MGD: Definition Versus Dry Eye Disease, Risk Factors

Association between Dyslipidemia and Meibomian Gland Dysfunction: A Systematic Review and Meta-Analysis

PURPOSE

This study aimed to use meta-analysis to estimate the association between dyslipidemia and meibomian gland dysfunction.

METHODS

The following databases were searched: PubMed, Google Scholar, and Scopus. Case-control and cohort studies assessing the association between dyslipidemia and meibomian gland dysfunction were included. The association was assessed using odds ratios. Heterogeneity between studies was assessed with the χ2 statistic and degree of inconsistency. The quality of studies was assessed using the Newcastle-Ottawa Scale. The systematic review was registered on PROSPERO (ID: CRD42022347982).

RESULTS

The systematic review included three case-control and two cohort studies. The odds of hypercholesterolemia and hypertriglyceridemia in meibomian gland dysfunction were 5.45 (95% confidence interval [CI], 1.65 to 17.95) and 3.28 (95% CI, 1.25 to 8.62), respectively. The odds of elevated serum low-density lipoprotein and reduced high-density lipoprotein in meibomian gland dysfunction were 2.72 (95% CI, 1.24 to 5.98) and 1.15 (95% CI, 0.74 to 1.79), respectively. The current study's limitation is that the effects of sex, age, and meibomian gland dysfunction severity on the association between dyslipidemia and meibomian gland dysfunction were not assessed.

CONCLUSIONS

The current study suggests a significant association between dyslipidemia and meibomian gland dysfunction. This finding suggests that meibomian gland dysfunction diagnosis may call for dyslipidemia screening.

Dry Eye Disease Associated with Meibomian Gland Dysfunction: Focus on Tear Film Characteristics and the Therapeutic Landscape

Meibomian gland dysfunction (MGD) is highly prevalent and is the leading cause of evaporative dry eye disease (DED). MGD is characterized by a reduction in meibum secretion and/or a change in meibum composition that results in the disruption of the tear film lipid layer and an increase in the tear film evaporation rate. Excessive evaporation causes tear film instability, desiccation, tear hyperosmolarity, inflammation, and apoptosis of ocular surface cells, resulting in a continuous cycle of DED. The primary treatment goal for DED associated with MGD is to restore the tear film lipid layer and decrease evaporation, thereby reducing ocular signs and symptoms. The management of MGD includes home care options (eyelid hygiene, warming eye masks, ocular lubricants) and office-based treatments (manual expression, microblepharoexfoliation, thermal pulsation, intense pulsed light, intraductal probing). Topical ophthalmic prescription medications attempt to alter various factors that may contribute to DED (e.g., inflammation, bacterial growth, inadequate tear production). In this review, clinical evidence regarding available treatments and emerging therapies from randomized studies in patients with DED associated with MGD is summarized. Although some treatment modalities have been evaluated specifically for DED patients with MGD, large-scale randomized controlled trials are needed to confirm efficacy and safety in this patient population. Currently, there are no approved prescription pharmacologic treatments specifically indicated for DED associated with MGD, and those medications approved for the treatment of DED do not target the key driver of the disease (i.e., excessive evaporation). NOV03 (perfluorohexyloctane; under review with the US Food and Drug Administration) is the most advanced emerging therapy for DED associated with MGD and has demonstrated statistically significant improvements in both signs and symptoms in randomized controlled trials. Development of novel pharmacotherapies will improve therapeutic options and allow for a more individualized approach for patients with DED associated with MGD.

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.

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.

Intense pulsed light (IPL) therapy for the treatment of meibomian gland dysfunction

BACKGROUND

Meibomian gland dysfunction (MGD) is the major cause of evaporative dry eye disease, which is the more prevalent form of dry eye disease. Intense pulsed light (IPL) therapy, involving treatment of the skin near the eyelids, has emerged as a potential treatment for MGD.

OBJECTIVES

To evaluate the effectiveness and safety of intense pulsed light (IPL) for the management dry eye disease resulting from meibomian gland dysfunction (MGD).

SEARCH METHODS

We searched CENTRAL, MEDLINE (Ovid), Embase Ovid and three trial registers for eligible clinical trials on 1 August 2019. There were no restrictions on publication status, date or language.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) studying the effectiveness or safety of IPL for treating MGD.

DATA COLLECTION AND ANALYSIS

Our outcomes of interest were the change from baseline in subjective dry eye symptoms, adverse events, changes to lipid layer thickness, tear break-up time (TBUT), tear osmolarity, eyelid irregularity, eyelid telangiectasia, meibomian gland orifice plugging, meibomian gland dropout, corneal sodium fluorescein staining and conjunctival lissamine green staining. Two review authors independently screened abstracts and full-text articles, extracted data from eligible RCTs and judged the risk of bias using the Cochrane tool. We reached consensus on any disagreements by discussion. We summarised the overall certainty of the evidence using the GRADE Working Group approach.

MAIN RESULTS

We included three RCTs, one from New Zealand, one from Japan and one from China, published between 2015 and 2019. Together, these trials enrolled 114 adults (228 eyes). Two studies used a paired-eye (inter-eye comparison) design to evaluate the effects of a sham (control) IPL treatment relative to an actual IPL treatment. One study randomised individuals to either an IPL intervention combined with meibomian gland expression (MGX), or MGX alone (standard therapy). The study follow-up periods ranged from 45 days to nine months. None of the trials were at low risk of bias in all seven domains. The first authors of two included studies were in receipt of funding from patents or the manufacturers of IPL devices. The funding sources and declaration of interests were not given in the report of the third included trial. All three trials evaluated the effect of IPL on dry eye symptoms, quantified using the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire. Pooling data from two trials that used a paired-eye design, the summary estimate for these studies indicated little to no reduction in dry eye symptoms with IPL relative to a sham intervention (mean difference (MD) -0.33 units, 95% confidence interval (CI) -2.56 to 1.89; I² = 0%; 2 studies, 144 eyes). The other study was not pooled as it had a unit-of-analysis error, but reported a reduction in symptoms in favour of IPL (MD -4.60, 95% CI -6.72 to -2.48; 84 eyes). The body of evidence for this outcome was of very low certainty, so we are uncertain about the effect of IPL on dry eye symptoms. There were no relevant combinable data for any of the other secondary outcomes, thus the effect of IPL on clinical parameters relevant to dry eye disease are currently unclear. For sodium fluorescein TBUT, two studies indicated that there may be an improvement in favour of IPL (MD 2.02 seconds, 95% CI 0.87 to 3.17; MD 2.40 seconds, 95% CI 2.27 to 2.53; 172 eyes total; low-certainty evidence). We are uncertain of the effect of IPL on non-invasive tear break-up time (MD 5.51 seconds, 95% CI 0.79 to 10.23; MD 3.20, 95% CI 3.09 to 3.31 seconds; two studies; 140 eyes total; very low-certainty evidence). For tear osmolarity, one study indicated that there may be an improvement in favour of IPL (MD -7.00 mOsmol/L, 95% -12.97 to -1.03; 56 eyes; low-certainty evidence). We are uncertain of the effect of IPL on meibomian gland orifice plugging (MD -1.20 clinical units, 95% CI -1.24 to -1.16; 84 eyes; very low-certainty evidence). We are uncertain of the effect of IPL on corneal sodium fluorescein staining. One study reported no evidence of a difference between the IPL and sham intervention arms at three months of follow-up (P = 0.409), and a second study reported data favouring IPL (MD -1.00 units, 95% CI -1.07 to -0.93 units; 172 eyes in total; very low-certainty evidence). We considered the incidence of adverse events at the study endpoint, as a measure of safety. As most trials did not specifically report adverse events, the safety of IPL as a treatment for MGD could also not be determined with any certainty. Very low-certainty results from individual studies suggest some adverse effects that may be experienced by participants, include mild pain and burning, and the potential for partially losing eyelashes (due to clinician error).

AUTHORS' CONCLUSIONS

This systematic review finds a scarcity of RCT evidence relating to the effectiveness and safety of IPL as a treatment for MGD. Whether IPL is of value for modifying the symptoms or signs of evaporative dry eye disease is currently uncertain. Due to a lack of comprehensive reporting of adverse events, the safety profile of IPL in this patient population is also unclear. The current limitations in the evidence base should be considered by clinicians using this intervention to treat MGD, and outlined to individuals potentially undergoing this procedure with the intent of treating dry eye disease. The results of the 14 RCTs currently in progress will be of major importance for establishing a more definitive answer regarding the effectiveness and safety of IPL for treating MGD. We intend to update this review when results from these trials become available.

Clinical Analysis: Aqueous-Deficient and Meibomian Gland Dysfunction in Patients With Primary Sjogren's Syndrome

Objective: To examine the time course of aqueous-deficient and meibomian gland dysfunction (MGD) in patients with primary Sjogren's Syndrome (pSS).

Methods: This prospective study was conducted on pSS female patients in the Department of Rheumatism of the Second Affiliated Hospital, School of Medicine, Zhejiang University. The age-matched MGD female patients without pSS (non-SS-MGD) were recruited as MGD controls from the Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University. After providing written informed consent, the patients underwent an eye examination and completed an Ocular Surface Disease Index questionnaire that assessed the symptoms of dry eye disease. The subjects were evaluated using Schirmer I test (SIt), tear meniscus height (TMH), noninvasive keratographic break-up time (NIKBUT), corneal fluorescein staining (CFS), and meibomian gland evaluation (meibomian gland infrared, lid margin score, expressible meibomian glands number and the secretions quality). The patients were divided into two groups: early stage (≤3 years) and late stage (>3 years) according to their medical history of dry eye. The data were analyzed using SPSS 20.0.

Results: There were 49 pSS and 52 non-SS-MGD female patients enrolled in this study from 1 January 2018 to 30 December 2018. There were no differences in age (49.38 ± 10.32 and 48.69 ± 13.57 years) and dry eye medical history (48.44 ± 40.16 and 47.79 ± 37.85 months) between the two groups. When the medical history was ≤3 years, the average SIt and TMH of the pSS patients were significantly smaller than those of the patients with MGD. However, the signs related to the MGD did not show a significant difference between the two groups. When the medical history was >3 years, both the SIt and TMH and the signs related to MGD in pSS group were significantly more severe than the MGD group.

Conclusions: Our results demonstrated that 3 years may be an important time node for the dry eye development in pSS patients, before this, the lacrimal glands received a greater influence, and then the meibomian glands began to be greatly affected.

Meibomian Gland Disease: The Role of Gland Dysfunction in Dry Eye Disease

TOPIC

To discuss the pathology, causes, and ocular surface impact of meibomian gland disease (MGD), as well as its relationship to dry eye.

CLINICAL RELEVANCE

MGD is a common disorder with various contributing mechanisms and clinical manifestations. Understanding MGD pathophysiology and its relationship to dry eye is important in order to optimize diagnosis and treatment algorithms.

METHODS

A review of current literature was performed to discern MGD in terms of pathophysiology, risk factors, and ocular surface impact, and the relationship to dry eye.

RESULTS

Meibomian gland obstruction and meibocyte depletion are important components of MGD. Many pathologies can disrupt function of meibomian glands, ranging from congenital to acquired causes. Once gland disruption occurs, the quality and quantity of meibum is altered, with a negative impact on the ocular surface. Increased tear evaporation, tear hyperosmolarity, increased ocular surface staining, increased inflammation, symptomatic irritation of the eyelid and globes, as well as decreased visual acuity have all been observed.

CONCLUSION

MGD leads to changes in meibum quality and quantity that can cause evaporative dry eye and ocular surface disruption, leading to dry eye symptoms in some individuals.

Compliance and Subjective Patient Responses to Eyelid Hygiene

OBJECTIVES

Lid hygiene is a commonly prescribed first-line therapy in patients with lid margin disease, yet compliance with therapy is not well characterized. The goals of this study were to assess patient compliance with lid hygiene and evaluate which factors predict a favorable symptomatic response to treatment.

METHODS

This was a cross-sectional study of patients seen in the Miami Veterans Affairs eye clinic between August and December 2014. An evaluation was performed to assess dry eye symptoms and lid margin signs. All patients were then instructed to perform warm compresses and lid scrubs. A follow-up phone survey assessed compliance and subjective therapeutic response 6 weeks later.

RESULTS

Two hundred seven of 211 (98%) patients (94% male, 60% white) completed the survey. Of the 207 patients, 188 (91%) completed the follow-up survey. Compliance with therapy was reported in 104 patients (55%); 66 reported complete improvement, 30 partial improvement, and 8 no improvement in symptoms. Patients who self-reported dry eye symptoms at first visit (n=86, 74%) were more likely to be compliant with lid hygiene than those who did not report symptoms (n=18, 25%) (P<0.0005). The only factor associated with poorer response to lid hygiene was longer time of self-reported dry eye symptoms. None of the other signs studied, including the presence of skin rosacea and lid margin telangiectasia, were associated with a differential response to lid hygiene.

CONCLUSIONS

Patients with dry eye symptoms were moderately compliant with lid hygiene, and patients who performed the routine noted improvement in symptoms.