Association between meibomian gland changes and aging, sex, or tear function

Inflammation in Dry Eye Disease-Pathogenesis, Preclinical Animal Models, and Treatments

Dry eye disease (DED) is a rapidly growing ocular surface disease with a significant socioeconomic impact that affects the patients' visual function and, thus, their quality of life. It is distinguished by a loss of tear film homeostasis, leading to tear film instability, hyperosmolarity, ocular surface inflammation, and neurosensory abnormalities, with all of these playing etiological roles in the propagation of the vicious DED circle. While current treatments primarily focus on reducing tear film instability and hyperosmolarity, increasingly more attention is being placed on tackling the underlying inflammation that propagates and potentiates these factors. As such, preclinical models are crucial to further elucidate the DED pathophysiology and develop novel therapeutic strategies. This review outlines the role of inflammation in DED, highlighting related signs and diagnostic tools before focusing on relevant preclinical animal models and potential therapeutic strategies to tackle DED-associated inflammation.

Complications and compliance in professionally-managed and self-managed contact lenses compared with non-contact lens wearers

PURPOSE

To test the impact of professional management of soft contact lens wear on symptoms and ocular complications.

METHODS

Subjective symptoms and ocular complications of soft CL users who did not seek professional follow-up care (self-managed, SM), were compared to users who were prescribed CLs and their care professionally managed in optometry practices (PM), and to a control group of non-CL wearers. Habitual visual acuity, subjective dry-eye symptoms, and corneal abnormalities were assessed in all participants. CL wearers filled-out a usage habits questionnaire, and their CL fit was assessed. Outcomes were compared using Kruskal-Wallis and Chi Squared tests.

RESULTS

The SM, PM, and non-CL wearers cohorts included 127 (mean age:24.3±5.1, median:23, range:16-45 years,104 female), 132 (mean age:25.5±6.2, median:23, range:18-43 years,103 female), and 56 (mean age:22.3±3.5, median:21, range:18-39 years,36 female) participants, respectively. Meibomian gland dysfunction grade (p = 0.004, p<0.0001), limbal redness (both p = 0.04), corneal neovascularization (both p = 0.003), and papillary conjunctivitis (p<0.0001,p = 0.005) were significantly worse in SM CL wearers compared with both the non-CL wearers and PM CL wearers, respectively. Conjunctival staining was significantly worse in the SM cohort compared with the PM cohort (p = 0.01). 38.6% of the SM compared with 22.8% of the PM CL wearers, had an inappropriate refractive correction (p = 0.006). SM CL wearers wore CLs significantly more years (mean and median 1 year,p = 0.008), for more daily hours (mean and median of 2 hours,p<0.00001), and tended to nap or sleep with their CLs compared with the PM CL wearers (47 vs. 29,p = 0.02). The cohorts did not differ in their subjective symptoms.

CONCLUSIONS

Complications are significantly more prevalent in SM CL wearers compared with PM CL wearers, and SM CL wearers tend to wear CLs with incorrect powers, and are less compliant with napping or sleeping with the CLs compared with PM CL wearers. These findings emphasize the importance of fitting, patient education and follow-ups in CL wearers.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Risk Factors for Meibomian Gland Disease Assessed by Meibography

Purpose

To elucidate risk factors for meibomian gland disease (MGD) and understand associated changes in meibography and in relation to ocular surface disease.

Patients and Methods

As part of the standard workup for ocular surface disease at a tertiary academic center, 203 patients received an ocular history and lifestyle questionnaire. The questionnaire included detailed inquiries about ocular health and lifestyle, including makeup use, cosmetic eyelid procedures, screen time, and contact lens habits. Subjects also took the standardized patient evaluation of eye dryness (SPEED) II questionnaire. Meibomian gland (MG) dropout and structural changes were evaluated on meibography and scored by three independent graders using meiboscores. Statistical analysis was conducted to identify significant risk factors associated with MG loss.

Results

This retrospective, cross-sectional study included 189 patients (378 eyes) with high-quality images for grading, and the average age was 67 years (77% female). Patients older than 45 years had significantly more dropout than younger patients (p < 0.01). Self-reported eye makeup use did not significantly impact MG loss. Patients with a history of blepharoplasty trended toward higher meiboscores, but the difference was not statistically significant. Self-reported screen time did not affect meiboscores. Contact lens use over 20 years was associated with significant MG loss (p < 0.05). SPEED II scores had no relationship to meiboscores (p = 0.75).

Conclusion

Older age is a significant risk factor for MG loss. Any contact lens use over 20 years also impacted MG dropout. Highlighting the incongruence of symptoms to signs, SPEED II scores showed no relationship to the structural integrity of MGs.

Prevalence of Meibomian Gland Atrophy in Patients Undergoing Cataract Surgery

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Changes in the preoperative ocular surface flora with an increase in patient age: A surveillance analysis of bacterial diversity and resistance to fluoroquinolone

PURPOSE

This study analyzed the relationship between patient age and the prevalence and fluoroquinolone susceptibility of gram-positive cocci from the ocular surface flora before ophthalmic surgery.

METHODS

This surveillance study included scraped samples from the conjunctival sac of 8923 eyes of 5490 patients (70.0 ± 13.7 years) without ocular infection before ophthalmologic surgery between August 2018 and December 2020. A review of microbiological records regarding patient age was used to determine the number of isolates and gram-positive species obtained, as well as their fluoroquinolone susceptibility. Fluoroquinolone susceptibility was determined using the Clinical and Laboratory Standards Institute protocols of broth microdilution. Statistical analysis was performed using a generalized additive model and a log-linear model.

RESULTS

In total, 9,894 bacterial isolates obtained from scraped samples from the patients were analyzed. The detected species were Staphylococcus epidermidis (31.0%), Staphylococcus aureus (6.1%), Staphylococcus lugdunensis (3.9%), Enterococcus faecalis (5.8%), Corynebacterium species (31.7%), and Cutibacterium acnes (7.5%) and others. The number of species isolated from the ocular surface was increased at the rate of 1.018 per 10 years of age (p < 0.0001). S. epidermidis, S. lugdunensis, E. faecalis, and Corynebacterium species were isolated more often with an increase in patient age. The levofloxacin resistance ratio of methicillin-sensitive S. epidermidis and Corynebacterium species increased at the rate of 1.204 and 1.087 respectively with a 10-year increase in age (both p < 0.0001).

CONCLUSION

Gram-positive bacteria in the ocular surface flora (OSF) exhibited gradual changes in diversity and fluoroquinolone resistance with an increase in patient age. It is important to monitor the OSF of the patients before ophthalmologic surgery to prevent refractory ocular postoperative infection.

Preoperative Treatment of Meibomian Gland Dysfunction with a Vectored Thermal Pulsation System Prior to Extended Depth of Focus IOL Implantation

INTRODUCTION

Patients implanted with a range-of-vision intraocular lens (IOL) (multifocal or extended depth of focus, EDOF) may be more susceptible to visual disturbances from poor tear film quality, and prophylactic treatment of meibomian gland dysfunction (MGD) has been recommended. The purpose was to evaluate whether vectored thermal pulsation (LipiFlow™) treatment prior to cataract surgery with a range-of-vision IOL safely improves postoperative outcomes.

METHODS

This is a prospective, randomized, open-label, crossover, multicenter study of patients with mild-to-moderate MGD and cataract. The test group underwent LipiFlow treatment prior to cataract surgery and implantation of an EDOF IOL, while the control group did not. Both groups were evaluated 3 months postoperatively, after which the control group received LipiFlow treatment (crossover). The control group was re-evaluated 4 months postoperatively.

RESULTS

A total of 121 subjects were randomized, with 117 eyes in the test group and 115 eyes in the control group. At 3 months after surgery, the test group had a significantly greater improvement from baseline in total meibomian gland score compared with the control group (P = 0.046). At 1 month after surgery, the test group had a significant decrease in corneal (P = 0.04) and conjunctival (P = 0.002) staining compared to the control group. At 3 months after surgery, the test group had significantly lower incidence of being bothered by halos compared with the control group (P = 0.019). The control group had a significantly lower incidence of being bothered by multiple or double vision compared with the test group (P = 0.016). After crossover, patients had significant improvement in vision (P = 0.03) and total meibomian gland score (P < 0.0001). No safety concerns or relevant safety findings were uncovered.

CONCLUSION

Presurgical LipiFlow treatment of patients implanted with range-of-vision IOLs improved meibomian gland function and postoperative ocular surface health. This supports guidelines recommending proactive diagnosis and management of MGD in patients with cataracts to improve patient experience.

TRIAL REGISTRATION

The study was registered on www.

CLINICALTRIALS

gov (NCT03708367).

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

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

Morphologic variants of Meibomian glands: age-wise distribution and differences between upper and lower eyelids

Purpose

To evaluate the distribution of various Meibomian gland morphologies across different age groups in healthy individuals.

Methods

The infrared meibographic morphologies of the Meibomian glands from the upper and lower eyelids of 236 healthy individuals (472 eyes; mean age 38.4 ± 17.5 years; 80 female participants: 156 male participants) were evaluated for their prevalence and differences across six decades of life, from 10 to 80 years. A linear mixed-effects modeling test was performed for statistical analysis.

Results

Of 14,452 glands, 8,830 (61%) glands were located in the upper eyelid. No significant differences in frequency were noted between different age groups for distorted, tortuous, hooked, overlapping, abnormal gap, fluffy areas, dropout (except for 51-60 vs. 10-20 years, P = 0.023), and thick and thin morphologies. Short glands were significantly more common in individuals aged over 30 years (P = 0.015), whereas moderately short and severely short glands were more common in the upper eyelids of individuals older than 50 years compared to those aged 10-20 years (P = 0.035). The frequency of distorted, hooked, tortuous, overlapping, and tadpole-shaped Meibomian glands was significantly higher in the upper eyelids than in the lower eyelids for all age groups. Dropout glands were more common in the lower eyelids of individuals younger than 50 years, but no difference was observed in the upper and lower eyelids of individuals over 50 years. Dropout (P = 0.006) and severely short glands (0.026) of the lower eyelid were associated with low non-invasive tear break-up time (NIBUT) values.

Conclusion

Various morphologic characteristics of the Meibomian glands that are considered abnormal can be present in healthy individuals, and only moderate to severely short glands display an increase in abnormal morphologic characteristics of the Meibomian glands with age.

Meibomian gland stem/progenitor cells: The hunt for gland renewal

Meibomian glands (MGs) secrete lipid (meibum) onto the ocular surface to form the outermost layer of the tear film. Proper meibum secretion is essential for stabilizing the tear film, reducing aqueous tear evaporation, and maintaining the homeostasis of the ocular surface. Atrophy of MG as occurs with aging, leads to reduction of meibum secretion, loss of ocular surface homeostasis and evaporative dry eye disease (EDED). Since MGs are holocrine glands, secretion of meibum requires continuous self-renewal of lipid-secreting acinar meibocytes by stem/progenitor cells, whose proliferative potential is dramatically reduced with age leading to MG atrophy and an age-related meibomian gland dysfunction (ARMGD). Understanding the cellular and molecular mechanisms regulating meibocyte stem/progenitor cell maintenance and renewal may provide novel approaches to regenerating MG and treating EDED. Towards that end, recent label retaining cell and lineage-tracing experiments as well as knock-out transgenic mouse studies have begun to identify the location and identities of meibocyte progenitor cells and potential growth and transcription factors that may regulate meibocyte renewal. In addition, recent reports have shown that ARMGD may be reversed by novel therapeutics in mice. Herein, we discuss our current understanding of meibocyte stem/progenitor cells and the hunt for gland renewal.

Impacts of gender and age on meibomian gland in aged people using artificial intelligence

Purpose: To evaluate the effects of age and gender on meibomian gland (MG) parameters and the associations among MG parameters in aged people using a deep-learning based artificial intelligence (AI). Methods: A total of 119 subjects aged ≥60 were enrolled. Subjects completed an ocular surface disease index (OSDI) questionnaire, received ocular surface examinations including Meibography images captured by Keratograph 5M, diagnosis of meibomian gland dysfunction (MGD) and assessment of lid margin and meibum. Images were analyzed using an AI system to evaluate the MG area, density, number, height, width and tortuosity. Results: The mean age of the subjects was 71.61 ± 7.36 years. The prevalence of severe MGD and meibomian gland loss (MGL) increased with age, as well as the lid margin abnormities. Gender differences of MG morphological parameters were most significant in subjects less than 70 years old. The MG morphological parameters detected by AI system had strong relationship with the traditional manual evaluation of MGL and lid margin parameters. Lid margin abnormities were significantly correlated with MG height and MGL. OSDI was related to MGL, MG area, MG height, plugging and lipid extrusion test (LET). Male subjects, especially the ones who smoke or drink, had severe lid margin abnormities, and significantly decreased MG number, height, and area than the females. Conclusion: The AI system is a reliable and high-efficient method for evaluating MG morphology and function. MG morphological abnormities developed with age and were worse in the aging males, and smoking and drinking were risk factors.

Association of meibomian gland morphology with orifice plugging and lid margin thickening in meibomian gland dysfunction patients

PURPOSE

We sought to investigate the association of meibomian gland morphology with lid margin abnormalities in patients with meibomian gland dysfunction.

METHODS

This retrospective study included 368 eyes of 184 patients. Meibography was used to evaluate meibomian gland (MG) morphological features, such as dropout, distortion, thickened ratio and thinned ratio. Lid margin photography was used to evaluate lid margin abnormalities including orifice plugging, vascularity, irregularity and thickening. The association between MG morphological features and lid margin abnormalities was analyzed using a mixed linear model.

RESULTS

The study found a positive correlation between plugging of gland orifices grade and MG dropout grade in both the upper lids (B = 0.40, p = 0.007) and the lower lids (B = 0.55, p = 0.001). Plugging of gland orifices grade was also positively correlated to MG distortion grade in the upper lids (B = 0.75, p = 0.006). In the upper lids, MG thickened ratio increased first (B = 0.21, p = 0.003) and then decreased (B = - 0.14, p = 0.010) with a higher lid margin thickening grade. MG thinned ratio was negatively correlated with lid margin thickening (B = - 0.14, p = 0.002, B = - 0.13, p = 0.007). MG distortion grade decreased with lid margin thickening (B = - 0.61, p = 0.012).

CONCLUSION

Orifice plugging was correlated to meibomian gland distortion and dropout. Lid margin thickening was associated with meibomian gland thickened ratio, thinned ratio, and distortion. The study also suggested that distorted and thinned glands may be transitional phases between thickened glands and glands dropout.

Features and influences on the normal tear evaporation rate

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

Identifying Meibomian Gland Dysfunction Biomarkers in a Cohort of Patients Affected by DM Type II

(1) Background: Meibomian gland dysfunction (MGD) among patients with diabetes mellitus (DM) is a common manifestation of dry eye syndrome (DES). (2) Methods: The purpose of this study is to identify clinical parameters and biomarkers useful to improve the follow-up and the treatment of these patients. We have used an ocular surface disease index (OSDI) questionnaire, Schirmer test I/II, tear film break-up time (TF-BUT), fluorescein plus lissamine green staining, Marx's line (ML), and meibomian gland (MGs) morphology using Sirius^® Topographer (CSO, Costruzione Strumenti Oftalmici, Florence, Italy). Blood sample analysis included glucose, glycated hemoglobin, lipid profile, cortisol, dehydroepiandrosterone sulfate (DHEA-S), androstenedione (ASD) and testosterone. (3) Results: Cortisol and ASD were positively correlated with an increase of MG tortuosity, and an Increased level of triglycerides was associated with a reduction of MGs length. DHEAS levels lowered with age and were associated with ocular surface staining. (4) Conclusions: Future studies, perhaps including meibum lipid analysis and tear cytokine levels, may also further elucidate the connection between these parameters, MG architecture and function.

Repeatability and reproducibility of Cobra HD fundus camera meibography in young adults with and without symptoms of dry eye

PURPOSE

The inter-session repeatability (ISR), inter-examiner reproducibility (IER) and within-subject variability (WSV) of the Cobra HD fundus camera meibographer were examined in participants with and without dry eye symptoms.

METHODS

Symptoms were determined based on Ocular Surface Disease Index scores (≥13 being considered symptomatic), and subgroups were compared using the Mann-Whitney U-test. Images of meibomian glands (MGs) from the upper and lower right eyelids were captured by two examiners on the same day (S1) to determine IER. One examiner repeated the measurements on a second day (S2) to obtain the ISR. ISR, IER and WSV were calculated using Friedman, correlation tests and Bland and Altman analyses with mean differences (md) and 95% confidence intervals (CIs), within-subject standard deviations (Sw) and intra-class correlation coefficients (ICC).

RESULTS

The ISR experiment included 72 participants (mean age: 23 ± 5 years, range: 19-43, 36 symptomatic). Mean MG loss of the upper (S1: 13.5 ± 9.5%, S2: 12.8 ± 8.5%) and lower eyelids (S1: 7.5 ± 6.9%, S2: 7.3 ± 6.3%) was not significantly different between sessions for all participants, symptomatic and asymptomatic subgroups for both eyelids. The ISR Sw for the upper and lower eyelids was 1.3% and 1.0%; md was 0.7 ± 3.5% (CI:-6.25% to 7.62%) and 0.1 ± 2.1% (CI: -3.94% to 4.17%), respectively. The IER experiment included 74 participants (mean age: 23 ± 5 years, range: 19-43, 37 symptomatic). Mean MG loss of the upper (Examiner 1: 12.7 ± 8.2%, Examiner 2: 13.1 ± 8.0%) and lower eyelids (Examiner 1: 7.0 ± 6.2%, Examiner 2: 7.4 ± 6.2%) was not significantly different between examiners for all participants, symptomatic and asymptomatic subgroups for both eyelids. The IER ICC values were >0.86 for all conditions, Sw was 1.3% and 1.2%, with a md of -0.4 ± 3.2% (CI: -6.65% to 5.90%) and -0.4 ± 2.9% (CI: -6.15% to 5.31%), respectively. The WSV Sw values were <1.4%, and ICC values were >0.89 for both eyelids, examiners and experimental sessions.

CONCLUSIONS

The Cobra HD fundus camera demonstrates good repeatability, reproducibility and low WSV, and is a reliable clinical instrument for meibography.

Ductal Hyperkeratinization and Acinar Renewal Abnormality: New Concepts on Pathogenesis of Meibomian Gland Dysfunction

Meibomian gland dysfunction (MGD) is a functional and morphological disorder of the meibomian glands which results in qualitative or quantitative alteration in meibum secretion and is the major cause of evaporative dry eye (EDE). EDE is often characterized by tear film instability, increased evaporation, hyperosmolarity, inflammation, and ocular surface disorder. The precise pathogenesis of MGD remains elusive. It has been widely considered that MGD develops as a result of ductal epithelial hyperkeratinization, which obstructs the meibomian orifice, halts meibum secretion, and causes secondary acinar atrophy and gland dropout. Abnormal self-renewal and differentiation of the acinar cells also play a significant role in MGD. This review summarizes the latest research findings regarding the possible pathogenesis of MGD and provides further treatment strategies for MGD-EDE patients.

Mask-associated Dry Eye Syndrome in Healthcare Professionals as a New Complication Caused by the Prolonged Use of Masks during Covid-19 Pandemic Period

PURPOSE

The aim of this study is to demonstrate the prevalence of self-reported mask-associated dry eye (MADE) in health-care professionals and the possible risk factors that give rise to MADE.

METHODS

A self-administered questionnaire consisting of 12 questions about MADE and possible risk factors that give rise to MADE was created on web-based "google forms" application, and was then sent to 437 healthcare professionals working in a coronavirus-19 (COVID-19) pandemic hospital, using common telecommunication devices.

RESULTS

Three hundred and thirty-three of the 437 health-care professionals, who answered the questionnaire, were included in the study. The prevalence of self-reported MADE among these health-care professionals was found to be 70% (n = 233). Having at least one of the symptoms of dry eye while not having a mask on and advanced age were determined as the possible risk factors for MADE (p = .02 and p < .001, respectively). The clinical examinations of the 195 participants, who had self-reported MADE and accepted the invitation to undergo a clinical evaluation with respect to the symptoms of MADE, revealed that only 60 (30.7%) of these participants had aqueous-type dryness with staining on the ocular surface with fluorescein.

CONCLUSION

The high prevalence of self-reported MADE among health-care professionals can be attributed to the prolonged use of masks associated with longer working hours. Therefore, it is important that the ocular complaints of professionals are addressed by ophthalmology consultants/ophthalmologists during these difficult times.

Spontaneous acinar and ductal regrowth after meibomian gland atrophy induced by deletion of FGFR2 in a mouse model

PURPOSE

We have demonstrated that deletion of fibroblast growth factor receptor 2 gene (Fgfr2) leads to Meibomian gland (MG) atrophy in an inducible conditional knockout mouse model, referred as Fgfr2^CKO. Herein, we investigated whether MG spontaneously recovers after atrophy in this model.

METHODS

Two months old Fgfr2^CKO mice were injected peritoneally once or twice of doxycycline (Dox) at 80 μg/gm of body weight to induce MG atrophy of various severities via Fgfr2 deletion. Recovery of acinar and ductal tissues was monitored by meibography, lipid staining and immunofluorescence against keratin-6a in MG whole-mount. Biomarkers for acinar and ductal differentiation and proliferation were also examined by immunostaining.

RESULTS

Single Dox injection in Fgfr2^CKO mice caused severe acinar and moderate ductal atrophy. Severe ductal shortening or loss occurred after second Dox injection, presumably related to the reported slower cycling of the ductal epithelia. Spontaneous acinar regrowth after atrophy was observed over a period of 60 days in both injection regimens. However, less robust acinar recovery was associated with more disrupted ductal structures in twice injected Fgfr2^CKO mice.

CONCLUSIONS

Our current findings further substantiate the role of FGFR2 in MG homeostasis, and suggest that FGFR2-signaling may provide a potential strategy for regenerating acini from age-related MG dysfunction in humans. Our data demonstrated that spontaneous MG recovery depends on the extent of ductal atrophy, suggesting that ductal epithelia may provide the progenitor cells for acinar regeneration. Nonetheless, the role of ductal tissue as the source of acinar progenitors awaits further investigation.

Changes in the tear film and meibomian gland morphology between preclinical dry eye and normal subjects represented by ocular surface disease index scores

Tear film and MG morphology play an essential role in detecting dry eyes and Meibomian Gland Dysfunction (MGD). Previous studies have reported these changes in cases diagnosed with dry eyes. However, it is important to study these changes among subjects with symptoms of dry eyes without signs. Hence, this study evaluated the changes in the tear film and meibomian gland (MG) morphology among subjects with pre-clinical dry eye and compared it with the normals defined by the Ocular Surface Disease Index score. One hundred and fifty subjects were enrolled in this prospective cross-sectional study. All the subjects completed the Ocular Surface Disease Index (OSDI) questionnaire and the Computer Vision Syndrome Questionnaire (CVS-Q). Tear film tests such as non-invasive break-up time (NIBUT), tear meniscus height (TMH), lipid layer pattern, Schirmer's test, and corneal staining were performed. Images were captured from both the upper and the lower eyelids to study the MG morphology. TMH, MG length, thickness, loss, and tortuosity were measured using ImageJ software. Subjects were differentiated into two groups based on an OSDI threshold score of ≥13 as preclinical dry eye and normals. Among all the subjects, 43.6% of them were categorized as pre-clinical dry eye, and 56.4% as normals. In the pre-clinical dry eye group, a significant reduction in NIBUT (Z = -2.13, p = 0.03) and MG length of the lower lid (Z = -2.58, p = 0.01) was found when compared to normals. TMH, Schirmer's test, and MG width did not vary among both groups (p > 0.05). Similarly, MG loss and tortuosity score was higher in the pre-clinical dry eye group, but did not show any statistical significance (p > 0.05). The majority of the young individuals presenting for the regular eye examination may have pre-clinical dry eye based on their OSDI scores. Hence, it is important to administer the OSDI questionnaire and perform non-invasive tests such as NIBUT and IR imaging of MG as a part of the routine eye examination.

Demodex folliculorum Infestation in Meibomian Gland Dysfunction Related Dry Eye Patients

Objective

To report the influence of Demodex folliculorum (D. folliculorum) infestation in patients with meibomian gland dysfunction (MGD) related dry eye and the associations of the infestation with MGD related dry eye.

Methods

Eyelashes (three from the upper eyelid and three from the lower eyelid) from 119 eyes of 119 patients diagnosed with MGD related dry eye were examined under a light microscope. There were 68 eyes of 68 patients with MGD related dry eye and D. folliculorum infestation (Demodex positive group) and 51 eyes of 51 patients without infestation (Demodex negative group). All patients completed an Ocular Surface Disease Index (OSDI) questionnaire and underwent tests for dry eye and MGD. The tests included fluorescein tear breakup time (TBUT), corneal fluorescein staining, Schirmer I test (SIT), lid margin abnormalities, meibum expression assessment, and meibomian gland dropout.

Results

The scores for OSDI, corneal fluorescein staining, lid margin abnormalities, meibum expression, and meibomian gland dropout were significantly higher (all P &lt; 0.05), while TBUT was significantly shorter in the Demodex positive group compared to the Demodex negative group (P = 0.020). The SIT values did not significantly differ between groups. Chalazion was significantly more prevalent in the Demodex positive group. The number of D. folliculorum was positively correlated with all three MGD parameters (P ≤ 0.035), OSDI; corneal fluorescein scores, and it was inversely correlated with BUT. The correlation for SIT was R2 = 0.075 (P = 0.064).

Conclusion

Demodex folliculorum infestation is possibly one of the key contributors in the pathogenesis of MGD related dry eye, and a higher prevalence of chalazion was found in D. folliculorum infected patients. The possible causal role of D. folliculorum infestation needs to be further studied.

Morphology of Meibomian Glands in a 65-Year-Old Norwegian Population without Dry Eye Disease

Analyses of meibography may help in the diagnosis, prevention, and management of meibomian gland dysfunction (MGD). However, there is currently a paucity of data regarding meibography analyses in the young elderly populations in the Nordic countries. In the current study, meibography of the upper and lower eyelids of 117 65-year-old residents in Oslo, Norway, who did not fulfil the diagnosis of dry eye disease (DED) were analysed. Meibomian gland (MG) dropout and tarsal areas were measured semi-automatically using ImageJ software. The relationship between morphological features of the MGs and clinical dry eye tests was examined. The median percent MG dropout was 26.1% and 40.7% in the upper and lower eyelids, respectively. There was no significant difference between males and females. None of the MG morphological parameters demonstrated significant values in discriminating abnormal dry eye symptom loads or MGD diagnosis from the normal loads. We therefore concluded that moderate MG atrophy was common among the Norwegian population of 65-year-olds without DED and showed no sexual differences. Meibography alone cannot discriminate MGD from non-MGD; thus, both morphological and functional MG tests are necessary when screening for MGD.

Changes of Dry Eye Related Markers and Tear Inflammatory Cytokines After Upper Blepharoplasty

Objectives: To investigate the changes of dry eye-related clinical manifestations, ocular surface parameters, and tear inflammatory cytokines after upper blepharoplasty.

Methods: Forty eyes of 20 who underwent upper blepharoplasty were divided into either the group with or the group without preexisting dry eye before upper blepharoplasty. Ocular Surface Disease Index (OSDI), Schirmer I test, tear meniscus height, lipid layer thickness, non-invasive tear break-up time (NIKBUT), fluorescein tear film break-up time (FBUT), corneal fluorescein staining, meibum expression, lid margin changes, and tear inflammatory cytokines were assessed preoperatively and at 1, 3, and 6 months postoperatively. Correlations between inflammatory cytokines and dry eye-related parameters were determined.

Results: The OSDI scores increased significantly at 1 month (p = 0.040) and subsequently decreased to the preoperative levels at 6 months postoperatively in subjects with dry eye. First (f)-NIKBUT and FBUT were significantly shortened at 1, 3, and 6 months postoperatively in subjects with dry eye (f-NIKBUT: p <0.001, p = 0.010, p = 0.042; FBUT: p = 0.002, p = 0.005, p = 0.037, respectively), but were only shortened at 1 month (p = 0.028, p = 0.005) and returned to baseline levels at 6 months postoperatively in subjects without preexisting dry eye. A significant increasing trend of interleukin (IL)-6 was found in both dry eye and subjects without preexisting dry eye (p = 0.016, p = 0.008), while IL-8 and tumor necrosis factor alpha (TNF-α) were only found to be increased in subjects with dry eye postoperatively (p = 0.031, p = 0.031). The levels of IL-8 and TNF-α were positively correlated with OSDI scores (p = 0.046, p = 0.043, respectively) and negatively correlated with f-NIKBUT and FBUT (p = 0.026, p = 0.006, respectively).

Conclusions: Upper blepharoplasty might increase the release of tear inflammatory cytokines and tear film instability that contribute to the development of postoperative dry eye in the early postoperative period and the changes most relieved in 6 months. Preexisting dry eye is a higher risk factor for worse and persistent ocular surface damage after upper blepharoplasty.

Meibomian gland dysfunction is highly prevalent among first-time visitors at a Norwegian dry eye specialist clinic

To investigate the prevalence of meibomian gland dysfunction (MGD) in patients presenting with subjective dry eye-related symptoms at their first-time consultation in a Norwegian specialized ocular surface clinic. Additionally, to explore the accuracy of the ocular surface disease index score (OSDI) as an extensively applied tool to assess the severity of dry eye symptoms and MGD diagnosis. Patients with subjective dry eye-related complaints (n = 900) attending the clinic for the first time, from 2012 to 2016, were included in the study. At the baseline, patients completed the OSDI questionnaire. Subsequently, objective clinical tests, including fluorescein break-up time (FBUT), Schirmer-I test, ocular surface staining (OSS), and meibomian gland function assessment using gland expressibility and meibum quality were performed. The association between MGD and its severity in relation to symptom severity defined by OSDI-score was examined. MGD was found in 93.8% of the study group. MGD prevalence was not significantly different between groups based on age (p = 0.302) or sex (p = 0.079). There was a significant association between severity of MGD and dry eye-related symptoms (p = 0.014). OSS was significantly higher in patients with severe symptoms (p = 0.031). Sensitivity and specificity of positive symptom-score (OSDI ≥ 13) for disclosing MGD were 85.5% and 30.4%, respectively. MGD was highly prevalent, not associated with age and sex. OSDI ≥ 13 had high sensitivity and high positive predictive value (PPV), but low specificity and negative predictive value (NPV) for disclosing MGD. This underscores the importance of meibomian gland assessment in patients with dry eye-related symptoms.

Electronic Device Screen Time and Meibomian Gland Morphology in Children

Purpose

To investigate changes in meibomian gland morphology and impact of electronic device usage time on meibomian glands in pediatric age group.

Methods

In this prospective study, 149 eyes of 149 children were enrolled. The participants also completed the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire and provided information regarding weekly hours spent in front of a digital screen. Meibography was performed in all subjects. Grading of images was evaluated using a previously validated 5-point meiboscale (0–4) for meibomian gland atrophy and a 3-point scale for meibomian gland tortuosity (0–2).

Results

Of the 149 enrolled children, 83 (55.7%) were female and 66 (44.3%) male. The mean age was 13.0 ± 3.0 (range, 5–18) years. The mean loss of meibomian gland area was 20.80 ± 9.32%. The mean meiboscore was 1.20 ± 0.58 for gland atrophy and the mean tortuosity score was 0.99 ± 0.62. The mean screen time was 29.32 ± 16.18 hr/week. There was a weak and significantly positive correlation between loss of meibomian gland area and screen time (r = 0.210, P = 0.010). There was a weak and significantly positive correlation between meiboscore for gland atrophy and screen time (r = 0.188, P = 0.022). We found a weak but significantly positive correlation between meibomian gland tortuosity and screen time (r = 0.142, P = 0.033).

Conclusion

Meibomian gland morphology may show changes in pediatric age group and excessive screen time may be a factor triggering these changes in gland morphology.

Alterations in meibomian glands in patients treated with intensity-modulated radiotherapy for head and neck cancer

Patients undergoing intensity-modulated radiotherapy (IMRT) for head and neck cancer may have increased incidence of dry eye disease and the exact mechanism is unclear. The present study aims to assess tear film and meibomian gland (MG) features in patients who received IMRT for head and neck cancer not involving the orbital area. Twenty-seven patients (64.7 ± 9.8 years) and 30 age-matched controls (61.4 ± 11.0 years) underwent a comprehensive dry eye work-up. Compared to the control group, the patients had more lid margin abnormalities, and worse meibum quality. The MG loss, calculated as (tarsal area-MG area)/tarsal area, was higher in the patient group in both the upper (53.0 ± 12.0% vs. 35.1 ± 10.3%, p < 0.001) and lower lids (69.5 ± 12.6% vs. 48.5 ± 12.5%, p < 0.001). In the patient group, more MG loss in the lower lids correlated with worse meibum quality (r = 0.445, p = 0.029). In contrast, there was no significant difference in aqueous tear production level, measured with Schirmer test. Patients treated with IMRT for head and neck cancer seemed to have comparable lacrimal gland function to the controls despite more dry eye symptoms. However, the patients had MG functional and morphological changes, which may present a higher risk for developing dry eye disease.

Measurement of the Lid Margin Thickness in Meibomian Gland Dysfunction with Vernier Micrometer

Introduction

To investigate the lid margin thickness (LMT) from the posterior lash line to the mucocutaneous junction at the middle position in adults with and without meibomian gland dysfunction (MGD) by vernier micrometer (VM).

Methods

This is a cross-sectional, observational study. A hundred eyes from 100 volunteers aged 20 to 79, including 56 normal participants and 44 participants with MGD, were recruited. Measurements of the LMT by VM were performed by the same person.

Results

The mean age of 56 normal subjects (24 males and 32 females) and 44 MGD subjects (16 males and 28 females) was 40.0 ± 13.2 years and 42.7 ± 17.1 years, respectively. There was a significant difference in the upper LMT between normal and MGD subjects (1.36 ± 0.25 vs. 1.60 ± 0.27 mm, P < 0.001), but not in the lower LMT (1.0 ± 0.23 vs. 1.10 ± 0.28 mm, P = 0.07). In both normal and MGD subjects, the upper or lower LMT was significantly positively correlated with age (P < 0.05), and the upper LMT was greater than the lower LMT (P < 0.001). In addition, the lower LMT in MGD subjects was significantly positively correlated with meibum expressibility (r_s = 0.35, P = 0.02).

Conclusions

The LMT was closely related to age and could be an important indicator for detecting MGD. Furthermore, we found that the upper LMT was greater than the lower LMT, and the lower LMT in MGD subjects seemed to be related to meibum expressibility.

Alteration in meibum lipid composition and subjective symptoms due to aging and meibomian gland dysfunction

PURPOSE

To investigate the alteration in lipid composition of meibum, objective clinical signs, and subjective symptoms associated with aging and meibomian gland (MG) dysfunction (MGD).

METHODS

In 10 MGD patients [4 males/6 females, mean age: 65.6 ± 7.9 years (range: 50-79 years)] and 24 healthy volunteer subjects [young subjects: 6 males/6 females, mean age: 25.7 ± 3.8 years (range: 20-35 years), elderly subjects: 6 males/6 females, mean age: 58.4 ± 7.5 years (range: 50-79 years)], three objective clinical signs were evaluated: MG orifice obstruction, meibum score, and tear film lipid layer interference pattern. Subjective symptoms were analyzed via a 15-item questionnaire. After careful collection of meibum samples, comprehensive lipid analysis was performed via liquid chromatography-mass spectrometry. Data was analyzed via JMP® ver. 13 (SAS Institute, Inc., Cary, NC) statistical analysis software.

RESULTS

In the MGD patients and elderly subjects, there was a significant decrease in non-polar lipids such as cholesterol esters (ChEs), while a significant increase in polar lipids [cholesterol (Ch), (O-acyl)-ω-hydroxy fatty acid (OAHFA), and free fatty acid (FA)] in total lipids (Tukey-Kramer test: p < 0.05). Triglyceride was significantly increased only in MGD patients (p < 0.05). Symptom scores representative of vision quality (i.e., blurred vision/haziness) were significantly negatively-correlated with the ratio of the non-polar lipid ChE, while significantly positively correlated with the polar lipids Ch, OAHFA, and FA (Spearman's rank correlation coefficient: p < 0.05).

CONCLUSIONS

Our findings revealed that both MGD and aging affect the composition ratio of major meibum lipids, resulting in the appearance of subjective symptoms.

Vision through Healthy Aging Eyes

As life expectancy grows, so too will the number of people adversely affected by age. Although it is acknowledged that many conditions and diseases are associated with age, this mini-review will present a current update of the various visual changes that generally occur in healthy individuals disregarding the possible effects of illness. These alterations influence how the world is perceived and in turn can affect efficiency or the ability to perform ordinary daily tasks such as driving or reading. The most common physical developments include a decreased pupil size and retinal luminance as well as changes both in intercellular and intracellular connections within the retina along the pathway to the visual cortex and within the visual cortex. The quantity and the physical location of retinal cells including photoreceptors, ganglion and bipolar retinal cells are modified. The clarity of intraocular organs, such as the intraocular lens, decreases. These all result in common visual manifestations that include reduced visual acuity, dry eyes, motility changes, a contraction of the visual field, presbyopia, reduced contrast sensitivity, slow dark adaptation, recovery from glare, variation in color vision and a decreased visual processing speed. Highlighting these prevalent issues as well as current and possible future innovations will assist providers to formulate treatments and thereby conserve maximum independence and mobility in the modern mature population.

The global prevalence of dry eye disease: A Bayesian view

PURPOSE

To provide estimates for the prevalence of dry eye disease globally and in sub-groups defined by: diagnostic criterion, sex, geographic location and age, using a Bayesian approach.

METHODS

Modelling prevalence as a Beta distribution, estimates were inferred from Bayesian posterior distributions obtained by combing an uninformed prior with likelihood functions generated from all relevant studies reporting dry eye prevalence between 1997 and 2021.

RESULTS

Global prevalence of dry eye disease was estimated at 11.59% (standard deviation (SD) = 0.04). For symptomatic disease, the estimate was 9.12% (SD = 0.04), with women 9.5% (SD = 0.05) and men 6.8% (SD = 0.06); prevalence was lowest in North America, 4.6% (SD = 0.03) and highest in Africa, 47.9% (SD = 1.8). For signs, prevalence was 35.2% (SD = 0.3), with woman 34.7% (SD = 0.7) and men 37.6% (SD = 0.7); North America showed the lowest regional prevalence, 3.5%, (SD = 0.4) with Eastern Asia the highest, 42.8% (SD = 0.4). Using TFOS DEWS II diagnostic criteria resulted in a global prevalence of 29.5% (SD = 0.8), with women 28.1% (SD = 1.2) and men 24.9% (SD = 1.4). Prevalence was lowest during the fifth decade, increasing approximately linearly with age thereafter. Estimates for other categories are given in accompanying tables.

CONCLUSION

A simple, flexible, yet powerful means of combining data from multiple sources to yield prevalence estimates across a range of circumstances is described, that is compatible with published guidelines for conducting meta-analysis. Estimates can be readily updated as new information emerges, or according to need. Understanding the specific characteristics of studies chosen for inclusion is critical to the validity of the outcome. Although dry eye disease is evidently common, affecting about one in 11 people world-wide, data are sparse for the young and all geographical locations except Eastern Asia.

Effects of Aging on Human Meibum

Purpose

The purpose of this study was to determine if aging affects meibum lipid composition in non-meibomian gland dysfunction (MGD)/non-dry eye (DE) population. Aging has been repeatedly linked to pathological changes in various tissues and organs, including the onset of MGD and DE, in a number of clinical and population-wide surveys. Both conditions have been associated with abnormal meibum secretion and composition, among other factors. However, the chemical basis for such a connection has not been established yet.

Methods

To identify and characterize possible changes in the meibum and meibogenesis with aging, lipidomic analyses of meibum samples collected from human subjects of two age groups - young (29 ± 5 years, n = 21) and elderly (68 ± 7 years, n = 29) - with similar male to female ratios in each group were conducted. Intact lipid species from major lipid groups of meibum (such as wax esters, cholesteryl esters, free cholesterol, triacylglycerols, etc.) were compared using lipidome-wide untargeted (such as Principal Component Analysis) and targeted (such as Orthogonal Projections to Latent Structures Discriminant Analysis) approaches, along with focused analyses of specific lipid species in liquid-chromatography mass spectrometry (LC-MS) and tandem mass spectrometry (MS-MS) experiments.

Results

Extremely high similarities of meibum lipids in the two age groups were observed, with only minor changes in the individual lipid species. The magnitude of the intergroup variability for tested lipid species was comparable to the intragroup variability for the same meibum components. No statistically significant differences in the lipid esterification, elongation, and unsaturation patterns were observed.

Conclusions

Chronological aging itself seems to have only minor effect on meibogenesis in healthy, non-MGD/non-DE subjects.

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.

Measurement of the Lower Lid Margin Thickness by Oculus Keratograph

OBJECTIVES

To investigate the lower lid margin thickness (LLMT) from the posterior lash line to the anterior edge of tear meniscus with Oculus Keratograph 4 (K4).

METHODS

This was a prospective, single-center, observational study. A total of 90 volunteers aged 18 to 79 years with no ocular diseases were included in this study. The LLMT of 90 subjects was measured twice by the same person with K4. To determine the reliability of K4, measuring the LLMT of 30 normal subjects was separately performed by two operators.

RESULTS

The LLMT measurements with K4 between two operators demonstrated a good reproducibility (0.94±0.18 vs. 0.96±0.16 mm; intraclass correlation coefficient=0.88; P=0.18). The mean age of 90 volunteers (42 men and 48 women) was 45.5±14.1 years. The LLMT was 0.95±0.17 mm, which was a significant positive correlation with age (rs=0.57; P<0.001). In addition, there was no significant difference in the LLMT between genders (0.97±0.16 vs. 0.93±0.18 mm; P=0.32).

CONCLUSIONS

We found that K4 was a reliable tool in the LLMT measurements, and the LLMT seemed to be closely related to age but not to gender.

The Relationship Between Vision and Comfort in Contact Lens Wear

OBJECTIVE

Understand relationship between vision and comfort in contact lens (CL) wear.

METHODS

Retrospective analysis of five trials using similar protocols with nonpresbyopic (NP) myopes or presbyopic participants (Px) wearing various simultaneous-image designs (SM) and single-vision (SV) CL (NP only). Questionnaires (vision satisfaction, vision clarity: distance/intermediate/near, comfort) on 1 to 10 scale were administered 1 week after fitting. Vision/comfort relationship was analyzed using linear mixed model and presented as regression coefficient with 95% confidence intervals (CIs).

RESULTS

Vision ratings correlated with comfort ratings, although this varied depending on type of vision rating and Px category. Vision satisfaction influenced comfort for the NP-SV group (slope: 0.8; 95% CI: 0.58-1.01, P≤0.001), but was significantly lower in the presbyopic group (slope: 0.38; 95% CI: 0.33-0.42; P≤0.001). Controlling for lens material obtained similar results. In the reverse relationship, comfort had a significant impact on vision satisfaction, although again at varying levels for each Px group. NP-SV demonstrated the weakest relationship (slope: 0.47; 95% CI: 0.35-0.59, P≤0.001) in comparison to NP-SM and P-SM groups.

CONCLUSION

Vision and comfort in CL wear are inter-related. Consideration of Px characteristics, visual stimulus, and CL comfort needs to be accounted for when assessing overall CL experience.

The ocular surface immune system through the eyes of aging

Since the last century, advances in healthcare, housing, and education have led to an increase in life expectancy. Longevity is accompanied by a higher prevalence of age-related diseases, such as cancer, autoimmunity, diabetes, and infection, and part of this increase in disease incidence relates to the significant changes that aging brings about in the immune system. The eye is not spared by aging either, presenting with age-related disorders of its own, and interestingly, many of these diseases have immune pathophysiology. Being delicate organs that must be exposed to the environment in order to capture light, the eyes are endowed with a mucosal environment that protects them, the so-called ocular surface. As in other mucosal sites, immune responses at the ocular surface need to be swift and potent to eliminate threats but are at the same time tightly controlled to prevent excessive inflammation and bystander damage. This review will detail how aging affects the mucosal immune response of the ocular surface as a whole and how this process relates to the higher incidence of ocular surface disease in the elderly.

Meibomian gland dysfunction in geriatric population: tehran geriatric eye study

PURPOSE

To determine the prevalence of Meibomian gland dysfunction (MGD) and its risk factors in an elderly Iranian population METHODS: This cross-sectional study was conducted in 2019. The target population was the subjects aged 60 and over living in Tehran. Multistage cluster sampling was done to select the subjects from all Tehran districts. After an initial interview, all subjects underwent complete ophthalmic examinations including the measurement of visual acuity and refraction as well as slit lamp biomicroscopy to evaluate Meibomian glands.

RESULTS

Of 3791 selected subjects, 3310 participated in the study. The data of 3284 participants were analyzed. The mean age of the subjects was 68.24 ± 6.53 years (range: 60-97 years) and 57.8% of them were female. The total prevalence of MGD was 71.2% (68.3-74.1), and 38.1% (8.35-40.4), 30.3% (27.4-33.2), and 2.8% (2-3.6) of the subjects had MGD stage 2, 3, and 4, respectively. The prevalence of MGD was significantly higher in men (p < 0.001) and increased with age from 64.4% in the age group 60-64 years to 82.4% in subjects aged 80 years and over. There was no significant difference in the prevalence of MGD between smokers and nonsmokers; however, severe MGD was more common in smokers. The prevalence of MGD was 76.3% and 68.52% in subjects with and without a history of ocular surgery, respectively. The prevalence of MGD stage 3 and 4 was higher in subjects with a history of ocular surgery.

CONCLUSIONS

In line with the results of other studies in Asian countries, this study found a high prevalence of MGD in an elderly population of Iran. It was found that male gender and advanced age were risk factors of MGD and smoking and history of ocular surgery might worsen this disease in MGD patients.

Evaluation of Meibomian Gland Dysfunction Among Ophthalmic Healthcare Workers

Purpose

To evaluate the prevalence of meibomian gland dysfunction (MGD) among ophthalmic healthcare workers.

Setting

A tertiary ophthalmic center.

Design

Prospective, observational study.

Methods

Forty-four volunteer ophthalmologists and ophthalmic nurses were recruited. Information including demographics, contact lens wear, history of refractive surgery and symptom score based on Standardized Patient Evaluation of Eye Dryness (SPEED) II Questionnaire for Dry Eye Disease/Ocular Surface Disease were recorded. Lipid layer thickness (LLT), meibomian glands dropout and dilation grades, and proportion of partial blinking were evaluated using an ocular surface interferometer with dynamic meibomian imaging (LipiView, Johnson & Johnson). Based on the chance of MGD, meibomian gland dropout and dilation, selected subjects also underwent treatment with a thermal pulsation system (LipiFlow, Johnson & Johnson) in one or both eyes.

Results

Eighty-eight eyes of 44 volunteers were evaluated during the study period. The mean LLT was 60.0nm. Twenty-seven (61.4%) subjects had a 90% or high chance of MGD and their mean lower lid meibomian gland dropout and dilation grades were 1.2 and 1.7, respectively. Twenty-eight eyes of 16 volunteers received treatment with the thermal pulsation system. Following treatment, the mean LLT improved from 50.3nm to 61.0nm (Wilcoxon's signed rank test, p=0.001).

Conclusion

Despite being more knowledgeable to MGD and more accessible to treatment, MGD is a highly prevalent condition among ophthalmic healthcare workers, with a 61.4% prevalence among the recruited subjects. This is similar to reported prevalence in Asian populations of up to 74.5%. Targeted therapy based on dynamic meibomian imaging is effective in improving both objective and subjective measures of MGD.

Meibomian Gland Dysfunction in a Hospital-Based Population in Central India

PURPOSE

To estimate the prevalence of meibomian gland dysfunction (MGD) in a hospital-based population in India.

METHODS

This cross-sectional study screened 3410 subjects ≥20 years or older attending the outpatient department by systematic random sampling. The patients were subjected to a comprehensive eye examination, Ocular Surface Disease Index questionnaire, fluorescein tear film breakup time, Schirmer I test, lissamine green stain, lid margin changes, and meibomian gland expression. MGD was diagnosed when 1 or both of the following was present in at least 1 eye: reduced or absent meibum secretion and cloudy to inspissated toothpaste-like secretion on digital pressure over the eyelids.

RESULTS

The study included 570 subjects with a mean age of 49.3 ± 16.2 (20-84) years. MGD was diagnosed in 317 (55.61%) subjects, of whom 272 (47.7%) had only MGD and 45 (7.9%) had coexisting MGD and aqueous tear deficiency. The age-adjusted prevalence rate of MGD was 48.4% (95% confidence interval: 43.9-52.1). This rate increased significantly with age (P < 0.001) in both men (P < 0.001) and women (P < 0.001). The crude and age-adjusted prevalence of symptomatic MGD (Ocular Surface Disease Index score ≥13) was 26.1% (71/272) and 32.9% (95% confidence interval: 27.4-38.6), respectively. The prevalence of symptomatic MGD significantly declined with increasing age (P = 0.003), and this was reflected in both men (P = 0.013) and women (P = 0.179) but was not statistically significant in the latter.

CONCLUSIONS

The prevalence of MGD was higher in Indian subjects than that previously reported. Although the total MGD prevalence increased with age, the prevalence of symptomatic MGD decreased. Asymptomatic MGD was more common than symptomatic MGD.

Next Generation Sequencing analysis suggests varied multistep mutational pathogenesis for Endocrine Mucin Producing Sweat Gland Carcinoma with comments on INSM1 and MUC2 suggesting a conjunctival origin

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a low-grade eyelid tumor. Small biopsies and insensitive immunohistochemistry predispose to misdiagnosis. We aimed to identify clarifying immunohistochemical and/or molecular markers. Clinicopathologic data (22 cases) was reviewed. Immunohistochemistry (Insulinoma-associated protein-1(INSM1), BCL-2, MUC2, MUC4, androgen-receptor, Beta-catenin, MCPyV) and next generation sequencing (MSK-IMPACT, 468 genes) was performed (3 cases). Female (n=15) and male (n=7) patients, mean-age 71.8 years (53-88), had eyelid/periorbital tumors (>90%) with mucin-containing solid/cystic neuroendocrine pathology. Immunohistochemistry (INSM1, BCL2, androgen-receptor, RB1, Beta-catenin) was diffusely-positive (5/5), MUC2 partial, MUC4 focal, and MCPyV negative. MSK-IMPACT identified 12 single-nucleotide-variants and one in-frame deletion in 3 cases, each with DNA damage response/repair (BRD4, PPP4R2, RTEL1) and tumor-suppressor pathway (BRD4, TP53, TSC1, LATS2) mutations. Microsatellite instability, copy number alterations, and structural alterations were absent. INSM1 and MUC2 are positive in EMPSGC. MUC2 positivity suggests conjunctival origin. Multistep pathogenesis involving DNA damage repair and tumor-suppressor pathways may be implicated.

Meibomian Gland Morphology Among Patients Presenting for Refractive Surgery Evaluation

Purpose

To report the prevalence of meibomian gland atrophy and gland tortuosity in patients presenting for refractive surgery evaluation.

Methods

Cross-sectional study of consecutive patients presenting for refractive surgery evaluation at the Duke Eye Center from December 2018 through January 2020. All patients underwent clinical examination and meibography imaging (Lippiview II, Johnson and Johnson Vision, CA) of the lower eyelids bilaterally. Images were graded by a masked rater using a previously validated 5-point meiboscale (0–4) for gland atrophy and 3-point scale for gland tortuosity (0–2). Lipid layer thickness and partial blinks were also recorded.

Results

One hundred and twenty patients (49 male) aged 21 to 62 years (mean 35.2 ± 9.2 years) were reviewed. The mean meiboscale was 1.1 ± 1.0 and the mean tortuosity score was 1.0 ± 0.7. Among all patients, 72.5% (n = 87) had any evidence of meibomian gland atrophy (meiboscale >0) and 69.2% (n = 83) had any evidence of meibomian gland tortuosity (tortuosity grade ≥1). The majority of patients (n = 52) with gland atrophy had mild gland atrophy (meiboscale = 1). The mean meiboscale was 0.89 ±0.79 and 1.38 ±1.07 for those <35 years and >/= 35 years old, respectively (p = 0.01). There was a moderate positive relationship between meiboscale and tortuosity (Spearman’s rho 0.3829, p <0.001).

Conclusion

Meibomian gland atrophy is a common occurrence in patients presenting for refractive surgery evaluation. Clinicians should consider incorporating meibography as part of refractive surgery evaluation, and proactively treat meibomian gland disease given the known association between meibomian gland dysfunction, dry eye disease, and the potential for suboptimal post-operative outcomes.

Associations with meibomian gland loss in soft and rigid contact lens wearers

PURPOSE

This study aimed to evaluate the structural changes in meibomian glands (MGs) and meibomian gland dysfunction (MGD)-associated ocular surface alterations in contact lens (CL) wearers.

METHODS

This prospective, multi-center, cross-sectional study included 44 soft CL wearers, 21 rigid CL wearers, and 26 healthy non-wearers. After completing the Ocular Surface Disease Index (OSDI) questionnaire, the participants were examined for lid margin abnormalities, tear breakup times, ocular surface staining, meibum quality and expressibility. Afterwards upper and lower eyelid meibography and Schirmer I test were performed.

RESULTS

A total of 91 participants (64 females and 27 males) (91 eyes) were classified into three groups. The mean percentage of meibomian gland loss (PMGL) was 25.3 ± 12.5 % in soft CL wearers, 34 ± 13.4 % in rigid CL wearers, and 18.4 ± 9.2 % in the control group. Mean OSDI score was higher in soft CL wearers (15.5 ± 18) than in the control group (3.5 ± 2.6) (p < 0.001) and the OSDI scores were correlated with mean PMGL in CL wearers (r = 0.411, p = 0.002, r = 0.588, p = 0.005, respectively). In soft CL wearers, the duration of CL use was the only predictive variable for mean PMGL in multivariate analysis. In a regression model including both CL groups, age and rigid CL material were predictive variables for mean PMGL.

CONCLUSIONS

CL use may cause MGD and this effect may be more pronounced in rigid CL wearers. In soft CL wearers, the duration of CL use is an important variable associated with MG loss, and subjective symptoms may guide the prediction of MG loss in these cases.

Relationship between eyelid margin irregularity and meibomian gland dropout

PURPOSE

To examine the relationship between lid margin abnormalities and meibomian gland loss in infrared meibography.

METHODS

This study was a retrospective chart review of 170 patients with dry eye disease. A correlation analysis between eyelid margin abnormalities and meibomian gland dropout in infrared meibography was performed using data from 141 eyes. We graded the following eyelid margin abnormalities: irregular lid margin, vascular engorgement, plugging, anterior placement of the mucocutaneous junction, exposed terminal duct, and presence of tattoos. Multiple regression analyses were performed with meiboscore (meibomian gland dropout grade) as the dependent variable and age, sex, lid margin abnormality grades, and total grading score of lid margin abnormalities as the covariates. In addition, Meibomian glands structure were examined in those with eyelid margin dimpling using meibography in 25 eyes.

RESULTS

In the multiple regression analysis, an irregular lid margin in the upper eyelid was associated with a higher meiboscore after controlling for age and sex (coefficients B = 1.379, p = 0.025). Other lid margin abnormalities did not significantly affect the meiboscore. In the lower eyelids, irregular lid margin (coefficients B = 0.602, p = 0.009) and total grading score of lid margin abnormality were associated with higher meiboscores (coefficients B = 0.100, p = 0.022). Of the 25 eyes with dimples, 21 (84%) showed focal or complete meibomian gland loss at the site.

CONCLUSIONS

Lid margin abnormalities were found to be associated with meibomian gland dropout.

A review of meibography for a refractive surgeon

Refractive surgery has evolved from being a therapeutic correction of high refractive errors to a cosmetic correction. The expectations associated with such a surgery are enormous and one has to anticipate all possible complications and side-effects that come with the procedure and prepare accordingly. The most common amongst these is post-refractive surgery dry eye of which Meibomian gland dysfunction is a commonly associated cause. We present an understanding of various diagnostic imaging modalities that can be used for evaluating meibomian glands which can also serve as a visual aid for patient understanding. We also describe various common conditions which can silently cause changes in the gland architecture and function which are to be considered and evaluated for.

Meibomian Gland Dysfunction: What Have Animal Models Taught Us?

Studies have estimated that currently 344 million people worldwide and 16.4 million adults in the US have some form of dry eye disease (DED). It is believed that approximately 70% of DED cases are due to some form of evaporative dry eye, for which Meibomian gland dysfunction (MGD) is the major cause. Unfortunately, currently there is no effective treatment for MGD, and solely palliative care is available. Given the importance of MGD in DED, there has been a growing interest in studying Meibomian gland development, homeostasis and pathology, and, also, in developing therapies for treating and/or preventing MGD. For such, animal models have shown to be a vital tool. Much of what is known today about the Meibomian gland and MGD was learnt from these important animal models. In particular, canine and rabbit models have been essential for studying the physiopathology and progression of DED, and the mouse model, which includes different knockout strains, has enabled the identification of specific pathways potentially involved in MGD. Herein, we provide a bibliographic review on the various animal models that have been used to study Meibomian gland development, Meibomian gland homeostasis and MGD, primarily focusing on publications between 2000 and 2020.

Comparison of two measurements for the lower lid margin thickness: vernier micrometer and anterior segment optical coherence tomography

PURPOSE

To investigate the reliability of using anterior segment optical coherence tomography (AS-OCT) to measure the lower lid margin thickness (LLMT) from the posterior lash line to the Marx's line by comparing with a vernier micrometer.

METHODS

This was a prospective, single-center, diagnostic test study. Sixty volunteers aged between 20 and 79 without ocular diseases were recruited. A vernier micrometer and AS-OCT were, respectively, used to measure the same lid margin thickness at the central lower lid.

RESULTS

The mean age of volunteers was 39.1 ± 13.7 years. The LLMT in 60 subjects (25 males and 35 females) measured by a vernier micrometer and AS-OCT was 1.03 ± 0.25 mm and 0.82 ± 0.21 mm, respectively. There was a significant difference between two measurements (P < 0.001). In addition, intraclass correlation coefficient (ICC) was engaged to evaluate the reliability and agreement of two measurements (ICC = 0.83). Bland-Altman plots demonstrated that 57 of 60 spots were within 95% limits of agreement. No adverse events were detected in all subjects after the measurements.

CONCLUSION

Although the LLMT measured by AS-OCT was less than that measured by a vernier micrometer, AS-OCT providing quantitative measurements and imaging data was also seemed to be a reliable method with a good agreement. It could be a substitute for a vernier micrometer in clinical practice in the future.

Global Prevalence of Meibomian Gland Dysfunction: A Systematic Review and Meta-Analysis

Purpose: The purpose of this study is to assess the pooled prevalence of meibomian gland dysfunction (MGD) and evaluate its risk factors by gender, age, and ethnicity.Methods: Articles were searched reporting the prevalence of MGD from PubMed, Scopus, Web of Science, and Embase databases.Results: The estimated pooled prevalence of MGD was 0.358 (95% CI 0.26-0.46; I²: 99.57%). The prevalence of MGD was 0.358 (95% CI 0.24-0.50) in clinical and 0.359 (95% CI 0.22-0.52) in population-based studies. Men were more prone to MGD than women (OR: 1.24, 95% CI 1.01-1.52, p = 0.034). The rate of MGD was between 21.2% and 29.5% in Africans and Caucasians, to 71.0% in Arabs, and 67.5% in Hispanics.Conclusion: MGD is a quite prevalent disorder with an estimated pooled prevalence of 35.8%. Men are more prone to MGD than women. There is a large variation between studies in terms of quality, sample size, age ranges, diagnostic criteria, and ethnicity.

Characterization of Meibomian Gland Atrophy and the Potential Risk Factors for Middle Aged to Elderly Patients With Cataracts

Purpose

To explore the characteristics of meibomian gland (MG) atrophy and its potential risk factors in the age-related cataract population.

Methods

Patients who underwent cataract surgery at age 40 or older were enrolled in this study. Preoperative clinical measurement records were obtained, including lipid layer thickness, tear meniscus height, noninvasive breakup time, and meiboscore. The meibomian gland atrophy ratio (MGAR) was measured by the ImageJ software. Univariate regression analysis and multivariate regression analysis were used to analyze the risk factors for MG atrophy.

Results

Female patients had less atrophy of the MG compared with male patients. The MGAR, meiboscore, tear meniscus height (TMH), and lipid layer thickness (LLT) gradually increased with age. However, the noninvasive breakup time decreased with age. The multivariate regression analysis indicated that dyslipidemia and increased triglyceride levels were identified as independent protective factors for MG atrophy. We further stratified the model by sex, and the following results showed only in the female patients with dyslipidemia and increased triglyceride had decreased MG atrophy. No significant correlation was observed between MG atrophy and tear film parameters including TMH, noninvasive breakup time, and LLT.

Conclusions

Our study suggests that age, sex, and diabetes are potential risk factors for MG atrophy. In addition, dyslipidemia and increased triglyceride levels are independent protective factors for MG atrophy in the elderly female population.

Translational Relevance

MG atrophy is the leading cause of meibomian gland dysfunction. To study the characteristics and risk factors of MG atrophy in cataract patients would be helpful to predict and prevent postoperative development of MGD.

The role of meibography in ocular surface diagnostics: A review

The meibomian glands are lipid-secreting glands located in the tarsal plates, whose secretory products cover the tear film, thereby reducing evaporation as well as ensuring lubrication of the ocular surface. The meibomian glands can be visualized at different levels of magnification by infrared meibography, laser confocal microscopy, and optical coherence tomography. These imaging modalities have been subject to much research and progress in clinical practice and have shaped our current understanding of meibomian glands in health and disease. In this review, we explore the evolution of meibography over the past decades, the major contributions of various meibographic modalities, and discuss their clinical significance.