Impact of seasonal variation in meteorological conditions on dry eye severity

Tear Fluid as a Matrix for Biomonitoring Environmental and Chemical Exposures

PURPOSE

Exposures to hazardous chemicals have been linked to many detrimental health effects and it is therefore critical to have effective biomonitoring methods to better evaluate key environmental exposures that increase the risk of chronic disease and death. Traditional biomonitoring utilizing blood and urine is limited due to the specialized skills and invasiveness of collecting these fluid samples. This systematic review focuses on tear fluid, which is largely under-researched, as a promising complementary matrix to the traditional fluids used for biomonitoring. The objective is to evaluate the practicability of using human tear fluid for biomonitoring environmental exposures, highlighting potential pitfalls and opportunities.

RECENT FINDING

Tear fluid biomonitoring represents a promising method for assessing exposures because it can be collected with minimal invasiveness and tears contain exposure markers from both the external and internal environments. Tear fluid uniquely interfaces with the external environment at the air-tear interface, providing a surface for airborne chemicals to diffuse into the ocular environment and interact with biomolecules. Tear fluid also contains molecules from the internal environment that have travelled from the blood to tears by crossing the blood-tear barrier. This review demonstrates that tear fluid can be used to identify hazardous chemicals from the external environment and differentiate exposure groups.

Demographic and Psychiatric Associations With Dry Eye in a Medicare Population

PURPOSE

The purpose of this study was to investigate the impact of demographic characteristics and psychiatric comorbidity on the prevalence of dry eye disease in the American geriatric population.

METHODS

Data were collected from a 2011 nationwide sample of Medicare beneficiaries aged 65 years and older (N = 1,321,000). Age, sex, race/ethnicity, residential area, climate region, and income, along with psychiatric comorbidities including depression and anxiety, were collected. Multivariable logistic regression models were used to assess the relationship between demographic and psychiatric factors and the prevalence of dry eye disease.

RESULTS

Among 21,059 patients with clinically significant dry eye, women had higher odds of having dry eye compared with men [odds ratio (OR) 2.03, 95% confidence interval (1.97-2.10)]. Asian and Native American patients had increased odds of having dry eye compared with White patients [OR 1.85 (1.69-2.02) and OR 1.51 (1.19-1.93)], while Black patients were less likely to have dry eye [OR 0.83 (0.79-0.87)]. Patients aged 75 to 84 years and 85+ were more likely to have dry eye compared with those aged 65 to 74 years [OR 1.49 (0.45-1.53) and OR 1.54 (1.48-1.60)]. Having both depression and anxiety were associated with higher odds of having dry eye [OR 2.38 (2.22-2.55)] compared with having depression alone [OR 1.95 (1.86-2.04)] or anxiety alone [OR 2.22 (2.10-2.35)].

CONCLUSIONS

Significant racial and regional disparities in dry eye prevalence were found. Psychiatric association with dry eye varied with age, sex, race, and residence region. Further research is needed to comprehend the underlying mechanisms, implications, and to address disparities in the diagnosis and management of dry eye.

Seasonality of Tear Meniscus Volume and Dry Eye-Related Symptoms - A Cross-Sectional Retrospective Cohort Study

Purpose

We aimed to determine the seasonal variation in the tear meniscus level on strip meniscometry and its association with ocular parameters and symptoms. In Japan, there are four distinct seasons characterized by marked differences in temperature and humidity, which may contribute to an observed seasonality of ocular surface symptoms.

Methods

We conducted a cross-sectional study in two Japanese clinics and recruited first-visit patients for 3 years. Tear strip meniscometry, tear break-up time (BUT), Schirmer test, and corneal staining were examined, and major ocular symptoms (dryness, irritation, pain, fatigue, blurred vision, and photophobia) were determined through interviews.

Results

The 1196 participants had a mean age of 58.9±15.2 years; 37.1% were of male sex. Strip meniscometry values and BUT revealed significant seasonality with one-way analysis of variance. The mean strip meniscometry value (mm) was 2.15±2.59 in spring (p=0.025 vs winter), 2.37±2.79 in summer (p<0.001), 2.38±2.80 in fall (p<0.001), and 1.64±2.29 in winter. Regression analysis indicated that strip meniscometry levels were correlated with BUT (p<0.001), Schirmer test values (p<0.001), corneal staining scores (p=0.022), and presence of dryness (p<0.001).

Conclusion

Strip meniscometry values exhibited distinct seasonality, being lowest in winter when the ambient condition is dry and cool, and were correlated with BUT, Schirmer test values, corneal staining scores, and the presence of subjective dryness.

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.

Periodic Trends in Internet Searches for Ocular Symptoms in the US

PURPOSE

To identify periodic trends in internet searches for ocular symptoms and to determine the seasonal peaks and troughs.

METHODS

This cross-sectional study examined publicly available Google Trends data from the United States (01/01/2015 to 12/31/2019). A list of common ocular symptoms was compiled from the American Academy of Ophthalmology Eye Health website and Wills Eye Manual. Ocular symptoms were stratified into categories involving vision change, eye pain, or eye redness. The search volume over time for each term was modeled using periodic regression functions and the goodness-of-fit was reported. Fisher's exact tests were used to compare the characteristics of periodic vs. non-periodic query terms.

RESULTS

Seasonal trends were demonstrated by 45% (48/106) of the ocular symptoms included in this investigation. Search terms with best fit to the periodic model included stye (r2 = 0.89), pink eye (r2 = 0.82), dry eye (r2 = 0.76), blurry vision (r2 = 0.72), and swollen eye (r2 = 0.71). Periodic search terms were more likely to involve eye redness (21% vs. 11%, p = .014) and less likely to involve vision change (11% vs. 36%; p < .001). Periodic queries involving eye redness most often peaked in the spring and those involving eye pain peaked in the summer.

CONCLUSION

Ocular symptom queries directly reflect seasonal trends for allergic eye disease and ocular trauma. Search query analyses can serve as accurate epidemiological tools with research and real-world clinical applications.

Joint effects of meteorological factors and PM2.5 on age-related macular degeneration: a national cross-sectional study in China

BACKGROUND

Weather conditions are a possible contributing factor to age-related macular degeneration (AMD), a leading cause of irreversible loss of vision. The present study evaluated the joint effects of meteorological factors and fine particulate matter (PM_2.5) on AMD.

METHODS

Data was extracted from a national cross-sectional survey conducted across 10 provinces in rural China. A total of 36,081 participants aged 40 and older were recruited. AMD was diagnosed clinically by slit-lamp ophthalmoscopy, fundus photography, and spectral domain optical coherence tomography (OCT). Meteorological data were calculated by European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis and were matched to participants' home addresses by latitude and longitude. Participants' individual PM_2.5 exposure concentrations were calculated by a satellite-based model at a 1-km resolution level. Multivariable-adjusted logistic regression models paired with interaction analysis were performed to investigate the joint effects of meteorological factors and PM_2.5 on AMD.

RESULTS

The prevalence of AMD in the study population was 2.6% (95% CI 2.42-2.76%). The average annual PM_2.5 level during the study period was 63.1 ± 15.3 µg/m³. A significant positive association was detected between AMD and PM_2.5 level, temperature (T), and relative humidity (RH), in both the independent and the combined effect models. For PM_2.5, compared with the lowest quartile, the odds ratios (ORs) with 95% confidence intervals (CIs) across increasing quartiles were 0.828 (0.674,1.018), 1.105 (0.799,1.528), and 2.602 (1.516,4.468). Positive associations were observed between AMD and temperature, with ORs (95% CI) of 1.625 (1.059,2.494), 1.619 (1.026,2.553), and 3.276 (1.841,5.830), across increasing quartiles. In the interaction analysis, the estimated relative excess risk due to interaction (RERI) and the attributable proportion (AP) for combined atmospheric pressure and PM_2.5 was 0.864 (0.586,1.141) and 1.180 (0.768,1.592), respectively, indicating a synergistic effect between PM_2.5 and atmospheric pressure.

CONCLUSIONS

This study is among the first to characterize the coordinated effects of meteorological factors and PM_2.5 on AMD. The findings warrant further investigation to elucidate the relationship between ambient environment and AMD.

The influence of a mineral oil cationic nanoemulsion or perfluorohexyloctane on the tear film lipid layer and higher order aberrations

PURPOSE

To prospectively assess the effect of a single and regular application of either a cationic nanoemulsion of mineral oil (CN) or perfluorohexyloctane (F6H8) on the lipid layer of the tear film and higher order aberrations (HOA) in patients with Dry Eye Disease (DED).

METHODS

Fifty-seven patients with a lipid layer thickness (LLT) ≤ 75 interferometric colour units (ICU) were included in the study. In group A (20 patients) the effect of a single drop of F6H8 or CN on HOA and LLT was assessed immediately after application and up to two hours later. For long term effects (Group B) 37 patients applied CN or F6H8 five times a day for 12 weeks. Measurement of LLT, HOA, non-invasive-tear-break-up-time (NIBUT) and meibography were assessed prior to as well as at 4 weeks and 12 weeks after initiation of treatment. Our study is registered in the "German Clinical Trials Register" under the trial number: DRKS00028696.

RESULTS

CN led to an increase of the LLT from 46.8 ± 16.9 ICU to 76.3 ± 23.5 ICU (p = 0.021) and to an increase of HOA from 0.43 ± 0.06 μm to 0.48 ± 0.08 μm immediately after application (p = 0.027). There was no correlation between the increase of LLT and HOA (r = -0.04; p = 0.90). In group B an increase of LLT was observed in the F6H8 group from 45.8 ± 8.8 ICU at baseline to 66.7 ± 19.5 ICU at 12 weeks (p = 0.002). No changes of HOA were measured throughout the observation period in group B. After 12 weeks CN increased NIBUT from 9.9 ± 5.3 seconds to 15.5 ± 5.6 seconds (p = 0.04). F6H8 increased NIBUT from 12.4 ± 5.9 seconds to 16.9 ± 4.7 seconds (p = 0.02) after 12 weeks.

CONCLUSION

CN leads to a short-term increase in LLT and HOA, but only immediately after application. In contrast F6H8 does lead to an increase of LLT after regular long-term use but has no effect on HOA. The regular application of lipid-based products does not seem to decrease the quality of vision as measured in HOA. Instead, CN and F6H8, both are able to stabilize the tear film after regular application.

Utilizing Baidu Index to Investigate Seasonality, Spatial Distribution and Public Attention of Dry Eye Diseases in Chinese Mainland

Purpose

To explore the characteristics of spatial-temporal prevalence and public attention of dry eye diseases (DED) through Baidu Index (BI) based on infodemiology method.

Methods

The data about BI of DED were collected from Baidu search engine using "Dry eye diseases" as keyword. The spatial and temporal distribution of DED were analyzed through timeseries data decomposition as well as spatial autocorrelation and hotspot detection of BI about DED. The most popular related words and demographic characteristics were recorded to determine the public attention of DED.

Results

The trends of BI about DED in Chinese mainland had gradually increased over time with a rapid increase from 2012 to 2014 and in 2018. The results of timeseries decomposition indicated that there was seasonality in the distribution of BI about DED with the peak in winter, especially in northern regions. The geographic distribution demonstrated the search activities of DED was highest in the east of Chinese mainland while lowest in the west. The vast majority of people searching for DED were teenagers (20-29 years), with a predominance of females. Glaucoma, keratitis and conjunctivitis were the diseases most often confused with DED, and the artificial tears were the most common treatment for DED in Chinese mainland according to the BI about DED.

Conclusions

The analysis revealed the seasonality, geographic hotspots and public concern of DED through BI in Chinese mainland, which provided new insights into the epidemiology of DED.

Environmental and Air Pollution Factors Affecting Allergic Eye Disease in Children and Adolescents in India

The aim of this study was to describe the correlation between the meteorological and air pollution parameters with the temporal pattern of presentation of recent onset allergic eye disease (AED). This cross-sectional hospital-based study included new patients (≤21 years of age) presenting between January 2016 and August 2018 from the district of Hyderabad with a clinical diagnosis of AED and an acute exacerbation of recent onset of symptoms of less than 3 months duration. Correlation analysis was performed with the local environmental rainfall, temperature, humidity, windspeed, and air pollution. Of the 25,354 new patients hailing from the district of Hyderabad, 2494 (9.84%) patients were diagnosed with AED, of which 1062 (4.19%) patients had recent onset of symptoms. The mean monthly prevalence in this cohort was 4.13%, and the month of May (6.09%) showed the highest levels. The environmental parameters of humidity (r² = 0.83/p = < 0.0001) and rainfall (r² = 0.41/p = 0.0232) showed significant negative correlation, while temperature (r² = 0.43/p = 0.0206) and ground-level ozone (r² = 0.41/p = 0.0005) showed significant positive correlation with the temporal pattern of AED in the population. An increase in rainfall and humidity was associated with a lower prevalence, and an increase of temperature and ground-level ozone was associated with a higher prevalence of AED cases during the year among children and adolescents.

Allergies, Allergic Comorbidities and the Home Environment in Pediatric Asthma in Southern Florida

Background: Environmental exposure is critical in sensitization to environmental allergens and pediatric asthma morbidity, especially in tropical climates where children are perennially exposed to bioaerosols, such as pollen and mold spores, and endotoxins. Objective: This cross-sectional study examines the association of allergies, associated allergic comorbidities, and the home environment separately and synergistically in pediatric asthma, including in asthma prevalence, severity of asthma, and undiagnosed asthma, in South Florida. Methods: An online survey was administered to the parents of children attending two of the University of Miami pediatric clinics from June to October 2016. Descriptive, factor, and multivariate regression analyses were used to analyze the data. Results: Of 163 children, 22% (36) children had physician-diagnosed asthma; 10% and 32% had allergic rhinitis diagnosis and rhinitis symptoms, respectively, in the past. The allergy diagnosis age was 2.3 years higher than the asthma diagnosis age (p < 0.01). Children with ≥ 2 allergies were 12.8 times more likely to have physician-diagnosed asthma than those without allergies (p < 0.01). Children with allergies and allergic rhinitis were 4.3 (p < 0.05) times more likely to have asthma, and those with asthma were 15 (p < 0.05) times more likely to have an asthma attack than those without known allergies and allergic rhinitis. Conclusion: Allergies and associated comorbidities are risk factors of asthma, asthma persistence, and multiple allergies exacerbate their effects. Early screening for allergies and treatment are warranted to manage asthma. Since the home environment plays an important role in sensitization to allergens, further research is needed to assess home-environment-mediated allergic conditions in the onset and persistence of asthma.

Total Tear IgE Levels Correlate with Allergenic and Irritating Environmental Exposures in Individuals with Dry Eye

Dry eye (DE) and allergic conjunctivitis may present similarly, and it remains unclear whether some individuals have an underlying allergic component to their DE. To better understand this relationship, we performed a cross-sectional study in 75 individuals with DE symptoms and/or signs. Immunoglobulin E (IgE) levels in tear samples were quantified and home environmental exposures assessed via standardized survey. Tears were collected by Schirmer strip, and total tear IgE levels were quantified using enzyme-linked immunosorbent assay (ELISA). Data were analyzed using descriptive statistics and linear and logistic regressions. The main outcome measures were total tear IgE levels and their association with environmental exposures. The mean age of the subjects was 66.2 ± 7.8 years. Sixty-two individuals had dry eye symptoms (Dry Eye Questionnaire-5 ≥ 6), and 75 had one or more signs of DE. Detectable total tear IgE levels were observed in 76% of subjects, and 17.3% had high levels (>1 ng/mL). Individuals with exposure to pet(s) (odds ratio (OR) 11.5, p = 0.002) and smoke (OR 38.6, p = 0.008) at home were more likely to have high IgE levels compared to those not exposed. Individuals with tears collected during spring or summer were 3.9 times (p = 0.028) more likely to have high IgE compared to those sampled at other times of year. Subjects born in the US were 3.45 times (p = 0.010) more likely to have high IgE compared to individuals born outside the US. To conclude, a majority of individuals with DE symptoms and/or signs had detectable IgE levels in their tears. High tear IgE levels were correlated with allergy season and exposures in the home linked with allergy.

Human Ocular Surface Particulate Composition in the Clinical Versus Home Environment

PURPOSE

Our eyes are chronically exposed to airborne particulate matter shown to adversely affect the ocular surface. This research examines size, type (organic vs. inorganic), and elemental composition of particles recovered from the ocular surface in 2 environments and their associations with dry eye (DE) metrics.

METHODS

Particles were recovered from the right eye using Schirmer strips obtained both in the clinic and home environments 9 ± 8 days apart. Particle size and elemental composition were assessed using scanning electron microscopy and energy dispersive spectroscopy. The paired t test was used to evaluate the differences in the size and types of ocular surface particles recovered from the clinic and home settings. Associations of particle size and type with home environmental conditions and DE measures were evaluated using correlation analyses.

RESULTS

The mean age of the 15 patients was 56 years, standard deviation (±) 12 years; 93% were men and 53% self-identified as white. Size, type, and elemental composition did not vary significantly between clinic and home. Particle surface area was marginally associated with home indoor temperature (25 °C ± 2, ρ=-0.53, P = 0.06) and significantly associated with the select DE signs: tear osmolality (304 mOsm/L ± 14, ρ= -0.60, P = 0.02), inflammation (0.7 ± 0.8, ρ = 0.53, P = 0.04), and tear breakup time (7 seconds ± 3, ρ = 0.56, P = 0.03).

CONCLUSIONS

Ocular surface particles were consistently detected across 2 different environments. Greater particle area detected on Schirmer strips correlated with some DE measures, suggesting that particles detected on the ocular surface may affect eye health.

Association Between Single Nucleotide Polymorphisms in the Vitamin D Receptor and Incidence of Dry Eye Disease in Chinese Han Population

Background

Dry eye disease (DED) is a chronic dysfunction of the ocular surface and has become an important public problem. Vitamin D receptor (VDR) gene polymorphism has been found to be associated with different kinds of diseases. The relationship between single nucleotide polymorphisms (SNPs) in the VDR gene should be studied.

Material/Methods

In the present case-control study, we investigated the association of VDR gene polymorphism with DED risk. Clinical data including age, gender, body mass index (BMI, kg/m²), smoking history, diabetes, and blood pressure were recorded. Serum 25-hydroxy vitamin D (25[OH]D) was chosen as the main parameter that reflected the level of vitamin D. We identified SNPs of VDR gene Apa-1, Bsm-1, Fok-1, and Taq-1 in both DED cases and healthy controls.

Results

A total of 124 DED cases and 135 healthy controls were included in this study. It was reported that aa in Apa-1 (OR=2.803, 95% CI, 1.350–5.820) and tt in Taq-1 (OR=0.362, 95% CI, 0.141–0.930) were associated with increased the risk of DED. Analysis of the allele frequencies of VDR gene polymorphisms among DED patients and healthy controls showed that allele differences in Apa-1 were significantly associated with higher risk.

Conclusions

SNPs of VDR gene (Apa-1 and Taq-1) were associated with the risk of DED. No significant association of Bsm-1 and Fok-1 in VDR gene demonstrated significant effect in the incidence of DED. Thus, we found that several SNPs of VDR gene could provide significant pathogenic effects in the risk of DED.