The effect of smoking on the ocular surface and the precorneal tear film

YAP O-GlcNAcylation contributes to corneal epithelial cell ferroptosis under cigarette smoke exposure

Cigarette smoke (CS) is an important indoor air pollutant associated with an increased risk of ocular surface disease. As the eye's outermost layer, the cornea is highly sensitive to air pollutants like CS. However, the specific mechanisms linking CS exposure to corneal dysfunction have not been fully elucidated. In the present study, we found that CS exposure damages corneal epithelial cells, accompanied by increased iron (Fe2+) levels and lipid peroxidation, both hallmarks of ferroptosis. Ferroptosis inhibitors, including Ferrostatin-1 (Fer-1) and Deferoxamine mesylate (DFO), protect against CS-induced cell damage. To understand the underlying mechanisms, we investigated how CS affects iron and lipid metabolism. Our results showed that CS could upregulate intracellular iron levels by increasing TFRC expression and promote lipid peroxidation by increasing ACSL4 expression. Silencing ACSL4 or TFRC expression prevented CS-induced ferroptosis. Furthermore, we found that the upregulation of TFRC and ACSL4 was driven by increased YAP transcription. Pharmacological or genetic inhibition of YAP effectively prevented corneal epithelial cell ferroptosis under CS stimulation. Additionally, our results suggest that CS exposure could increase O-GlcNAc transferase activity, leading to YAP O-GlcNAcylation. This glycosylation of YAP interfered with its K48-linked ubiquitination, resulting in YAP stabilization. Collectively, we found that CS exposure induces corneal epithelial cell ferroptosis via the YAP O-GlcNAcylation, and provide evidence that CS exposure is a strong risk factor for ocular surface disease.

Assessment of the prevalence and risk factors for dry eye symptoms among Romanian medical students using the ocular surface disease index - a cross-sectional study

BACKGROUND

This study aims to assess how Romanian medical students suffer from dry eye disease symptoms, establish the prevalence and severity of dry eye (DE) symptoms and identify potential risk factors.

METHODS

An analytical, cross-sectional study was conducted on students from "Carol Davila" University of Medicine, Romania, after the final examination period of July 2022. The OSDI score (Ocular Surface Disease Index©) was applied in an online survey. The study adopted the standards used by other authors, who defined symptomatic DED as an OSDI score greater than 12. The chi-square test was used to establish statistical significance at a cutoff value of p < 0.05. The predictive model was created using linear logistic regression analysis. The goodness of fit of the logistic regression model was assessed using the Hosmer-Lemeshow test. When the severity outcome had a nominal categorical form, multinomial regression analysis with normal subjects as a reference was performed. The distribution of the severe type of symptomatology across sex categories and years of study was analyzed using a nonparametric test (Independent-Samples Kruskal-Wallis Test).

RESULTS

A total of 274 answers were received from 81.4% females and 18.6% males with a response rate of 35.58%. The mean age was 22.7 years ± 1.66 with an age range between 20 and 25 years old. Using the OSDI score, we established that the overall prevalence of DE symptoms was 83.6% (95%CI: 79.6%, 88%), with an 85.2% (95%CI: 80.5%, 89.8%) prevalence in females and 76.5% (95%CI: 65%,88%) in males. The severe form of DE was the most prevalent, regardless of the study year or sex. Increased screen time (p-value < 0.05) and non-smokers (p-value < 0.05) were proven risk factors. The predictive model which includes the explanatory variables (sex, contact lens wearers, smoking, oral contraceptives, screen time) proved an 84.7% predictability for symptomatic DE and was able to better predict the dependent variable than the intercept model only (p-value < 0.05). Smoking (p = 0.002) and screen time (p = 0.009) preserved their significance in the multinominal regression as well.

CONCLUSIONS

This is the first study to report the epidemiology of DE symptoms among Romanian medical students. OSDI revealed a high prevalence of symptomatic DE in medical students. Screen time, although not the only factor, likely plays a role in exacerbating the disease. This information can be used to inform healthcare policies, establish occupational health guidelines, and implement preventive measures for individuals in similar high-stress academic or professional environments.

Prevalence of dry eye during the COVID-19 pandemic: A systematic review and meta-analysis

OBJECTIVE

During the COVID-19 pandemic, many people devoted longer time to screen viewing due to the need for study, work, and online social activities, instead of outdoor activities, which may have led to an increase in dry eye symptoms. This study aimed to evaluate the prevalence of dry eye during the COVID-19 pandemic.

METHODS

PubMed, Cochrane Library, Embase, and Web of Science were searched from January 1, 2020 to October 20, 2022. Cross-sectional surveys on dry eye prevalence conducted after January 1, 2020 were included. Two review authors independently performed data extraction and assessed study quality. The random-effects model was used to analyze the prevalence of dry eye, and the odds ratio was used to assess the strength of the association between variables. Subgroup analysis was performed to detect heterogeneity, the leave-one-out method for sensitivity analysis, and the Egger test for publication bias.

RESULTS

A total of eleven studies with 15692 individuals met the eligibility criteria. The prevalence of dry eye during the COVID-19 pandemic was 61.0% (95%CI: 51.8%-70.2%) globally and 56.7% (95%CI: 45.3%-68.1%) in Asia. The prevalence of dry eye had significant differences in sex and visual display time, with higher prevalence among females and visual display time of more than 4 hours per day. Subgroup analysis was performed based on diagnostic tools, study population, and average age. A significant difference was found in diagnostic tools, but no significant change in heterogeneity (P<0.05). The leave-one-out method showed stable results, and the Egger test identified no significant publication bias.

CONCLUSION

The prevalence of dry eye during the COVID-19 pandemic is significantly higher than before, and a higher prevalence is found among females and those having a visual display time of more than 4 hours per day.

TFOS lifestyle: Impact of societal challenges on the ocular surface

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

TFOS Lifestyle: Impact of lifestyle challenges on the ocular surface

Many factors in the domains of mental, physical, and social health have been associated with various ocular surface diseases, with most of the focus centered on aspects of dry eye disease (DED). Regarding mental health factors, several cross-sectional studies have noted associations between depression and anxiety, and medications used to treat these disorders, and DED symptoms. Sleep disorders (both involving quality and quantity of sleep) have also been associated with DED symptoms. Under the domain of physical health, several factors have been linked to meibomian gland abnormalities, including obesity and face mask wear. Cross-sectional studies have also linked chronic pain conditions, specifically migraine, chronic pain syndrome and fibromyalgia, to DED, principally focusing on DED symptoms. A systematic review and meta-analysis reviewed available data and concluded that various chronic pain conditions increased the risk of DED (variably defined), with odds ratios ranging from 1.60 to 2.16. However, heterogeneity was noted, highlighting the need for additional studies examining the impact of chronic pain on DED signs and subtype (evaporative versus aqueous deficient). With respect to societal factors, tobacco use has been most closely linked to tear instability, cocaine to decreased corneal sensitivity, and alcohol to tear film disturbances and DED symptoms.

Tobacco effects on ocular surface, meibomian glands, and corneal epithelium and the benefits of treatment with a lipid-based lubricant

PURPOSE

Our aim was to evaluate the ocular surface in chronic smokers and to assess the benefit of sodium hyaluronate (SH) versus semi-fluorinated alkane (SFA) eyedrops on tear film, meibomian glands, and corneal epithelial thickness (CET).

METHODS

This prospective randomized single-blinded study included smokers, who applied one eyedrop of Hyabak® on one eye (SH group) and one eyedrop of EvoTears® on the fellow eye (SFA group) 4 times daily for 2 months, and age-matched non-smokers. Ocular surface parameters, including tear film break-up time (TBUT) test and corneal fluorescein staining (CFS) score, lipid layer thickness (LLT), meibography (LipiView®), and CET measurements (Zeiss Cirrus HD-5000®), were assessed at baseline and after treatment.

RESULTS

Seventy-eight eyes were included in the smokers group (39 in the SH subgroup and 39 in the SFA subgroup) and 42 eyes in the control group. At baseline, the smokers group had a higher prevalence of dry eye (100% vs 0%, p < 0.001) and of meibomian gland dysfunction (MGD) and lower CET measurements than controls (p < 0.05). TBUT, CFS, and LLT (controls vs SFA group: 64.02 ± 1.87 nm vs 49.56 ± 4.33 nm, p = 0.05) improved in the SFA subgroup after treatment, but not in the SH subgroup, and became equivalent to those of controls. Prevalence of dry eye decreased in the smokers group after treatment (controls vs SH group vs SFA group: 0% vs 12.82% vs 16.26%, p > 0.05). Meibomian gland morphological parameters and CET did not improve after treatment (p < 0.05).

CONCLUSIONS

Smoking is associated with dry eye, MGD, and corneal epithelial thinning that seem to be only partially reversible with topical lubricants, preferably SFA.

Indoor air pollution and human ocular diseases: Associated contaminants and underlying pathological mechanisms

People spend a long time indoors, especially young children. The risk of indoor pollution on human health is one of the current hotspots in environmental and public health. The human ocular surface is highly susceptible to indoor environment quality. Epidemiological data have linked human ophthalmological disorders with exposure to indoor pollution. In this review, we summarized the adverse impacts of indoor pollution on the human ocular surface. Several studies demonstrated that indoor contaminants including particulate matter, volatile/semi-volatile organic compounds, heavy metals, and fuel combustion and cigarette smoke exposure were associated with the incidence of human dry eye, conjunctivitis, glaucoma, cataracts, age-related macular degeneration, and keratitis. In addition, toxicological investigations revealed that indoor pollution-induced induced chronic inflammation, oxidative damage, and disruption of tight junctions are the main underlying pathological mechanisms for ocular surface diseases. Taken together, this review may expand the understanding of pollution-induced eye disorder and highlight the importance of reducing associated contaminants to decrease their detrimental effects on human eyes.

Assessment of Tear Osmolarity in Smokers Using TearLab and I-Pen Systems

Purpose. Smoking has a negative effect on health and ocular tear film. The purpose of the current study is to investigate the correlation between the TearLab and I-Pen osmolarity scores in smokers and compare them with those of non-smoking healthy males. Methods. Thirty male smokers (25.3 ± 2.2 years) participated in the study. An age-matched (22.9 ± 2.0 years) control group of non-smoking healthy males (N = 30) was also recruited for comparison purposes. The ocular surface disease index (OSDI) was completed first, followed by the TearLab and I-Pen osmolarity measurements. Results. The median TearLab osmolarity score was lower (P < 0.001) than that obtained using the I-Pen in both the study and the control groups. The OSDI scores and osmolality measurements were higher (P < 0.001) in smokers than in the control subjects. In the smoker group, there were moderate correlations between the OSDI scores and the measurements obtained using the TearLab (Spearman’s correlation coefficient, r = 0.463; P = 0.010) and I-Pen (r = 0.449; P = 0.013) systems. In addition, there was a strong correlation between the osmolarity scores obtained from the TearLab and I-Pen systems in smokers (r = 0.911; P < 0.001). Conclusion. The I-Pen scores in smokers were significantly higher than those obtained using TearLab. The TearLab scores showed small variations compared with those obtained using I-Pen. A strong correlation was found between the TearLab and I-Pen scores in smokers. The osmolarity TearLab and I-Pen scores were significantly higher in smokers compared with normal eye subjects.

A Google Trends Approach to Identify Distinct Diurnal and Day-of-Week Web-Based Search Patterns Related to Conjunctivitis and Other Common Eye Conditions: Infodemiology Study

Background

Studies suggest diurnal patterns of occurrence of some eye conditions. Leveraging new information sources such as web-based search data to learn more about such patterns could improve the understanding of patients’ eye-related conditions and well-being, better inform timing of clinical and remote eye care, and improve precision when targeting web-based public health campaigns toward underserved populations.

Objective

To investigate our hypothesis that the public is likely to consistently search about different ophthalmologic conditions at different hours of the day or days of week, we conducted an observational study using search data for terms related to ophthalmologic conditions such as conjunctivitis. We assessed whether search volumes reflected diurnal or day-of-week patterns and if those patterns were distinct from each other.

Methods

We designed a study to analyze and compare hourly search data for eye-related and control search terms, using time series regression models with trend and periodicity terms to remove outliers and then estimate diurnal effects. We planned a Google Trends setting, extracting data from 10 US states for the entire year of 2018. The exposure was internet search, and the participants were populations who searched through Google’s search engine using our chosen study terms. Our main outcome measures included cyclical hourly and day-of-week web-based search patterns. For statistical analyses, we considered P<.001 to be statistically significant.

Results

Distinct diurnal (P<.001 for all search terms) and day-of-week search patterns for eye-related terms were observed but with differing peak time periods and cyclic strengths. Some diurnal patterns represented those reported from prior clinical studies. Of the eye-related terms, “pink eye” showed the largest diurnal amplitude-to-mean ratios. Stronger signal was restricted to and peaked in mornings, and amplitude was higher on weekdays. By contrast, “dry eyes” had a higher amplitude diurnal pattern on weekends, with stronger signal occurring over a broader evening-to-morning period and peaking in early morning.

Conclusions

The frequency of web-based searches for various eye conditions can show cyclic patterns according to time of the day or week. Further studies to understand the reasons for these variations may help supplement the current clinical understanding of ophthalmologic symptom presentation and improve the timeliness of patient messaging and care interventions.

The effects of tobacco waterpipe smoking on the ocular surface

CLINICAL RELEVANCE

This study was conducted to determine the effect of tobacco waterpipe smoking on the ocular surface. The findings could be useful in understanding ocular surface changes and associated symptoms in waterpipe smokers.

BACKGROUND

Tobacco smoking has been reported to have many systemic and ocular adverse effects. However, the effect of specific delivery methods of tobacco using a waterpipe on the eye has not been commonly studied.

METHODS

This study enrolled 33 waterpipe smokers (with no history of cigarette smoking) and 31 non-smokers of age-matched control group. Participants were tested in the following sequence: the presence of ocular symptoms using Ocular Surface Disease Index questionnaire, tear osmolarity, tear film break-up time and corneal staining. Statistical analysis using unpaired sample t-tests was performed to study the difference in ocular surface parameters obtained for each group. The prevalence of dry eye disease was also measured in each group.

RESULTS

The mean tear osmolarity values and corneal staining were significantly higher (P < 0.05) in the waterpipe smoking group (314.64 ± 15.24 mOsm/L and 0.73 ± 0.94, respectively) compared to non-smokers (306.42 ± 13.48 mOsm/L and 0.10 ± 0.30, respectively). The mean values obtained from tear film break-up time test were significantly lower (P < 0.05) in the waterpipe smoking group (5.82 ± 3.77 s) compared to non-smokers (8.32 ± 3.46 s). The difference in the average Ocular Surface Disease Index scores in the study groups was not statistically significant (P > 0.05). The prevalence of dry eye disease was significantly higher (p < 0.05) in the waterpipe smoking group (57.6%), compared to the control group (35.5%).

CONCLUSION

Waterpipe smoking could have a significant effect on tear film parameters and be associated with dry eye disease. Dryness also seems to be more prevalent among waterpipe smokers.

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.

Chromatic Contrast Sensitivity Functions and Colour Discrimination in Smoker Patients

In this study, effects of smoking on colour vision with the Farnsworth−Munsell 100 Hue test (FM100h) and achromatic (A), red-green (RG), and blue-yellow (BY) contrast sensitivity functions were evaluated. In total, 50 non-smoker controls and 25 smokers, divided into two groups (group 1, less than 10 cigarettes per day, with 15 patients, and group 2, >10 cigarettes per day, with 10 patients) took part in the experiments. Best-corrected visual acuity (BCVA), FM100h, and A, RG, and BY contrast sensitivity functions were measured. Total and partial RG and BY error scores (TES and PTES) and colour axis index (CA) were used in the analysis. No differences between smoker and non-smoker groups were found in BCVA, CA and A and BY contrast sensitivity, but TES and PTES values and RG contrast sensitivity at 1 cpd were statistically different. Differences between smoker groups were not significant. Error scores in smokers were positively correlated with the number of cigarettes smoked per day, and in BY also with age. Tobacco caused discrimination losses in both chromatic mechanisms but affected the red-green pathway more than the blue-yellow, and therefore, a partial RG score of FM100h test seems to be a good predictor of smoker colour deficiencies.

Association of dry eye disease with smoking: A systematic review and meta-analysis

There is conflicting evidence for the association between smoking and dry eye disease (DED). We conducted a meta-analysis to determine the true relationship between smoking and DED. A systematic literature search was performed using electronic databases, including PubMed, Embase and Cochrane Library, till August 2021 to identify observational studies with data on smoking as risk factor of DED. Quality assessment of the included studies was conducted using Joanna Briggs Institute (JBI) critical appraisal checklists. The random-effects model was used to calculate the pooled odds ratio (OR). Heterogeneity was evaluated by Cochrane Q and I² index; in addition, subgroup, sensitivity, and meta-regression analyses were performed. Publication bias was assessed using funnel plot and Egger’s regression test. A total of 22 studies (4 cohort and 18 cross-sectional studies) with 160,217 subjects met the inclusion criteria and were included in this meta-analysis. There is no statistically significant relationship between current smokers (OR_adjusted = 1.14; 95% CI: 0.95–1.36; P = 0.15; I² = 84%) and former smokers (OR_adjusted = 1.06; 95% CI: 0.93–1.20; P = 0.38; I² = 26.7%) for the risk of DED. The results remained consistent across various subgroups. No risk of publication bias was detected by funnel plot and Eggers’s test (P > 0.05). No source of heterogeneity was observed in the meta-regression analysis. Our meta-analysis suggest current or former smoking may not be involved in the risk of dry eye disease. Further studies to understand the mechanism of interaction between current smokers and formers smokers with DED are recommended.

Prevalence and Risk Factors Associated with Symptomatic Dry Eye in Nurses in Palestine During the COVID-19 Pandemic

Introduction

Working in closed wards at hospitals during night-time shifts and using electronic health records may raise the risk of dry eye disease in nurses.

Objective

The purpose of the current study was to assess the prevalence and associated factors of dry eye disease among hospital nurses in the North West Bank, Palestine.

Methods

A descriptive cross-sectional study. The study included 300 nurses who work at hospitals in the North West Bank, Palestine. The Ocular Surface Disease Index (OSDI) questionnaire on dry eye disease was used to estimate the prevalence of symptomatic dry eye disease.

Results

The percentage of dry eye disease prevalence among study participants was 62% with an OSDI score of >13 (mild to moderate and severe OSDI status). Nurses who wore contact lenses worked during the night-time, and worked in the intensive care unit were more likely to report significantly higher OSDI scores (p < .05). Moreover, gender, smoking, and computer use were not statistically associated with dry eye disease (p > .05).

Conclusion

Symptomatic dry eye disease is one of the most common ocular diseases among hospital nurses in Palestine.

Phenotypic and transcriptomic changes in the corneal epithelium following exposure to cigarette smoke

Cigarette smoke extract (CSE), a complex mixture of compounds, contributes to a range of eye diseases; however, the underlying pathophysiological responses to tobacco smoke remain ambiguous. The purpose of the present study was to evaluate the cigarette smoke-induced phenotypic and transcriptomic changes in the corneal epithelium with a view to elucidating the likely underlying mechanism. Accordingly, for the first time, we characterized the genome-wide effects of CSE on the corneal epithelium. The ocular surface of the mice in the experimental groups was exposed to CSE for 1 h per day for a period of one week, while mice in the control group were exposed to preservative-free artificial tears. Corneal fluorescein staining, in vivo confocal microscopy and scanning electron microscopy were performed to examine the corneal ultrastructure. Transcriptome sequencing and bioinformatics analysis were performed followed by RT-qPCR to validate gene expression changes. The results indicate that CSE exposure disrupted the structural integrity of the superficial epithelium, decreased the density of microvilli, and compromised the corneal epithelial barrier intactness. RNA-seq revealed 667 differentially expressed genes, and functional analysis highlighted the enhancement of several biological processes such as antioxidant activity and the response to oxidative stress. Moreover, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that glutathione metabolism and drug metabolism cytochrome P450 were the most relevant pathways contributing to the effects of CSE on the corneal epithelium. Protein-protein interaction (PPI) network analysis illustrated that GCLC, NQO1, and HMOX1 were the most relevant nodes. In conclusion, the present study indicates that CSE exposure induces changes in the phenotype and genotype of the corneal epithelium. The antioxidant response element is essential for counteracting the effects of cigarette smoke on this tissue layer. These results shed novel insights into how cigarette smoke damages this ocular surface.

The effect of active smoking, passive smoking, and e-cigarettes on the tear film: An updated comprehensive review

Active tobacco smoking, passive smoking, and e-cigarette smoking have been associated with different systemic and ocular diseases. The precorneal tear film plays an important role in eye health and its analysis can provide useful information on ocular status. This review investigates the effects of different types of smoking on the precorneal tear film, by analyzing the peer-reviewed literature on this topic. Specifically, tear evaporation rate, stability, volume, ferning, osmolarity, and physical composition (lipids and proteins) of tear film are detailed. Most of the reported works show that cigarette smoking reduces tear film stability and quality by affecting its components. This review highlights that smoking severely affects the tear film, but a single test is not sufficient to determine these effects because smoking can impact different parts of the eye.

The effect of smoking on ocular surface and tear film based on clinical examination and optical coherence tomography

Purpose:

Smoking is a global health problem with a high burden of smokers in India and the world as well. Smoking is a known eye irritant that may have a significant effect on the anterior ocular surface. Hence, the present study was aimed to investigate the effect of smoking on dry eye parameters, ocular surface, and central corneal thickness (CCT) and to compare the results with nonsmokers.

Methods:

In this cross-sectional study, 40 (80 eyes) smokers and 40 (80 eyes) age-matched nonsmokers were included. The severity of ocular surface disease symptoms was assessed by the Ocular Surface Disease Index (OSDI) tool. All participants underwent a series of measurements, that is, the Schirmer’s II test score and tear breakup time (TBUT). Tear meniscus height (TMH) and CCT were measured using anterior segment optical coherence tomography (OCT).

Results:

The mean value of all dry eye parameters was statistically different among the group of smokers and nonsmokers. The mean score of symptomatic assessment (OSDI) was observed to be significantly higher in smokers than in nonsmokers (P < 0.0001), and dry eye parameters, that is, Schirmer’s score (P = 0.0127), TMH (P < 0.0001), and TBUT (P < 0.0001) were significantly lower among smokers than nonsmokers. There was no significant difference in CCT between smokers and nonsmokers (P = 0.06).

Conclusion:

Cigarette smoking has deteriorating effects on the ocular surface. Exposure to smoking was found to be associated with dryness of the eye. Further studies are needed on a molecular basis.

Dry eye disease and retinal nerve fiber layer changes in chronic smokers

Purpose:

To study the effect of smoking on tear film parameters and retinal nerve fiber layer thickness (RNFL) in chronic smokers.

Methods:

This was a cross-sectional study, which included 60 (120 eyes) smokers who have smoked at least 10 pack-year and an equal number of healthy subjects as a control for comparison. In addition to history, a detailed slit-lamp examination was done to evaluate the anterior and posterior segments. All patients underwent Schirmer’s I test (SIT) with Whatman-41 filter paper, tear meniscus height (TMH), and RNFL with a Fourier-domain optical coherence tomography (OCT) and tear film breakup time (TBUT) with 2% fluorescein and cobalt blue filter using slit-lamp biomicroscopy.

Results:

The (mean ± SD) age of the participants was 56.48 ± 10.38 years. There was a statistically significant reduction in tear film parameters in smokers compared to nonsmokers (P = 0.000). The incidence of MGD was found to be higher in smokers when compared to nonsmokers with a P value of 0.000. RNFL in all four quadrants was also significantly reduced in smokers compared to nonsmokers (P = 0.00).

Conclusion:

This study shows that chronic smoking leads to an increased incidence of dry eye disease and is associated with RNFL thinning. Smoking can result in cumulative RNFL loss in patients with ocular neurodegenerative disorder and OCT of these patients may have to be interpreted keeping this in mind.

The prevalence, severity, and risk factors for dry eye disease in Dubai - a cross sectional study

Background

The prevalence of dry eye disease is increasing globally and requires the attention of healthcare professionals as it worsens patients’ quality of life. No published studies on the epidemiology of dry eyes have been found in Dubai.

Purpose

To describe the epidemiology, prevalence, severity, and associated factors of dry eyes in Dubai, United Arab Emirates, in 2019.

Methods

This was an analytical, cross-sectional, survey-based study. An online survey was distributed by email to Mohammed Bin Rashid University students, staff, and faculty and to the staff at Mediclinic City and Parkview Hospitals in Dubai, United Arab Emirates, from April–June 2019. The survey included demographic questions and the Ocular Surface Disease Index (OSDI).

Results

The survey was completed by 452 participants; the majority were females (288/452; 63.7 %). The prevalence of dry eyes in Dubai was estimated to be 62.6 % (283/452), with severely dry eyes being the most prevalent (119/283; 42 %). Females, high daily screen time (> 6 h), and the use of contact lenses were found to be associated with dry eyes (P-value < 0.05, 95 % confidence interval). Age was found to be negatively correlated with prevalence of dry eyes. Exposure to smoking/shisha, history of eye injury/surgery, and nationality were not associated with dry eyes.

Conclusions

This is the first cross-sectional study to investigate the prevalence of dry eyes in Dubai (62.6 %). The majority of participants had severe dry eyes symptoms. Severely dry eyes were more common among females and users of contact lenses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01978-4.

Systemic Conditions Associated with Severity of Dry Eye Signs and Symptoms in the Dry Eye Assessment and Management Study

PURPOSE

Certain systemic conditions are reported to be risk factors for dry eye disease (DED), but their associations with DED severity are not well studied. We evaluated whether systemic conditions reported to be DED risk factors are associated with severity of DED signs and symptoms.

DESIGN

Secondary analysis of data from the Dry Eye Assessment and Management Study, a large-scale multicenter randomized clinical trial of patients with moderate to severe DED.

PARTICIPANTS

Five hundred thirty-five adult patients with moderate to severe DED from 27 United States centers.

METHODS

Patients reported their medical history at baseline. They underwent ocular surface examinations and symptom evaluation using standardized protocols at baseline, 6 months, and 12 months. We analyzed the associations of systemic conditions (a systemic disease or smoking history) reported as potential DED risk factors with the severity of DED signs and symptoms using generalized linear regression models adjusted by age, gender, race, and visit.

MAIN OUTCOME MEASURES

Dry eye disease symptoms assessed using the Ocular Surface Disease Index (OSDI), 6 DED signs (tear film break-up time, anesthetized Schirmer testing, corneal fluorescein staining, conjunctival lissamine green staining, tear osmolarity, and meibomian gland dysfunction), and a composite signs severity score from 0 to 1 (1 = most severe).

RESULTS

The mean age was 58 years; 81% were women. More severe DED signs were associated significantly with Sjögren syndrome (mean composite signs severity score 0.52 with disease vs. 0.43 without disease; P < 0.001), facial rosacea (0.47 vs. 0.43; P = 0.002), rheumatoid arthritis (0.47 vs. 0.42; P = 0.002), peripheral artery disease (0.50 vs. 0.43; P < 0.001), and daily smoking history (0.45 vs. 0.43; P = 0.047). Thyroid dysfunction, osteoarthritis, diabetes, irritable bowel syndrome, hypercholesterolemia, hypertension, and hypertriglyceridemia were not associated significantly with DED signs. No conditions were associated significantly with OSDI.

CONCLUSIONS

In this large, well-characterized cohort of patients with DED assessed under standardized procedures, patients with certain systemic diseases and smoking history showed more severe DED signs compared with patients without the conditions. The profile of significant DED signs varied by systemic condition, reflecting different DED causes. Understanding the systemic conditions and underlying causes that predispose some patients to severe DED can improve management.

The contact Lens risk survey to assess risk of soft contact lens-related inflammatory events

PURPOSE

To test the Contact Lens Assessment in Youth Contact Lens Risk Survey (CLRS) scoring algorithm in soft contact lens (SCL) wearers presenting with SCL-related adverse events and healthy matched controls.

METHODS

This prospective case-control study compared CLRS responses in SCL wearers presenting with symptomatic red eyes (Cases) with age-, sex- and site-matched healthy SCL wearers (Controls) at six locations across North America. Responses to individual questions from Cases and Controls were analyzed using either the Pearson, Mantel-Haenszel chi-square, or Fisher's exact test. Differences in the CLRS scores were compared using t-tests.

RESULTS

A total of 171 SCL wearers were enrolled (n = 57 Cases, 114 Controls). Cases were adjudicated to consensus and classified as contact lens-related serious and significant (S&S) or non-serious events. S&S Cases scored significantly higher on the CLRS (56.1 ± 11.1) than either their matched Controls (44.3 ± 11.1) (P <  0.001) or the non-Serious Cases (44.8± 12.8 P =  0.002). Scores of non-serious Cases were not significantly different than scores of their Controls (43.4 ± 10.7, P = 0.33) CONCLUSIONS: The CLRS scoring algorithm discriminated between SCL wearers presenting with S&S CL-related adverse events from healthy SCL wearers and those with non-serious events. This survey and scoring system could help practitioners identify patients at greatest risk for CL-related adverse events and support targeted interventions aimed at reducing risk behaviors.

Effect of Smoking on Tear Stability and Corneal Surface

Purpose

To determine the effect of smoking on tear stability and ocular surface of the cornea among students aged between 19 and 25 years. This study also aimed to find a correlation between tear film stability with a score of McMonnies Dry Eye Questionnaire (MDEQ) and Ocular Surface Disease Index Questionnaire (OSDI).

Methods

This is a prospective, non-interventional, comparative study of 59 male (27 smokers and 32 non-smokers) undergraduates of a public university. Tear film stability was evaluated using non-invasive tear break-up time and fluorescein tear break-up time. Corneal staining was determined using Efron grading scale. MDEQ and OSDI Questionnaires were used to assess dry eye symptoms. Data were obtained from the right eye only and analyzed using descriptive and correlation analysis.

Results

The age range of the participants was between 19 and 25 years. The mean age for smokers and non-smokers was 22.19 ± 2.20 and 21.22 ± 1.83 years, respectively (P = 0.07). The smoker group had statistically significant lower tear film stability than the non-smoker group (P < 0.0001). Corneal staining was statistically significant higher at the nasal and temporal parts of the cornea in smokers (P < 0.05). There was a moderate correlation between tear film stability and scores of MDEQ and OSDI.

Conclusions

Tobacco smoke has a significant effect on the tear film stability, seen in reduced tear stability values among smokers. Corneal staining was found to be more extensive in the smokers. These findings would be useful to eye-care providers in the management of their dry eye patients related to smoking.

Cosmetic blepharoplasty and dry eye disease: a review of the incidence, clinical manifestations, mechanisms and prevention

Dry eye disease is a multifactorial disease of the ocular surface and can be caused by a variety of iatrogenic interventions, especially ophthalmic surgical procedures. This article reviews the incidence, clinical manifestations, mechanisms and prevention of dry eye disease caused or worsened by cosmetic blepharoplasty, and focus on how to reduce and prevent the occurrence of postoperative dry eye disease and provide the basis for the selection of operation methods and the rational drug during the perioperative period.

Ocular conditions and dry eye due to traditional and new forms of smoking: A review

Addiction to cigarette smoking has high prevalence rates recorded worldwide. Smoking has been linked to several life-threatening systemic conditions such as cancer, heart attack and stroke, in addition to a range of ocular pathologies. In recent years, electronic cigarettes (EC) have emerged as alternatives to smoking. ECs are nicotine delivery devices which produce an aerosol by heating, rather than combusting, a liquid which contains nicotine, flavours and preservatives. This review focuses on the association of traditional and new forms of smoking with dry eye disease, contact lens wear and four other common ocular diseases: cataract, age-related macular degeneration, glaucoma and Graves' ophthalmopathy. It is concluded that smoking and vaping appear as a risk factor for the aforementioned ocular conditions. An evidence-based, clear link between cigarette smoking, or EC vaping and ocular problems is yet to be discovered.

The Tear Function in Electronic Cigarette Smokers

SIGNIFICANCE

Prominent ocular surface dryness and poor tear film quality among electronic cigarette (e-cigarette) smokers (or vapers) indicate potential harm to the eyes from vaping. These findings may serve as precautionary signs for e-cigarette users and exposed bystanders.

PURPOSE

Little is known about the effect of e-cigarettes on the eyes except for reported eye irritation among individuals who were exposed to e-cigarette vapors and e-liquids. This study aims to investigate the effect of vaping on ocular surface health of long-term vapers.

METHODS

Twenty-one vapers and 21 healthy nonsmokers who are all male underwent measurements of the Ocular Surface Disease Index, noninvasive tear breakup time, fluorescein breakup time, ocular surface staining, tear meniscus height, and the Schirmer test. The effect of voltage used during vaping was also evaluated against the measurements.

RESULTS

Vapers experienced moderate-to-severe eye dryness (25.0 [interquartile range, 14.6 to 43.7]) as indicated by the Ocular Surface Disease Index. Significant reductions of noninvasive tear breakup time (3.13 ± 0.97 vs. 6.57 ± 2.31 seconds; P < .0001), fluorescein breakup time (2.68 [interquartile range, 2.33 to 3.18] vs. 4.12 [3.56 to 5.07] seconds; P < .0001), and tear meniscus height (203.0 [193.0 to 225.5] vs. 235.0 [210.0 to 253.50] μm; P = .002) were noted in vapers, but the Schirmer test showed higher results (14.5 [12.0 to 17.0] vs. 8.0 [7.0 to 11.0] mm; P = .001) compared with nonsmokers. Increase in vaping voltage aggravated the dry eye symptoms and tear instability (P < .05). Higher Schirmer test result was also noted as voltage increases.

CONCLUSIONS

Vapers showed moderate-to-severe symptomatic dry eye and poorer tear film quality compared with nonsmokers. High vaping voltage may have aggravated the dry eye syndrome because of hazardous by-products from pyrolysis of the e-liquid constituents. Investigation of the ocular surface health at cellular and molecular levels is warranted to gain a deeper understanding on the effect of e-cigarette to the eyes.

Ocular Surface, Meibomian Gland Alterations, and In Vivo Confocal Microscopy Characteristics of Corneas in Chronic Cigarette Smokers

PURPOSE

To evaluate the ocular surface, meibomian gland alterations, and in vivo confocal microscopy (IVCM) parameters through correlation with nicotine dependency level (NDL) and duration of smoking (DS) in chronic smokers.

METHODS

This cross-sectional study included 50 eyes of 50 chronic smokers, and 50 eyes of 50 age- and gender-matched healthy nonsmokers. To examine the ocular surface and tear film, corneal sensitivity (CS) measurement with Cochet-Bonnet esthesiometer, tear film break-up time (TBUT), lissamine green (LG) staining, Schirmer I test with anesthesia, and Ocular Surface Disease Index (OSDI) questionnaire were performed consecutively. Basal epithelial cell, keratocyte, and endothelial cell density, the percentage of endothelial polymegethism/pleomorphism, and subbasal nerve plexus were evaluated using IVCM. Meibomian gland density was evaluated with a meibography unit. The Fagerström test was used to measure NDL, and DS was recorded.

RESULTS

In the chronic smokers group, the basal epithelial cell density, anterior and posterior keratocytes, endothelial cell density, and long and total subbasal nerve numbers were lower, and LG staining, meiboscore, and OSDI scores were higher, compared with the control group, whereas other parameters were similar. The percentage of polymegethism was higher and the percentage of pleomorphism was lower in the chronic smokers group. In the correlation analysis, no significant relationship was found between the DS, NDL and ocular surface, and IVCM findings.

CONCLUSION

Decreased corneal basal epithelium, anterior and posterior keratocytes, endothelial cell density, meibomian gland density, and subbasal nerve numbers were found in chronic smokers. The results of the study show that smoking has an adverse effect on ocular surface parameters.

A pre-test post-test assessment of non-invasive keratograph break up time and corneal epithelial thickness after vaping

BACKGROUND

The effects of electronic cigarettes on the ocular surface has yet to be shown. The purpose of the study was to assess the impact of e-cigarette use on the anterior corneal surface integrity.

METHODS

Forty three males and 21 females with an average of 21years were required to vape 0.05ml of e-liquid of 8mg nicotine concentration. Corneal epithelial thickness (CET) and Non Invasive Keratograph Tear Break up Time (NIKBUT) measurements were obtained prior to and post vaping. The Optovue iVue optical coherence topographer was used to measure central; superior; inferior; nasal and temporal CET and NIKBUT was assessed using the Oculus Keratograph 5M.

RESULTS

There was a mean increase for central corneal epithelial thickness of 0.3448 microns. The superior CET increased by 0.2414 microns. The inferior CET increased by 0.2931microns. The nasal CET increased by 0.2069 microns. The temporal CET increased by 0.2759 microns. The mean change in NIKBUT post-vaping was an increase of 1.40 seconds. All observations occurred at p > 0.05.

CONCLUSION

The acute effect of e-cigarette use does not impact corneal epithelial thickness and non-invasive keratography tear break up time after 10 puffs mild exposure but more research is needed to assess if this remains the case with more frequent, higher exposure.

Acute tobacco smoke exposure exacerbates the inflammatory response to corneal wounds in mice via the sympathetic nervous system

Exposure to tobacco smoke is a major public health concern that can also affect ophthalmic health. Based on previous work demonstrating the important role of the sympathetic nervous system (SNS) in corneal wound repair, we postulated that acute tobacco smoke exposure (ATSE) may act through the SNS in the impairment of corneal wound repair. Here we find that ATSE rapidly increases the markers of inflammatory response in normal corneal limbi. After an abrasion injury, ATSE exaggerates inflammation, impairs wound repair, and enhances the expression of nuclear factor-κB (NF-κB) and inflammatory molecules such as interleukin-6 (IL-6) and IL-17. We find that chemical SNS sympathectomy, local adrenergic receptor antagonism, NF-κB1 inactivation, and IL-6/IL-17A neutralization can all independently attenuate ATSE-induced excessive inflammatory responses and alleviate their impairment of the healing process. These findings highlight that the SNS may represent a major molecular sensor and mediator of ATSE-induced inflammation.

External eye symptoms in indoor environments

Eye irritation, for example dry or irritated eyes, is generally among top three reported symptoms in office-like environments, in particular among workplaces with cognitive demanding visual display unit (VDU) work. The symptoms are especially among middle and advanced ages and particularly among women more than men. The symptoms are also among the most commonly reported complaints in the eye clinic. To be in a position to interpret the high prevalence of eye symptoms, a multidisciplinary and integrated approach is necessary that involves the external eye physiology (separate from internal eye effects), eye diseases (evaporative dry eye (DE), aqueous-deficient DE, and gland dysfunctions), and risk factors that aggravate the stability of precorneal tear film (PTF) resulting in hyperosmolarity and initiation of inflammatory reactions. Indoor environmental, occupational and personal risk factors may aggravate the PTF stability; factors such as age, contact lenses, cosmetics, diet, draft, gender, low humidity and high temperature, medication, outdoor and combustion pollutants, and VDU work. Psychological stressors may further influence the reporting behavior of eye symptoms. The impact of the risk factors may occur in a combined and exacerbating manner.

Mucosal immune tolerance at the ocular surface in health and disease

The ocular surface is constantly exposed to environmental irritants, allergens and pathogens, against which it can mount a prompt immune response to preserve its integrity. But to avoid unnecessary inflammation, the ocular surface's mucosal immune system must also discriminate between harmless and potentially dangerous antigens, a seemingly complicated task. Despite its unique features, the ocular surface is a mucosal lining, and as such, it shares some homeostatic and pathophysiological mechanisms with other mucosal surfaces. The purpose of this review is to explore the mucosal homeostatic immune function of the ocular surface in both the healthy and diseased states, with a special focus on mucosal immunology concepts. The information discussed in this review has been retrieved by PubMed searches for literature published from January 1981 to October 2016.

Assessment of Tear Film Quality among Smokers Using Tear Ferning Patterns

Purpose. To investigate the effect of cigarette smoking on the ocular tear film. Methods. Thirty healthy young male cigarette smokers (20–38 years old) and 30 healthy age matched nonsmokers were enrolled in the study. McMonnies questionnaire, slit lamp, and PRT test were used to screen the subjects. Tear samples were collected from the right eyes and tear ferning patterns were observed and graded. Results. The mean MacMonnies scores and TF grades were significantly higher in the smoker subjects (mean ± SD = 9.83 ± 5.22 and 0.96 ± 0.54, resp.) compared to nonsmokers (mean ± SD = 5.96 ± 3.06 and 0.41 ± 0.38, resp.). The mean values obtained from PRT and TBUT tests were 22.23 ± 6.35 mm and 12.17 ± 3.81 s for smokers and 22.16 ± 5.63 mm and 14.13 ± 2.62 s for nonsmokers, respectively. Strong correlations were found between MacMonnies scores and both PRT (r = 0.596) and TF (r = 0.516). There was statistically significant difference in TF grades (p = 0.00), TBUT (p = 0.036) and McMonnies (p = 0.02) between smokers and nonsmokers. Conclusion. Cigarette smoking could have a significant effect on the tear film quality of the eye.

Smoking and the risk of dry eye: a Meta-analysis

AIM

To collect the evidence to estimate the correlation between smoking and the incidence of dry eye.

METHODS

The PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL, last issue), CBM (Chinese BioMedical Literature Database), and CNKI (China National Knowledge Infrastructure/Chinese Academic Journals full-text Database) were searched for eligible studies published from January 1964 to December 2015 to investigate the association of smoking with the risk of dry eye. The odds ratio (OR) and 95% confidence interval (CI) were summarized and calculated. The extracted studies were pooled by the fixed-effects model or a random-effects model.

RESULTS

Two cohort studies and eight cross-sectional surveys were included in our Meta-analysis. There was no statistically significant relationship between current (OR=1.32; 95% CI: 0.99-1.76; P=0.055) or ever smoking (OR=1.12; 95% CI: 0.98-1.28; P=0.107) and the risk of dry eye among the studies, even when age and gender were adjusted (OR=1.16; 95% CI: 0.83-1.64; P=0.383). In the sensitivity analysis in which only general population were included, the association was significant between smoking and dry eye (OR=1.50; 95% CI: 1.08-2.09; P=0.016).

CONCLUSION

This Meta-analysis suggests that smoking may associate with the risk of dry eye in general population.

The pathophysiology, diagnosis, and treatment of dry eye disease

BACKGROUND

Dry eye disease (DED) is common; its prevalence around the world varies from 5% to 34%. Its putative pathogenetic mechanisms include hyperosmolarity of the tear film and inflammation of the ocular surface and lacrimal gland. Dry eye is clinically subdivided into two subtypes: one with decreased tear secretion (aqueous-deficient DED), and one with increased tear evaporation (hyperevaporative DED).

METHODS

This review is based on pertinent publications retrieved by a selective PubMed search and on the authors' own clinical and scientific experience.

RESULTS

The diagnostic evaluation of dry eye disease should include a detailed patient history, thorough split-lamp examination, and additional tests as indicated. Few randomized controlled therapeutic trials for dry eye have been published to date. Artificial tears of various kinds are recommended if the symptoms are mild. Lid hygiene is helpful in the treatment of hyperevaporative dry eye, while collagen or silicon plugs can be used for partial occlusion of the efferent lacrimal ducts to treat severe hyposecretory dry eye. The benefit of long-term topical anti-inflammatory treatment of moderate or severe dry eye disease with corticosteroids or cyclosporine A eye drops has been documented in clinical trials on a high evidence level. Orally administered tetraycycline derivatives and omega-3 or omega-6 fatty acids are also used.

CONCLUSION

The treatment of dry eye has evolved from tear substitution alone to a rationally based therapeutic algorithm. Current research focuses on pathophysiology, new diagnostic techniques, and novel therapies including secretagogues, topical androgens, and new anti- inflammatory drugs.

Tear film stability: a review

Tear film stability can be assessed via a number of tools designed for clinical as well as research purposes. These techniques can give us insights into the tear film, and allow assessment of conditions that can lead to dry eye symptoms, and in severe cases, to significant ocular surface damage and deterioration of vision. Understanding what drives tear film instability and its assessment is also crucial for evaluating existing and new therapies. This review examines various techniques that are used to assess tear film instability: evaluation of tear break-up time and non-invasive break-time; topographic and interferometric techniques; confocal microscopic methods; aberrometry; and visual function tests. It also describes possible contributions of different tear film components; namely meibomian lipids, ocular mucins and proteins, and factors such as age, contact lens wear, ocular surgery and environmental stimuli, that may influence tear film instability.