Single Nucleotide Polymorphisms in the BDNF, VDR, and DNASE 1 Genes in Dry Eye Disease Patients: A Case-Control Study

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.

Dry Eye Disease: What Is the Role of Vitamin D?

Dry eye disease (DED) is a multifactorial condition resulting from reduced tear secretion from the lacrimal glands, increased tear water evaporation or the production of poor-quality tears. Such tear instability can lead to inflammation and damage of the ocular surface, as well as to abnormal nociception. Historically, tear substitutes and corticosteroids have been the bastion of DED therapy, but a substantial number of patients still suffer from residual symptoms even after being treated with traditional treatments. Aiming to find safe and effective alternative therapies, recent efforts have been focused on the role of vitamin D in the cellular physiology of the eye. Possibly because of its positive effect in modulating the immune and inflammatory responses, the systemic supplementation of vitamin D seems, indeed, to be an effective therapeutic strategy, especially, but not only, for patients affected by DED that does not respond to conventional treatments. In this context, this review focuses on the literature reporting on the pathogenesis and treatment of DED, with a special emphasis on the recent investigations reporting on the potential role of the systemic administration of vitamin D as a therapeutic approach in the management of such condition.

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.

A, B, C's of Trk Receptors and Their Ligands in Ocular Repair

Neurotrophins are a family of closely related secreted proteins that promote differentiation, development, and survival of neurons, which include nerve growth factor (NGF), brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4. All neurotrophins signal through tropomyosin receptor kinases (TrkA, TrkB, and TrkC) which are more selective to NGF, brain-derived neurotrophic factor, and neurotrophin-3, respectively. NGF is the most studied neurotrophin in the ocular surface and a human recombinant NGF has reached clinics, having been approved to treat neurotrophic keratitis. Brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4 are less studied neurotrophins in the ocular surface, even though brain-derived neurotrophic factor is well characterized in glaucoma, retina, and neuroscience. Recently, neurotrophin analogs with panTrk activity and TrkC selectivity have shown promise as novel drugs for treating dry eye disease. In this review, we discuss the biology of the neurotrophin family, its role in corneal homeostasis, and its use in treating ocular surface diseases. There is an unmet need to investigate parenteral neurotrophins and its analogs that activate TrkB and TrkC selectively.

Vitamin D, the Vitamin D Receptor, Calcitriol Analogues and Their Link with Ocular Diseases

The global prevalence of eye diseases continues to grow, bringing with it a reduction in the activity levels and quality of life of patients, and partial or complete blindness if left untreated. As such, there is considerable interest in identifying more effective therapeutic options and preventive agents. One such agent is vitamin D, known to have a range of anti-cancer, anti-angiogenic, anti-inflammatory and anti-oxidative properties, and whose deficiency is linked to the pathogenesis of a range of cardiovascular, cancer, and inflammatory diseases. This review presents the current stage of knowledge concerning the link between vitamin D and its receptor and the occurrence of eye disease, as well as the influence of analogues of calcitriol, an active metabolite of vitamin D. Generally, patients affected by various ocular disorders have vitamin D deficiency. In addition, previous findings suggest that vitamin D modulates the course of eye diseases and may serve as a marker, and that its supplementation could mitigate some disorders. However, as these studies have some limitations, we recommend further randomized trials to clarify the link between vitamin D and its activity with eye disease.

Dry eye disease and psychiatric disorders: A systematic review and meta-analysis

The association between dry eye disease (DED) and psychiatric conditions is a highly researched topic. This work reviews the literature on this relationship, examining the prevalence and correlations of depression and anxiety with dry eye signs and symptoms. A comprehensive literature search of MEDLINE, EMBASE, PsycINFO, and gray literature was conducted, with keywords for dry eye and mood disorders, depression, anxiety, and suicide. Eligible studies underwent quality assessment using the Newcastle-Ottawa Scale. Meta-analysis was performed using STATA 15.0. Fixed- and random-effects models were computed based on the presence of heterogeneity. Thirty-two studies were included, with 31 reporting on depression and 19 on anxiety. Meta-analysis results found a depression prevalence of 40% (CI: [0.29, 0.52]) in DED patients, with 1.81 times higher odds of prevalence compared to controls (CI: [1.61, 2.02]). Prevalence of anxiety was 39% (CI: [0.15, 0.64]), with 2.32 times higher odds of prevalence compared to controls (CI: [1.67, 3.23]). Depression scores were significantly higher in patients with DED in all studies. Anxiety scores were significantly higher in DED patients in studies using all scales except the Hospital Anxiety and Depression Scale-Anxiety Subscale. DED symptom scores were significantly associated with depression (ES = 0.43; CI: [0.31, 0.55]) and anxiety (ES = 0.41; CI: [0.32, 0.50]) scores. In conclusion, depression and anxiety are more prevalent and severe in DED patients and are correlated with dry eye symptoms but not signs. These findings highlight the interrelationship between these disorders and have important implications for providing appropriate care to these patients.

Do epigenetic changes caused by commensal microbiota contribute to development of ocular disease? A review of evidence

There is evidence that genetic polymorphisms and environmentally induced epigenetic changes play an important role in modifying disease risk. The commensal microbiota has the ability to affect the cellular environment throughout the body without requiring direct contact; for example, through the generation of a pro-inflammatory state. In this review, we discuss evidence that dysbiosis in intestinal, pharyngeal, oral, and ocular microbiome can lead to epigenetic reprogramming and inflammation making the host more susceptible to ocular disease such as autoimmune uveitis, age-related macular degeneration, and open angle glaucoma. Several mechanisms of action have been proposed to explain how changes to commensal microbiota contribute to these diseases. This is an evolving field that has potentially significant implications in the management of these conditions especially from a public health perspective.

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

Background

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

Material/Methods

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

Results

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

Conclusions

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

Enriched environment alleviates stress-induced dry-eye through the BDNF axis

The number of patients with dry eye disease (DED) is increasing, and DED has become an urgent public health problem. A comorbidity of mental disorders has been reported in DED patients. We hypothesized that physical and psychological stressors impair tear secretion. To examine the relationship between stress loading and decreased tear secretion, we established a stress-induced DED mouse model, which permitted us to address the underlying mechanism of pathogenesis and resilience. Enriched environment (EE) was an effective intervention to prevent and alleviate stress-induced decreased tear secretion. Because stress loading resulted in decreased brain-derived neurotrophic factor (BDNF) expression while EE resulted in increased expression, we focused on the role of BDNF in tear secretion. Using two distinct Bdnf gene knockdown mice, we evaluated whether BDNF was a deterministic factor in regulating tear secretion in healthy and stressed conditions. Bdnf knockdown mice showed decreased basal tear secretion and loss of stress tolerance by EE for tear secretion. These results suggest that BDNF expression is related to tear secretion and to the pathology of DED.

TFOS DEWS II Epidemiology Report

The subcommittee reviewed the prevalence, incidence, risk factors, natural history, morbidity and questionnaires reported in epidemiological studies of dry eye disease (DED). A meta-analysis of published prevalence data estimated the impact of age and sex. Global mapping of prevalence was undertaken. The prevalence of DED ranged from 5 to 50%. The prevalence of signs was higher and more variable than symptoms. There were limited prevalence studies in youth and in populations south of the equator. The meta-analysis confirmed that prevalence increases with age, however signs showed a greater increase per decade than symptoms. Women have a higher prevalence of DED than men, although differences become significant only with age. Risk factors were categorized as modifiable/non-modifiable, and as consistent, probable or inconclusive. Asian ethnicity was a mostly consistent risk factor. The economic burden and impact of DED on vision, quality of life, work productivity, psychological and physical impact of pain, are considerable, particularly costs due to reduced work productivity. Questionnaires used to evaluate DED vary in their utility. Future research should establish the prevalence of disease of varying severity, the incidence in different populations and potential risk factors such as youth and digital device usage. Geospatial mapping might elucidate the impact of climate, environment and socioeconomic factors. Given the limited study of the natural history of treated and untreated DED, this remains an important area for future research.

Association of dry eye disease with psychiatric or neurological disorders in elderly patients

Dry eye disease (DED) is a common disease that can impair quality of life significantly. Its prevalence increases with advancing age, and the economic burden of the disease on both a patient and the society is increasing with elongation of life expectancy. The diagnosis and treatment of DED are often difficult due to the discordance between symptoms and signs of the disease. Recent studies have suggested the role of neurological or psychological factors in the development of dry eye symptoms and discrepancy of the symptoms and signs, particularly in elderly patients. In this review, the authors discuss the association of DED with various psychiatric and neurological disorders. In addition to psychiatric conditions, including depression, anxiety, stress, posttraumatic stress disorder and sleep disorders, medications for the psychiatric disorders have association with DED. Neurological disorders, such as neuropathic pain, chronic pain syndrome, peripheral neuropathy and several central nervous system disorders, are related to DED. Treatment of DED, combined with psychiatric or neurological disorders, is also discussed. Attention should be paid to the DED patients with discordant symptoms and signs, and unsatisfactory response to conventional treatment for associated psychiatric or neurological disorders, as well as an integrated treatment approach, could be helpful for these patients.

Lower Serum Vitamin D Level Was Associated with Risk of Dry Eye Syndrome

BACKGROUND To determine the association between serum 25(OH)D and dry eye syndrome (DES) incidence. This study was also designed to determine whether serum 25(OH)D levels were associated with ocular parameter of DES patients. MATERIAL AND METHODS This is a case-control study with 70 DES cases and 70 healthy controls. Clinical data included body mass index (BMI, kg/m²), smoking history, diabetes, and blood pressure. Serum 25(OH)D was chosen as the main parameter and reflected the level of vitamin D. The DES parameters included ocular surface disease index (OSDI) scales, tear film breakup time (TBUT) and Schirmer test I. The differences in each parameter between case and control groups were detected and the association of serum 25(OH)D and DES parameter were detected. RESULTS It was shown that 25(OH)D levels were lower in patients with DES than in healthy controls. When the 25(OH)D levels was stratified, vitamin D deficiency was more common in the DES cases. In advanced studies, it was found that there were statistically significant associations between serum 25(OH) D levels and the Schimer test, TBUT, and OSDI scales. CONCLUSIONS A significant association between serum 25(OH)D level and DES incidence was detected in this study. Considering the relatively small sample size of this study, larger studies are needed in the future.

Prevalence of Dry Eye in Uyghur and Han Ethnic Groups in Western China

PURPOSE

To describe and compare the prevalence and characteristics of dry eye among Han and Uyghur persons living in Kashi, the most inland city of China.

METHODS

A total of 1015 residents of Kashi participated in this 2013 cross-sectional study. To evaluate clinical characteristics, each subject completed (1) a dry-eye questionnaire detailing symptoms of dry eye, (2) Schirmer's I-test (SIT), (3) tear-film break-up time (BUT) test, and fluorescein staining of the cornea. Dry eye was defined as the existence of dry eye symptoms and at least two positive clinical signs. Data were analyzed using SPSS software. The prevalence and risk factors of dry eye were evaluated using a multivariate model.

RESULTS

Overall, 282 (27.8%) of the 1015 participants were diagnosed with dry eye (95% confidence interval (CI): range, 25.5-30.1). The prevalence of dry eye among Han persons (37.9 %) (95% CI: range, 35.8-40.0) was higher than that among Uyghurs (21.8%) (95% CI: 19.6-24.0) (p < 0.05). The prevalence of dry eye was 25.6% (95% CI: range, 23.3-27.8) among men and 28.7% (95% CI: 26.5-30.9) among women (p > 0.05). Risk factors for dry eye included ethnicity, age, occupation, arthritis, and dry mouth.

CONCLUSIONS

Our study revealed a higher prevalence of dry eye among Han than Uyghur persons in Kashi. Dry eye was significantly associated with environment and ethnicity.