The international workshop on meibomian gland dysfunction: report of the subcommittee on anatomy, physiology, and pathophysiology of the meibomian gland

Human meibomian gland epithelial cell culture models: Current progress, challenges, and future directions

The widely used immortalised human meibomian gland epithelia cell (iHMGEC) line has made possible extensive studies of the biology and pathophysiology of meibomian glands (MG). Tissue culture protocols for iHMGEC have been revised and modified to optimise the growth conditions for cell differentiation and lipid accumulation. iHMGEC proliferate in serum-free medium but require serum or other appropriate exogenous factors to differentiate. Several supplements can enhance differentiation and neutral lipid accumulation in iHMGEC grown in serum-containing medium. In serum-free medium, rosiglitazone, a peroxisome proliferator activator receptor-γ (PPARγ) agonist, is reported to induce iHMGEC differentiation, neutral lipid accumulation and expression of key biomarkers of differentiation. iHMGEC cultured in serum-containing medium under hypoxia or with azithromycin increases DNAse 2 activity, a biomarker of terminal differentiation in sebocytes. The production of lipids with composition similar to meibum has not been observed in vitro and this remains a major challenge for iHMGEC culture. Innovative methodologies such as 3D ex vivo culture of MG and generation of MG organoids from stem cells are important for further developing a model that more closely mimics the in vivo biology of human MG and to facilitate the next generation of studies of MG disease and dry eye.

Evaluation of the MGDRx eyebag treatment in young and older subjects with dry eye symptoms

OBJECTIVES

This study aims to evaluate the relationship between application of the MGDRx thermal eyebag and dry eye signs and symptoms in young and older subjects and to compare the results between the two groups.

METHODS

Thirty young, healthily volunteers between 18 and 31 years of age (23.95±3.94 years) and thirty older subjects between 61 and 90 years of age (77.97±8.11 years) participated in this study. Ocular surface parameters were assessed using the Oculus Keratograph 5M, following the guidelines of the Tear Film and Ocular Surface Dry Eye Workshop II Diagnostic Methodology report. Only subjects with a positive score on at least one questionnaire and an initial Non-Invasive Keratograph Break-Up Time (NIKBUT) under 10seconds were included in the study. After thermal bag self-application in both eyes every day for 2 weeks, the protocol was carried out again. Lid massage was performed after lid warming. Compliance and degree of improvement were also assessed.

MAIN RESULTS

The young volunteer group showed an improvement in NIKBUT, lipid layer score, upper eyelid gland drop-out percentage and dry eye symptoms over the two week treatment period. Improvements in meibum quality, gland obstruction, telangiectasia scores, and dry eye symptoms were found in the older subjects. Mixed ANOVA revealed better NIKBUT and lipid layer values in the young subjects. Despite the treatment compliance being statistically higher in the older group than in the younger subjects (P=0.002), there were no significant differences in subjective improvement between groups (P=0.097).

CONCLUSION

Dry eye-related symptoms were improved after thermal bag application, while NIKBUT and lipid layer thickness were improved only in the younger subjects.

The Ocular Surface Characteristics in Prostate Cancer Patients Treated with Androgen Deprivation Therapy

Background

To investigate the association of long-term androgen deprivation therapy (ADT) with ocular surface characteristics in prostate cancer patients.

Methods

A total of 30 male prostate cancer patients who received ADT were selected. All candidates were scored using the Ocular Surface Disease Index (OSDI) and subsequently divided into two groups containing 9 symptomatic patients (scores >12) and 21 asymptomatic patients (scores ≤ 12). Another 20 healthy age-matched males were selected as the control group. Each candidate was assessed with respect to eyelid margin abnormality, tear film break-up time (NI-BUT), tear meniscus height (TMH), meiboscore, meibum expressibility, and demodex infection.

Results

The NI-BUT in the ADT group was significantly shorter than that in the control group. The scores for OSDI, eyelid margin abnormality, meibum expressibility, and meiboscores were significantly higher in the ADT group (P < 0.05). Moreover, the NI-BUT in the symptomatic ADT group was significantly shorter than that in the asymptomatic ADT group (P < 0.05). The meiboscores and meibum expressibility score in the symptomatic ADT group were significantly higher than those in the asymptomatic ADT group (P < 0.05). The presence of demodex in the symptomatic ADT group was also higher than that in the asymptomatic ADT group (P < 0.05).The length of time that patients had been taking ADT was positively correlated with meiboscores and negatively correlated with NI-BUT.

Conclusion

Androgen levels were associated with significant changes in relative meibomian gland function. Subjective symptoms, such as dryness and foreign body sensation, were more obvious in prostate cancer patients receiving ADT, which may be caused by MGD and demodex infection. It's recommended that more attention be paid to the ocular surface in prostate cancer patients taking ADT by performing examination of NI-BUT and meibomian gland morphology and function with a view to providing more comprehensive prevention and treatment protocols.

Meibomian Gland Dysfunction: A Dermatological Perspective on Pathogenesis and Treatment Outlook

Meibomian glands are modified oil-producing glands that produce meibum and can become dysfunctional and negatively affect the lipid layer in the tear film, resulting in ocular surface diseases such as evaporative dry eye. Abnormal keratin production and aggregation at the meibomian gland orifice has been implicated in the pathogenesis of meibomian gland dysfunction (MGD). Current treatments largely ignore the role of keratin proteins. This review paper synthesizes various publications on hyperkeratinization and its role in MGD pathogenesis and proposes a novel treatment strategy for MGD that involves the use of keratolytic agents commonly used in dermatological treatments.

TheraPearl Eye Mask and Blephasteam for the treatment of meibomian gland dysfunction: a randomized, comparative clinical trial

Meibomian gland dysfunction (MGD) is the most common cause of dry eye disease (DED). In this study, we aimed to compare the effects of eyelid warming treatment using either TheraPearl Eye Mask (Bausch & Lomb Inc., New York, USA) or Blephasteam (Spectrum Thea Pharmaceuticals LTD, Macclesfield, UK) in a Norwegian population with mild to moderate MGD-related DED. An open label, randomized comparative trial with seventy patients (49 females, 21 males; mean age 53.6 years). Patients were randomly assigned to treatment with Blephasteam (n = 37) or TheraPearl (n = 33). All received a hyaluronic acid based artificial tear substitute (Hylo-Comod, Ursapharm, Saarbrücken, Germany). Patients were examined at baseline, and at three and six months initiation of treatment. Treatment efficacy was primarily evaluated by fluorescein breakup time (FBUT) and Ocular Surface Disease Index (OSDI) scores. Other outcome measures included ocular surface staining (OSS), Schirmer’s test, and meibomian quality and expressibility. Baseline parameter values did not differ between the groups. After six months of treatment, Blephasteam improved FBUT by 3.9 s (p < 0.01) and OSDI by 13.7 (p < 0.01), TheraPearl improved FBUT by 2.6 s (p < 0.01) and OSDI by 12.6 (p < 0.01). No difference between treatments was detected at 6 months (p = 0.11 for FBUT and p = 0.71 for OSDI), nor were there differences in the other tested parameters between the treatment groups. Blephasteam and TheraPearl are equally effective in treating mild to moderate MGD in a Norwegian population after 6-months of treatment.

Clinicaltrials.gov ID: NCT03318874; Protocol ID: 2014/1983; First registration: 24/10/2017.

Chambered warm moist air eyelid warming devices - a review

BACKGROUND

Eyelid warming is an important treatment for meibomian gland dysfunction (MGD). Specialized chambered devices, using warm moist air have been developed.

PURPOSE

To critically evaluate the literature on the safety and efficacy of chambered warm moist air devices in MGD treatment and pinpoint areas of future research.

METHODS

PubMed and Embase were searched on 06 June 2021. The search term was '(warm OR heat OR steam OR goggle OR spectacle OR moist air) AND (meibomian OR MGD OR blepharitis OR eyelid OR dry eye OR DED)'. All relevant articles with available English full text were included.

RESULTS

Eighteen articles assessing the application of chambered warm moist air eyelid warming devices were identified. In single-application studies, steam-based eyelid warming increased the eyelid temperature and improved symptoms, lipid layer thickness, and tear film breakup time (TBUT). In treatment studies, the steam-based devices improved TBUT and symptom scores. However, in the only randomized controlled trial (RCT) comparing chambered steam-based heat to hot towel treatment, there was no difference between groups for the primary outcome measure; the proportion of subjects noting symptom improvement after 4 weeks.

CONCLUSION

Currently available chambered warm moist air eyelid warming devices are safe and effective at raising eyelid temperature to therapeutic levels and improving signs and symptoms of dry eye. However, it is not clear if they provide a greater benefit than other eyelid warming therapies. Further well-conducted RCTs comparing moist and dry heat devices should be conducted on patients across the range of DED severities and subtype spectrum.

Delayed Re-epithelialization After Epithelium-Off Crosslinking: Predictors and Impact on Keratoconus Progression

Purpose: To investigate the demographic and corneal factors associated with the occurrence of delayed reepithelialization (DRE) after epithelium-off crosslinking (epi-off CXL).

Design:Retrospective case series.

Methods:A chart review was performed to identify patients treated with epi-off CXL. DRE was defined as a corneal epithelial defect detected by fluorescein staining that persisted for more than 10 days. Slit-lamp examination, anterior segment optical coherence tomography, corneal topography, and corneal in vivo confocal microscopy (IVCM) were always performed preoperatively and at each follow-up visit (1, 3, 6, 12 months). A generalized estimating equation was used to assess the baseline factors associated with DRE.

Results:Data from 153 eyes were analyzed. The mean age of patients was 24.9 ± 8.5 years, and 47 (30.7%) were women. The average reepithelization time was 4.7 ± 1.8 days. Six eyes (3.9%) experienced DRE. In the multivariate model, both the age of the patient (OR = 1.30; p = 0.02) and the corneal steepest meridian (OR = 0.44, p = 0.047) were associated with DRE. Baseline nerve count was also associated with DRE (0.87, p = 0.03). Male gender was associated with a slower early nerve regrowth (1–6 months) (p = 0.048), but not with the occurrence of DRE (p = 0.27). Preoperative central corneal thickness was not related to DRE (p = 0.16). DRE was not associated with keratoconus progression after epi-off CXL (p = 0.520).

Conclusions:The association between DRE and age may reflect the age-related decrease in the corneal healing response. Also, low baseline corneal nerve count is associated with DRE. Gender seems to affect reinnervation measured by IVCM but not the reepithelization time. DRE does not seem to affect the efficacy of epi-off CXL.

Eyelid blood vessel and meibomian gland changes in a sclerodermatous chronic GVHD mouse model

PURPOSE

To investigate pathological changes in blood vessels and meibomian glands (MGs) in the eyelids of sclerodermatous chronic graft-versus-host disease (cGVHD) model mice.

METHODS

We used an established major histocompatibility complex compatible, multiple minor histocompatibility antigen-mismatched sclerodermatous cGVHD mouse model. Blood vessels and MGs of eyelids from allogeneic bone marrow transplantation (allo-BMT) recipient mice and syngeneic bone marrow transplantation (syn-BMT) recipient mice were assessed by histopathology, immunohistochemistry and transmission electron microscopy. Peripheral blood samples from the recipients were examined by flow cytometry.

RESULTS

Allo-BMT samples showed dilating, tortuous and branching vessels and shrunk MGs in the eyelids; showed significantly higher expression of VEGFR2 (p = 0.029), CD133 (p = 0.016), GFP (p = 0.006), and α-SMA (p = 0.029) in the peripheral MG area; showed endothelial damage and activation, fibrotic change, and immune cell infiltration into MGs compared with syn-BMT samples. Fewer Ki-67⁺ cells were observed in allo- and syn-BMT samples than in wild-type samples (p = 0.030). Ultrastructural changes including endothelial injury and activation, fibroblast activation, granulocyte degranulation, immune cell infiltration into MGs, and necrosis, apoptosis of MG basal cells were found in allo-BMT samples compared with syn-BMT samples.

CONCLUSION

A series of our studies indicated that cGVHD can cause eyelid vessel and MGs changes, including endothelial injury and activation, neovascularization, early fibrotic changes, immune cell infiltration, MG basal cell necrosis and apoptosis, and resultant MG atrophy.

Epithelial stem cell homeostasis in Meibomian gland development, dysfunction, and dry eye disease

Dry eye disease affects over 16 million adults in the US, and the majority of cases are due to Meibomian gland dysfunction. Unfortunately, the identity of the stem cells involved in Meibomian gland development and homeostasis is not well elucidated. Here, we report that loss of Krox20, a zinc finger transcription factor involved in the development of ectoderm-derived tissues, or deletion of KROX20-expressing epithelial cells disrupted Meibomian gland formation and homeostasis, leading to dry eye disease secondary to Meibomian gland dysfunction. Ablation of Krox20-lineage cells in adult mice also resulted in dry eye disease, implicating Krox20 in homeostasis of the mature Meibomian gland. Lineage-tracing and expression analyses revealed a restricted KROX20 expression pattern in the ductal areas of the Meibomian gland, although Krox20-lineage cells generate the full, mature Meibomian gland. This suggests that KROX20 marks a stem/progenitor cell population that differentiates to generate the entire Meibomian gland. Our Krox20 mouse models provide a powerful system that delineated the identity of stem cells required for Meibomian gland development and homeostasis and can be used to investigate the factors underlying these processes. They are also robust models of Meibomian gland dysfunction-related dry eye disease, with a potential for use in preclinical therapeutic screening.

Assessing public awareness of daily eyelid hygiene habits in Saudi Arabia: An online survey study

PURPOSE

Incidences of ocular conditions, including meibomian gland dysfunction (MGD), blepharitis, and dry eye have been increasing globally. Eyelid hygiene is key to maintaining ocular surface health and improving ocular symptoms. This study investigated the awareness of eyelid hygiene among the Saudi population.

METHODS

This cross-sectional survey was conducted between April 2020 and May 2020 across all regions of Saudi Arabia through the distribution of an electronic self-administered questionnaire among the Saudi population.

RESULTS

A total of 1102 responses were received (women, 76.3%; men, 23.7%). Only 33.2% respondents reported consciously washing their eyelids, while 70.1% had never heard about MGD; however, most of the respondents (93.2%) had heard about dry eye. Based on the questionnaire results, the Saudi population had suboptimal (18.4%) level of awareness of eyelid hygiene. At least one ocular symptom was reported by 98.1% of the respondents.

CONCLUSION

The level of awareness of eyelid hygiene in Saudi Arabia was found to be suboptimal, particularly among patients with MGD and dry eyes. Poor knowledge about the benefits of daily eyelid hygiene was the primary barrier to its practice. We recommend that ophthalmologists raise awareness of good eyelid hygiene among patients with MGD and eye dryness. Despite the current findings, further studies and evidence are required before recommending daily eyelid hygiene practices in the general population, including those without clinical symptoms of MGD or eye dryness.

Animal models of dry eye disease: Useful, varied and evolving (Review)

Dry eye disease (DED), which is a prevalent disease that still lacks successful treatment options, remains a major challenge in ophthalmology. Multiple animal models of DED have been used to decipher its pathophysiology and to develop novel treatments. These models use mice, rats, rabbits, cats, dogs and non-human primates. Each model assesses aspects of DED by focusing on elements of the lacrimal functional unit, which controls the homeostasis of the tear film. The present review outlines representative DED animal models and assesses their contribution to the study of DED. Murine models are the most extensively used, followed by rabbit models; the latter offer the advantage of larger eyes, a favorable biochemical profile for drug studies, experimental ease and relatively low cost, contrasting with non-human primates, which, although closer to humans, are not as accessible and are expensive. No comprehensive ‘ideal’ animal model encompassing all aspects of human DED exists nor is it feasible. Investigators often choose an animal model based on their experimental needs and the following four features of a given model: The size of the eye, its biochemical composition, the available research reagents and cost. As research efforts in DED expand, more refined animal models are needed to supplement the enormous contribution made to date by existing models.

Focused ultrasound stimulation on meibomian glands for the treatment of evaporative dry eye

Current treatments for meibomian gland dysfunction have several limitations, creating a necessity for other advanced treatment options. The purpose of this study is to determine the effectiveness of focused ultrasound stimulation for the treatment of dry eye disease caused by meibomian gland dysfunction. An in vivo study of nine Dutch Belted rabbits was conducted with focused ultrasound stimulation of the meibomian glands. A customized line-focused ultrasonic transducer was designed for treatment. Fluorescein imaging, Schirmer's test, and Lipiview II ocular interferometer were used to quantify outcomes from three aspects: safety, tear production, and lipid layer thickness. Both tear secretion and lipid layer thickness improved following ultrasound treatment. Five to 10 min after the ultrasound treatment, the mean values of lipid layer thickness increased from 55.33 ± 11.15 nm to 95.67 ± 22.77 nm (p < 0.05), while the mean values measured with the Schirmer's test increased from 2.0 ± 2.3 to 7.2 ± 4.3 (p < 0.05). Positive effects lasted more than three weeks. Adverse events such as redness, swelling, and mild burn, occurred in two rabbits in preliminary experiments when the eyelids sustained a temperature higher than 42°C. No serious adverse events were found. The results suggest that ultrasound stimulation of meibomian glands can improve both tear production and lipid secretion. Ultimately, ultrasound stimulation has the potential to be an option for the treatment of evaporative dry eye disease caused by meibomian gland dysfunction.

Change in rat meibomian gland structure with external pressure on the eyelid

PURPOSE

This study investigated structural changes in rat meibomian glands following repeated and sustained application of external pressure on the eyelids using a magnet and then subsequent removal of the external pressure.

METHODS

Twenty-eight Sprague-Dawley rats were used. The upper eyelid was externally compressed using a pair of magnets. One magnet was placed inside the upper eyelid, another was placed outside the eyelid, and varying periods of pressure were investigated. Untreated eyes were used as controls. Meibography was performed, and the transverse eyelid tissue sections were stained with hematoxylin and eosin and anti-cytokeratin 5 antibody at one hour, two and four weeks after removing the magnets.

RESULTS

Meibography showed increased meibomian gland loss (30.0 ± 5.0%), and tissue sections showed decreased area of secretory acini (0.04 ± 0.08 mm²) at one hour after applying external pressure using magnets versus in the control eyes (5.0 ± 5.0% and 0.08 ± 0.08 mm², respectively). On the other hand, there was no meibomian gland loss or reduction of the area of secretory acini at two and four weeks after removing the magnets in comparison with the control eyes.

CONCLUSIONS

Repeated and sustained application of external pressure on the eyelid could induce meibomian gland loss; however, this meibomian gland loss can be restored when the external pressure is removed. Therefore, the repeated application of external pressure on the eyelid is a safe treatment method for obstructive MGD.

Should we care about the ocular surface in the anophthalmic patient?

PURPOSE

To assess clinical and biomolecular changes of the conjunctival epithelium in anophthalmic patients wearing an ocular prosthesis.

METHODS

Thirty-five unilateral anophthalmic patients were enrolled. Patients with blepharitis, lid abnormalities, and topical/systemic medication affecting the ocular surface were excluded. Symptom Assessment in Dry Eye (SANDE) questionnaire and tear function test (Schirmer Test Type I) were recorded. Conjunctival inflammation and meibomian gland dysfunction (MGD) were graded in the anophthalmic side and fellow eye. Impression cytology sampling of the upper, lower tarsal, and posterior/bulbar conjunctiva from the anophthalmic socket were collected and compared to healthy controls.

RESULTS

Patients had significantly higher SANDE (p < 0.001), Schirmer I test (p = 0.004), conjunctival inflammation (p < 0.001), and MGD scores (p < 0.001) on the anophthalmic side compared to the fellow eye. Mucin 5AC, inflammatory markers (MMP-9, ICAM-1) expression (p < 0.001), and response to oxidative stress (NRF2-KEAP1 signaling pathway) (p < 0.05) were significantly upregulated in the posterior conjunctival surface in the anophthalmic socket.

CONCLUSIONS

Anophthalmic patients complained of more pronounced dry eye symptoms and presented more significant signs of inflammation and MGD on the anophthalmic side. The bulbar conjunctiva, behind the prosthesis, showed more significant hyperexpression of mucins, markers of inflammation, and increased response to oxidative stress compared to the tarsal conjunctiva. Patients wearing ocular prosthesis had signs of inflammation resembling dry eye disease.

Hyperkeratinization and Proinflammatory Cytokine Expression in Meibomian Glands Induced by Staphylococcus aureus

Purpose

This exploratory study aimed to investigate the morphological and pathological alterations of the meibomian gland (MG) with the Staphylococcus aureus crude extracts (SACEs) treatment.

Methods

Mouse MG explants were cultured and differentiated with or without SACEs for 48 hours. Explant's viability and cell death were determined by thiazolyl blue tetrazolium bromide (MTT) assay and TUNEL assay. MG morphology was observed by Hematoxylin and Eosin staining. Lipid droplet production was detected by Nile Red staining and LipidTox immunostaining. The pro-inflammatory cytokines were detected by ELISA. The relative gene and protein expression in MG explants was determined via quantitative RT-PCR, immunostaining, and immunoblotting. The components of the SACEs were analyzed by immunoblotting and silver staining.

Results

Our findings demonstrated that the SACEs treatment induced overexpression of keratin 1 (Krt1) in the ducts and acini of MG explants, accompanied by a decrease in viability and an increase in cell death in explants. Furthermore, the SACEs treatment dose-dependently increased the levels of TNF-α, IL-1β, and IL-6 in MG explants. The SACEs treatment induced activation of the nuclear factor kappa B (NF-κB) and AIM2 (absent in melanoma 2)/ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain) inflammasome signaling pathway in explants. Further investigation showed expression of the key adipogenesis-related molecule peroxisome proliferator-activated receptor γ was decreased after SACEs treatment. However, no change was found in the lipid synthesis of MG explants after treatment with the SACEs. Staphylococcal enterotoxins B (SEB) was detected in the SACEs. SEB induced the overexpression of Krt1 and IL-1β in ducts and acini of MG explants.

Conclusions

Our findings confirm that Staphylococcus aureus induced hyperkeratinization and pro-inflammatory cytokines expression in MG explants ducts and acini. These effects might be mediated by SEB. Activation of the NF-κB and AIM2/ASC signaling pathway is involved in this process.

Changes in anterior segment parameters and presence of dry eye disease in patients with acromegaly: A Sirius topography study combined with meibography

PURPOSE

To investigate anterior segment parameters (ASPs) and dry eye disease (DED), including the status of the meibomian glands, in patients with acromegaly.

METHODS

In this cross-sectional, comparative study, 36 acromegaly patients and 40 healthy sex- and age-matched controls were included. Participants received a comprehensive ophthalmological examination, including intraocular pressure measurements with Goldmann applanation tonometry (IOP_GAT) and central corneal thickness corrected intraocular pressure (IOP_CCT) measurements, and were evaluated for ASPs and DED. For ASPs, white-to-white (WTW), apical (ACT) and thinnest corneal thickness (TCT), corneal volume (CV), keratometry readings (K₁, K₂, and K_mean), anterior chamber depth (ACD) and volume (ACV), and iridocorneal angle (ICA) were obtained via Sirius topography. DED was assessed with Schirmer's test, tear breakup time (TBUT), and Ocular Surface Disease Index (OSDI) scores. Meibography scores (MSs) were obtained with the Sirius topography device.

RESULTS

Patients had higher mean IOP_GAT (P = .006), IOP_CCT (P = .01), ACT (P = .024), and TCT (P = .005) but narrower ICA (P = .014) than controls. Although Schirmer's test did not differ between the groups (P = .442), patients had higher OSDI (P < .001), higher MS (P = .001), and shorter TBUT (P = .002).

CONCLUSION

Patients with acromegaly have greater IOP, greater corneal thickness, but narrower ICA than healthy individuals, as well as DED with increased MSs, which suggests meibomian gland dysfunction.

Meibomian Gland Changes in Open-angle Glaucoma Users Treated with Topical Medication

SIGNIFICANCE

Glaucoma patients treated with topical hypotensive eye drops often experience changes in the ocular surface, including the lid margin and the meibomian glands. In this study, the clinical parameters of the ocular surface have been analyzed to detect the presence of meibomian gland dysfunction-related dry eye disease.

PURPOSE

This study aimed to evaluate the meibomian gland dysfunction in glaucoma patients secondary to topical antiglaucomatous treatment.

METHODS

A total of 131 eyes from different patients with open-angle glaucoma treated with topical medication and 92 eyes from different patients with untreated ocular hypertension were consecutively and prospectively enrolled. The structure of the meibomian glands was assessed using noncontact meibography (Keratograph 5M; Oculus, Wetzlar, Germany), and their function was evaluated by measurement of meibomian glands expressibility, the duct appearance, and the Marx line location. Moreover, tear osmolarity measurement, corneal staining score (Oxford scale), and ocular symptom assessment (Ocular Surface Disease Index questionnaire) were performed. We also compared these variables in the glaucoma group according to the presence (or not) of preservative in topical treatment.

RESULTS

Meibomian gland depletion was higher in glaucoma patients with topical medication (P < .001). Furthermore, the quantity of meibomian glands and expressibility of meibum in these patients were altered compared with the control group (P < .001 in both cases). In addition, the glaucoma group presented a higher degree of corneal staining as measured with the Oxford scale (P < .001). The Marx line location score was higher (P < .001 in central Marx line and P < .003 in temporal Marx line) in patients using drugs containing preservative than in those having preservative-free treatment. Logistical regression found that Marx line central, Marx line temporal, quantity of meibum expression, and quality of meibum expression have predictive ability to detect meibomian gland dysfunction-related dry eye disease.

CONCLUSIONS

Glaucoma topical treatments produce meibomian gland dysfunction altering their structure and function, and this condition can be worsened using topical treatments containing preservative.

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).

TearCare for the Treatment of Meibomian Gland Dysfunction in Adult Patients With Dry Eye Disease: A Masked Randomized Controlled Trial

The aim of this study was to demonstrate the safety and effectiveness of a single TearCare procedure compared with a single LipiFlow procedure in treatment of the dry eye disease associated with meibomian gland dysfunction.

Immune signaling in rosacea

Rosacea is a common chronic skin disease affecting mostly people aged 40 and above, with currently no cure. When it affects the eyelids and periocular skin, it leads to dry eye and potentially corneal damage. Research performed over the last decade shed light into the potential mechanisms leading to skin hypersensitivity and provided promising avenues for development of novel, rational therapeutics aimed at reducing the skin inflammatory state. In this review, we discuss the current knowledge on the mechanisms of rosacea in general and of periocular skin-affecting disease in particular, identify key questions that remain to be answered in future research, and offer a disease model that can explain the key characteristics of this disease, with particular emphasis on a potential positive feedback loop that could explain both the acute and chronic features of rosacea.

Comparison of the Effect of Tea Tree Oil Shampoo With Regular Eyelid Shampoo in Meibomian Gland Dysfunction Treatment

PURPOSE

This study is aimed at comparing the effects of tea tree oil (TTO) shampoo with regular eyelid shampoo on the treatment of meibomian gland dysfunction (MGD) signs and symptoms.

DESIGN

Double-masked randomized clinical trial METHODOLOGY: Forty patients with MGD were treated by daily eyelid scrubbing with TTO shampoo in one eye and regular eyelid shampoo in the other one. Before treatment and then after 1 and 3 months, the effect on ocular surface symptoms, tear production and stability, and conjunctival and eyelid signs of the 2 eyes were compared.

RESULTS

Plugging and capping of meibomian gland orifices, foamy tear, glands expressibility, 5-Item Dry Eye Questionnaire score (DEQ5), and tear breakup time were improved more significantly in TTO shampoo-treated eyes (capping P = .050, plugging and glands expressibility P = .001, others P < .001). In spite of improvement in both eyes, scores of meibum quality, conjunctival hyperemia, corneal and conjunctival staining, and Schirmer1 test value showed no statistically significant difference between the eyes (P = .06, .187, .192, .19, respectively). Moreover, eyelid margin telangiectasia resolved only in TTO shampoo-treated eyes (P < .001). Trichiasis and distichiasis changed in neither group (P > .99). Furthermore, ocular surface irritation during scrubbing was more common with TTO shampoo (P = .002).

CONCLUSION

TTO shampoo was found to be more efficient than regular eyelid shampoo in controlling MGD signs and symptoms although ocular surface irritation during its application was more frequent.

A clinical study on the correlation between demodex infestation and ocular surface changes in patients with meibomian gland dysfunction

Purpose

To observe the effect of demodex infection on the ocular surface changes of patients with meibomian gland dysfunction (MGD) and analyze the correlation between the number of demodex and the changes of the ocular surface.

Methods

Hundred patients with MGD aged 18-70 years who visited the dry eye center of Shanghai Aier Eye Hospital were recruited. All patients were examined with in vivo confocal microscopy to quantify the demodex and divided them into two groups (demodex negative group and demodex positive group) according to the number of demodex mites. The subjects underwent questionnaires of ocular surface disease index (OSDI) and a series of examinations. Parameters including the OSDI score, fluorescein tear film break-up time (FBUT), meibum quality, meibum gland expressibility, meibomian gland dropout (MG dropout), and ocular redness were recorded and compared between the two groups. The correlation between the number of demodex and the ocular surface changes was further analyzed.

Results

Among 100 patients, 51 were positive for demodex. The demodex-positive group showed significantly increased scores of OSDI (24.41 ± 3.43 vs 20.98 ± 2.31, P = 0.00), ocular redness score (1.38 ± 0.46 vs 1.00 ± 0.30, P = 0.00), and MG dropout (3.00 ± 1.13 vs 2.18 ± 0.64, P = 0.00) and decreased FBUT (6.40 ± 1.63 vs 6.54 ± 1.83, P = 0.00), compared to the demodex-negative group. A significant correlation was noted between the number of demodex and OSDI, ocular redness, and FBUT.

Conclusion

: Ocular demodex infestation might play a role in the ocular surface discomfort, inflammation, and meibomian gland dropout in MGD patients. It is necessary to pay attention to the examination and treatment of demodex mite in patients with MGD.

Recent Developments About the Pathogenesis of Dry Eye Disease: Based on Immune Inflammatory Mechanisms

Dry eye disease is a common and frequently occurring ophthalmology with complex and diverse causes, and its incidence is on the upward trend. The pathogenesis of DED is still completely clear. However, the immune response based on inflammation has been recognized as the core basis of this disease. In this review, we will systematically review the previous research on the treatment of DED in immune inflammation, analyze the latest views and research hotspots, and provide reference for the prevention and treatment of DED.

Meibomian gland atrophy with duration of Sjogren's syndrome in adult females

BACKGROUND

To investigate the correlation between the duration of Sjögren syndrome (SS) and ocular surface parameters in patients with SS-related dry eye.

METHODS

We analyzed 108 eyes of 108 female patients with primary SS-related dry eye. All patients underwent rheumatoid serologic tests and ocular surface assessments. The ocular surface assessment included the Standard Patient Evaluation of Eye Dryness (SPEED) score, meibomian gland (MG) atrophy, lipid layer thickness (LLT), partial and total blinking, partial blinking rate, Schirmer's I test, non-invasive tear break-up time, and ocular surface staining score. Correlations between the duration of SS and ocular surface assessments were calculated.

RESULTS

The average age and SS duration of the participants were 56.7 ± 10.2 (range 21-78) years and 54.15 ± 41.10 (range 1-134) months, respectively. There was a strong positive correlation between SS duration and MG atrophy (r = 0.766, p < 0.001). The correlation between SS duration and MG atrophy rate remained significant after controlling for age (r = 0.559, p < 0.001). Average, maximum, and minimum LLTs showed weak negative correlations with SS duration (r = - 0.310, - 0.211, and-0.304, respectively, p = 0.014, 0.028, and 0.022, respectively) and MG atrophy (r = - 0.191, - 0.326, and - 0.299, respectively, p = 0.049, 0.002, and 0.009, respectively). SPEED score showed a weak positive correlation to SS duration (r = 0.303, p = 0.042) and a moderate positive correlation to MG atrophy (r = 0.450, p = 0.029).

CONCLUSIONS

Longer duration of primary SS was related to more severe MG atrophy. Therefore, it is necessary to perform meibography in SS patients to verify MG atrophy status. A comparative study with non-SS dry eye patients is required to validate this study.

Relationship between serum lipid level and meibomian gland dysfunction subtype in Korea using propensity score matching

To analyze the relationship between systemic lipid profile levels and meibomian gland dysfunction (MGD) subtype in Korea. The ophthalmic data of 95 eyes and the serum lipid profiles of 95 patients were reviewed. These factors were compared with those of the general population using data from the Korean National Health and Nutrition Examination Survey (KNHANES), which evaluated 2,917 subjects. Of these, the comparison group (1:5 ratio; n = 475) was selected using propensity score matching according to age and sex. In addition, we analyzed the relationship between serum lipid profile levels and MGD subtypes in MGD patients. The mean high-density lipoprotein (HDL) value of the MGD patients was significantly higher than that of the general population (P < 0.0001). Moreover, the mean low-density lipoprotein (LDL) levels of the MGD patients was significantly lower than that of the general population (P = 0.0002). However, the mean total cholesterol (TC), and triglyceride (TG) levels of the MGD patients were not significantly different from those of the general population (TC: P = 0.4282, TG: P = 0.5613). In addition, no serum lipid levels statistically differed among the MGD subtypes (TC: P = 0.7650, HDL: P = 0.2480, LDL: P = 0.3430, TG: P = 0.7030). A statistically significant increase in HDL and decrease in LDL concentration were observed in the MGD group, although there was no difference in any serum lipid level among the MGD subtypes.

Eye Make-up Products and Dry Eye Disease: A Mini Review

Dry eye disease (DED), a multifactorial condition of the tear film and ocular surface, is one of the leading reasons for patients seeking eye care. Despite the multiple toxic ingredients of eye make-up products and their long-term application close to the ocular surface, few studies have analyzed their role in initiating and worsening DED. Females and the elderly experience the highest prevalence of DED and may be particularly vulnerable to the effects of eye make-up. The multifactorial nature of DED and common mechanisms behind several ocular surface diseases make it difficult to link a particular ingredient-driven mechanism to DED. Therefore, here, we list potential responses to eye cosmetics that may be involved in DED development. The first part of this review introduces the anatomy of the eye and DED, the second section explains the classification of eye cosmetic products, and the final part discusses the undesired effects under physical, pathogenic, and chemical insults.

Semi-quantification of lipids in human meibomian gland epithelial cells using dual staining microplate assays

Two spectrophotometric microplate assays with dual staining for either fluorescent Nile red (NR) plus 4,6-diamidino-2-phenylindole (DAPI) or non-fluorescent Oil red O (ORO) plus Crystal violet (CV) were applied and optimised to evaluate the lipid producing capacity of immortalised human meibomian gland epithelial cells (iHMGEC). Cells were treated with rosiglitazone (Rosi, 10-50 μM), a known lipid producing inducer for iHMGEC, and were analysed for lipids using the NR-DAPI and ORO-CV microplate assays. The lipid producing capacity of iHMGEC after each treatment was determined by normalising lipid quantity (measured with NR or ORO) to cell number (measured with DAPI or CV). The dye concentrations of NR 1 μg/mL, DAPI 5 μg/mL, ORO 0.3% (v/v) and CV 0.5% (v/v), provided optimal linearity and coverage of signals over a range of cell densities (corresponding to 10-100% cell confluence). Both NR-DAPI and ORO-CV showed a dose-dependent effect of Rosi on lipid production in iHMGEC, consistent with the results reported previously using traditional microscopic imaging methods. The microplate assays offer a rapid, high throughput and objective measurement of the amount of lipids in iHMGEC (and potentially other lipid-producing cells) and can be used for screening the effects of biological agents or incubation changes on lipid production in cells in future studies.

PREVALENCE OF MEIBOMIAN GLAND DYSFUNCTION IN AFRICA: A SYSTEMATIC REVIEW AND META-ANALYSIS OF OBSERVATIONAL STUDIES

PURPOSE

To review and summarize information on meibomian gland dysfunction (MGD) epidemiology in Africa.

METHODS

A systematic search of online databases was conducted for literature/studies on MGD in Africa. Meta-analysis was conducted to estimate the prevalence of MGD in Africa. Meta-regression was used to explore sources of heterogeneity.

RESULTS

Twelve studies conducted in five countries were included in the review. All studies were hospital-based studies. Nine studies were included in the meta-analysis; the total sample size was 4963 and participants' age range was 17-96 years. The overall prevalence estimate of MGD in Africa was 45.9% (95% CI: 27.6-64.1%). Prevalence of MGD among males and females were each pooled from three studies and in urban and rural setting from 6 and 3 studies, respectively. Prevalence of MGD among males and females were 56.0% (95% CI: 22.4-89.5%) and 58.9% (95% CI: 28.5-89.4%) respectively; in urban and rural settings were 42.8% (95% CI: 21.1-64.5%) and 65.7% (95% CI: 25.7-95.7%), respectively. There was no association of MGD with sex (p = .872) and with study setting (p = .231).

CONCLUSION

There is a paucity of evidence on MGD prevalence in Africa, emphasizing the need for epidemiological studies to enhance our understanding of region-specific differences in MGD in Africa. The pooled estimate from hospital-based studies, however, suggests a substantial MGD burden in Africa. Epidemiological studies are needed to assess if this translates to a high disease burden within the general African population.

The role of topical N-acetylcysteine in ocular therapeutics

N-acetylcysteine (NAC) was first discovered as a mucolytic agent in 1960. We investigate the role of topical NAC in ocular therapeutics, including its mechanism of action, current applications, and adverse effects. A systematic search of peer-reviewed articles identified 106 references including in vitro, in vivo and clinical studies on the use of NAC in the treatment of ocular diseases. NAC can be synthetically manufactured, and its mechanisms of action include mucolysis, scavenging hydroxyl radicals, and modulation of inflammatory cascades. These unique properties contribute to the diverse applications of NAC, including its steroid-sparing potential. NAC has been used topically in the treatment of corneal wounds, chemical injuries, keratitis, dry eye disease and meibomian gland dysfunction. The clinical benefits of NAC are evident over a wide range of concentrations, the most common being 5-10% topical NAC applied four times daily. Adverse effects such as corneal necrosis are rare, but have been reported with higher doses. NAC also has potential applications in laser epithelial keratomileusis, diabetic eye disease, retinitis pigmentosa, senile nuclear cataracts, macular degeneration, and cigarette smoke-induced corneal damage. Recently, chitosan-NAC has been used as a nanocarrier for the topical administration of medications to the ocular surface. Owing to its potent antioxidant, anti-inflammatory and mucolytic properties, topical NAC has had extensive use in the treatment of ocular pathology.

Lipidomic analysis of meibomian glands from type-1 diabetes mouse model and preliminary studies of potential mechanism

Diabetes is a significant risk factor for meibomian gland dysfunction (MGD), but its mechanism is poorly understood. The main function of the meibomian glands (MGs) is to synthesize, store, and secrete lipids. In this study, we found that the amount of lipids in the meibomian acini in STZ-induced type 1 diabetic mice decreased, and the lipid droplets became larger and irregular. In all, 31 lipid subclasses were identified in the mouse MGs, which contained 1378 lipid species in total through lipidomics analysis based on LC-MS/MS. Diabetes caused a significant increase in the content of ceramides (Cer) in the MGs but a significant decrease in the ration of sphingomyelin to ceramides (SM/Cer). The quantity of meibocytes in diabetic mice was dramatically decreased, and the proliferation activity was alleviated, which may be associated with cell cycle arrest caused by diabetes-induced abnormal Cer metabolism in MGs. We found an increase in macrophage and neutrophils infiltration in the diabetic MGs, which may be related to the significant reduction of AcCa in diabetic MGs. Taken together, the results of the present study demonstrated that diabetes induced disruption of lipid homeostasis in MGs, which may mediate the decreased cell proliferation and increased inflammation caused by diabetes in MGs.

Evaluation of Meibomian Gland Loss and Ocular Surface Changes in Patients with Mild and Moderate-to-Severe Graves' Ophthalmopathy

OBJECTIVES

To evaluate the association of Graves' Ophthalmopathy (GO) with the meibomian glands and investigate the relation of ocular surface changes with meibomian gland parameters in patients with GO.

METHODS

This prospective study included 44 eyes of 44 mild and moderate-to-severe GO patients and 38 eyes of 38 control subjects. After a complete ophthalmologic examination, patients were assessed according to the Clinical Activity Score (CAS). The area of meibomian gland loss and meibography score was evaluated using meibography (Sirius; CSO, Florence, Italy). Schirmer test, tear break-up time (TBUT) and Ocular Surface Disease Index (OSDI) scores were evaluated.

RESULTS

Mean meibomian gland dropout area was 26.29 ± 1.58% in the GO group and 14.46 ± 1.52% in the healthy controls (p < .001). Mean meibography score in the GO group was 2.61 ± 0.15 while it was 1.32 ± 0.25 in the healthy controls (p < .001). Meibomian gland dropout area was positively correlated with CAS and OSDI questionnaire results (p = .015, r = 0.391; p < .001, r = 0.662, respectively) and negatively correlated with TBUT and Schirmer test scores (p < .001, r = -0.635; p = .003, r = -0.474, respectively). Meibography score was positively correlated with CAS and OSDI questionnaire results (p = .012, r = 0.383; p = .007, r = 0.419, respectively) and negatively correlated with TBUT and Schirmer test scores (p = .002, r = -0.467; p = .023, r = -0.359, respectively).

CONCLUSION

Meibomian glands are quantitatively decreased in patients with GO. The decrease of meibomian glands is correlated with objective and subjective dry eye findings. Dry eye treatment in GO patients should include meibomian gland deficiency as well.

Hedgehog Signaling Pathway Regulates the Proliferation and Differentiation of Rat Meibomian Gland Epithelial Cells

Purpose

Meibomian glands play a vital role in maintaining ocular surface stability. This study aimed to investigate whether Hedgehog signaling is involved in the regulation of meibomian gland epithelial cells.

Methods

Rat meibomian glands epithelial cells (RMGECs) were isolated from ducts and ductules, and then were cultivated to passage two on Matrigel coated wells in meibomian gland epithelial cells medium (MGECM). Cells were switched from MGECM to differentiation medium (DM) or DM added 10 µg/mL azithromycin (DM + AZM) when reached 50% to 60% confluence. The effects of the Smoothened (Smo) agonist (Smo agonist [SAG]) and antagonist (by cyclopamine) on RMGECs were analyzed using quantitative RT-PCR, cell proliferation analysis, immunofluorescence staining, and Nile red staining.

Results

The Hedgehog receptor, Smo, and its downstream molecules, Glis, were expressed both in vivo and in vitro. Smo and Gli1 both decreased with the increase of differentiation in vitro. Smo antagonist, cyclopamine, reduced cell numbers, and the expression of Ki67 in MGECM, and promoted the expression of SREBP1 and lipid production in DM + AZM. Smo agonist, SAG, inhibited the expression of SREBP1 and lipid accumulation in DM + AZM but showed no significant effects on raising cell numbers and the expression of Ki67 in MGECM.

Conclusions

The Hedgehog signaling pathway appears to play important roles in RMGECs proliferation and differentiation. This may provide a potential therapeutic way to treat meibomian gland dysfunction (MGD).

Effectiveness and Safety of Combined Application of Three Modes of 2940-nm Erbium:YAG and 1064-nm Neodymium:YAG Lasers in Treatment of Meibomian Gland Dysfunction

Purpose

To study the effectiveness and safety of upper and lower eyelid treatment with combined application of three modes of 2940-nm erbium-doped yttrium aluminium garnet (Er:YAG) and 1064-nm neodymium-doped yttrium aluminium garnet (Nd:YAG) lasers in patients with baggy eyelids (formed by intraorbital fat herniation) who exhibited meibomian gland dysfunction (MGD).

Patients and Methods

In this prospective cohort study, patients with baggy eyelid who exhibited MGD received combined laser treatment at baseline, as well as at the 4-, 8-, and 12-week follow-ups. The primary endpoint was meibum quality score at 16- and 24-week follow-ups; secondary endpoints were ocular surface index scores, tear film lipid layer thicknesses, tear break up times (TBUTs), Oxford scheme grades, and meibography grades at 16- and 24-week follow-ups. Adverse events, uncorrected visual acuities, best-corrected visual acuities, and intraocular pressures were also recorded.

Results

Sixteen patients (four men and 12 women; mean age, 56.38 ± 8.64 years) were included. Meibum quality scores at the 16-week follow-up were significantly lower than scores at baseline (p=0.043) and at the 24-week follow-up (p=0.015). TBUT was significantly exacerbated at the 24-week follow-up, compared with baseline (p=0.001) and the 16-week follow-up (p=0.006). There were no significant changes in other parameters. All adverse events were mild and resolved without additional treatment.

Conclusion

Combined application of three modes of 2940-nm Er:YAG and 1064-nm Nd:YAG lasers on upper and lower eyelids significantly improved meibum quality in patients with MGD; it ameliorated symptoms and signs of dry eye disease at 4 weeks after completion of laser treatment.

Evaluation of dry eye and Meibomian gland dysfunction in female androgenetic alopecia patients

PURPOSE

To evaluate dry eye tests and Meibomian gland functions in female androgenetic alopecia patients.

MATERIALS AND METHODS

Twenty left eyes of 20 female androgenetic alopecia patients (Group 1) and 20 left eyes of 20 healthy female volunteers (Group 2) were enrolled in the study. The presence of dry eye was evaluated with Schirmer 1 test, invasive tear film break-up time (T-BUT), Oxford scale scoring and Ocular Surface Disease Index (OSDI) score assessments. Evaluation of upper and lower eyelid Meibomian glands was performed using infrared filter of a slit-lamp biomicroscope, and the drop out ratio was scored for each eyelid.

RESULTS

The mean ages of Group 1 and Group 2 were 48.3 ± 6.6 (range, 38-58) and 49.8 ± 5.4 (range, 38-59) years, respectively (P = 0.437). Mean T-BUT was statistically significantly lower in Group 1 (P = 0.013); mean OSDI score was significantly higher in Group 1 (P = 0.049). Mean Schirmer 1 score was lower and mean Oxford score was higher in Group 1, but the differences were not statistically significant (P = 0.291, P = 0.088, respectively). In addition, upper, lower and total meiboscores were significantly higher in Group 1 (P = 0.007, P = 0.003, P = 0.002, respectively).

CONCLUSION

Alterations in sex hormones play a role in the pathogenesis of both female androgenetic alopecia and Meibomian gland dysfunction. Significant differences were detected in the results of dry eye tests and Meibomian gland dropout ratios between subjects with female androgenetic alopecia and healthy control subjects. For this reason, female androgenetic alopecia patients should be examined for dry eye and Meibomian gland dysfunction and should be treated to prevent serious consequences.

Human Meibum and Tear Film Derived (O-Acyl)-Omega-Hydroxy Fatty Acids as Biomarkers of Tear Film Dynamics in Meibomian Gland Dysfunction and Dry Eye Disease

Purpose

To investigate the association between precorneal tear film (PCTF)- and meibum-derived (O-Acyl)-omega-hydroxy fatty acids (OAHFAs) and PCTF thinning in meibomian gland health and dysfunction.

Methods

Of 195 eligible subjects (18-84 years, 62.6% female), 178 and 170 subjects provided both PCTF optical coherence tomography (OCT) imaging and mass spectrometry data for tears (n = 178) and meibum (n = 170). The PCTF thinning rate was measured in the right eye using an ultra-high-resolution, custom-built OCT. Tear and meibum samples from the right eye were infused into the SCIEX 5600 TripleTOF mass spectrometer in the negative ion mode. Intensities (m/z) of preidentified OAHFAs were measured with Analyst 1.7TF and LipidView 1.3 (SCIEX). Principal component (PC) analyses and Spearman's correlations (ρ) were performed to evaluate the association between OAHFAs and PCTF thinning rates.

Results

In meibum and tear samples, 76 and 78 unique OAHFAs were detected, respectively. The first PC scores of the meibum-derived OAHFAs had statistically significant correlations with PCTF thinning rates (ρ = 0.18, P = 0.016). Among 10 OAHFAs with the highest first PC loadings, six OAHFAs had negative correlations with PCTF thinning rate (18:2/16:2, ρ = -0.19, P = 0.01; 18:2/30:1, ρ = -0.21, P = 0.008; 18:1/28:1, ρ = -0.22, P = 0.004; 18:1/30:1, ρ = -0.22, P = 0.005; 18:1/25:0, ρ = 0.22, P = 0 .006; and 18:1/26:1, ρ = -0.22, P = 0.006), while one OAHFA had a positive correlation with PCTF thinning rate (18:2/18:1, ρ = 0.48, P = 0.006). Tear film-derived OAHFAs had no association with the PCTF thinning rate.

Conclusions

Several human meibum-derived OAHFAs showed significant associations with PCTF thinning, suggesting that these OAHFAs could be implicated in the mechanism underlying the stabilization and thinning of the PCTF. The tear-film derived OAHFAs were, however, independent of the rate of PCTF thinning.

The effect of active smoking, passive smoking, and e-cigarettes on the tear film: An updated comprehensive review

Active tobacco smoking, passive smoking, and e-cigarette smoking have been associated with different systemic and ocular diseases. The precorneal tear film plays an important role in eye health and its analysis can provide useful information on ocular status. This review investigates the effects of different types of smoking on the precorneal tear film, by analyzing the peer-reviewed literature on this topic. Specifically, tear evaporation rate, stability, volume, ferning, osmolarity, and physical composition (lipids and proteins) of tear film are detailed. Most of the reported works show that cigarette smoking reduces tear film stability and quality by affecting its components. This review highlights that smoking severely affects the tear film, but a single test is not sufficient to determine these effects because smoking can impact different parts of the eye.

Demodex Infection Changes Ocular Surface Microbial Communities, in Which Meibomian Gland Dysfunction May Play a Role

INTRODUCTION

Demodex and bacteria are both components of the ocular surface micro-ecology, constituting a complex interaction. This study aims to explore how ocular surface Demodex infestation (DI) affects ocular surface microbial communities and diversity.

METHODS

We recruited 255 subjects, and examined the correlation between ocular surface mite infestation and clinical indicators such as age, blood glucose level, dry eye symptoms, and blood pressure. 16S rRNA sequencing was performed on the conjunctival swab samples of 14 patients with ocular DI (P group) and 17 healthy people (N group). For further analysis, the subjects were divided into four subgroups, i.e. N-NMGD (n = 11), N-MGD (n = 6), P-NMGD (n = 6), and P-MGD (n = 8), according to meibomian gland dysfunction (MGD) or no MGD (NMGD).

RESULTS

There was no difference in the α-diversity of ocular surface microbial communities between the DI and healthy control groups. In linear discriminant analysis effect size (LEfSe), there were more Acinetobacter, Novosphingobium, and Anoxybacillus in the DI group and fewer Novosphingobium, Lactobacillus, and Candidatus Microthrix in the healthy control group. P-NMGD had more Thermaceae and fewer Pseudomonas than P-MGD. There were more Bacteroidetes in N-NMGD than in N-MGD. The α-diversity of P-NMGD was lower than that of N-NMGD (Shannon index, P = 0.027). At the same time, the α-diversity of N-MGD was lower than that of N-NMGD (Shannon, Simpson, and dominance index, P = 0.048). There was no significant difference in β-diversity or in the primary flora at the phylum and genus levels between groups and subgroups.

CONCLUSION

DI had no significant effect on the diversity of ocular surface microbial communities. DI primarily changed the dominant flora and relative abundance of ocular surface microbial communities. MGD may play an important role in this process.

Sex Hormones Related Ocular Dryness in Breast Cancer Women

Background: Dry eye syndrome (DES) is strictly connected to systemic and topical sex hormones. Breast cancer treatment, the subsequent hormonal therapy, the subsequent hyperandrogenism and the early sudden menopause, may be responsible for ocular surface system failure and its clinical manifestation as dry eye disease. This local dryness is part of the breast cancer iatrogenic dryness, which affects overall mucosal tissue in the fragile population of those with breast cancer. Methods: A literature review regarding the role of sex hormone changes and systemic hormonal replacement treatments (SHRT) in DES available on PubMed and Web of Science was made without any restriction of language. Results: Androgens exert their role on the ocular surface supporting meibomian gland function and exerting a pro-sebaceous effect. Estrogen seems to show a pro/inflammatory role on the ocular surface, while SHRT effects on dry eye are still not well defined, determining apparently contradictory consequences on the ocular surface homeostasis. The role of sex hormones on dry eye pathogenesis is most likely the result of a strict crosstalk between the protective androgens effects and the androgen-modulating effects of estrogens on the meibomian glands. Conclusions: Patients with a pathological or iatrogenic hormonal imbalance, such as in the case of breast cancer, should be assessed for dry eye disease, as well as systemic dryness, in order to restore their social and personal quality of life.

Comparative Study of Two Infrared Meibographers in Evaporative Dry Eye Versus Nondry Eye Patients

OBJECTIVE

To compare the measurement of the meibomian gland (MG) dropout between two infrared meibographers in patients with and without dry eye.

METHODS

The right eyelids of each patient were imaged using the Antares and Cobra meibography devices. All images were analyzed using Phoenix software to calculate the percentage of the MG dropout. Lipid layer thickness, eyelid margin characteristics, ocular surface staining, MG secretion, number of expressible glands, and noninvasive tear breakup time were also evaluated. A comparison between nondry eye and evaporative dry eye was performed.

RESULTS

Eighty participants (mean age, 36.93 years and 51.3% women) were included, of which 67.5% had nondry eye. A significant difference was observed in the dropout percentage of the superior eyelid between the Antares and Cobra devices (P=0.007) for all participants and when only the nondry eye patients were examined. In patients with dry eye, no significant differences were found in the dropout measurements of both eyelids.

CONCLUSIONS

Statistically significant differences in the MG dropout percentage in the upper eyelid of nondry eye patients were obtained from both meibographers. The measurements were similar in patients with dry eye, suggesting that the two instruments can be interchanged.

Human meibum and tear film derived (O-acyl)-omega-hydroxy fatty acids in meibomian gland dysfunction

PURPOSE

The molecular basis of the tear film and lipid layer alterations in meibomian gland dysfunction (MGD) is unknown. This study aimed to identify and compare (O-acyl)-omega-hydroxy fatty acids (OAHFAs) derived from human meibum and tears in MGD.

METHODS

Of 195 eligible subjects (18-84 years, 62.6% female), 183 and 174 provided samples for tears and meibum, respectively. Subjects were classified into four groups: Normal, Asymptomatic MGD, MGD, and Mixed. Samples from the right eye of each subject were infused into the SCIEX 5600 TripleTOF mass spectrometer in negative ion mode. Lipid intensities identified with Analyst1.7 TF and SCIEX LipidView1.3 were normalized by an internal standard and total ion current, then statistically compared in MetaboAnalyst 4.0.

RESULTS

In meibum and tears, 76 and 78 unique OAHFAs were identified, respectively. The five most frequent and abundant OAHFAs were 18:2/16:2, 18:1/32:1, 18:1/30:1, 18:2/32:1, and 18:1/34:1. Two OAHFAs, 18:2/20:2 and 18:2/20:1, were identified only in tears. Initial univariate analysis revealed three differently regulated OAHFAs in meibum and eight in tears. Partial Least Square Discriminant Analysis showed 18:1/32:1, 18:2/16:2, 18:1/34:1 and 18:0/32:1 in tears, and 18:2/16:2, 18:1/32:1 and 18:2/32:2 in meibum, had variable importance in projection scores >1.5 and contributed the most to the separation of groups. In both meibum and tears, all OAHFAS except 18:2/16:2 were reduced in MGD compared to the normal group.

CONCLUSION

MGD is accompanied by differential expression of specific OAHFAs in meibum and tears. These results suggest OAHFAs play a role in the altered biochemical profile of the tear film lipid layer in humans with MGD.

The Effect of Oral Vitamin A Supplementation on Chalazion in Young Children with Vitamin A Deficiency: A Pilot Study

Purpose: Many researchers have reported that vitamin A (VA) deficiency is related to chalazion. The purpose of this article is to clarify the effects of VA supplementation on chalazion in young children with VA deficiency. Methods: Forty-eight young children with VA deficiency suffering from chalazia were enrolled from our previous studies and were followed continuously for 1 year. Serum VA levels and recurrence of chalazion were observed. Results: The mean serum VA levels increased after supplementation (P = 2.17E-15). The mean serum VA levels of subjects who experienced recurrence were lower than those without recurrence (P = 0.015). The recurrence rate and the mean recurrent frequency after supplementation were lower than before supplementation (P = 0.01, P = 6E-6); the mean time to the first recurrence of subjects without recurrence was longer after supplementation than before supplementation (P < 0.01). Conclusions: Oral VA supplementation could reduce the recurrence of chalazion in young children with preexisting VA deficiency.

Diverse meibum lipids produced by Awat1 and Awat2 are important for stabilizing tear film and protecting the ocular surface

A lipid layer consisting of meibum lipids exists in the tear film and functions in preventing dry eye disease. Although the meibum lipids include diverse lipid classes, the synthesis pathway and role of each class remain largely unknown. Here, we created single and double knockout (KO and DKO, respectively) mice for the two acyl-CoA wax alcohol acyltransferases (Awat1 and Awat2) and investigated their dry eye phenotypes and meibum lipid composition. Awat2 KO and DKO mice exhibited severe dry eye with meibomian gland dysfunction, whereas Awat1 KO mice had mild dry eye. In these mice, specific meibum lipid classes were reduced: (O-acyl)-ω-hydroxy fatty acids and type 1ω wax diesters in Awat1 KO mice, wax monoesters and types 1ω and 2ω wax diesters in Awat2 KO mice, and most of these in DKO mice. Our findings reveal that Awat1 and Awat2 show characteristic substrate specificity and together produce diverse meibum lipids.

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Awat2 knockout mice exhibit severe dry eye phenotypes

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Awat1 knockout mice exhibit mild dry eye phenotypes

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Awat2 is responsible for the production of wax monoesters and type 2ω wax diesters

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Awat1 is involved in (O-acyl)-ω-hydroxy fatty acid production

Quantitative evaluation of lipid layer thickness and blinking in children with allergic conjunctivitis

Purpose

To quantitatively evaluate the lipid layer thickness (LLT) and blinking in children with or without allergic conjunctivitis (AC), and to compare those between the different types of AC.

Methods

For this case–control study, 81 children with symptomatic AC with an average age of 9.62 ± 2.67 years were enrolled and subdivided according to the subtypes of AC, including seasonal/perennial allergic conjunctivitis group and vernal keratoconjunctivitis (VKC)/atopic keratoconjunctivitis (AKC) group. Another 82 age-matched healthy children were enrolled as control group. All subjects underwent routine eye examination and measurements of LLT, the number of incomplete or total blinking, partial blinking rate by the LipiView interferometer over a 10-s period. Other ocular surface assessment included fluorescein tear breakup time (TBUT), lower tear meniscus height, meibomian gland loss (MGL), meibum expressibility and quality.

Results

Pediatric patients with AC had significant thinner LLT, shorter TBUT, decreased total blinking but increased partial blinking rate, especially in those with VKC/AKC (all P < 0.05). A significant deterioration of meibomian gland parameters was observed in AC group when compared with control subjects, demonstrated by severe upper and lower MGL, lid margin abnormalities, decreased meibum expressibility, and abnormal meibum quality, all of which were worse in the severe type of AC (all P < 0.05). Thinner LLT was significantly correlated with decreased TBUT (β = 3.666, P < 0.001) and severity of upper MGL (β =  − 7.701, P = 0.002).

Conclusion

Decreased LLT and blinking disorders in pediatric patients with AC may contribute to lipid layer deficiency in the long run, which should be considered and appropriately diagnosed for a more precise treatment.

Does Sjogren's syndrome affect only the lacrimal gland in the eye? Time to replace the missing stones

Purpose:

This study aimed to reveal the cause of meibomian gland disease and meibomian gland loss in patients with Sjögren's syndrome (SS) as the leading factor for dry eyes.

Methods:

The study included a total of 30 patients with SS and dry eye symptoms and a control group of 50 age- and gender-matched healthy subjects. The dryness parameters of all the participants were evaluated. At first, meibography was performed to measure meibomian gland loss using noninvasive methods. Later, meibomian gland expression and secretion quality were evaluated using silt-lamp biomicroscopy. Correlations between the measurements were analyzed statistically.

Results:

In patients with SS, MG loss was significantly greater than in the control group (19.7 ± 71%, 12.7 ± 9.6%, P < 0.001). All dry eye parameters (tear film breakup time, Schirmer's test score, OSDI, stain score, dry eye disease) were statistically significant in the SS group. There was an extremely negative correlation between upper MB loss and BUT (P = 0.08, r: 0.781). There was an extremely positive correlation between upper MB loss and staining (P = 0.015, r: 0.739). An extremely negative correlation was determined between sub-MB loss and BUT (P = 0.18, r:-0.781), and a moderately positive significant correlation was found between sub-MB loss and staining (P = 0.031, r: 0.659).

Conclusion:

The results of this study demonstrated that patients with SS were at a higher risk of being exposed to meibomian gland loss, which directly leads to the severe dry eye symptoms associated with SS.

Cutaneous and ocular rosacea: Common and specific physiopathogenic mechanisms and study models

Rosacea is a chronic inflammatory disease that affects the face skin. It is clinically classified into the following four subgroups depending on its location and severity: erythematotelangiectatic, papulopustular, phymatous, and ocular. Rosacea is a multifactorial disease triggered by favoring factors, the pathogenesis of which remains imperfectly understood. Recognized mechanisms include the innate immune system, with the implication of Toll-like receptors (TLRs) and cathelicidins; neurovascular deregulation involving vascular endothelial growth factor (VEGF), transient receptor potential (TRP) ion channels, and neuropeptides; and dysfunction of skin sebaceous glands and ocular meibomian glands. Microorganisms, genetic predisposition, corticosteroid treatment, and ultraviolet B (UVB) radiation are favoring factors. In this paper, we review the common and specific molecular mechanisms involved in the pathogenesis of cutaneous and ocular rosacea and discuss laboratory and clinical studies, as well as experimental models.

Pathophysiology of Meibomian Glands - An Overview

Purpose: The meibomian glands are located in the tarsal plate of the upper and lower eyelid and are responsible for the production of a lipid-rich secretion, the meibum, which forms the outer component of the tear film. Meibomian gland dysfunction results in excessive evaporation of the tear film and is the leading cause of dry eye disease (DED). Despite the high prevalence of DED, the etiology of meibomian gland dysfunction is only basically understood. In addition, the molecular mechanisms of meibomian gland maturation and physiological function are currently the focus of research.Methods: A systematic literature search was performed using the main scientific databases, including all relevant published articles up to September 2020.Results: This article provides an overview of the current state of knowledge about meibomian gland stem cells, cell surface marker expression and PPARγ signaling, as well as the pathological causes of meibomian gland dysfunction.Conclusion: Androgen deficiency, hyperkeratinization, PPARγ signaling and inflammatory reactions including neutrophil extracellular traps (NETs) seem to be key factors within the pathological processes of the meibomian gland.

Complications and Adverse Effects of Periocular Aesthetic Treatments

The popularity and variety of temporary and permanent periocular aesthetic treatments has increased over the past decade. Patients frequently present to eye clinics with ocular complications and side effects following these treatments, their severity ranging from ocular irritation from dry eyes to visual loss from vascular occlusion. A careful, thorough history is essential, as many patients may not associate aesthetic procedures with ocular complications, and some may be embarrassed to disclose this information. All ophthalmologists should understand the potential ocular sequelae of these treatments and be able to initiate treatment in sight-threatening cases. Wesummarises the current literature on ophthalmic complications of the most common periocular aesthetic treatments.

Prevalence of ocular surface disease symptoms in peri- and postmenopausal women

OBJECTIVE

The objective of the study was to determine the prevalence of ocular surface disease (OSD) symptoms and the possible existence of differences between peri- and postmenopausal women, based on the result of the Ocular Surface Disease Index (OSDI).

METHODS

A transversal observational study based on the results of an e-mail survey between October 2018 and January 2019 involving 1,947 women. The study was performed on a group of peri- and postmenopausal women aged between 45 and 79 years. The personal data in the survey included age, menopause status, age at menopause, prediagnosis of dry eye, undergoing dry eye treatment, and the OSDI questionnaire. Student's t test and Chi squared test were used to compare means or percentages between results on the survey and peri- and postmenopausal women. Finally, a univariate logistic regression was carried out to estimate the prevalence of OSD. The OSDI score is assessed on a scale of 0 to 100.

RESULTS

The mean age of the entire sample was 54.2 ± 6.8 years, with a mean age at menopause of 49.45 ± 4.02 years. The mean OSDI score was 29.2 ± 19.4, considered as moderate dry eye. The global prevalence of OSD symptoms was 64% (1,247/1,947), which increased significantly in postmenopausal women, being 66.8% (820/1,228) (P = 0.001). The probability of OSD symptoms prevalence increases with age (odds ratio: 1.02; 95% CI [1.01-1.03]). The greater the age at menopause, the lower the probability of OSD symptoms prevalence (odds ratio: 0.96 95% CI [0.93-0.99]).

CONCLUSIONS

Sixty-four percent of the pre- and postmenopausal women studied had OSD symptoms. There was a correlation between OSD symptoms and age, postmenopause, and earlier age at menopause, which was associated with an increased prevalence. : Video Summary:http://links.lww.com/MENO/A603.

Inhibitory effect of host ocular microenvironmental factors on chlorhexidine digluconate activity

Acanthamoeba spp. are free-living protozoan that cause a serious human eye disease called Acanthamoeba keratitis (AK). Several new and effective medical therapy for AK patients remains highly debated and therefore, CHG is still considered one of the first lines of treatment for AK patients. We hypothesized that ocular microenvironmental factors are responsible for Acanthamoeba drug resistance and clinical AK treatment failure. To investigate the influence of the ocular surface on CHG treatment, we tested the effect of several ocular elements on the anti-amoeba activity of CHG. The suspected inhibitory elements, including mucin, albumin, human and amoeba cell lysates, live and heat-killed bacteria, and cornea, were added to the amoebicidal activity platform, where amoeba was incubated with CHG at varying concentrations. Mucin showed a significant inhibitory effect on CHG activity against Acanthamoeba castellanii In contrast, albumin did not affect CHG treatment. Furthermore, human and amoeba cell lysates as well as live and heat-killed bacterial suspensions also significantly inhibited CHG activity. Additionally, we found that pig corneas also reduced CHG activity. In contrast, dry eye drops and their major component, propylene glycol, which is commonly used as eyewash material, did not have an impact on CHG activity. Our results demonstrate the effect of ocular microenvironmental factors on CHG activity and suggest that these factors may play a role in the development of amoeba resistance to CHG and treatment failure.