Evidence of seasonality and effects of psychrometry in dry eye disease

[Climate change and ocular surface diseases]

BACKGROUND

The ocular surface is directly exposed to environmental influences. Noxae that have already been identified for the ocular surface are heat, air dryness, pollutant gases, fine dust particles and ultraviolet radiation.

METHODS

The current literature was used to investigate the relationship between frequent ocular surface diseases and various environmental factors and to analyze their development over the years.

RESULTS

Epidemiological studies on dry eye disease and allergic conjunctivitis have shown an increase in the incidences in recent years. Environmental pollutants have been identified as disease triggers. In addition, the prolonged pollen season and increased pollen concentrations are also risk factors. There is also a higher prevalence of pterygium in population groups with high UV exposure. Other diseases with potential environmental pathogenesis are acute photokeratitis, photoconjunctivitis and malignant melanoma of the conjunctiva.

CONCLUSION

For ocular surface diseases, large epidemiological cohorts have shown climate-related increases in the incidence. A further increase in environmentally associated noxious substances can be expected in the coming decades. In addition to measures to mitigate climate change, the underlying mechanisms of disease development and new approaches to prevention and treatment, such as room humidification, air filters or contact lenses with UV filters, should be investigated.

Seasonal variations and environmental influences on dry eye operations in Japan

The surface of the eye is constantly exposed to the external environment and is affected by atmospheric conditions and air pollution, and dry eye is a typical ocular surface disease. The aim of this study is to determine whether there are seasonal differences in the number of dry eye operations in Japan and to investigate whether meteorological conditions and air pollutants are related to. The operations were examined using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) database from fiscal years 2019 to 2021. Temperature, atmospheric pressure, relative humidity, volume humidity, wind speed, sulfur dioxide (SO₂), nitrogen oxides X (NOX), photochemical oxidants (OX), carbon monoxide (CO) and particulate matter 2.5 (PM2.5) were considered. The number of dry eye operations was significantly higher in winter than in summer. (p = 0.0023) No significant differences were found among the other seasons. Volume humidity and temperature were strongly negative correlated, NOX and atmospheric pressure were strongly positive correlated.

Spaceflight associated dry eye syndrome (SADES): Radiation, stressors, and ocular surface health

Crewed spaceflight missions require careful scrutinization of the health risks including alterations to the tear film lipid layer in astronauts. We review the current literature and prior published work on tear film lipid layer biophysics and secondary spaceflight-associated dry eye syndrome (SADES). We define the term spaceflight-associated dry eye syndrome to describe the collection of ocular surface signs and symptoms experienced by astronauts during spaceflight. Our review covers the ocular surface and lipidomics in the spaceflight environment. From our literature review, we extrapolate biophysical principles governing the tear film layer to determine the changes that may arise from the harsh conditions of spaceflight and microgravity. Our findings provide vital information for future long-duration spaceflight, including a return to the Moon and potential missions to Mars.

Influence of Environmental Factors with Clinical Signs and Symptoms in the Management of Dry Eye Disease

Background

This research aims to investigate the influence of environmental factors on the treatment efficacy of ocular lubricants in patients from urban areas with dry eye disease (DED).

Methods

A phase IV clinical trial, which included 173 patients from major cities in Mexico, was randomly assigned to use ocular lubricants four times a day for 30 days. Ocular Surface Disease Index (OSDI), noninvasive tear film break-up time (NIBUT), ocular staining, and conjunctival hyperemia (CH) among other factors like weather, and air pollution as covariates were analysed.

Results

After 30 days, OSDI score decreased by 14.8 points (p<0.001), and NIBUT increased by 2.9 seconds (p< 0.001), with longer values observed in patients recruited in autumn and winter (additional 1.8 seconds, p< 0.05) compared to those recruited in spring. Patients living in cities with cooler weather and high humidity, but low air quality had higher OSDI and conjunctival stain scores of up to 4.4 and 0.3 points, respectively, as compared to those living in cities with similar pollution and humidity levels but with higher temperatures (p-values= 0.019 and 0.050). Patients with moderate CH had an increase of up to 0.8 points in their corneal stain score (p< 0.010). We also found that ozone levels were related to the predicted changes in OSDI and NIBUT.

Conclusion

This study demonstrated the impact of environmental factors on the signs and symptoms of DED and suggests that patients residing in cities with inadequately controlled air pollution can benefit from using ocular lubricants to alleviate their symptoms.

Trial Registration

Trial is registered at clinicaltrials.gov (NCT04702776).

Cellular Stress in Dry Eye Disease-Key Hub of the Vicious Circle

Disturbance or insufficiency of the tear film challenges the regulatory systems of the ocular surfaces. The reaction of the surfaces includes temporary mechanisms engaged in the preservation of homeostasis. However, strong or persisting challenges can lead to the potential exhaustion of the coping capacity. This again activates the vicious circle with chronic inflammation and autocatalytic deterioration. Hence, the factors challenging the homeostasis should be addressed in time. Amongst them are a varying osmolarity, constant presence of small lesions at the epithelium, acidification, attrition with mechanical irritation, and onset of pain and discomfort. Each of them and, especially when occurring simultaneously, impose stress on the coping mechanisms and lead to a stress response. Many stressors can culminate, leading to an exhaustion of the coping capacity, outrunning normal resilience. Reaching the limits of stress tolerance leads to the manifestation of a lubrication deficiency as the disease we refer to as dry eye disease (DED). To postpone its manifestation, the avoidance or amelioration of stress factors is one key option. In DED, this is the target of lubrication therapy, substituting the missing tear film or its components. The latter options include the management of secondary sequelae such as the inflammation and activation of reparative cascades. Preventive measures include the enhancement in resilience, recovery velocity, and recovery potential. The capacity to handle the external load factors is the key issue. The aim is to guard homeostasis and to prevent intercellular stress responses from being launched, triggering and invigorating the vicious circle. Considering the dilemma of the surface to have to cope with increased time of exposure to stress, with simultaneously decreasing time for cellular recovery, it illustrates the importance of the vicious circle as a hub for ocular surface stress. The resulting imbalance triggers a continuous deterioration of the ocular surface condition. After an initial phase of the reaction and adaption of the ocular surface to the surrounding challenges, the normal coping capacity will be exhausted. This is the time when the integrated stress response (ISR), a protector for cellular survival, will inevitably be activated, and cellular changes such as altered translation and ribosome pausing are initiated. Once activated, this will slow down any recovery, in a phase where apoptosis is imminent. Premature senescence of cells may also occur. The process of prematurization due to permanent stress exposures contributes to the risk for constant deterioration. The illustrated flow of events in the development of DED outlines that the ability to cope, and to recover, has limited resources in the cells at the ocular surface. The reduction in and amelioration of stress hence should be one of the key targets of therapy and begin early. Here, lubrication optimization as well as causal treatment such as the correction of anatomical anomalies (leading to anatomical dry eye) should be a prime intent of any therapy. The features of cellular stress as a key hub for the vicious circle will be outlined and discussed.

Short-Term Efficacy of Ophthalmic Cyclosporine: A 0.1% Cationic Emulsion in Dry Eye Patients Assessed Under Controlled Environment

INTRODUCTION

To evaluate the short-term efficacy of cyclosporine A (CsA)-0.1% cationic emulsion (CE) in patients with dry eye disease (DED) and mitigation of the inflammatory flares triggered by desiccating stress environments.

METHODS

A single-center non-randomized clinical trial was performed at a tertiary care setting. Twenty patients with DED treated with CsA 0.1% CE were exposed to a normal controlled environment (NCE) (23 °C, 50% relative humidity) and an adverse controlled environment (ACE) (23 °C, 10% relative humidity, 0.43 m/s localized airflow) during baseline and the 1- and 3-month visits. Patients underwent the following evaluations: conjunctival hyperemia and staining, corneal fluorescein staining (CFS) using the Oxford and Cornea and Contact Lens Research Unit (CCLRU) scale, meibomian gland (MG) secretion quality, Dry Eye Questionnaire-5, Symptom Assessment in Dry Eye (SANDE II), and Change in Dry Eye Symptoms Questionnaire. Multivariate models were adjusted for statistical analysis.

RESULTS

Nineteen women and one man (mean age, 58.9 ± 12.3 years) completed the study. All symptom questionnaires, CFS, conjunctival hyperemia and staining, and MG secretion quality improved (p ≤ 0.003) with 1 month of treatment; improvements were maintained after 3 months (p ≤ 0.02), except for SANDE II (p ≥ 0.07). The CFS worsening (total CCLRU) after baseline ACE exposure (from 8.6 to 10.1) was higher, although not significant (p = 0.64), compared with 1 month (from 5.4 to 5.8) and 3 months (from 5.0 to 5.9) after treatment.

CONCLUSION

Topical CsA-0.1% CE improved DED signs and symptoms after 1 month of treatment under controlled environmental conditions. Future studies should confirm the benefit of CsA-0.1% CE in desiccating stress environments.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04492878.

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.

The Human Ocular Surface Microbiome and Its Associations with the Tear Proteome in Dry Eye Disease

Although dry eye disease (DED) is one of the most common ocular surface diseases worldwide, its pathogenesis is incompletely understood, and treatment options are limited. There is growing evidence that complex interactions between the ocular surface microbiome (OSM) and tear fluid constituents, potentially leading to inflammatory processes, are associated with ocular surface diseases such as DED. In this study, we aimed to find unique compositional and functional features of the OSM associated with human and microbial tear proteins in patients with DED. Applying whole-metagenome shotgun sequencing of forty lid and conjunctival swabs, we identified 229 taxa, with Actinobacteria and Proteobacteria being the most abundant phyla and Propionibacterium acnes the dominating species in the cohort. When DED patients were compared to controls, the species Corynebacterium tuberculostearicum was more abundant in conjunctival samples, whereas the family Propionibacteriaceae was more abundant in lid samples. Functional analysis showed that genes of L-lysine biosynthesis, tetrapyrrole biosynthesis, 5-aminoimidazole ribonucleotide biosynthesis, and the super pathway of L-threonine biosynthesis were enriched in conjunctival samples of controls. The relative abundances of Acinetobacter johnsonii correlated with seven human tear proteins, including mucin-16. The three most abundant microbial tear proteins were the chaperone protein DnaK, the arsenical resistance protein ArsH, and helicase. Compositional and functional features of the OSM and the tear proteome are altered in patients with DED. Ultimately, this may help to design novel interventional therapeutics to target DED.

Ocular Surface Allostasis-When Homeostasis Is Lost: Challenging Coping Potential, Stress Tolerance, and Resilience

The loss of ocular surface (OS) homeostasis characterizes the onset of dry eye disease. Resilience defines the ability to withstand this threat, reflecting the ability of the ocular surface to cope with and bounce back after challenging events. The coping capacity of the OS defines the ability to successfully manage cellular stress. Cellular stress, which is central to the outcome of the pathophysiology of dry eye disease, is characterized by intensity, continuity, and receptivity, which lead to the loss of homeostasis, resulting in a phase of autocatalytic dysregulation, an event that is not well-defined. To better define this event, here, we present a model providing a potential approach when homeostasis is challenged and the coping capacities have reached their limits, resulting in the stage of heterostasis, in which the dysregulated cellular stress mechanisms take over, leading to dry eye disease. The main feature of the proposed model is the concept that, prior to the initiation of the events leading to cellular stress, there is a period of intense activation of all available coping mechanisms preventing the imminent dysregulation of ocular surface homeostasis. When the remaining coping mechanisms and resilience potential have been maximally exploited and have, finally, been exceeded, there will be a transition to manifest disease with all the well-known signs and symptoms, with a shift to allostasis, reflecting the establishment of another state of balance. The intention of this review was to show that it is possibly the phase of heterostasis preceding the establishment of allostasis that offers a better chance for therapeutic intervention and optimized recovery. Once allostasis has been established, as a new steady-state of balance at a higher level of constant cell stress and inflammation, treatment may be far more difficult, and the potential for reversal is drastically decreased. Homeostasis, once lost, can possibly not be fully recovered. The processes established during heterostasis and allostasis require different approaches and treatments for their control, indicating that the current treatment options for homeostasis need to be adapted to a more-demanding situation. The loss of homeostasis necessarily implies the establishment of a new balance; here, we refer to such a state as allostasis.

Symptoms of dry eye related to the relative humidity of living places

PURPOSE

To investigate the impact of relative humidity (RH) and climate variables of the place of residence on symptoms of dry eye disease (DED) in primary eye care practice.

METHODS

A cross-sectional analysis of the Ocular Surface Disease Index (OSDI) dry eye classification of 1.033 patients [classified as non-DED (OSDI ≤22) and DED (OSDI >22)] was conducted in a multicentre study in Spain. Participants were classified according to the 5-year RH value (data from the Spanish Climate Agency -www.aemet.es) into two groups: those who lived in low RH (<70%) places and those who lived in high RH (≥70%) places. Additionally, differences in daily climate records (EU Copernicus Climate Change Service) were assessed.

RESULTS

The prevalence of DED symptoms was 15.5% (95% CI 13.2%-17.6%). Participants who lived in places with <70% RH showed a higher prevalence of DED (17.7%; 95% CI 14.5%-21.1%; P < 0.01 adjusted for age and sex) than those who lived in places with ≥70% RH (13.6%; 95% CI 11.1%-16.7%) and a closer, but not statistically significant, risk for DED (OR = 1.34, 95% CI 0.96 to 1.89; P = 0.09) than previously described DED risk factors [age older than 50 years (OR = 1.51, 95% CI 1.06 to 2.16; P = 0.02) and female sex (OR = 1.99, 95% CI 1.36 to 2.90; P < 0.01)]. Some climate data showed statistically significant differences (P < 0.05) between participants with DED and non-DED (mean wind gusts; atmospheric pressure; mean and minimum relative humidity); these variables did not significantly increase DED risk (OR close to 1.0 and P > 0.05).

CONCLUSION

This study is the first to describe the impact of climate data on dryness symptomatology in Spain, confirming that participants who live in locations with RH <70% have a higher prevalence (corrected for age and sex) of DED. These findings support the use of climate databases in DED research.

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.

Dealing with the Persistent Pathogenic Issues of Dry Eye Disease: The Importance of External and Internal Stimuli and Tissue Responses

The immune system plays a central role in protecting the ocular surface from exogenous and endogenous insults, maintaining tissue homeostasis thanks to the mechanism of para-inflammation. This physiological adaptive response may induce resident macrophages/monocytes to produce cytokines and growth factors in order to promote epithelial cell recovery. In case of well-controlled para-inflammation, caused by a low amount of stress, cell viability and function are maintained. When stress becomes too intense, there is a response characterized by the activation of autophagic pathways and consequent cell death. Dysregulated homeostasis and chronic sub-clinical inflammation are the starting points for the development of a stable, chronic inflammatory disease, which leads to ocular surface damage, and, in turn, to the onset or progression of chronic dry eye disease (DED). The long-term management of DED should consider all of the pathogenic issues involved in the disease, including the control of persistent external or internal stresses that are capable of activating and maintaining the para-inflammatory adaptive mechanisms, potentially leading to full-blown inflammation. Dysregulated para-inflammation can be corrected by means of the prolonged use of tear substitutes containing minimal doses of safe corticosteroids or other anti-inflammatory molecules (e.g., corticosteroid, cyclosporine) in order to re-equilibrate ocular surface homeostasis.

Assessment of risk factors on eye dryness in young adults using visual display device in both contact lens wearers and non-wearers

PURPOSE

Researchers are interested in examining the impact of visual display devices (VDDs) on the development of dry eye illness because their use is becoming more common among college students. The goal of this study was to see if there was a link between certain risk factors and the development of eye dryness in VDDs using young adults who wore contact lenses and those who did not.

METHODS

The self-administrated survey was hosted in Google Forms, sent via e-mail to the participants. It consisted of two parts of assessing different risk factors (i.e., environmental conditions, angle of gaze, and years of VDD use) with contact lens use and Ocular Surface Disease Index (OSDI) questionnaire. The OSDI scores of the entire sample who suffer from dry eye and the subgroup using contact lenses were calculated. The relationship between different risk factors with the OSDI scores was also assessed.

RESULTS

A total of 274 young adults from college students and academic staff (216 female, 58 male) were suffering from eye dryness. Eighty-eight of the 274 participants wore contact lenses. The mean OSDI scores of the 274 young adults were 32.92. Mean OSDI scores in contact lens wearers and non-wearers were 34.36 and 32.24, respectively (p < 0.01). There was a statistically significant relationship between OSDI score and indoor environmental conditions in computer using VDD group. Using a computer in a dark environment and above the line of sight resulted in a higher OSDI scores. Females who wore contact lenses while using a computer for more than three years had significantly higher OSDI scores than non-wearer females. Tablet type VDD use increased the mean ODSI scores of the contact lens wearers significantly.

CONCLUSIONS

Dry eye symptoms were shown to be increased in the contact lens wearer group with the increased duration of computer VDD use, decreased indoor environmental brightness conditions, and above the line of sight.

Seasonal variations in presenting symptoms and signs of dry eye disease in Norway

The study investigated the seasonal variations of presenting symptoms and signs of dry eye disease (DED) in Norway. 652 consecutive DED patients examined between August 2012 and May 2015 in Oslo, Norway, were included. Presenting symptoms and signs were related to the season according to when each patient was examined. Weather report data from the examination day were compared with the presenting symptoms and signs. Oslo's mean seasonal temperatures during spring, summer, fall, and winter were 6.4 °C, 15.6 °C, 9.3 °C, and - 2.1 °C, respectively. Dry eye severity level and self-reported symptoms measured by the Ocular surface disease index questionnaire did not differ between seasons. Schirmer I was lower during summer than in other seasons (P < 0.01). The percentage of patients with a pathological tear meniscus height (< 0.2 mm) was higher during fall (P < 0.01) and lower during winter (P < 0.05) compared to the other seasons. Signs and symptoms of DED generally did not correlate with weather report data, although intraocular pressure was weakly associated with mean daily air temperature (r = - 0.22; P < 0.001). Neither dry eye severity level nor dry eye symptoms differ between seasons in Oslo, Norway. However, some parameters for assessing DED show seasonal variations (Schirmer I and tear meniscus height), which are essential to consider when examining patients with DED.

Association between dry eye disease and depression: An umbrella review

Purpose

This umbrella review aimed to summarize the available evidence on the association between dry eye disease and depression.

Methods

We searched the Pubmed, Embase, and Cochrane databases using the search string "(Dry eye syndrome OR Keratoconjunctivitis sicca OR KCS OR Aqueous tear deficiency OR Sjogren syndrome) AND (depression OR depressive symptoms) AND (meta-analysis OR systematic review)" from inception to 20 July 2022. We considered all meta-analyses investigating the association between dry eye disease and depression.

Results

After summarizing the included meta-analyses, it was concluded that dry eye disease is associated with depression. The symptoms of dry eye disease affect the daily lives of patients, thus affecting their mood. However, further evidence is required to confirm this association.

Conclusion

This finding highlights the importance of psychological support for patients with dry eye disease. Future clinical studies should investigate the mechanism underlying the association between dry eye disease and depression.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022320619.

The Management of Dry Eye Disease: Proceedings of Italian Dry Eye Consensus Group Using the Delphi Method

Dry eye disease (DED) is a highly prevalent, chronic and progressive condition that affects 5-33% of the world's adult population [...].

Clinical association between trace elements of tear and dry eye metrics

Trace elements exposure is proposed to play a role in the pathogenesis of the systemic disease. Emerging studies have suggested that trace metal exposure may contribute to dry eye disease. Our study primarily aimed to investigate the association between trace metal exposure in tear samples and the presence of dry eye metrics in the shipyard industry. Overall, 84 eligible participants from the shipyard industry were included in this cross-sectional study. The parameters for identifying dry eye symptoms included O.S.D.I., SPEED, N.I.B.U.T., and ocular surface conditions, such as tear meniscus height, eye blinking, and meibomian gland area were performed by S.B.M. sistemi ocular surface analyzer. The concentration of tear trace elements was detected by inductively coupled plasma mass spectroscopy (ICP-MS). The association between tear trace elements and dry eye parameters was investigated using regression models. Participants in the exposure group had significantly higher levels of tear Pb than the control group. In the exposure group, tear Pb was significantly associated with increased SPEED and O.S.D.I. score with beta coefficients of 0.144 (95% CI 0.092, 0.197), 0.121 (95% CI 0.049, 0.194), respectively, and decreased lower and upper meibomian gland area with beta coefficients of - 0.158 (- 0.283, - 0.033) and - 0.228 (- 0.396, - 0.061), respectively. Tear trace elements exposure is considered to impact the appearance of dry eye metrics. Improving the occupational environment and monitoring the ocular surface health may benefit workers under exposure to trace elements.

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.

Effect of facemasks on the tear film during the COVID-19 pandemic

PURPOSE

To evaluate the effect of wearing facemasks on dry eye symptoms and on the tear film while comparing surgical face masks to N95 particulate respirators.

METHODS

A prospective observational study was conducted at Ain Shams University Hospitals in the period from September 2020 to January 2021. Two hundred volunteers were recruited, and the daily number of hours spent by each participant wearing a facemask was recorded. Recruits were divided into two groups: 100 volunteers were allocated to Group A to use the surgical mask, and 100 participants to Group B to use the N95 particulate respirator. The tear film parameters were assessed at baseline by answering the Ocular Surface Disease Index (OSDI) questionnaire and performing tear break-up time (TBUT), corneal fluorescein staining, and Schirmer-I test Subjects then wore a facemask for 60 min and then the tear film parameters were reassessed by repeating TBUT, corneal staining and Schirmer-I test.

RESULTS

Facemask use for 60 min significantly worsened all tear film parameters in both groups (P-value <0.0001). The deterioration was significantly larger in Group A subjects (P < 0.0001). The daily number of hours spent wearing a facemask correlated strongly with the OSDI and corneal staining. There was a strong negative correlation between the daily number of hours spent wearing a facemask and Schirmer test, and a weak negative correlation with TBUT.

CONCLUSIONS

Wearing facemasks during the COVID-19 pandemic is a risk factor for worsening tear film parameters. This deterioration is significantly greater with surgical masks than with N95 particulate respirators and increases with the duration of facemask use.

Evaluation of safety and anti-obesity effects of DWP16001 in naturally obese dogs

Background

The aim of this study was to investigate the anti-obesity effects of DWP16001, a sodium-glucose cotransporter-2 (SGLT2 inhibitor), in naturally obese dogs. A total of 20 dogs were divided into four equal groups: one obese control (OC group), and three treated groups; DWP0.2 group, DWP0.5 group, and DWP1 group. OC group fed with food for maintenance and treated groups were fed with food for maintenance with 0.2 mg/kg DWP16001, 0.5 mg/kg DWP16001 and 1 mg/kg DWP16001, respectively. The food for maintenance was provided to dogs as 2 RER (Resting energy requirement) in kcal and DWP16001-supplemented food was administered once a day for 8 weeks.

Results

Body condition score, body weight, and fat thickness were significantly reduced (P < 0.05) in the DWP0.2 group compared with the OC group, respectively without affecting the food consumption. At the 10^th week the food consumption rate was 101.35 ± 2.56, 166.59 ± 4.72, 98.47 ± 1.44 and 123.15 ± 2.45% compared with initial food consumption rate. Body fat percentage, chest and waist circumference, blood glucose, and insulin were reduced compared to OC group but not significantly different from those of the OC group during experimental period. Serum alanine aminotransferase, alkaline phosphatase, creatine phosphokinase, and creatinine were significantly reduced in DWP0.2 group on 8 weeks. Serum cholesterol and triglycerides were reduced but not significantly. No specific adverse effects were observed throughout the experiment, and hematological parameters were unchanged. The results indicate that DWP16001 was not harmful to the dogs in our study and might have anti-obesity effects in naturally obese dogs.

Conclusions

The above results and discussion suggest that DWP16001 is safe and might have anti-obesity effects in naturally obese dogs.

Dry eye syndrome: comprehensive etiologies and recent clinical trials

Dry eye syndrome (DES) is multifactorial and likely to be a cause of concern more so than ever given the rapid pace of modernization, which is directly associated with many of the extrinsic causative factors. Additionally, recent studies have also postulated novel etiologies that may provide the basis for alternative treatment methods clinically. Such insights are especially important given that current approaches to tackle DES remains suboptimal. This review will primarily cover a comprehensive list of causes that lead to DES, summarize all the upcoming and ongoing clinical trials that focuses on treating this disease as well as discuss future potential treatments that can improve inclusivity.

Attrition und Osmokinetik – Zwei Konzepte zur Pathogenese des Trockenen Auges

Die neuen Erkenntnisse der Pathophysiolgie des Trockenen Auges erkennen das Zusammenspiel von Tränen, Augenoberfläche und Lidoberfläche als eine funktionelle Einheit an. Der Begriff der Benetzungsfähigkeit der Tränen in Abhängigkeit der mikrotektonischen Anatomie der Augenoberfläche relativiert die Anforderungen an Träne und Tränenersatzmittel. Das Model der Attrition, welches die Effekte der friktionsneutralisierenden Kapazität des Tränenfilms, der Reibung und die Bedeutung der Mechanotransduktionskapazität des Epithels zusammenfasst, wird eingeführt und dessen pathophysiologische Bedeutung erläutert. Attrition und Benetzung bestimmen zusammen grundlegende pathophysiologische Vorgänge in der Augenoberfläche wie Aktivierung von Nerven (subjektive Beschwerden) sowie Entzündung und beeinflussen damit die Dynamik der Pathophysiologie, und den Übergang von vorübergehenden Beschwerden zu einer manifesten Erkrankung des Trockenen Auges. Die Betrachtung der Osmolarität als numerischer statischer Grenzwert zur alleinigen Diagnose des Trockenen Auges ist klinisch nicht haltbar. Das neue, dynamische Model der Osmokinetik, zeigt dagegen eine Alternative auf, in der die Tageschwankungen und die Beachtung des durchschnittlichen Osmolaritätsniveaus gröβere Bedeutung gewinnen und damit der eigentlichen pathophysiologischen Bedeutung der Osmolarität gerechter wird.

The Enduring Experience in Dry Eye Diagnosis: A Non-Interventional Study Comparing the Experiences of Patients Living With and Without Sjögren's Syndrome

INTRODUCTION

Previous studies have examined the patient experience regarding the diagnosis and management of dry eye disease (DED). The current study explored the ways in which the DED diagnostic pathway differs for those living with and without Sjögren's syndrome (SS), to identify aspects that influence the patient experience and associated quality of life (QoL).

METHODS

An observational/descriptive, non-interventional, retrospective, self-reported online survey was conducted among adults living in France, Spain and Italy who were diagnosed with DED (with/without SS), were using topical DED treatments (≥ 6 months), and were not contact lens users. Recruitment was via an online database for non-SS participants and through local patient advocacy groups for SS respondents.

RESULTS

The analysis included 827 respondents; 416 (50.3%) had SS and 82% were female. The mean age was 55 (SD 11; range 16-99) years. The mean age at diagnosis was 46 (SD 12; range 13-78) years and 50 (SD 10; range 21-73) years for SS and non-SS groups, respectively (p < 0.0001). The mean time to diagnosis was extended for SS participants [32 (SD 62) months] versus non-SS individuals [8.6 (SD 28) months (p < 0.0001)] and was associated with reduced QoL scores (r = 0.113; p = 0.0169). More SS participants (31%) consulted ≥ 4 healthcare professionals (HCPs) before DED diagnosis, versus non-SS individuals (6%) (p < 0.0001). Diagnosing clinician varied for SS respondents according to country, probably due to differences in healthcare systems/structures. More SS participants viewed their condition as a handicap than a discomfort, reporting greater QoL impact (p < 0.0001).

CONCLUSIONS

Patient experiences in DED diagnosis vary substantially when comparing SS and non-SS individuals. Time to diagnosis significantly impacts QoL for SS patients, who see more HCPs ahead of DED diagnosis. The number of HCPs consulted before diagnosis and perceptions of DED are important for both groups. Country-specific variations highlight opportunities to improve consistency and efficiency across DED diagnostic pathways. These data should be considered alongside existing evidence from high-quality sources (e.g. clinical records).

Modern approach to the treatment of dry eye, a complex multifactorial disease: a P.I.C.A.S.S.O. board review

Dry eye disease (DED) is a growing public health concern affecting quality of life and visual function, with a significant socio-economic impact. It is characterised by the loss of homoeostasis, resulting in tear film instability, hyperosmolarity and inflammation of the ocular surface. If the innate immune response is unable to cope with internal bodily or environmental adverse conditions, the persistent, self-maintaining vicious circle of inflammation leads to the chronic form of the disease. Treatment of DED should be aimed at the restoration of the homoeostasis of the ocular surface system. A proper diagnostic approach is fundamental to define the relevance and importance of each of the DED main pathogenic factors, namely tear film instability, epithelial damage and inflammation. Consideration also needs to be given concerning two other pathogenic elements: lid margin changes and nerve damage. All the factors that maintain the vicious circle of DED in the patient's clinical presentation have to be considered and possibly treated simultaneously. The treatment should be long-lasting and personalised since it has to be adapted to the different clinical conditions observed along the course of the disease. Since DED treatment is frequently unable to provide fast and complete relief from symptoms, empathy with patients and willingness to explain to them the natural history of the disease are mandatory to improve patients' compliance. Furthermore, patients should be instructed about the possible need to increase the frequency and/or change the type of treatment according to the fluctuation of symptoms, following a preplanned rescue regimen.

Association between ambient temperature, particulate air pollution and emergency room visits for conjunctivitis

BACKGROUND

Numerous studies have confirmed the association of ambient temperature and air pollution with a higher risk of morbidities, yet few have addressed their effect on the ocular system. The purpose of this study was to assess the association between temperature, air pollution, and emergency room visits for conjunctivitis.

METHODS

In this case-crossover study, the records of all emergency room visits to Soroka University Medical Center (SUMC) from 2009 to 2014 were reviewed for patients with conjunctivitis. Daily exposure to fine and coarse particulate matter and temperature were determined by a hybrid model involving satellite sensors. Mean relative humidity was obtained from the Ministry of Environmental Protection meteorological monitoring station located in Beer-Sheva.

RESULTS

Six hundred one patients were diagnosed with conjunctivitis in the SUMC emergency room. We discovered a positive association between temperature increments and incidence of conjunctivitis. The strongest effect was found during summer and autumn, with an immediate (lag0) incidence increase of 8.1% for each 1 °C increase in temperature (OR = 1.088, 95%CI: 1.046-1.132) between 24 and 28 °C in the summer and 7.2% for each 1 °C increase in temperature (OR = 1.072, 95%CI: 1.036-1.108) between 13 and 23 °C in the autumn. There was no statistically significant association between fine and coarse particulate matter and conjunctivitis incidence.

CONCLUSION

Temperature increases during summer and autumn are significantly associated with an increased risk of conjunctivitis. Conjunctivitis is not associated with non-anthropogenic air pollution. These findings may help community clinics and hospital emergency rooms better predict conjunctivitis cases and will hopefully lead to improved prevention efforts that will lower the financial burden on both the individual and the public.

Impact of Air Pollution and Weather on Dry Eye

Air pollution has broad effects on human health involving many organ systems. The ocular surface is an excellent model with which to study the effects of air pollution on human health as it is in constant contact with the environment, and it is directly accessible, facilitating disease monitoring. Effects of air pollutants on the ocular surface typically manifest as dry eye (DE) symptoms and signs. In this review, we break down air pollution into particulate matter (organic and inorganic) and gaseous compounds and summarize the literature regarding effects of various exposures on DE. Additionally, we examine the effects of weather (relative humidity, temperature) on DE symptoms and signs. To do so, we conducted a PubMed search using key terms to summarize the existing literature on the effects of air pollution and weather on DE. While we tried to focus on the effect of specific exposures on specific aspects of DE, environmental conditions are often studied concomitantly, and thus, there are unavoidable interactions between our variables of interest. Overall, we found that air pollution and weather conditions have differential adverse effects on DE symptoms and signs. We discuss these findings and potential mitigation strategies, such as air purifiers, air humidifiers, and plants, that may be instituted as treatments at an individual level to address environmental contributors to DE.

The HYLAN M Study: Efficacy of 0.15% High Molecular Weight Hyaluronan Fluid in the Treatment of Severe Dry Eye Disease in a Multicenter Randomized Trial

The aim of the HYLAN M study was to investigate if symptoms and/or signs of patients suffering from severe dry eye disease (DED) can be improved by substituting individually optimized artificial tear therapy by high molecular weight hyaluronan (HMWHA) eye drops. In this international, multicenter study, patients with symptoms of at least ocular surface disease index (OSDI) 33 and corneal fluorescein staining (CFS) of at least Oxford grade 3 were included. A total of 84 per-protocol patients were randomized in two study arms. The control group continued to use their individual optimum artificial tears over the study period of eight weeks; in the verum group, the artificial tears were substituted by eye drops containing 0.15% HMWHA. At the week 8 visit, the average OSDI of the verum group had improved by 13.5 as compared to the control group (p = 0.001). The best corrected visual acuity (BCVA) had improved by 0.04 logMAR (p = 0.033). CFS, tear film break-up time (TBUT), Schirmer I, lid wiper epitheliopathy (LWE), mucocutaneous junction (Yamaguchi score), and tear osmolarity were not significantly different between the verum and control groups (p > 0.050). We conclude that for most patients with severe DED, 0.15% HMWHA eye drops provide excellent improvement of symptoms without impairment of dry eye signs.

Dry Eye Disease: Early Recognition with Guidance on Management and Treatment for Primary Care Family Physicians

Primary care presentations of dry eye disease (DED) are common and pose a diagnostic challenge due to the variety of symptoms and the absence of certainty for family practitioners. While there are many published articles on the topic, the 2017 Tear Film and Ocular Surface Society Dry Eye Workshop was a landmark report in distinguishing multifactorial differences. Redefined terms clarified the DED disorder. The ocular surface—the tear/air interface—is the primary refractive component of the eye, which is why DED is so significant and impacts vision. There is a high prevalence of DED in the community, ranging from 5% to 30% of people across multiple studies. Elderly patients have up to 75% increased risk of DED and receive more intensive treatment than younger age groups. DED is also more common in women than men, occurring in 9.8% of postmenopausal women. The causes of DED span defective lacrimal apparatus and systemic disorders. Despite its prevalence, up to one-half of patients with confirmed DED do not receive proper alleviating treatment. Risk factors on functional and environmental bases follow. Tools to elicit a diagnosis more confidently are outlined using the Ocular Surface Disease Index (OSDI) and the Symptom Assessment in Dry Eye questionnaires (SANDE). Lacritin, lutein, vitamin A, and balanced nutrition are essential contributors to maintaining healthy eyes with appropriate management and treatment. The authors hope that this paper will prompt a more accurate and expedient diagnosis of DED in primary care practice and an earlier recognition of specialist referrals.

Dry eye disease (DED) poses a diagnostic challenge to primary care physicians. The condition involves the tear/air interface, at the corneal (ocular) surface, where light enters the eye. Any change in light refraction affects regular sight. Symptoms of DED include itching, grittiness, foreign body sensation, redness, excessive tearing, and visual blurring, the lattermost being the most common presentation. Ultimately, the untreated disease leads to continued discomfort and visual deficit, but when severe, it can result in blindness. Up to 30% of the population suffers from DED, with the elderly, particularly women, more affected. Unfortunately, up to 50% of those affected have inadequate treatment. Questionnaires help in diagnosis. Simple office tests can indicate the severity of eye problems. Technology with smartphone photography can take high-resolution images, which are useful in education and teaching. A multitude of conditions cause DED, including blepharitis, an infection of the eyelids. Environmental risks also abound. Proper nutrition is essential in maintaining eye health. Intermittent eye symptoms are likely to be underrated by the public, by purchasing over-the-counter products such as artificial tears rather than seeking a proper medical check. Newer prescription medications are now available for DED relief before advancing to debility requiring specialist treatment.

Tear Break-Up Time and Seasonal Variation in Intraocular Pressure in a Japanese Population

PURPOSE

To evaluate seasonal variation in intraocular pressure (IOP) with and without short tear break-up time (SBUT, BUT ≤5 s) since dry eye and IOP are known to have seasonal variation.

METHODS

This study enrolled 176 patients who visited one of six eye clinics, in Japan, four times for IOP measurement, in every season. The mean patient age was 67.9 years, including 79 males. Participants were divided into four groups based on the presence of glaucoma and/or SBUT and we compared the seasonal variation in IOP (winter and summer) among the four groups.

RESULTS

The IOP (mmHg) in winter and summer, respectively, was 12.8 ± 3.7 and 12.8 ± 3.1 for non-glaucoma patients without SBUT (n = 47, p = 0.964), 14.8 ± 3.4 and 13.3 ± 3.4 for non-glaucoma patients with SBUT (n = 57, p < 0.001), 14.3 ± 3.2 and 14.1 ± 3.4 for glaucoma patients without SBUT (n = 36, p = 0.489), and 13.3 ± 3.0 and 11.6 ± 2.9 for glaucoma with SBUT (n = 36, p < 0.001). Seasonal variation was largest across the seasons in the glaucoma with the SBUT group, and the magnitude of seasonal variation correlated with BUT (β = 0.228, p = 0.003).

CONCLUSIONS

Seasonal variation tended to be larger in patients with SBUT than those without SBUT.

Epidemiological profile and north–south gradient driving baseline systemic involvement of primary Sjögren’s syndrome

Objective

To characterize the systemic phenotype of primary Sjögren’s syndrome at diagnosis by analysing the EULAR-SS disease activity index (ESSDAI) scores.

Methods

The Sjögren Big Data Consortium is an international, multicentre registry based on worldwide data-sharing cooperative merging of pre-existing databases from leading centres in clinical research in Sjögren’s syndrome from the five continents.

Results

The cohort included 10 007 patients (9352 female, mean 53 years) with recorded ESSDAI scores available. At diagnosis, the mean total ESSDAI score was 6.1; 81.8% of patients had systemic activity (ESSDAI score ≥1). Males had a higher mean ESSDAI (8.1 vs 6.0, P &lt; 0.001) compared with females, as did patients diagnosed at &lt;35 years (6.7 vs 5.6 in patients diagnosed at &gt;65 years, P &lt; 0.001). The highest global ESSDAI score was reported in Black/African Americans, followed by White, Asian and Hispanic patients (6.7, 6.5, 5.4 and 4.8, respectively; P &lt; 0.001). The frequency of involvement of each systemic organ also differed between ethnic groups, with Black/African American patients showing the highest frequencies in the lymphadenopathy, articular, peripheral nervous system, CNS and biological domains, White patients in the glandular, cutaneous and muscular domains, Asian patients in the pulmonary, renal and haematological domains and Hispanic patients in the constitutional domain. Systemic activity measured by the ESSDAI, clinical ESSDAI (clinESSDAI) and disease activity states was higher in patients from southern countries (P &lt; 0.001).

Conclusion

The systemic phenotype of primary Sjögren’s syndrome is strongly influenced by personal determinants such as age, gender, ethnicity and place of residence, which are key geoepidemiological players in driving the expression of systemic disease at diagnosis.

TRPV1 activity and substance P release are required for corneal cold nociception

As a protective mechanism, the cornea is sensitive to noxious stimuli. Here, we show that in mice, a high proportion of corneal TRPM8⁺ cold-sensing fibers express the heat-sensitive TRPV1 channel. Despite its insensitivity to cold, TRPV1 enhances membrane potential changes and electrical firing of TRPM8⁺ neurons in response to cold stimulation. This elevated neuronal excitability leads to augmented ocular cold nociception in mice. In a model of dry eye disease, the expression of TRPV1 in TRPM8⁺ cold-sensing fibers is increased, and results in severe cold allodynia. Overexpression of TRPV1 in TRPM8⁺ sensory neurons leads to cold allodynia in both corneal and non-corneal tissues without affecting their thermal sensitivity. TRPV1-dependent neuronal sensitization facilitates the release of the neuropeptide substance P from TRPM8⁺ cold-sensing neurons to signal nociception in response to cold. Our study identifies a mechanism underlying corneal cold nociception and suggests a potential target for the treatment of ocular pain.

The eye shows protective responses to noxious stimuli including cold. Here, the authors show that TRPV1, found co-expressed on TRPM8 + fibres in the cornea, is necessary for cold nociception in the eye.

Influence of Sociodemographic Factors on Disease Characteristics and Vision-related Quality of Life in Primary Open-angle Glaucoma Patients: The Italian Primary Open Angle Glaucoma Study (IPOAGS)

PURPOSE

The purpose of this article was to evaluate the potential association between sociodemographic factors with clinical characteristics, vision-related quality of life (QoL), and glaucoma-related symptoms scores in a large cohort of primary open-angle glaucoma patients.

MATERIALS AND METHODS

Multicenter, cross-sectional study involving academic and nonacademic centers. Previously diagnosed primary open-angle glaucoma patients aged >18 years were enrolled. At baseline, information on demographic characteristics, social, medical and ocular history, clinical presentation and treatments was collected. Vision-related QoL was evaluated by means of the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25), while glaucoma-related symptoms were evaluated using the Glaucoma Symptom Scale (GSS) questionnaire. The associations between sociodemographic factors with clinical characteristics (mean deviation, pattern standard deviation, best-corrected visual acuity), NEI-VFQ-25, and GSS scores were evaluated by means of univariate and multivariate general linear models.

RESULTS

A total of 3227 patients were enrolled. Older age and male sex were significantly associated with lower mean deviation (P<0.01) and higher pattern standard deviation (P<0.01), whereas older age was associated with lower best-corrected visual acuity (P<0.01). The composite GSS score was related to age (P=0.02), sex (P<0.01), employment (P=0.01), and profession (P=0.04), while the total NEI-VFQ-25 score was associated with sex (P<0.01), marital status (P=0.02), and employment (P=0.02).

CONCLUSIONS

Age and sex were significantly associated with almost all indicators of glaucoma severity at baseline. Other variables, such as employment, profession, and marital status were significantly associated with vision-related QoL scores.

Global Associations of Air Pollution and Conjunctivitis Diseases: A Systematic Review and Meta-Analysis

(1) Background: As the most common eye disease diagnosed in emergency departments, conjunctivitis has caused serious health and economic burdens worldwide. However, whether air pollution may be a risk factor for conjunctivitis is still inconsistent among current evidence. (2) Methods: We searched the literature on the relationship between air pollution and conjunctivitis in multiple English databases before 18 March 2019. Meta-analysis, meta-regression, and funnel plots were used to integrate the data, identify the sources of bias, and determine the publication bias, respectively. (3) Results: A total of 2450 papers were found, 12 of which were finally included. The pooled relative risk for each 10 μg/m³ increase of air pollution on conjunctivitis was 1.0006 (95%CI: 0.9993–1.0019) for CO, 1.0287 (1.0120–1.0457) for NO₂, 1.0089 (1.0030–1.0149) for O₃, 1.0004 (0.9976–1.0032) for PM_2.5, 1.0033 (0.9982–1.0083) for PM₁₀, and 1.0045 (0.9908–1.0185) for SO₂. In the subgroup, PM_2.5 and O₃ had a greater impact on conjunctivitis risk in women than in men, and people <18 years old than those ≥18 years old. Relative humidity significantly modified the risk of O₃ on conjunctivitis (p = 0.023), explaining 45% of the between-study heterogeneity. (4) Conclusion: Globally, air pollution has considerable health risks for conjunctivitis. Females and the youth were more vulnerable to PM_2.5, NO₂, and O₃. Reductions of air pollution levels are still warranted to protect the vulnerable populations.

Osmokinetics: A new dynamic concept in dry eye disease

INTRODUCTION

Tear fluid osmolarity has been increasingly accepted as an accessible parameter in the diagnosis of ocular surface and dry eye disease. After having been proposed as the gold standard, recent results have put this into question. However, the most recent guidelines for dry eye disease identify specific values of osmolarity as thresholds to help to differentiate between various stages of severity of ocular surface disease. The limits of this approach were investigated to propose a new concept, that of osmokinetics.

MATERIALS AND METHODS

Available data on tear fluid osmolarity in normal and diseased eyes were compared. The possibility of normo-osmolar dry eye was investigated and repeated measurements of osmolarity performed.

RESULTS

The currently applied static model of a threshold value of osmolarity for diagnosing dry eye disease is apparently insufficient. Not only does it not take into account normo-osmolar dry eye, but it also applies too much significance to a single parameter. Instead, it was found that there is a daily variation in osmolarity (DVO), which appears to be higher in eyes with tear film deficiencies than in healthy eyes.

DISCUSSION

Tear film osmolarity does vary considerably throughout the day. Its value should be considered in a kinetic model taking into account the dynamics of osmolarity changes moreso than the current static model. The terms of osmotic stress and diurnal variation of osmolarity were found to offer a more physiological understanding of osmolarity.

CONCLUSION

A more dynamic model for osmolarity is presented in which not the value itself but the daily variation of osmolarity is identified. It is suggested that the amplitude of change in osmolarity over the course of a day or even shorter time periods could play a decisive role as a stress factor for the surface cells. The varying osmolar stress could be one of the key mechanisms leading to the cell death, inflammation, apoptosis, and goblet cell disappearance as observed in dry eye disease. Perhaps it is the mean osmolarity level at which these changes occur together with the magnitude of DVO which could identify the level of severity of dry eye disease.

Efficacy and safety of 0.1% ciclosporin A cationic emulsion in dry eye disease: a pooled analysis of two double-masked, randomised, vehicle-controlled phase III clinical studies

BACKGROUND/AIM

To assess the treatment effect of 0.1% ciclosporin A cationic emulsion (CsA CE) versus vehicle on signs/symptoms of dry eye disease (DED) in various subgroups (moderate-to-severe DED/severe DED/Sjögren's syndrome (SS)/SS with severe DED).

METHODS

Pooled data were analysed from two similar phase III studies: SICCANOVE (moderate-to-severe DED) and SANSIKA (severe DED with severe keratitis). In both studies, patients aged ≥18 years received CsA CE 0.1% (n=395) or vehicle (n=339) once daily for 6 months. A composite responder efficacy endpoint (corneal fluorescein staining-Ocular Surface Disease Index (CFS-OSDI) at month 6) was used to evaluate the efficacy of CsA CE in alleviating signs/symptoms of DED (response defined as improvement of ≥2 grades in CFS and ≥30% in OSDI (baseline to month 6)). Human leucocyte antigen-DR (HLA-DR) conjunctival expression was used as a biomarker of ocular surface inflammation.

RESULTS

CsA CE-treated patients were significantly more likely to be CFS-OSDI responders than vehicle-treated patients in the overall (OR 1.66, 95% CI 1.11 to 2.50; P=0.015), severe DED (1.80, 1.04 to 3.19; P=0.038) and SS with severe DED (3.37, 1.20 to 11.19; P=0.030) populations. The difference was not significant for CsA CE versus vehicle for the overall Sjögren's population (OR 1.77, CI 0.89 to 3.66; P=0.109). CsA CE also significantly reduced median HLA-DR expression versus vehicle at 6 months (P=0.002).

CONCLUSION

Pooled phase III data indicate CsA CE produced significant improvement in signs/symptoms versus vehicle in patients with moderate-to-severe DED (especially in those with severe keratitis), including patients with SS with severe DED.

Impact of seasonal variation in meteorological conditions on dry eye severity

Purpose

To compare dry eye (DE) diagnosis patterns by season in Miami vis-a-vis the US and examine differences in DE symptoms and signs by season in Miami.

Patients and methods

US veteran affairs (VA) patient visits with ICD-9 codes for DE (375.15) and routine medical examination (V70.0) from 2010 to 2013 were retrospectively analyzed to evaluate the seasonal pattern of DE diagnosis. A total of 365 patients with normal ocular anatomy were prospectively recruited from the Miami VA eye clinic from 2014 to 2016 for the assessment of symptoms and signs.

Results

While DE visit prevalence in Miami was about 10% lower than that of the rest of the country (22.5% vs 33.7%), Miami had roughly four times higher variability in DE visit prevalence throughout the year than the US. Peak values for DE symptoms in the Miami cohort aligned with peak DE prevalence seen in the retrospective sample, occurring in spring and fall. A similar, but less dramatic, pattern was noted with DE signs. The seasonal pattern in DE symptoms remained even after controlling for confounders including demographics and medication use.

Conclusion

DE symptoms, and to a lesser degree signs, varied by month, with the highest severity of symptoms occurring in spring and fall, which corresponded with peak allergy season and weather fluctuations, respectively. These findings have important implications for season-specific diagnosis, treatment, and management of DE.

Dry eye disease and oxidative stress

Dry eye, an age-related condition, is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance and tear film instability. Environmental factors are also often implicated in dry eye including exposure to pollutants, ultraviolet (UV) radiation and ozone as well as the chronic use of preserved eyedrops such as in the treatment of glaucoma. These factors increase oxidative stress and ocular surface inflammation. Here, we reviewed the cellular, animal and clinical studies that point to the role of oxidative stress in dry eye disease. The biomarkers used to indicate oxidative damage in ocular surface tissues include 8-hydroxy-2 deoxyguanosine (8-OHdG), 4-hydroxynonenal (HNE) and malondialdehyde (MDD). Antioxidative defences in the ocular surface occur in the form of tear proteins such as lactoferrin and S100A proteins, and enzymes such as superoxide dismutase (SOD), peroxidase, catalase and mitochondrial oxidative enzymes. An imbalance between the level of reactive oxygen species (ROS) and the action of protective enzymes will lead to oxidative damage, and possibly inflammation. A small number of interventional studies suggest that oxidative stress may be directly targeted in topical therapy of dry eye treatment. For example, in vitro studies suggest that L-carnitine and pterostilbene, a blueberry component may reduce oxidative stress, and in animal studies, alpha-lipoic acid (ALP) and selenoprotein P may be helpful. Examples of treatments used in clinical trials include vitamin B12 eyedrops and iodide iontophoresis. With recent emphasis on ageing medicine and preventive holistic health, as well as the role of environmental science, research on oxidative stress in the ocular surface is likely to have increasing impact in the coming years.

Clinical impact of inflammation in dry eye disease: proceedings of the ODISSEY group meeting

Dry eye disease (DED) is a common, multifactorial ocular condition with major impact on vision and quality of life. It is now well recognized that the pathophysiology of chronic DED can include a cycle of inflammation involving both innate and adaptive immune responses. Recently, in vitro/in vivo models have been used to obtain a better understanding of DED‐related inflammatory processes at molecular/cellular levels although they do not truly reproduce the complex and chronic hallmarks of human DED. In clinical DED research, advanced techniques such as impression cytology, conjunctival biopsy, in vivo confocal microscopy and multiplex tear analyses have allowed an improved assessment of inflammation in DED patients. This was supported by the identification of reliable inflammatory markers including matrix metalloproteinase‐9, human leucocyte antigen‐DR or intercellular adhesion molecule‐1 in tears and impression cytology samples. One of the current therapeutic strategies focuses on breaking the inflammatory cycle perpetuating the ocular surface disease, and preclinical/clinical research has led to the development of promising anti‐inflammatory compounds. For instance, cyclosporine, already approved in the United States, has recently been authorized in Europe to treat DED associated with severe keratitis. In addition, other agents such as corticosteroids, doxycycline and essential fatty acids, through their anti‐inflammatory properties, show encouraging results. We now have a clearer understanding of the inflammatory processes involved in DED, and there is hope that the still emerging preclinical/clinical findings will be translated into new and highly effective therapies for patients in the near future.

Controlled Adverse Environment Chambers in Dry Eye Research

Dry eye disease (DED) is a common condition with signs and symptoms that vary depending on a wide range of environmental factors to which people are exposed in their daily lives. Factors such as variable temperature, airflow velocity, relative humidity, seasonality, and pollutants can alter the rate of tear film evaporation, improving or exacerbating symptoms of DED. Results from currently available clinical tests do not always correlate well with patient-reported symptoms, and the continually changing environment and variability in DED symptoms present challenges for the design and conduct of clinical trials. Controlled adverse environment chambers allow standardization of temperature, humidity, and airflow and may minimize potential confounding factors in clinical investigations. Their use can promote accurate study of the pathophysiology of DED, discovery of disease biomarkers, and assessment of the effect of various therapeutic approaches on patients' symptoms. Controlled adverse environment chambers have been used to simulate indoor surroundings such as airplane cabins and to test their effects on contact lens wearers. This review summarizes how these chambers may be useful for the development, approval, and differentiation of potential new treatments for DED.

Pregnancy probabilistically augments potential precursors to chronic, immune-mediated or autoimmune lacrimal gland infiltrates

PURPOSE

This study asked whether pregnancy, a risk factor for dry eye disease associated with both chronic, immune-mediated- and autoimmune etiologies, augments development of clusters of coordinately functioning cells (CCFC) that may be precursors to pathological lacrimal gland infiltrates.

METHODS

Lacrimal glands were from six virgin- and six term-pregnant rabbits of the same age and environmental exposure history. Seventy-two immune response-related gene transcripts were assayed by real time RT-PCR. Principal component (PC) analysis identified transcript signatures of CCFC contributing negative (^⊖) or positive (^⊕) PC loadings and determined gland PC projections, which reflect levels of CCFC development.

RESULTS

Three CCFC were of interest as potential precursors to pathological infiltrates. CCFC 1^⊖ was suggestive of an ectopic lymphoid structure with resting T cells and B cells. CCFC 1^⊕ was suggestive of an immune-mediated infiltrate with T_H1 cells and mature, cytotoxic B cells. CCFC 2^⊖ was suggestive of an ectopic lymphoid structure with activated T cells, mature B cells, germinal center, and plasmacytes. CCFC 4^⊖ and CCFC 5^⊖ also included plasmacytes. Pregnancy augmented CCFC 1^⊖ in some glands; augmented CCFC 1^⊕ in others; and augmented CCFC 2^⊖, CCFC 4^⊖, and CCFC 5^⊖ different combinations.

CONCLUSIONS

Potential precursors of pathological infiltrates form in the lacrimal glands by the time of sexual maturity. Pregnancy augments lacrimal gland plasmacyte populations, and it can augment development of potential precursors to either chronic, immune-mediated infiltrates or autoimmune infiltrates of various phenotypes. Systemic and strictly local, probabilistic phenomena interact with pregnancy to determine which combinatorial phenotypes are favored.

Possible association between subtypes of dry eye disease and seasonal variation

Purpose

The purpose of this study was to evaluate the influence of seasons on the signs and symptoms of dry eye disease (DED).

Methods

This is a cross-sectional, case-control study, and participants were non-DED subjects (n=1,916, mean age 54.4±14.4 years) and DED patients (n=684, 54.2±12.1 years) visiting six eye clinics at various practices and locations in Japan. We evaluated the signs and symptoms of DED and the seasons with the most severe results were compared to those with the least severe results in both groups. Main outcome measures were differences in the severity of the signs and symptoms of DED between the most and least severe seasons.

Results

The majority of DED symptoms were most severe during spring and least severe in summer. Significant differences between these two seasons were found for irritation (P=0.001), pain (P=0.007), blurring (P=0.000), and photophobia (P=0.007) in the DED group. Superficial punctate keratopathy (P=0.001) and tear break-up time (BUT; P=0.000) results also indicated that DED was most severe in spring. In contrast, fewer patients had low Schirmer test results in spring, although this was not statistically significant (P=0.061).

Conclusion

Our results demonstrated that the severity of DED is seasonal, which may explain the increase of short BUT-type DED cases observed in spring when air pollen counts are highest.

Seasonality and autoimmune diseases: The contribution of the four seasons to the mosaic of autoimmunity

Autoimmune diseases (ADs) are a heterogeneous groups of diseases that occur as a results of loss of tolerance to self antigens. While the etiopathogeneis remain obscure, different environmental factors were suggested to have a role in the development of autoimmunity, including infections, low vitamin D levels, UV radiation, and melatonin. Interestingly, such factors possess seasonal variation patterns that could influence disease development, severity and progression. Vitamin D levels which reach a nadir during late winter and early spring is correlated with increased disease activity, clinical severity as well as relapse rates in several disease entities including multiple sclerosis (MS), non-cutaneous flares of systemic lupus erythematosus (SLE), psoriasis, and rheumatoid arthritis (RA). Additionally, immunomodulatory actions of melatonin secretion ameliorate the severity of several ADs including MS and SLE. Melatonin levels are lowest during spring, a finding that correlates with the highest exacerbation rates of MS. Further, melatonin is postulated to be involved in the etiopathogenesis of inflammatory bowel diseases (IBD) through it influence on adhesion molecule and therefore transcription factor expression. Moreover, infections can mount to ADs through pro-inflammatory cytokine release and human antigen mimicry. Seasonal patterns of infectious diseases are correlated with the onset and exacerbation of ADs. During the winter, increased incidence of Epstein-Barr virus (EBV) infectious are associated with MS and SLE flares/onset respectively. In addition, higher Rotavirus infections during the winter precedes type 1 diabetes mellitus onset (T1DM). Moreover, Escherichia coli (E. coli) infection prior to primary biliary cirrhosis (PBC) and T1DM disease onset subsequent to Coxachievirus infections are seen to occur during late summer, a finding that correlate with infectious agents' pattern of seasonality. In this review, the effects of seasonality on the onset, relapses and activity of various ADs were discussed. Consideration of seasonal variation patterns of ADs can possibly provide clues to diseases pathogenesis and lead to development of new approaches in treatment and preventative care.