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

Impact of Overnight Wear of Orthokeratology Lens on Thickness of Tear Film Lipid Layer in Children with Myopia

BACKGROUND

To elucidate the influence of overnight wear of orthokeratology (OOK) lenses on the thickness of the tear lipid layer (LLT).

METHODS

We conducted a retrospective cross-sectional study of children who visited The First Affiliated Hospital of USTC between July and September 2021. LLT and blinking dynamics were assessed. Diopters and corneal topography were also recorded.

RESULTS

The number of children enrolled in this program was 402 (804 eyes). One hundred and seventy-one children (342 eyes, 79 males and 92 females) aged 4 - 17 years (10.59 ± 2.54 years) who never wore OOK were included in the control group, while 231 children (462 eyes, 121 males and 110 females) aged 7 - 18 years (11.09 ± 2.24 years) who wore OOK for more than 1 week were included in the observation group. Compared to the control group with an LLT of 58.5 ± 18.19 nm, the OOK group exhibited a significant decrease in the LLT value to 54.42 ± 17.60 nm. In addition, the LLT in females was significantly thicker than that in males in both the control (male 54.78 ± 16.56 nm, female 61.70 ± 18.95 nm) and observation groups (male 51.88 ± 16.68 nm, female 57.21 ± 18.18 nm). It is worth noting that the influence of wearing OOK on the LLT value was only detected up to 18 months. Eighteen months later, there was almost no difference in LLT between the control and observation groups. We also noted that there was no change in LLT correlated to the surface regularity index/surface asymmetry index.

CONCLUSION

Wearing OOK can affect tear film LLT within the first 18 months after wear. More attention should be given to children wearing OOK for less than 18 months, especially males.

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.

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

Purpose

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

Methods

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

Results

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

Conclusion

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

Proposed Algorithm for Management of Meibomian Gland Dysfunction Based on Noninvasive Meibography

Although the pathophysiology of meibomian gland dysfunction (MGD) remains incompletely understood, many treatment options have recently become available. According to an international workshop report, treatment selection for MGD should be based on a comprehensive stage classification dependent on ocular symptoms, lid margin abnormalities, meibum grade, and ocular surface staining. However, it is often difficult to evaluate all parameters required for such classification in routine clinical practice. We have now retrospectively evaluated therapeutic efficacy in MGD patients who received five types of treatment in the clinic setting: (1) meibocare (application of a warm compress and practice of lid hygiene), (2) meibum expression plus meibocare, (3) azithromycin eyedrops plus meibocare, (4) thermal pulsation therapy plus meibocare, or (5) intense pulsed light (IPL) therapy plus meibocare. Patients in each treatment group were classified into three subsets according to the meiboscore determined by noncontact meibography at baseline. Eyes in the IPL group showed improvement even if the meiboscore was high (5 or 6), whereas meibocare tended to be effective only if the meiboscore was low (1 or 2). The meiboscore may thus serve to guide selection of the most appropriate treatment in MGD patients. Prospective studies are warranted to confirm these outcomes.

Tear Lipid Layer Thickness in Children after Short-Term Overnight Orthokeratology Contact Lens Wear

Meibomian gland lipid secretion is important to the stability of the tear film and ocular surface comfort. Changes in the tear film’s lipid layer thickness (LLT) after orthokeratology treatment may reflect underlying changes to the meibomian gland function. The purpose of this study was to investigate the features of the tear lipid layer in normal children and the effects of short-term orthokeratology treatment. Altogether, 163 myopic children (age: 10.7 ± 1.9 years, 8–15 years; 71 males) with no contact lens use history were enrolled in this study, of whom 56 were successfully fitted with orthokeratology lenses and completed the 1-month study. The tear film’s LLT (average, maximum, and minimum) and blinking pattern were measured by a LipiView® interferometer in 163 participants at baseline and in 56 orthokeratology participants at 1 week and 1 month after overnight lens wear. Results show that LLT (average) was 58.09 ± 21.66 nm in Chinese normal children. LLT was significantly correlated with rate of partial blinks at every follow-up (all $p<0.05$ ). Compared to baseline, the LLT (average and minimum) and partial blinks (number and rate) at 1 week and 1 month after orthokeratology treatment both significantly increased, and the increase of LLT was correlated with elevation of rate of partial blinks. In conclusion, LLT was shown to be elevated after short-term overnight orthokeratology treatment and was related to change in rate of partial blinks. Further studies are needed to clarify the long-term effect and the underlying mechanism.

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.

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.

Measurement of the Lower Lid Margin Thickness by Anterior Segment Optical Coherence Tomography

PURPOSE

To verify the feasibility of using anterior segment optical coherence tomography (AS-OCT) to measure the lower lid margin thickness (LLMT) from posterior lash line to the mucocutaneous junction.

METHODS

This was a prospective, single-center, observational study. Fifty-six volunteers between 20 and 79 years old with normal healthy eyes were included in this study. Using AS-OCT to measure the LLMT at the middle position was separately performed by two operators under the same conditions.

RESULTS

The mean age of 56 subjects (24 males and 32 females) was 45.4 ± 15.7 years. The LLMT measured by AS-OCT between two operators was 0.86 ± 0.23 mm and 0.85 ± 0.22 mm, respectively. The reliability and repeatability between two operators were evaluated by intraclass correlation coefficient (ICC = 0.97). Based on one operator's measurements, the LLMT was 0.70 ± 0.10 mm at ages 20-29, 0.68 ± 0.09 mm at ages 30-39, 0.94 ± 0.12 mm at ages 40-49, 0.93 ± 0.20 mm at ages 50-59, 1.03 ± 0.15 mm at ages 60-69, and 1.24 ± 0.19 mm at ages 70-79, which indicated a significant positive correlation with age (rs = 0.74, p < 0.001). In addition, there was a significant difference in the LLMT between genders (0.94 ± 0.26 vs. 0.80 ± 0.19 mm, p = 0.03).

CONCLUSIONS

A good agreement between two operators indicated that it seemed to be feasible to use AS-OCT to measure the LLMT. Additionally, we found that the LLMT appeared to be closely related to age and gender.

Meibomian Gland Dysfunction and Dry Eye Are Similar but Different Based on a Population-Based Study: The Hirado-Takushima Study in Japan

PURPOSE

To evaluate the prevalence and risk factors of and the relationship between meibomian gland dysfunction (MGD) and dry eye (DE) in Japan.

DESIGN

A population-based cross-sectional study.

METHODS

Participants filled in questionnaires regarding ocular symptoms, systemic diseases, and lifestyle factors. Meibomian gland-related parameters and tear film-related parameters were evaluated. Risk factors for MGD and DE were analyzed by using univariate and multivariate logistic regression. Age-specific prevalence of MGD and DE was estimated by using a general additive model with degree-3 natural splines. The structural relation between MGD and DE was assessed by factor analysis using the principal components method and promax rotation.

RESULTS

A total of 356 residents of Takushima Island (133 males, 223 females) at the mean ± SD age of 55.5 ± 22.4 years (range, 6-96 years) were enrolled. The prevalence of MGD and DE was 32.9% and 33.4%, respectively, with a coexistence rate of 12.9%. The prevalence of MGD was associated with male sex (odds ratio [OR], 2.42), age (OR per decade increment,1.53), and oral intake of lipid-lowering agents (OR, 3.22). The prevalence of DE was associated with female sex (OR, 3.36), contact lens wear (OR, 2.84), conjunctivochalasis (OR, 2.57), and lid margin abnormalities (OR, 3.16). The age-specific prevalence of MGD and DE differed, and factor analysis for 16 parameters showed that MGD and DE had independent hidden sources (interfactor correlation, -0.017).

CONCLUSIONS

MGD and DE are common in this population. Although their ocular symptoms are similar, the pathogenesis of MGD differs from that of DE.

Meibography and corneal volume optical coherence tomography to quantify damage to ocular structures in children with blepharokeratoconjunctivitis

PURPOSE

To evaluate non-contact infrared meibography and anterior segment optical coherence tomography (AS-OCT) to detect meibomian gland (MG) and corneal changes in children with blepharokeratoconjunctivitis (BKC).

METHODS

We acquired infrared meibography images of upper and lower lids and AS-OCT corneal scans. One masked observer graded meiboscore, full/partial MG dropout, and measured total corneal volume and differential corneal volume per quadrant and central corneal thickness (CCT).

RESULTS

We enrolled 63 children, 31 with BKC and 32 without ocular surface inflammation; median (interquartile range) age BKC 10.6 (7.2-13.9) years, healthy volunteers (HV) 11.4 (9.5-13.8) years. Likert scale scores for meibography and OCT indicate no to low discomfort. Meiboscores for upper and lower lids as well as the total meiboscore were significantly higher in children with BKC than in HV. Subscores for full and partial MG dropout were also significantly higher in children with BKC than in healthy volunteers. There was no statistically significant difference between upper and lower lid for meiboscore nor full/partial MG dropout scores. The corneal volume in the superior quadrant was significantly higher in children with BKC than in HV, whereas the corneal volume in the nasal and inferior quadrants was significantly lower.

CONCLUSIONS

Non-contact imaging technologies objectively demonstrate damage to meibomian glands and changes in corneal volume secondary to BKC. The tests are well tolerated by children with mild/moderate ocular surface inflammation and can detect changes without the requirement for routine eversion of the upper lid. These parameters may be useful both for clinical follow-up and clinical trials.

Noninvasive evaluation of anterior segment and tear film parameters and morphology of meibomian glands in a pediatric population with hypogonadism

PURPOSE

To compare the meibomian gland (MG), non-invasive tear film break-up time (NITFBUT), anterior segment measurements between healthy children and children with hypogonadism.

METHODS

A total of 80 eyes of 40 children with hypogonadism and 86 eyes of 43 age- and sex-matched healthy subjects were included in the study. The mean keratometry (Km), maximum keratometry (Kmax), central (CCT), thinnest (TCT) and apical (ACT) corneal thicknesses, corneal volume (CV), anterior chamber depth (ACD), irido-corneal angle (ICA), first and average non-invasive NITFBUT, MG loss, morphology of MGs, and MG distortion grade, specular endothelial cell density (CD), coefficient of variation (CoV), and percentage of hexagonal cells (HG) were analysed.

RESULTS

The mean CCT and TCT values were approximately 20 μm lower on average in patients with hypogonadism (p < 0.05). MG loss was present 56.1% of the healthy children, the ratio increased to 81.3% in children with hypogonadism (p < 0.001). The morphology and distortion grade did not show any significant differences between groups (p > 0.05). The mean NITFBUT value were similar between groups (p > 0.05). The mean CD value did not show any significant difference between groups, however it decreased in the hormone replacement therapy (HRT) group (p = 0.005).

CONCLUSIONS

MG loss is a physiological process that is prominent in the condition of sex steroid deficiency, but does not cause tear film alterations in children. Future studies investigating sex and gender effect on the ocular surface system in an age-based fashion are required to clearly communicate influences in the arenas of ocular surface research.

IMI - Clinical Management Guidelines Report

Best practice clinical guidelines for myopia control involve an understanding of the epidemiology of myopia, risk factors, visual environment interventions, and optical and pharmacologic treatments, as well as skills to translate the risks and benefits of a given myopia control treatment into lay language for both the patient and their parent or caregiver. This report details evidence-based best practice management of the pre-, stable, and the progressing myope, including risk factor identification, examination, selection of treatment strategies, and guidelines for ongoing management. Practitioner considerations such as informed consent, prescribing off-label treatment, and guides for patient and parent communication are detailed. The future research directions of myopia interventions and treatments are discussed, along with the provision of clinical references, resources, and recommendations for continuing professional education in this growing area of clinical practice.

Evaluation of incomplete blinking as a measurement of dry eye disease

PURPOSE

To investigate the association between partial blinking during spontaneous blinking as measured by interferometry and ocular exams for the assessment of dry eye disease (DED).

METHODS

This retrospective study included 58 eyes of patients previously diagnosed with DED. Ocular surface assessment included ocular surface disease index (OSDI) score, tear film osmolarity, tear breakup time (TBUT), grading of corneal fluorescein staining, Schirmer I test, and dry eye parameters by the LipiView™ interferometer (TearScience, Morrisville, NC, USA), including lipid layer thickness of the tear film (LLT), meibomian gland dropout (MGd), number of incomplete and complete blinks per 20 s and the partial blinking rate (PBR). Generalized estimation equations (GEE) were used for association testing between each variable of interest. The working correlation for each GEE model was selected using the Corrected Quasi-likelihood under the Independence Model Criterion.

RESULTS

The number of incomplete blinks was significantly associated with TBUT (P = 0.006), OSDI (P = 0.000) and MGd (P = 0.000). PBR was significantly associated with OSDI (P = 0.032) and MGd (P = 0.000). The number of complete blinks was significantly associated with TBUT (P = 0.032), but not with other ocular surface parameters. MGd was significantly associated with TBUT (P = 0.002) and OSDI (P = 0.001). LLT was significantly associated with tear film osmolarity (P = 0.007), and tear film osmolarity was significantly associated with LLT (P = 0.000).

CONCLUSIONS

Incomplete blinking is associated with decreased TBUT, increased OSDI, and increased MGd possibly through its contribution to meibomian gland obstruction and subsequent loss of tear film homeostasis. It may, therefore, be considered an additive measure for mild-to-moderate DED assessment.

Meibography: A Japanese Perspective

Meibography allows observation of meibomian glands in an objective and repeatable manner. Original meibography systems were invasive and not readily adopted by ophthalmology clinics. The development of noncontact infrared meibography allowed the rapid and noninvasive observation of meibomian glands, and such systems have now been widely adopted for standard examinations in dry eye clinics. Noncontact meibography has also spurred research into meibomian glands and has been applied to evaluation of their structure and status in various ocular surface diseases. Although the images obtained by meibography are objective and repeatable, the interpretation of these images is subjective, with the relationship between image features and actual gland structure and composition remaining unclear. Additional clinical and basic research with regard to the interpretation of meibography images is thus necessary. Future improvements to meibography will likely provide new insights into the pathophysiology of meibomian gland diseases as well as enhance its contribution to the diagnosis and evaluation of treatments for such diseases.

Effects of Lipid- Versus Sodium Hyaluronate-Containing Eye Drops on Optical Quality and Ocular Surface Parameters as a Function of the Meibomian Gland Dropout Rate

PURPOSE

To evaluate the effect of lipid- versus sodium hyaluronate-based eye drops on optical quality and ocular surface parameters.

METHODS

Sixty eyes of 30 patients with mild-to-moderate dry eye disease were included in a prospective randomized study. Each patient received either lipid- or sodium hyaluronate-based eye drops. Ocular symptom scores, breakup time, Schirmer test, fluorescein staining, noncontact meibography, and aberrometry were evaluated before and after 3 months of therapy.

RESULTS

At the 3-month visit, a statistically significant improvement (P ≤ 0.05) was noted in both groups on the Schirmer test, breakup time, ocular surface staining, and symptom score. In the lipid group, patients with progressive meibomian gland (MG) loss (>50%) showed a significantly greater increase in their corneal higher-order (HO) Strehl ratio (0.25 ± 0.26 vs. -0.01 ± 0.25, P = 0.02) and modulation transfer function (MTF) (0.12 ± 0.17 vs. -0.02 ± 0.06, P = 0.03) than patients with less advanced MG disease. In the lipid group, a significant positive correlation was noted between the MG dropout rate and improvement in Schirmer values [Spearman correlation coefficient (CC): 0.79], corneal HO Strehl (CC: 0.75), and HO modulation transfer function (CC: 0.6), but a significant negative correlation was noted between the MG dropout rate and the HO root mean square (CC: -0.73).

CONCLUSIONS

Lipid-containing artificial tears seem to be superior to sodium hyaluronate-containing drops in terms of improving HO aberrations and optical quality in patients with significant MG dysfunction.