The Association Between Risk Factors for Metabolic Syndrome and Meibomian Gland Disease in a Dry Eye Cohort

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.

Association between dyslipidaemia and dry eye disease: a systematic review and meta-analysis

PURPOSE

To report a systematic review and meta-analysis of the association between dry eye disease (DED) and dyslipidaemia.

METHODS

PubMed, Embase, Web of Science and Cochrane Library were systematically searched from January 2000 to December 2021. We included observational studies to assess the correlation of DED with meibomian gland dysfunction and dyslipidaemia without any language restrictions. The pooled OR with 95% CI was calculated in Stata V.15.

RESULTS

Of 6727 identified studies, 18 studies (21 databases) with a total of 2 663 126 patients were analysed in our meta-analysis. The results showed that DED risk was associated with dyslipidaemia (OR=1.53, 95% CI: 1.41 to 1.66, p=0.001), especially elevated total cholesterol levels (OR=1.57, 95% CI: 1.25 to 1.99, p<0.001), elevated low-density lipoprotein cholesterol levels (OR=1.13, 95% CI: 1.06 to 1.20, p<0.001) and high-density lipoprotein cholesterol levels (OR=1.06, 95% CI: 1.01 to 1.11, p<0.001), but not with serum triglyceride levels. Moreover, having a history of lipid-lowering drug use (OR=1.41, 95% CI: 1.19 to 1.67, p<0.001) was also found to be positively associated with DED risk.

CONCLUSIONS

The findings suggested that dyslipidaemia and lipid-lowering drug use might be associated with an increased risk of DED. More evidence is needed to confirm the findings by prospective studies.

PROSPERO REGISTRATION NUMBER

CRD42022296664.

Short-term effect of meteorological factors and extreme weather events on daily outpatient visits for dry eye disease between 2013 and 2020: a time-series study in Urumqi, China

Dry eye disease (DED) is a common disorder of tear secretion on the ocular surface caused by multiple factors with dry eyes as the main symptom, but until now studies focusing on relationship between local meteorological factors and ocular surface diseases in Urumqi are very limited. Besides, the effects of long-term and extreme meteorological factors on DED and the lag effect have not been fully evaluated. Electronic case information of 9970 DED outpatients from the Ophthalmology Department of the First Affiliated Hospital of Xinjiang Medical University (Urumqi, Xinjiang, China) between January 1, 2013, and December 31, 2020, was screened and analyzed. We used a time-series analysis design and a quasi-Poisson generalized linear regression model combined with a distributed lagged nonlinear model (DLNM) to fit the effects of exposure to different meteorological factors and extreme weather on DED outpatient visits. Subgroup analyses were further performed for gender, age, and season. The results showed that exposure to extremely low mean temperature (P1:RR = 1.18), atmospheric pressure (P1:RR = 1.11), and extremely high relative humidity (P99:RR = 1.35) were the risk factors, while extremely high atmospheric pressure (P90:RR = 0.883) and extremely low humidity (P10:RR = 0.856) appeared to have a positive effect on reduced risk of DED. Relative humidity exhibited a 1-day lag effect (RR = 1.06). Increased mean temperature positively affected female DED patients (RR = 0.761) with similar effects in the cold season (RR = 0.926). However, elevated relative humidity had a negative effect on female patients (RR = 1.14). We conducted the first large sample size time-series analysis study in this major city at the farthest distance from the ocean in the world and in northwest China, confirming the association of DED outpatient visits with the remaining three meteorological factors except wind speed in Urumqi, and a larger sample size multi-center epidemiological study with a longer duration is still needed.

Relationship between Dry Eye Disease and Dyslipidemia: A Systematic Review

BACKGROUND

Dyslipidemia has been suggested to be associated with the occurrence of dry eye disease (DED). However, whether dyslipidemia is responsible for the development of DED remains unclear. In this systematic review, we explored the relationship between DED and dyslipidemia by using quantitative data.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted a comprehensive literature search in several databases, including PubMed, Embase, Cochrane Library, Web of Science, and Google Scholar, and obtained six relevant studies.

RESULTS

Our findings indicated that the majority of the selected studies reported a statistically significant association between dyslipidemia and DED, particularly in women. However, our quantitative analysis revealed that only two studies reported statistically significant differences in total cholesterol and high-density lipoprotein cholesterol values.

CONCLUSION

No statistically significant differences exist in the majority of lipid profile parameters between individuals with and without DED, but there is a statistically significant association between dyslipidemia and DED.

TFOS lifestyle: Impact of societal challenges on the ocular surface

Societal factors associated with ocular surface diseases were mapped using a framework to characterize the relationship between the individual, their health and environment. The impact of the COVID-19 pandemic and mitigating factors on ocular surface diseases were considered in a systematic review. Age and sex effects were generally well-characterized for inflammatory, infectious, autoimmune and trauma-related conditions. Sex and gender, through biological, socio-economic, and cultural factors impact the prevalence and severity of disease, access to, and use of, care. Genetic factors, race, smoking and co-morbidities are generally well characterized, with interdependencies with geographical, employment and socioeconomic factors. Living and working conditions include employment, education, water and sanitation, poverty and socioeconomic class. Employment type and hobbies are associated with eye trauma and burns. Regional, global socio-economic, cultural and environmental conditions, include remoteness, geography, seasonality, availability of and access to services. Violence associated with war, acid attacks and domestic violence are associated with traumatic injuries. The impacts of conflict, pandemic and climate are exacerbated by decreased food security, access to health services and workers. Digital technology can impact diseases through physical and mental health effects and access to health information and services. The COVID-19 pandemic and related mitigating strategies are mostly associated with an increased risk of developing new or worsening existing ocular surface diseases. Societal factors impact the type and severity of ocular surface diseases, although there is considerable interdependence between factors. The overlay of the digital environment, natural disasters, conflict and the pandemic have modified access to services in some regions.

Association of Meibomian Gland Dysfunction with Oral Statin Use

This retrospective cross-sectional study aimed to determine the association of oral statin use, dry eye disease (DED), and meibomian gland dysfunction (MGD). A total of 93 subjects were included and divided into two groups: statin users (n = 45) and nonstatin users (n = 47). Significant differences were observed in the total cholesterol (p = 0.013), low-density lipoprotein (LDL) (p = 0.005), and meiboscore (p = 0.000) levels between the two groups. For stratified analysis, the statin group was divided into subgroups according to the type or dose of statin and total duration of statin use. However, there were no differences in clinical features between the subgroups. In multiple regression analysis, meiboscore was significantly associated with age (slope = 0.05, p = 0.00) and statin use (slope = −1.19, p = 0.00), with an R² of 0.44. Thus, older adults and participants who do not use statin appeared to have higher scores. In conclusion, although the mechanism is unclear, statins may exert a protective effect on the meibomian gland. Further lipidomic studies are required to determine the pharmacological effects of statins on the meibomian gland and other meibum components.

Association of Serum Lipid Level with Meibum Biosynthesis and Meibomian Gland Dysfunction: A Review

The primary role of meibomian glands (MGs) is to actively synthesize and secret lipids and proteins spread onto the tear film, and the glandular lipids promote tear stability, prevent evaporation, and reduce friction. Meibomian gland dysfunction (MGD) is the leading cause of dry eye disease and one of the most common ophthalmic problems worldwide. MGs are densely innervated and regulated by hormones and growth factors. However, since the polar and nonpolar lipids are produced through processes in MGs that are not completely understood, a relevant question has been raised: Would the altered systemic lipids metabolism affect the physiology and structure of MGs? This review introduces the recent update regarding the relationships between serum lipid and MGD in clinical and basic research while providing answers to this question. A causal relationship remains to be established; however, serum lipid level or dyslipidemia may be related to MGD directly or indirectly, or both. Further studies are warranted to establish the role of serum lipid level and meibocyte differentiation/maturation and lipid synthesis.