 3.1 vs. -0.2 ± 2.2), and HADS-D (-1.0 ± 2.4 vs. -0.4 ± 1.9). Significant changes were observed in the TBUT (warm group), fluorescein staining score (warm group), and HADS-D (warm group).

CONCLUSIONS

Using a warming eye mask improves not only the ocular surface conditions but also the subjective depression scores.