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

Assessment of meibomian gland morphology by noncontact infrared meibography in Shih Tzu dogs with or without keratoconjunctivitis sicca

Objective

To investigate meibomian gland (MG) morphology by noncontact infrared meibography in Shih Tzu dogs with or without keratoconjunctivitis sicca (KCS).

Procedures

Fourteen eyes of 12 Shih Tzu dogs (mean age of 10.7 years, range of 7‐13 years) presented to Yakumo Animal Hospital or Triangle Animal Eye Clinic from 2011 to 2017 with clinical signs and a Schirmer tear test (STT) result consistent with KCS (<10 mm/min) were examined. Twenty‐eight eyes of 16 Shih Tzu dogs (mean age of 12.4 years, range of 8 to 15 years) with a STT > 15 mm/min served as healthy controls. Both groups of dogs underwent routine slitlamp biomicroscopy followed by noncontact infrared meibography of the upper eyelid with both desktop‐type and mobile‐type systems.

Statins in ophthalmology

Statins, 3-hydroxy-3-methyl-gutaryl coenzyme A reductase inhibitors, are a class of lipid-lowering drugs with anti-inflammatory, immunomodulatory, and vascular effects. Statins are increasingly being used in the treatment of a variety of medical conditions. We examine the actions of statins on the eye and its associated ophthalmic disorders. Statins can be synthetic or nonsynthetic, and their differentiating derivations may contribute to their varying cholesterol-lowering and pleiotropic effects. There is conflicting evidence on the ocular therapeutic and adverse effects of the statins. Statins may play a role in reducing the burden of dry eye, corneal ulcer scarring, thyroid-associated orbitopathy, glaucoma, uveitis and other associated ocular inflammatory states, cataract, proliferative vitreoretinopathy, diabetic retinopathy, macular degeneration, and choroidal melanoma. Topical preparations of statins can be formulated, thereby extending the range of ocular diseases that may be amenable to treatment. Statins have a relatively safe side effect profile, but rare and serious adverse reactions have been reported with their usage in ophthalmology, including myopathies and rhabdomyolysis with acute renal failure.

A Review of Periocular Botulinum Neurotoxin on the Tear Film Homeostasis and the Ocular Surface Change

Clinical usage of botulinum neurotoxin (BoNT) in ophthalmology has dramatically increased since the 1980s and has become one of the most widely used agents for treating facial movement disorders, autonomic dysfunction and aesthetic wrinkles. Despite its high efficacy, there are some complications with periocular BoNT injections due to its chemodenervation effect. Among these, there is still controversy over the BoNT effect on tear film homeostasis and the ocular surface. A periocular BoNT injection could dry the eye by reducing tear production of the lacrimal gland and increase tear evaporation due to potential eyelid malposition and abnormal blinks. On the contrary, the injection of BoNT in the medial eyelids could treat dry eye disease by impairing lacrimal drainage. Regarding the ocular surface change, corneal astigmatism and high-order aberrations may decrease due to less eyelid tension. In conclusion, the entire awareness of the effect of BoNT and the patients’ ocular condition is crucial for successful and safe results.

Tear film analysis and evaluation of optical quality: A review of the literature

Dry eye is a complex multifactorial disease of the ocular surface and tears. It is associated with ocular surface symptoms and is one of the most common causes for ophthalmologic consultation. Despite their frequent use in clinical practice, the usual tests to evaluate dry eye and ocular surface disease-history of symptoms, tear break-up time (TBUT), Meibomian gland evaluation, corneal fluorescein staining, Schirmer test-have shown low reproducibility and reliability. In addition, subjective symptoms are often weakly or poorly correlated with objective signs. Since the tear film is the first system through which light must pass, the optical quality of the eye is highly dependent on the homogeneity of the tear film. Various investigative methods have been developed to evaluate both the structural and functional quality of the tear film, such as corneal topography, interferometry, tear meniscus measurement, evaporation rate, tear osmolarity and even aberrometry. Some are easily accessible to clinicians, while others remain in the field of clinical research. All of these tests provide a better understanding of the pathophysiology of the tear film. This review hopes to provide an overview of the existing tests and their role in evaluating the significance of the tear film in visual function.

Lipidomic analysis of meibomian gland secretions from the tree shrew: Identification of candidate tear lipids critical for reducing evaporation

Lipids secreted from the meibomian glands form the outermost layer of the tear film and reduce its evaporation. Abnormal changes in the quantities or compositions of lipids present in meibomian gland secretions (meibum) are known to lead to dry eye disease, although the underlying mechanism is not yet well understood. The tree shrew is the non-primate mammal most closely related to humans. To assess the utility of the tree shrew as a model for the study of dry eye disease, we analyzed the lipid profile of tree shrew meibum using an untargeted ESI-MS and MS/MS^all shotgun approach. The resulting lipidome shared many similarities with human meibum, while displaying some interesting differences. For example, several classes of lipids, including wax esters, cholesteryl esters, diesters, and (O-acyl)-ω-hydroxy fatty acids, had relatively longer chain lengths in tree shrew meibum. These increases in length may promote more effective reduction of tear evaporation in the tree shrew, which likely underlies the much longer blinking interval of this mammal. Our results suggest that the tree shrew could be an effective model for the study of dry eye.

A Randomized Controlled Double-Masked Study of Transdermal Androgen in Dry Eye Patients Associated With Androgen Deficiency

PURPOSE

To evaluate the efficacy, safety, and quality of life (QOL) of transdermal androgen in treatment of dry eye patients associated with androgen deficiency.

DESIGN

Randomized controlled trial.

METHODS

Fifty patients with dry eye from a tertiary eye center in northern Thailand were randomized to receive transdermal androgen (AndroGel; Besins Healthcare, Brussels, Belgium) or placebo for 4 weeks. Main outcome measures were symptoms and signs of dry eye. Serum level of sex hormone and QOL questionnaires were also evaluated at the baseline and after treatment.

RESULTS

After 4 weeks, the Ocular Surface Disease Index decreased significantly in the AndroGel group compared to the placebo (-14.36 ± 7.76 vs 0.14 ± 14.60, P < .001). Significant improvements of tear break-up time (7.40 ± 3.37 vs -1.14 ± 1.68 seconds, P < .001), corneal fluorescein staining (-0.62 ± 0.30 vs 0.19 ± 0.37, P < .001), and Schirmer test (6.84 ± 5.10 vs -0.48 ± 2.14 mm, P < .001) were observed in the AndroGel group compared to the placebo. Serum testosterone in female patients significantly increased in the AndroGel group compared to the placebo (P < .001), while no different change was observed in serum testosterone in male subjects and the sex hormone-binding globulin in both groups. In the AndroGel group, 20% of patients had oily skin and 4% had acne. No serious adverse effects were reported. The menopause rating score improved significantly in the AndroGel group compared to the placebo (P < .001), while the aging male symptoms were not different in both groups (P = .589).

CONCLUSIONS

Transdermal androgen was effective in relieving symptoms and signs of dry eye as well as improving QOL in aging patients. There were no serious side effects during a short-term treatment.

In vitro effects of benzalkonium chloride and prostaglandins on human meibomian gland epithelial cells

PURPOSE

Benzalkonium chloride is the most widely used preservative in ophthalmic topical solutions. The aim of this study was to investigate the influence of BAC as a single substance or as a component of several commercially available ophthalmic solutions on meibomian gland epithelial cells in vitro.

MATERIALS AND METHODS

An immortalized human meibomian gland epithelial cell line (HMGEC) was used and cells were cultured in the absence or presence of fetal bovine serum to assess cell morphology, cell proliferation, cell viability (MTS assay) and impedance sensing (ECIS) after stimulation with BAC. Further, the viability of HMGECs stimulated with BAC-containing and BAC-free bimatoprost, travoprost and latanoprost was evaluated using the MTS assay. Real-time PCR analysis for hyperkeratinization associated genes (cornulin, involucrin) was performed.

RESULTS

In the absence of serum, the proliferation rate of HMGECs decreased starting with 0.1μg/ml BAC. At concentrations of 50μg/ml BAC and higher, cell viability was reduced after 10min exposure with a corresponding change in cell morphology. Toxicity of BAC-containing ophthalmic solutions was greater than that of BAC alone, whereas BAC-free alternative products did not significantly influence cell viability. Confluence, cell-cell contacts and serum-containing medium appeared to facilitate HMGECs survival. Expression rate of involucrin and cornulin declined after exposure to preserved bimatoprost and BAC.

CONCLUSIONS

BAC showed cytotoxic effects on HMGECs starting with a concentration of 0.1μg/ml. The combination of BAC and prostaglandin-analogs might have a synergistic effect which results in higher toxicity than BAC alone. Unpreserved eye drops and eye drops preserved with Polyquaternium-1 are less damaging to HMGECs.

What's new in dry eye disease diagnosis? Current advances and challenges

Dry eye disease (DED) is a commonly encountered condition in general ophthalmology practice and imparts a significant socioeconomic burden. Despite its prevalence, there remain challenges regarding its diagnosis and management. A major reason behind these challenges is the fact that DED represents an umbrella term that encompasses many different underlying conditions and pathophysiological mechanisms. The purpose of this article is to highlight aspects of DED pathophysiology and focus on targeted diagnostic and therapeutic approaches to this multifactorial, chronic condition.

Human meibum chain branching variability with age, gender and meibomian gland dysfunction

NMR spectroscopy was used to measure hydrocarbon chain branching variability in meibum with age, gender and Meibomian gland dysfuction (MGD). A cohort of 65 meibum donors without dry eye and 31 donors with MGD was studied. Heteronuclear 2D NMR was used to confirm CH₃ resonance assignments allowing us to positively identify 23 of the 27 proton resonances of cholesteryl ester and ¹H resonances due to straight chain, iso-branched and anteiso-branched hydrocarbons. Meibum from donors without dry eye contained 57 ± 1% straight-chains, 23 ± 1% iso-branched chains and 20 ± 1% anteiso-branched hydrocarbon chains. Compared with meibum from donors without dry eye, meibum from donors with MGD contained less, 50 ± 2% straight-chains, more, 32 ± 2% iso-branched chains and the same amount, 18.0 ± 0.07%, of anteiso-branched hydrocarbon chains. Meibum hydrocarbon chain branching did not change with age between 22 and 68 years of age, nor was it influenced by gender. Based on previous studies, one would expect anteiso-branched chains would contribute to lowering the phase transition temperature of meibum, decrease the elasticity of the tear film lipid layer and increase the molecular area and spreading of meibum on the surface of the eye. Although we speculate that the observed differences in iso-chain branching do not influence tear film stability or rheology, the speculation has yet to be tested.

Relationships Between Meibomian Gland Loss and Age, Sex, and Dry Eye

PURPOSE

This study evaluated relationships between meibomian gland loss (MGL) and age, sex, and dry eye.

METHODS

Dry eye and MGL of the lower eyelid was evaluated from 112 randomly selected subjects (66 women; mean age 62.8; SD ±15.7; and age range: 19-89 years) from Horst Riede GmbH, Weinheim, Germany. In addition, subjects were grouped into dry eye and non-dry eye by the Ocular Surface Disease Index (OSDI) score, lid-parallel conjunctival folds and non-invasive break-up time. Symptoms were evaluated by the OSDI. Meibography of the lower eyelid was performed using a Cobra camera (bon Optic, Lübeck, Germany), and images were analyzed by its digital grading tool. Data were analyzed by backward, multiple regression analyses and Pearson correlation.

RESULTS

Analyzing all subjects, multiple regression analyses detected that age and dry eye status (dry eye diagnosis or OSDI) but not sex were significantly related to MGL. In both, non-dry eye (n=66) and dry eye subjects (n=46), dry eye status (OSDI) but not age or sex was significantly related to MGL. Ocular Surface Disease Index scores were significantly correlated with MGL, but this correlation was stronger among all subjects (Pearson correlation; r=0.536, P<0.001) and dry eye group subjects (r=0.520, P<0.001) than in non-dry eye group subjects (r=0.275, P=0.014).

CONCLUSIONS

Dry eye group subjects showed significantly increased MGL of the lower eyelid. Age and dry eye status were related to MGL of the lower eyelid, but sex was not; dry eye status was the dominant factor.

Hypoxia: A breath of fresh air for the meibomian gland

PURPOSE

Optimal meibomian gland (MG) function is critically important for the health and wellbeing of the ocular surface. We hypothesize that low oxygen (O₂) conditions promote the function of human MG epithelial cells (HMGECs) and that human MGs exist in a relatively hypoxic environment. The purpose of this study was to test our hypotheses.

METHODS

We used human and mouse eyelid segments, and immortalized human MG epithelial cells (IHMGECs) in our studies. To evaluate oxygen (O₂) levels in the mouse MG and vicinity, we injected pimonidazole (pimo), a hypoxia marker, before sacrifice. Human eyelid samples were stained with the hypoxia marker glucose transporter 1 (Glut-1). To determine the effect of low O₂ levels on IHMGECs, we cultured cells under proliferating and differentiating conditions in both normoxic (21% O₂) and hypoxic (3% O₂) conditions for 5-15 days. IHMGECs were evaluated for cell number, neutral lipid content, lysosome accumulation, expression of biomarker proteins and DNase II activity.

RESULTS

Our results demonstrate that human and mouse MGs, but not the surrounding connective tissue, exist in a relatively hypoxic environment in vivo. In addition, our findings show that hypoxia does not influence IHMGEC numbers in basal or proliferating culture conditions, but does stimulate the expression of SREBP-1 in differentiating IHMGECs. Hypoxia also significantly increased DNase II activity, and apparently IHMGEC terminal differentiation.

CONCLUSIONS

Our Results support our hypotheses, and indicate that relative hypoxia promotes MG function.

[Modern methods of evaluating the morphological and functional state of the eyelids in chronic blepharitis]

The article reviews the literature on methods of evaluating the morphological and functional state of the eyelids in chronic blepharitis. Development of methods continues together with further research on the etiology and pathogenesis of the disease.

Impact of Unilateral Orbital Radiotherapy on the Structure and Function of Bilateral Human Meibomian Gland

Background

Radiotherapy (RT) has widely been used to treat ocular tumors, yet the impact of orbital radiation to the meibomian gland has rarely been studied. Our study aims at evaluating the bilateral meibomian gland structure and function 12 months after unilateral orbital RT in patients with ocular tumors.

Methods

An observational case-control study. A total of 10 eyes 12 months after unilateral orbital RT, 10 contralateral eyes, and 10 normal controls were enrolled. Meibomian gland loss (MGL), lipid layer thickness (LLT), tear film breakup time (TBUT), Schirmer I test, and cornea fluorescein staining were measured. Ocular Surface Disease Index (OSDI) of the RT patients was assessed and compared with normal controls.

Results

The cumulative median radiotherapy dosage for the patients was 45 (range: 30, 70) Gy. The OSDI score of the patients was significantly greater than the normal controls (22.92 (range: 10.42, 37.50) vs 6.25 (range: 2.08, 10.42), p ≤ 0.001). Significant differences of upper MGL, lower MGL, LLT, and TBUT were found between the diseased eyes and normal controls (37.79% (range: 12.87, 92.41) vs 12.63% (range: 6.13, 42.34), p=0.007; 61.31% (range: 44.67, 87.98) vs 15.53% (range: 7.65, 45.13), p ≤ 0.001; 40 ICU (range: 23, 100) vs 81.5 ICU (range: 54, 100), p=0.007; 3.5 s (range: 2, 8) vs 6.5 s (range: 5, 10), p=0.002). The upper MGL and TBUT of the contralateral eyes were also considerably damaged compared with normal controls. Lower eyelid MGL and cornea staining score of the diseased eye were significantly correlated with radiation dosage (r = 0.913 and 0.680; p=0.001 and 0.044, respectively).

Conclusion

Orbital radiotherapy could cause significant damage to the meibomian gland structure and function, not only the diseased eyes but also the contralateral eyes.

Tear-Film Evaporation Rate from Simultaneous Ocular-Surface Temperature and Tear-Breakup Area

SIGNIFICANCE

A corneal heat-transfer model is presented to quantify simultaneous measurements of fluorescein tear-breakup area (TBA) and ocular-surface temperature (OST). By accounting for disruption of the tear-film lipid layer (TFLL), we report evaporation rates through lipid-covered tear. The modified heat-transfer model provides new insights into evaporative dry eye.

PURPOSE

A quantitative analysis is presented to assess human aqueous tear evaporation rate (TER) through intact TFLLs from simultaneous in vivo measurement of time-dependent infrared OST and fluorescein TBA.

METHODS

We interpret simultaneous OST and TBA measurements using an extended heat-transfer model. We hypothesize that TBAs are ineffectively insulated by the TFLL and therefore exhibit higher TER than does that for a well-insulting TFLL-covered tear. As time proceeds, TBAs increase in number and size, thereby increasing the cornea area-averaged TER and decreasing OST. Tear-breakup areas were assessed from image analysis of fluorescein tear-film-breakup video recordings and are included in the heat-transfer description of OST.

RESULTS

Model-predicted OSTs agree well with clinical experiments. Percent reductions in TER of lipid-covered tear range from 50 to 95% of that for pure water, in good agreement with literature. The physical picture of noninsulating or ruptured TFLL spots followed by enhanced evaporation from underlying cooler tear-film ruptures is consistent with the evaporative-driven mechanism for local tear rupture.

CONCLUSIONS

A quantitative analysis is presented of in vivo TER from simultaneous clinical measurement of transient OST and TBA. The new heat-transfer model accounts for increased TER through expanding TBAs. Tear evaporation rate varies strongly across the cornea because lipid is effectively missing over tear-rupture troughs. The result is local faster evaporation compared with nonruptured, thick lipid-covered tear. Evaporative-driven tear-film ruptures deepen to a thickness where fluorescein quenching commences and local salinity rises to uncomfortable levels. Mitigation of tear-film rupture may therefore reduce dry eye-related symptoms.

Association of the severity of meibomian gland dysfunction with dyslipidemia in Indian population

Purpose:

To correlate the severity of meibomian gland dysfunction (MGD) with the serum lipoprotein levels.

Methods:

The study was conducted as a prospective observational study over a period of 18 months. Ninety patients diagnosed with MGD were enrolled after they gave their informed consent according to the inclusion–exclusion criteria. Meibomian gland status was evaluated by meibum quality, expressibility, and numerical scoring. Lipid profile was done from an overnight fasting blood sample and evaluated for total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides (TGs).

Results:

Patients with higher stages of MGD more often had serum TGs >150 mg/dL, total cholesterol >200 mg/dL, an LDL >130 mg/dL, and serum HDL >40 mg/dL, and there exists an association between increasing stage of MGD, and age, female sex, and increasing values of all the lipid profile components.

Conclusion:

A very strong association exists between increasing age and increasing severity of stage of MGD. A positive association exists between female sex and increasing severity of stage of MGD. A positive association exists between increasing severity of MGD and increasing levels of all the components of lipid profiles, namely LDL, HDL, total cholesterol, and triglycerides.

Characterization of expressed human meibum using hyperspectral stimulated Raman scattering microscopy

PURPOSE

This study examined whether hyperspectral stimulated Raman scattering (hsSRS) microscopy can detect differences in meibum lipid to protein composition of normal and evaporative dry eye subjects with meibomian gland dysfunction.

METHODS

Subjects were evaluated for tear breakup time (TBUT), staining, meibum expression and gland dropout. Expressed meibum was analyzed using SRS vibrational signatures in the CH stretching region (2800-3050 cm^-1). Vertex component analysis and K-means clustering were used to group the spectral signatures into four fractions containing high lipid (G1) to high protein (G4).

RESULTS

Thirty-three subjects could be statistically analyzed using pooled meibum (13 with stable tear films (TBUTs > 10 s) and 20 with unstable tear films (TBUTs ≤ 10 s). Significant differences in meibum from subjects with unstable vs. stable TBUTs were found for the G1 fraction (medians 0.164 and 0.020, respectively; p = 0.012) and the G2 fraction (medians 0.244 and 0.272, respectively; p = 0.045). No differences were observed for the G3 and G4 fractions. Single orifice samples were not significantly different vs. pooled samples from the fellow eye, and eyelid sector samples (nasal, central and temporal) G2:G3 fractional components were not significantly different (p = 0.449). Spearman analysis suggested a significant inverse correlation between G1 fraction and TBUT (R = -0.351; p = 0.045).

CONCLUSIONS

hsSRS microscopy allows compositional analysis of expressed meibum from humans which correlated to changes in TBUT. These findings support the hypothesis that hsSRS may be useful in classifying meibum quality and evaluating the effects of therapy.

Molecular regulation of ocular gland development

The tear film is produced by two ocular glands, the lacrimal glands, which produce the aqueous component of this film, and the meibomian glands, which secrete the lipidic component that is key to reduce evaporation of the watery film at the surface of the eye. Embryonic development of these exocrine glands has been mostly studied in mice, which also develop Harderian glands, a third type of ocular gland whose role is still not well understood. This review provides an update on the signalling pathways, transcription factors andextracellular matrix components that have been shown to play a role in ocular gland development.

Biomarkers for Progenitor and Differentiated Epithelial Cells in the Human Meibomian Gland

The meibomian gland (MG) is a sebaceous gland that secretes through a holocrine process. Because such secretion requires the destruction of MG acinar epithelial cells, they need constant renewal and differentiation. The processes that promote these regenerative events in the human MG are unknown, nor is it known how to distinguish MG progenitor and differentiated cells. We discovered that Lrig1 and DNase2 serve as biomarkers for human MG progenitor and differentiated cells, respectively. Lrig1 is expressed in MG basal epithelial cells in the acinar periphery, a location where progenitor cells originate in sebaceous glands. DNase2 is expressed in the differentiated epithelial cells of the MG central acinus. Furthermore, proliferation stimulates, and differentiation suppresses, Lrig1 expression in human MG epithelial cells. The opposite is true for DNase2 expression. Our biomarker identification may have significant value in clinical efforts to restore MG function and to regenerate MGs after disease‐induced dropout. Stem Cells Translational Medicine2018;7:887–892

Ethnic differences between the Asian and Caucasian ocular surface: A co-located adult migrant population cohort study

PURPOSE

To investigate the ethnic differences in tear film quality, ocular surface parameters, and dry eye symptomology between co-located Asian and Caucasian populations.

METHODS

Two hundred and six participants (103 East Asian and 103 Caucasian) were recruited in an age and gender-matched cross-sectional study. Dry eye symptomology, ocular surface parameters, and tear film quality were evaluated for each participant within a single clinical session.

RESULTS

The mean ± SD age of the 206 participants (82 male, 124 female) was 45 ± 16 years. Overall, a greater proportion of Asian participants were symptomatic of dry eye and fulfilled the TFOS DEWS II dry eye diagnostic criteria than Caucasian participants (74% versus 51%, p = 0.002), with an odds ratio (95% CI) of 2.7 (1.5-4.8) times. Poorer OSDI scores, tear film stability, lipid layer quality, tear osmolarity, lid wiper epitheliopathy, meibomian gland dropout, and expressed meibum quality were observed in the Asian group (all p < 0.05). A significantly higher proportion of participants exhibited incomplete blinking in the Asian group than the Caucasian group (81% versus 45%, p < 0.001).

CONCLUSIONS

Asian participants exhibited more severe dry eye signs and symptoms than Caucasian participants. The poorer meibomian gland function and higher degree of incomplete blinking observed among Asian participants may potentially contribute towards the ethnic predisposition towards dry eye development.

Exploring the Asian ethnic predisposition to dry eye disease in a pediatric population

PURPOSE

To investigate the differences in ocular surface characteristics, tear film parameters, and dry eye symptomology between co-located pediatric populations of Asian and Caucasian ethnicity.

METHODS

Seventy New Zealand-born pediatric participants, aged between 5 and 18 years, were recruited in an age and environmentally controlled cross-sectional study. Participants were classified into three groups according to ethnicity and eyelid morphology: Asian single lid (ASL), Asian double lid (ADL), and Caucasian double lid (CDL). Ocular biometry, tear film parameters, ocular surface characteristics, and dry eye symptomology were evaluated in a single clinical session.

RESULTS

Overall, no significant intergroup differences were observed in tear film quality, dry eye symptomology, and meibomian gland dropout. A higher proportion of ASL and ADL participants exhibited incomplete blinking than the Caucasian group (both p < 0.001). Meibomian gland shortening was more frequently observed among the two Asian groups (both p < 0.05), while gland tortuosity was more common in the Caucasian group (both p < 0.001). ASL participants exhibited greater inferior lid wiper epitheliopathy grades than ADL participants (p = 0.01), and corneal astigmatism was more pronounced in the ASL than CDL group (p = 0.02).

CONCLUSIONS

Ethnic differences in meibomian gland morphological patterns were observed in the current pediatric cohort, although overall meibomian gland dropout did not differ between groups. Asian participants exhibited a higher degree of incomplete blinking, and more marked inferior lid wiper epitheliopathy and corneal astigmatism were observed in the ASL group. These findings would suggest that eyelid anatomy and tension may potentially be implicated in the development of ethnic differences in dry eye disease later in life.

The prevalence of meibomian gland dysfunction, tear film and ocular surface parameters in an Austrian dry eye clinic population

PURPOSE

The purpose of this study was to assess the prevalence of meibomian gland dysfunction (MGD) and its association with tear film and ocular surface parameters in an Austrian clinical population of dry eye patients.

METHODS

The records of 1372 consecutive patients from a dry eye unit were analysed retrospectively. Symptoms and objective tear film and ocular surface parameters were evaluated. Patients were classified into pure MGD, pure aqueous tear deficiency (ATD), MGD combined with ATD, pure anterior blepharitis (AB), Sjogren's syndrome (SS) without MGD and SS together with MGD.

RESULTS

Nine-hundred and sixty-five patients, that is 70.3% of the investigated population, mean age 55.4 ± 16.6 years, had signs of MGD. Of these, 684 (70.9%) were female. The intensity of symptoms did not differ between subgroups. Four hundred and ninety (50.8%) MGD patients had Schirmer test values ≤10 mm/5 min. The fluorescein break-up time and Schirmer test values were significantly higher in the pure AB and MGD group. The pure MGD group showed a significantly lower fluorescein staining of the cornea compared to the other groups, except for pure AB. Lissamine green staining of the ocular surface was present in all groups, but was at least pronounced in the pure MGD and AB group.

CONCLUSION

Meibomian gland dysfunction is a major cause of ocular discomfort and could often be found in combination with a reduced aqueous tear secretion. Although the intensity of subjective complaints was similar to all other subgroups, pure MGD exhibited the lowest severity of signs of ocular surface damage and also affected younger people.

Botulinum toxin injection and tear production

PURPOSE OF REVIEW

In 1980, botulinum toxin type A (BTX-A) was introduced for the treatment of strabismus and benign essential blepharospasm. Since then, a number of additional indications have been introduced, which continue to expand, providing less invasive solutions in managing different ophthalmic conditions.

RECENT FINDINGS

Successful trials of BTX-A injection into the lacrimal gland have been reported for the treatment of epiphora caused by primary lacrimal gland hyperlacrimation, functional tearing, gustatory tearing, and lacrimal outflow obstruction. This is achieved through blockage of the cholinergic receptors by BTX-A at the glandular level. Interestingly, BTX-A has also been found to be useful in treating patients with dry eyes by compromising the tear drainage from the eye through injection of BTX-A in the medial part of the lower eyelid. BTX-A may help provide effective relief for patients who have two different ophthalmic comorbidities such as benign essential blepharospasm and dry eye.

SUMMARY

Better understanding of the mechanism of BTX-A action in the treatment of the growing applications in ophthalmology helps provide relatively noninvasive solutions for patients. Full awareness of possible side effects of BTX-A and the optimal way to manage them is vital for the success of this treatment option.

Assessment of meibomian glands using a custom-made meibographer in dry eye patients in Ghana

BACKGROUND

Meibomian Gland Dysfunction (MGD) is a leading cause of evaporative Dry Eye Disease (DED). This makes non-invasive meibography an important procedure in the clinical evaluation of DED patients. Our purpose was to conduct a lead-off investigation focused on the practicality of performing meibography in a developing country, with limited access to complex ophthalmic imaging systems, using a custom meibographer, as a step to future comparative studies on meibomian glands and DED in Africa.

METHODS

Meibomian glands(MG) in 76 upper eyelids (UL) and 49 lower eyelids (LL) in 1 eye each of 125 patients randomly selected from a patient population presenting with subjective DED symptoms at a clinic were photographed using a custom meibographer. Single frames were captured, and the MG area determined by intensity threshold segmentation and area calculation using Image J software. MG loss (MGL) was quantified by outlining its area and expressing it as a percentage of the total MG per Pult's grading scheme. Dry eye measures included Tear Film Break Up - Time (TUBT), Schirmer's test and Ocular Surface Staining (OSS). Symptoms were evaluated using the SPEED II questionnaire. Correlations between MGL and age, ocular signs and symptoms were analyzed by Pearson's. Differences between comparable groups were analyzed by Mann - Whitney test; p < 0.05 was considered significant.

RESULTS

Overall mean MGL was 32.10% ± 25.0% (26.25% ± 22.40% for UL and 40.33% ± 26.70% for LL). MGL correlated significantly with age [r = 0.91, p = 0.001], SPEED scores [r = 0.90, p = 0.001], OSS [r = 0.75, p = 0.001] and TBUT [r = - 0.81, p = 0.001]. MGL scores were significantly higher in the UL than LL [U = 1293.5 p = 0.004].

CONCLUSION

This study for the first time presents data on the status of Meibomian glands in Africa. It furthermore suggests that it is feasible to examine Meibomian glands using a custom meibographer in developing countries with limited access to complex imaging systems. It also demonstrates the benefit and cost-effectiveness of a simple device by the observed significant relations between meibomian gland loss and DED in these patients.

PPARγ regulates meibocyte differentiation and lipid synthesis of cultured human meibomian gland epithelial cells (hMGEC)

PURPOSE

To evaluate the role of PPARγ in regulating meibocyte differentiation and lipid synthesis in a human meibomian gland epithelial cell line (hMGEC).

METHODS

HMGEC were exposed to the PPARγ agonist, Rosiglitazone, from 10-50 μM. Cultures were also exposed to specific PPARγ antagonist, T0070907, to block PPARγ receptor signaling. Cells were then stained with Ki-67 and LipidTox to determine the effects on cell cycling and lipid synthesis, respectively. Expression of meibocyte differentiation related proteins, ADFP, PPARγ, ELOVL4, and FABP4, were evaluated by quantitative PCR and western blotting. A human corneal epithelial cell line (hTCEpi) was used as a control.

RESULT

Rosiglitazone significantly decreased Ki-67 staining within 2 days in a dose-dependent manner (P = 0.003) and increased lipid accumulation in hMGEC in a dose dependent manner. T0070907 suppressed both lipid droplet synthesis and cell cycle exit. Rosiglitazone significantly upregulated expression of ADFP, PPARγ, ELOVL4, and FABP4 by 9.6, 2.7, 2.6, and 3.3 fold on average (all P < 0.05 except for FABP4, P = 0.057) in hMGEC. T0070907 significantly abrogated rosiglitazone-induced upregulation of these genes when treated prior to rosiglitazone treatment (all P < 0.05). The observed lipogenic differentiation response was not duplicated in hTCEpi after exposure to rosiglitazone.

CONCLUSION

Rosiglitazone induced cell cycle exit and upregulation of lipogenic gene expression leading to lipid accumulation in hMGEC. These effects were suppressed by PPARγ antagonist indicating that PPARγ signaling specifically directs lipogenesis in hMGEC. These findings suggest that PPARγ plays a critical role in meibocyte differentiation.

Hyaluronan Regulates Eyelid and Meibomian Gland Morphogenesis

Purpose

The Meibomian gland (MG) produces the lipid layer of the tear film, and changes to the MG that lead to a decrease or alteration in lipid quality/content may lead to MG dysfunction, a major cause of evaporative dry eye disease with prevalence ranging from 39% to 50%. Little is known about the developmental cues that regulate MG morphogenesis and homeostasis. Our study investigates the role of hyaluronan (HA), a major extracellular matrix component, in eyelid formation and MG development and function.

Methods

Hyaluronan synthase (Has) knockout mice were used to determine the role of HA in the eyelid and MG. Eyelids were obtained during different developmental stages and MG morphology was analyzed. Tet-off H2B-GFP/K5tTA mice and 5-ethynyl-2'-deoxyurdine (EdU) incorporation were used to determine the role of HA in maintaining slow-cycling and proliferating cells within the MG, respectively. Data were confirmed using an in vitro proliferation assay, differentiation assay and spheroid cultures.

Results

Has knockout mice present precocious MG development, and adult mice present MG hyperplasia and dysmorphic MGs and eyelids, with hyperplastic growths arising from the palpebral conjunctiva. Our data show that a highly organized HA network encompasses the MG, and basal cells are embedded within this HA matrix, which supports the proliferating cells. Spheroid cultures showed that HA promotes acini formation.

Conclusions

HA plays an important role in MG and eyelid development. Our findings suggest that Has knockout mice have abnormal HA synthesis, which in turn leads to precocious and exacerbated MG morphogenesis culminating in dysmorphic eyelids and MGs.

Ocular Surface Workup With Automated Noninvasive Measurements for the Diagnosis of Meibomian Gland Dysfunction

PURPOSE

To analyze diagnostic performance of an ocular surface workup based on automated noninvasive measurements in the diagnosis of meibomian gland dysfunction (MGD).

METHODS

Two hundred ninety-eight eyes of 149 patients with MGD and 54 eyes of 27 control patients were analyzed. Ocular Surface Disease Index (OSDI), noninvasive breakup time (BUT), lipid layer thickness, meibomian gland loss, and tear osmolarity were calculated. The correlations among variables in the MGD group were analyzed. The area under the curve (AUC) of receiver operating characteristic curves was calculated.

RESULTS

OSDI, noninvasive BUT, and meibomian gland loss were significantly different between MGD and control groups (respectively, 37.9 ± 19.6 vs. 7.1 ± 2.8; 8.8 ± 3.6 vs. 11.0 ± 3.0; 28.0 ± 17.6 vs. 21.2 ± 13.0; always P < 0.05). Positive correlations were found between lipid layer thickness and noninvasive BUT and between meibomian gland loss and OSDI (respectively, r = 0.169, P = 0.004; r = 0.187, P = 0.004). Noninvasive BUT had the highest diagnostic power as a single parameter, followed by meibomian gland loss (respectively AUC = 0.686, AUC = 0.598). When the diagnosis of MGD was made based on either noninvasive BUT or meibomian gland loss being abnormal, sensitivity was 86.2% and specificity 38.5%. When the diagnosis was made on both noninvasive BUT and meibomian gland loss being abnormal, sensitivity was 39.3% and specificity 85.6%.

CONCLUSIONS

This automated noninvasive ocular surface workup may represent a useful screening tool for the diagnosis of MGD. In case of positivity of either noninvasive BUT or meibomian gland loss, subsequent qualitative clinical tests should be performed to achieve a reliable diagnosis and more precise characterization of MGD.

Impact of blinking on ocular surface and tear film parameters

PURPOSE

To investigate the influence of blinking on tear film parameters, ocular surface characteristics, and dry eye symptomology.

METHODS

A total of 154 participants were recruited in an age, gender and ethnicity-matched cross-sectional study, of which 77 exhibited clinically detectable incomplete blinking, and 77 did not. Blink rate, dry eye symptomology, tear film parameters, and ocular surface characteristics were assessed in a single clinical session.

RESULTS

Overall, a higher proportion of participants exhibiting incomplete blinking fulfilled the TFOS DEWS II dry eye diagnostic criteria (64% versus 44%, p = 0.02), with an odds ratio (95% CI) of 2.2 (1.2-4.2) times. Participants exhibiting incomplete blinking had higher Ocular Surface Disease Index scores (18 ± 13 versus 12 ± 9, p = 0.01), and greater levels of meibomian gland dropout (41.3 ± 15.7% versus 27.5 ± 14.1%, p < 0.001). Furthermore, poorer tear film lipid layer thickness, non-invasive tear film stability, expressed meibum quality, eyelid notching, and anterior blepharitis grades were also observed in those exhibiting incomplete blinking (all p < 0.05). Blink frequency did not correlate significantly with any ocular surface parameters (all p > 0.05).

CONCLUSIONS

Incomplete blinking was associated with a two-fold increased risk of dry eye disease. The greater levels of meibomian gland dropout, as well as poorer expressed meibum quality and tear film lipid layer thickness, observed would suggest that incomplete blinking may predispose towards the development of evaporative dry eye.

The Effect of Solithromycin, a Cationic Amphiphilic Drug, on the Proliferation and Differentiation of Human Meibomian Gland Epithelial Cells

PURPOSE

We previously discovered that azithromycin (AZM) acts directly on immortalized human meibomian gland epithelial cells (IHMGECs) to stimulate their lipid and lysosome accumulation and overall differentiation. We hypothesize that this phospholipidosis-like effect is due to AZM's cationic amphiphilic drug (CAD) nature. If our hypothesis is correct, then other CADs (e.g., solithromycin [SOL]) should be able to duplicate AZM's action on IHMGECs. Our purpose was to test this hypothesis.

MATERIALS AND METHODS

IHMGECs were cultured in the presence of vehicle or SOL (2, 10, or 20 µg/ml) for up to 7 days under proliferating or differentiating conditions. Positive (epidermal growth factor and bovine pituitary extract for proliferation; AZM for differentiation) and negative (vehicle) controls were included with the experiments. IHMGECs were evaluated for cell number, neutral lipid content, and lysosome accumulation.

RESULTS

Our results demonstrate that SOL induces a rapid and dose-dependent increase in the accumulation of neutral lipids and lysosomes in HMGECs. The lysosomal effects were most prominent with the 10 and 20 µg/ml doses, and occurred earlier (i.e., 1 day) with SOL than with the AZM (10 µg/ml) control. The effects of SOL and AZM on IHMGEC differentiation were essentially the same after 3 days of culture. SOL did not influence the proliferation of HMGECs during a 7-day time period.

CONCLUSIONS

Our results support our hypothesis that SOL, a CAD, is able to reproduce AZM's impact on lysosome and lipid accumulation, as well as the differentiation, of HMGECs. The effect of SOL on lysosome appearance was faster than that of AZM.

Influence of lipopolysaccharide on proinflammatory gene expression in human corneal, conjunctival and meibomian gland epithelial cells

PURPOSE

Lipopolysaccharide (LPS), a bacterial endotoxin, is known to stimulate leuokotriene B4 (LTB4) secretion by human corneal (HCECs), conjunctival (HConjECs) and meibomian gland (HMGECs) epithelial cells. We hypothesize that this LTB4 effect represents an overall induction of proinflammatory gene expression in these cells. Our objective was to test this hypothesis.

METHODS

Immortalized HCECs, HConjECs and HMGECs were cultured in the presence or absence of LPS (15 μg/ml) and ligand binding protein (LBP; 150 ng/ml). Cells were then processed for RNA isolation and the analysis of gene expression by using Illumina BeadChips, background subtraction, cubic spline normalization and GeneSifter software.

RESULTS

Our findings show that LPS induces a striking increase in proinflammatory gene expression in HCECs and HConjECs. These cellular reactions are associated with a significant up-regulation of genes associated with inflammatory and immune responses (e.g. IL-1β, IL-8, and tumor necrosis factor), including those related to chemokine and Toll-like receptor signaling pathways, cytokine-cytokine receptor interactions, and chemotaxis. In contrast, with the exception of Toll-like signaling and associated innate immunity pathways, almost no proinflammatory ontologies were upregulated by LPS in HMGECs.

CONCLUSIONS

Our results support our hypothesis that LPS stimulates proinflammatory gene expression in HCECs and HConjECs. However, our findings also show that LPS does not elicit such proinflammatory responses in HMGECs.

Increase lipid tear thickness after botulinum neurotoxin A injection in patients with blepharospasm and hemifacial spasm

The aim of this study was to investigate changes in the tear film lipid layer thickness (LLT) and aqueous tear production after botulinum neurotoxin A (BoNT) injection in patients with benign essential blepharospasm (BEB) and hemifacial spasm (HFS). Eleven and six patients with BEB and HFS, respectively, who received BoNT injection were consecutively enrolled in this prospective study. The blepharospasm disability index (BSDI), blink pattern, dry eye symptoms, Schirmer test 1 findings, LLT, eyelid performance, and corneal integrity were evaluated before and after treatment. Both BEB and HSF patients experienced remarkable relief from spasms and ocular discomfort after BoNT injection. LLT, the partial blink rate, the snap-back time, the lid distraction distance, and lateral canthal laxity were significantly increased at 1 month after treatment. There were no significant changes in Schirmer test 1 findings and meibomian gland dropout. Our findings suggest that LLT, a decisive factor for tear film stability, significantly increases at 1 month after BoNT injection for BEB and HFS. A decrease in BSDI and an increase in the snap-back time may contribute to the increase in LLT; this mechanism is probably responsible for the relief from dryness after BoNT injection in patients with facial movement disorders.

Prevalence of Meibomian Gland Atrophy in a Pediatric Population

Purpose:

To report the prevalence of meibomian gland atrophy and gland tortuosity in a pediatric population.

Methods:

Participants who presented with no history of dry eye disease or meibomian gland dysfunction were recruited from the Duke University Eye Center. Meibography was performed and subjective symptoms were assessed through the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire. Grading of images was assessed by a masked rater using a previously validated 5-point meiboscale (0–4) for gland atrophy and a 3-point scale for gland tortuosity (0–2).

Results:

Ninety-nine eyes of 99 participants (50 females) aged 4 to 17 years (mean 9.6 years) were imaged. The mean meiboscore was 0.58 ± 0.80 (mean ± SD) for gland atrophy and 0.45 ± 0.64 for tortuosity. In all subjects, 42% (n = 42) had any evidence of meibomian gland atrophy (meiboscore >0) and 37% (n = 37) had any evidence of meibomian gland tortuosity. The majority of subjects had mild gland atrophy. No significant association was found between age, sex, or race and presence of gland atrophy. Males were significantly more likely to have gland tortuosity (P = 0.0124, odds ratio 3.36).

Conclusions:

This study reveals a relatively high level of mild meibomian gland atrophy in the pediatric population, though moderate-severe gland atrophy was also present in this young population. This calls into question our current understanding of baseline gland architecture and suggests that perhaps clinicians should be examining young patients for meibomian gland atrophy and dysfunction because it may have implications for future development of dry eye disease.

Interexaminer Reliability of Meibography: Upper or Lower Eyelid?

OBJECTIVES

To investigate the interexaminer reliability of meibography evaluation and the impact of eyelid selection for the procedure.

METHODS

Meibography images of 30 subjects' right eye, including both lids, were evaluated by three clinicians. Meibomian gland (MG) dropout was noted with respect to both percentage and grading (0-4). The examiners' (E1, E2, and E3) consistency was assessed by the intraclass correlation coefficient for MG loss percent and weighted kappa for grading. Correlations between the meibography findings and the fluorescein tear break-up time (FBUT), ocular surface disease index (OSDI) questionnaire, and noninvasive tear break-up time (NIBUT) data were also analyzed.

RESULTS

The patients' mean age was 49.2±13.4 years, and the male/female ratio distribution was 15/15. Mean FBUT was 9.6±3.1 sec. OSDI and NIBUT were not correlated with meibography findings. FBUT measurements were correlated with the MG loss assessments of all examiners for the upper lid (Spearman correlation test, E1: r=-0.617, P<0.001; E2: r=-0.428, P<0.018; E3: r=-0.429, P=0.018) but not for the lower lid. Weighted kappa statistics based on MG dropout grading revealed moderate-to-good agreement for the upper lid (E1-E2: κ=0.516, P<0.001; E1-E3: κ=0.621, P<0.001; E2-E3: κ=0.650, P<0.001) and fair-to-moderate agreement for the lower lid (E1-E2: κ=0.212; E1-E3: κ=0.272; E2-E3: κ=0.530).

CONCLUSIONS

Meibography is an objective tool for the detection of MG loss. Because of the correlation with FBUT and better interexaminer agreement on dropout by grading, the upper lid might be the preferred lid to make an evaluation.

Randomized Controlled Study to Investigate the Effect of Topical Diquafosol Tetrasodium on Corneal Sensitivity in Short Tear Break-Up Time Dry Eye

INTRODUCTION

Complex mechanisms underlie dry eye (DE) symptom provocation. In particular, corneal hypersensitivity may provoke symptoms in short tear break-up time (BUT) DE characterized by tear film instability. We hypothesized that improved tear film stability may alleviate corneal sensitivity in patients with short tear BUT DE. Therefore, we investigated the effect of topical diquafosol tetrasodium (DQS) on corneal sensitivity in unstable tear film DE.

METHODS

This prospective, randomized study included 27 subjects (age: 39.1 ± 8.4 years; range: 25-59 years) with short tear BUT DE, defined based on the presence of DE symptoms and tear film instability. Subjects were randomly divided into DQS (3% DQS, 12 subjects) and artificial tear (AT; preservative-free AT, 15 subjects) groups. Subjects applied the medication 6 times a day for 5 weeks. The perception of touch (S-touch) and pain (S-pain) sensitivity was measured using a Cochet-Bonnet esthesiometer. Tear evaluation, corneal sensitivity, and DE symptoms were compared before and after DQS or AT administration. The correlation between the improvement degrees of corneal sensitivity and DE symptoms following medication was analyzed.

RESULTS

DQS significantly improved tear BUT and tear meniscus height (TMH) scores (p < 0.05), while AT significantly improved tear BUT (p < 0.05) but not TMH score. Mean S-pain and DE symptom scores were lower after medication use in the DQS (S-pain and DE symptoms: p  < 0.05) and AT groups (S-pain: p  = 0.05; DE symptoms: p  < 0.05). However, S-touch did not change significantly in either group. A positive correlation was observed between the improvement degrees of S-pain and DE symptoms in the overall subjects studied.

CONCLUSION

Both DQS and AT alleviate corneal hypersensitivity and DE symptoms in eyes with short tear BUT DE. However, DQS seems to be more effective to adjust tear environment, leading to the normalization of corneal sensitivity and DE symptoms.

TRIAL REGISTRATION

UMIN Clinical Trials Registry Identifier, UMIN000014536.

Relation Between Dietary Essential Fatty Acid Intake and Dry Eye Disease and Meibomian Gland Dysfunction in Postmenopausal Women

PURPOSE

To evaluate the relationship between omega-3 (n-3) and omega-6 (n-6) fatty acids with dry eye disease (DED) and meibomian gland dysfunction (MGD).

DESIGN

Cross-sectional study.

METHODS

Postmenopausal women (n = 439) underwent a clinical evaluation and completed the Vio Food Frequency Questionnaire to estimate their dietary intake of n-3s and n-6s. Subjects were categorized into 2 binary classifications based on whether or not they had (1) DED and (2) MGD. Mean intake of dietary fatty acids was compared with 2-sample t tests. Univariate logistic regression models were used to estimate the odds ratios for each condition associated with each quintile of n-3s, n-6s, and n-6:n-3 ratios.

RESULTS

For DED vs non-DED, there were no significant differences in n-3 intake (1.95 ± 1.47 g vs 1.92 ± 1.24 g, P = .86), n-6 intake (15.58 ± 11.56 g vs 15.44 ± 10.61 g, P = .91), and n-6:n-3 (8.30 ± 2.57 vs 8.30 ± 2.57, P = .99). For MGD vs non-MGD, there were no significant differences in n-3 intake (1.87 ± 1.35 vs 1.96 ± 1.39, P = .61), n-6 intake (15.26 ± 11.85 vs 15.62 ± 10.93, P = .80), and n-6:n-3 (8.35 ± 2.94 vs 8.28 ± 2.42, P = .84). The odds ratios (OR) for DED did not differ significantly from 1.0 for n-3, n-6, or n-6:n-3. High n-3 consumption (OR = 0.22 [0.06–0.78]) and moderate n-6 consumption (OR = 0.37 [0.15–0.91]) were associated with a decreased frequency of MGD.

CONCLUSIONS

Dietary consumption of n-3s and n-6s showed no association with DED, but high n-3 consumption and moderate n-6 consumption were protective against MGD in this large sample of postmenopausal women.

Meibomian Gland Dysfunction Associated With Periocular Radiotherapy

PURPOSE

To investigate the influence of periocular radiotherapy on meibomian glands.

METHODS

We evaluated 28 patients (40 eyes) who received radiotherapy (RT group) for conjunctival or orbital lymphoma and 30 age-matched control subjects (60 eyes). Subjects underwent slit-lamp examination of the eyelids, Schirmer test, meibography, and evaluation of tear film breakup time (TBUT), Ocular Surface Disease Index (OSDI) scores, meibomian glands evaluation (meiboscore, meibum expressibility, and lid margin abnormality scores), and tear film lipid layer thickness using an ocular surface interferometer. These parameters were compared between subjects in the RT and control groups.

RESULTS

Meiboscores as well as meibum expressibility and OSDI scores in the RT group were significantly higher compared with those in the control group (1.6 ± 0.9 vs. 0.4 ± 0.6, 1.6 ± 1.0 vs. 0.2 ± 0.4, and 48.1 ± 21.4 vs. 6.2 ± 4.4, respectively, P < 0.001, all), whereas the Schirmer value (9.2 ± 5.1 vs. 12.3 ± 5.2, P = 0.004), TBUT (4.2 ± 2.5 vs. 6.4 ± 2.6, P = 0.001), and lipid layer thickness (61.0 ± 29.3 vs. 85.2 ± 20.0, P < 0.001) in the RT group were lower compared with those in the control group. The percentage of meibomian gland dropout was significantly correlated with age (P = 0.025) and total radiation dose (P = 0.012), regardless of the target location of irradiation. Even low-dose irradiated eyes (<30 Gy) exhibited significantly higher meiboscores (P < 0.001) and shorter TBUT (P = 0.005) compared with control eyes.

CONCLUSIONS

Eyes that received periocular radiotherapy exhibited relatively high tear film instability induced by meibomian gland dysfunction, contributing to the high severity of dry eye symptoms.

Meibomian Glands and Ocular Surface Changes After Closure of Meibomian Gland Orifices in Rabbits

PURPOSE

To investigate changes in the corneal surface, tear film, and meibomian glands after meibomian gland orifice closure.

METHODS

Seventy-two eyes of 36 rabbits were used. In the study group (n = 36), the meibomian gland orifices of both upper and lower eyelids in the right eyes were electrosurgically coagulated. The 36 untreated left eyes were used as controls. Corneal wetting properties were measured 1, 3, 7, and 14 days after coagulation. The eyelid sections were stained with anti-cytokeratin (CK)1, CK5, and CK6 antibody 8 weeks after coagulation. The area of the secretory acini around one meibomian gland duct was measured, and meibography of rabbits was performed 8 weeks after meibomian gland orifice closure.

RESULTS

Three days after coagulation, the corneal wetting property was decreased compared with controls. The meibomian gland ducts gradually dilated in the study group over time. The epithelium of the central ducts in both groups was stained with CK5 and CK6, but not CK1. Although the mean area of the secretory acini in the study group (0.10 ± 0.04 mm) was significantly smaller than that of the control group (0.18 ± 0.04; P = 0.004), meibography showed normal morphology in both study and control groups.

CONCLUSIONS

Meibomian gland orifice closure reduced corneal wetting property and induced meibomian gland duct dilation accompanied by shrinkage of secretory acini. Meibography could not detect early changes in the meibomian gland after closure of the orifice. Therefore, when the orifice is obstructed, more active treatments are needed before structural changes occur.

The function and morphology of Meibomian glands in patients with thyroid eye disease: a preliminary study

BACKGROUND

To investigate function and morphology of the meibomian gland (MG) in patients with thyroid eye disease (TED).

METHODS

In this prospective case series study, patients with unilateral or bilateral TED were consecutively enrolled. The diagnosis of TED was based on the typical orbital findings and/or radiographic evidence. The disease activity of TED was classified according to the clinical activity score (CAS). Degrees of lagophthalmos and exophthalmos, blinking rates, and results of the Schirmer test 1 were also recorded. All patients completed the SPEED questionnaire and underwent MG assessment, including lipid layer thickness (LLT), MG dropout (MGd), and MG expression.

RESULTS

In total 31 eyes from 17 patients with unilateral or bilateral TED were included. Patients were divided into inactive TED (CAS 0-1; 20 eyes from 11 patients) and active TED (CAS 2-3, 11 eyes from 6 patients) groups. MGd was significantly more severe in the active TED than the inactive TED group [Median (Inter-quartile region): 3.0 (2.0-3.0) vs. 2.0 (1.0-2.0) degree, P = 0.04]. However, patients with active TED had thicker LLT than those with inactive TED (90.0 [80.0-100.0] vs. 65.0 [47.8-82.5] nm, P = 0.02), and LLT was positively correlated with lagophthalmos (r = 0.37, P = 0.04).

CONCLUSIONS

Patients with active TED had more severe MGd, but thicker LLT. Active TED may cause periglandular inflammation of MGs, leading to MGd, but compensatory secretion from residual MGs and lagophthalmos-induced forceful blinking might temporarily release more lipids over the tear film.

Meibomian Gland Dysfunction in Primary and Secondary Sjögren Syndrome

PURPOSE

We hypothesized that women with primary (pSS) and secondary Sjögren syndrome (sSS; with systemic lupus erythematosus [SLE] or rheumatoid arthritis [RA]) have meibomian gland dysfunction (MGD). We sought to test our hypothesis.

METHODS

Subjects with pSS, sSS + SLE, sSS + RA, and non-SS-related MGD were recruited from the Sjögren's Syndrome Foundation or outpatient clinics at Tufts University School of Dental Medicine or Brigham and Women's Hospital. The control population was recruited from the Greater Boston area. After providing written informed consent, the subjects underwent an eye examination and/or completed two questionnaires that assess symptoms of dry eye disease (DED).

RESULTS

Our results demonstrate that pSS and sSS patients have MGD. These subjects had meibomian gland orifice metaplasia, an increased number of occluded meibomian gland orifices, and a reduced quality of meibomian gland secretions. Further, patients with pSS, sSS + SLE, sSS + RA, and MGD had significant alterations in their tear film, lid margin, cornea, and conjunctiva. Symptoms of DED were increased ∼10-fold in all pSS, sSS, and MGD groups relative to controls.

CONCLUSIONS

Our findings support our hypothesis and show that individuals with pSS, sSS + SLE, and sSS + RA have MGD. In addition, our study indicates that patients with pSS and sSS have both aqueous-deficient and evaporative DED.

Morphology and Function of Meibomian Glands and Other Tear Film Parameters in Junior High School Students

Purpose:

We measured tear film parameters, including the morphology and function of meibomian glands, in junior high school students at 15 years of age.

Methods:

A total of 111 eyes of 111 students (56 males and 55 females) were enrolled in the study. The ocular symptom score (0–14), after-school study time, lipid layer thickness (LLT) of the tear film, partial blink rate, lid margin abnormalities (0–4), tear film breakup time, corneal and conjunctival epithelial damage (fluorescein staining score, 0–9), meiboscore as determined by noncontact meibography (0–6), Schirmer test value, and meibum grade (0–3) were determined. The relationships between parameters were evaluated with the Spearman correlation coefficient (ρ).

Results:

The meiboscore was 2.8 ± 1.2, and the meibum grade was 1.8 ± 1.2. The meiboscore significantly correlated with the meibum grade (ρ = 0.272, P = 0.004), Schirmer test value (ρ = −0.220, P = 0.021), and LLT (ρ = −0.264, P = 0.005). The breakup time significantly correlated with LLT (ρ = 0.261, P = 0.006), meibum grade (ρ = −0.338, P < 0.001), and fluorescein staining score (ρ = −0.214, P = 0.025). The partial blink rate significantly correlated with the Schirmer test value (ρ = −0.240, P = 0.011). The meiboscore (P < 0.001) and meibum grade (P = 0.032) were significantly greater in males than in females.

Conclusions:

The morphology and function of meibomian glands are altered even at 15 years of age, with the changes being more prominent in males than in females.

[Ocular surface aging: Pathophysiology and consequences for management]

All the components of the ocular surface and the lacrimal system are affected by aging. Aging induces lacrimal gland fibrosis, Meibomian gland dysfunction, loss of corneal sensitivity, decreased corneal cell density, impairment of immune defences, increased local inflammation associated with hormonal changes, conjunctivochalasis, lid abnormalities, etc. Furthermore, homeostasis of the ocular surface may be altered by various age-related systemic comorbidities and iatrogenic interventions. Altogether, aging is considered the most predominant risk factor for dry eye disease. The increasing knowledge of the pathophysiology of aging of the ocular surface allows for refinement of the management of ocular surface disease in the elderly.