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

Low Expression of Vitamin D Receptor in Patients With Dry Eye Disease

PURPOSE

This study aimed to compare the expression of vitamin D receptor (VDR) on the ocular surface of patients with dry eye disease (DED) and controls without ophthalmological pathologies.

METHODS

Patients with DED without previous treatment were studied and compared with healthy subjects. Ocular Surface Disease Index assessement and ocular surface cytology were performed in all patients. The immunohistochemical expression of VDR was evaluated using fully automated immunohistochemistry. The evaluation involved multiplying the percentage of nuclear-labeled cells (0-100) by their intensity (0-3), resulting in a score ranging from 0 to 300 (VDR H-score). Squamous metaplasia was morphologically evaluated using liquid-phase cytology with Papanicolaou/periodic acid-Schiff staining using Nelson's grade (scale 0-3, higher grade to higher metaplastic change).

RESULTS

Eighteen patients with DED without previous treatment and 10 healthy subjects were studied. Squamous metaplasia was observed in 74% of patients with DED, in contrast to 0% in the control group. In patients with DED, there was a lower expression of VDR than in the control group (VDR H-score: 11.2 ± 13.9 vs. 80.9 ± 56; P = 0.0001). Furthermore, an inverse correlation was observed between Nelson grade and VDR H-score ( P = 0.0001, rs = -0.71). No correlation was observed between Ocular Surface Disease Index and VDR H-score.

CONCLUSIONS

This is the first study to evaluate the VDR in patients with DED. These patients presented with a lower expression of VDR than healthy subjects. No correlation was found with more severe symptoms. Patients with DED also had a higher frequency of squamous metaplasia.

Safety and Efficacy of Topical Vitamin D in the Management of Dry Eye Disease Associated With Meibomian Gland Dysfunction: A Placebo-Controlled Double-Blind Randomized Controlled Trial

PURPOSE

The aim of this study was to investigate the safety and efficacy of topical vitamin D in the management of dry eye disease associated with meibomian gland dysfunction (MGD).

METHODS

In this randomized controlled trial, patients with symptomatic MGD were divided into 2 groups to receive topical vitamin D drops or placebo in their randomized eyes. The exclusion criteria consisted of patients with vitamin D deficiency, previous ocular surgery, and patients with ocular diseases affecting the tear film. Patients and researchers were masked to the study groups. The outcomes included the score of Dry Eye Questionnaire (DEQ) 5 and Ocular Surface Disease Index (OSDI), corneal and conjunctival staining score, tear breakup time (TBUT), Schirmer, and MG expressibility score evaluated at baseline and weeks 4 and 8.

RESULTS

Twenty-eight eyes of 28 patients were recruited in each group. In addition to the improvement of subjective parameters in both groups, there was a statistically significantly greater improvement in the vitamin D group compared with control for average scores of OSDI (13.38 ± 7.32 vs. 27.94 ± 7.49) and DEQ5 (9.67 ± 1.86 vs. 14.14 ± 2.45) at week 8 (Ps <0.001). In addition, a significant improvement in TBUT and Schirmer test was observed in both groups in weeks 4 and 8 ( P value <0.05). There was a significant difference between the treatment and control groups after 8 weeks for OSDI, DEQ5, Schirmer, TBUT, corneal fluorescein staining, and MG expressibility score ( P value <0.05).

CONCLUSIONS

The preliminary results of this randomized controlled trial suggested that use of topical vitamin D drops with a lipid vehicle could be safe and might significantly improve the symptoms and signs of dry eye associated with MGD.

Impact of Dietary Nutrients on the Prevalence of Dry Eye Syndrome among Korean Women Aged 40 and above: Evidence from the Korea National Health and Nutrition Examination Survey

This study aimed to assess the prevalence of dry eye syndrome among Korean women aged 40 and above and explore the correlation between the syndrome and daily dietary nutrient intake. We analyzed data from 92,888 female participants (mean age: 63.35 ± 8.86 years) from the 8th Korea National Health and Nutrition Examination Survey (KNHANES 2019). Dietary intake was evaluated using a personalized 24 h recall method for 21 nutrients, including macronutrients, macro- and micro-minerals, and both water- and fat-soluble vitamins. Associations between nutrient intake and dry eye syndrome were determined using odds ratios from multivariate logistic regression. We found a 7.7% prevalence of dry eye syndrome in the population studied. Intake of dietary fiber (adjusted OR: 0.72), protein (adjusted OR: 0.84), omega-3 fatty acids (adjusted OR: 0.90), water (adjusted OR: 0.76), calcium (adjusted OR: 0.82), phosphate (adjusted OR: 0.87), potassium (adjusted OR: 0.88), magnesium (adjusted OR: 0.87), vitamin A (adjusted OR: 0.78), vitamin C (adjusted OR: 0.73), and vitamin E (adjusted OR: 0.86) was inversely associated with dry eye syndrome prevalence (p < 0.0001 for all). Conversely, a higher intake of carbohydrates (adjusted OR: 1.23), sugar (adjusted OR: 1.30), fat (adjusted OR: 1.25), cholesterol (adjusted OR: 1.32), sodium (adjusted OR: 1.18), iron (adjusted OR: 1.28), and zinc (adjusted OR: 1.26) correlated with an increased risk (p < 0.0001 for all). No significant associations were found between the prevalence of dry eye syndrome and the intake of omega-6 fatty acids and vitamin D. Our study identified significant associations between specific dietary nutrients and the risk of dry eye syndrome among Korean women aged 40 and above. These findings suggest that dietary choices could influence the likelihood of developing dry eye syndrome, indicating a potential role for dietary intervention in its management. However, it is important to note that these observations are preliminary, and further research is necessary to confirm these relationships and explore their implications for dietary recommendations in dry eye syndrome prevention and management.

Dry eye in mind: Exploring the relationship between sleep and ocular surface diseases

PURPOSE

Dry Eye Disease (DED) is regarded as the most common ocular surface disease worldwide, entailing symptoms that have a major impact on the physical and psychological well-being of DED patients. In this context, the impact of sleep quality on DED has recently attracted attention. Indeed, although little is known about the mechanisms underlying the relationship between sleep and ocular surface diseases, recent evidence suggests that a reciprocal relationship exists between sleep quality and DED. Aim of the study was to investigate such relationship by means of both survey-based and instrumental analysis in a large population.

PATIENTS AND METHODS

The present cross-sectional study included 1182 DED patients who completed the Insomnia Severity Index (ISI) and the Ocular Surface Disease Index (OSDI) questionnaires. Moreover, tear break-up time (TBUT) and ocular surface staining (OSS) data of included patients were collected by physicians.

RESULTS

According to the findings of this study, in DED patients, the severity of dry eye symptoms and signs, assessed by OSDI score, TBUT, and ocular surface staining, is associated with more severe insomnia symptoms. Furthermore, higher severity of DED symptoms seems to be associated with the occurrence of nocturnal awakenings rather than with problems in falling asleep.

CONCLUSIONS

Present work contributes to the understanding of the complex relationship between DED and insomnia by showing that in a large population of DED patients, the more severe the insomnia, the more severe the DED symptoms and signs.

A randomized controlled trial involving college student: Comparing 0.15% hyaluronic acid with 0.05% cyclosporine A and 3% diquafosol sodium in the Treatment of Dry Eye

BACKGROUND

To compare the efficacy of 0.15% hyaluronic acid (HA), 0.05% cyclosporine A (CsA) and 3% diquafosol sodium (DQS) ophthalmic solution for the treatment of moderate-to-severe dry eye disease (DED) in college students and the effect on inflammatory factors in tears.

METHODS

This was a prospective, randomized, multicenter trial. A total of 282 college students diagnosed with moderate-to-severe DED between October 2, 2022 and March 1, 2023 were included. A total of 282 patients were randomized to treatment in the group of 0.15% HA or 0.05% CsA or 3% DQS in a 1:1:1 assignment. There was a main end point which is the variations in the corneal staining score to determine non-inferiority of 0.15% HA. Secondary target end points were ocular surface disease index score, Schirmer test, tear meniscus height and tear film breakup time. In addition, the inflammatory factor levels of Interleukin-1β, Interleukin-6, transforming growth factor-β1 in tears were measured. Effectiveness was assessed at baseline, 4- and 12-weeks.

RESULTS

In our analysis, the average change from baseline in corneal staining score confirmed non-inferiority of 0.15% HA to 0.05% CsA and 3% DQS and manifested obvious improvement of all groups as well (P < .05). Values for ocular surface disease index score, Schirmer test, tear meniscus height and tear film breakup time showed obvious improvements in all groups (P < .05), however, the difference intergroup was not statistically significant. Value for inflammatory factor was significant improvement across all groups, although inflammatory factor scores in the 0.05% CsA group showed a clear trend of better improvement at 12 weeks compared with 0.15% HA groups (P < .01). No serious adverse reactions were observed.

CONCLUSIONS

College students taking 0.15% HA had clinically and statistically significant improvement in corneal staining score and other indicators, but it was inferior to 0.05% CsA in anti-inflammatory therapy for moderate to severe DED. However, 0.15% HA is still an effective, safe and well-tolerated treatment option that may offer additional benefits in terms of convenience and compliance.

Regulation of Axon Guidance by Slit2 and Netrin-1 Signaling in the Lacrimal Gland of Aqp5 Knockout Mice

Purpose

Dry eye disease (DED) is multifactorial and associated with nerve abnormalities. We explored an Aquaporin 5 (AQP5)-deficiency-induced JunB activation mechanism, which causes abnormal lacrimal gland (LG) nerve distribution through Slit2 upregulation and Netrin-1 repression.

Methods

Aqp5 knockout (Aqp5-/-) and wild-type (Aqp5+/+) mice were studied. LGs were permeabilized and stained with neuronal class III β-tubulin, tyrosine hydroxylase (TH), vasoactive intestinal peptide (VIP), and calcitonin gene-related peptide (CGRP). Whole-mount images were acquired through tissue clearing and 3D fluorescence imaging. Mouse primary trigeminal ganglion (TG) neurons were treated with LG extracts and Netrin-1/Slit2 neutralizing antibody. Transcription factor (TF) prediction and chromatin immunoprecipitation-polymerase chain reaction (ChIP-PCR) experiments verified the JunB binding and regulatory effect on Netrin-1 and Slit2.

Results

Three-dimensional tissue and section immunofluorescence showed reduced LG nerves in Aqp5-/- mice, with sympathetic and sensory nerves significantly decreased. Netrin-1 was reduced and Slit2 increased in Aqp5-/- mice LGs. Aqp5+/+ mice LG tissue extracts (TEs) promoted Aqp5-/- TG neurons axon growth, but Netrin-1 neutralizing antibody (NAb) could inhibit that promotion. Aqp5-/- mice LG TEs inhibited Aqp5+/+ TG axon growth, but Slit2 NAb alleviated that inhibition. Furthermore, JunB, a Netrin-1 and Slit2 TF, could bind them and regulate their expression. SR11302, meanwhile, reversed the Netrin-1 and Slit2 shifts caused by AQP5 deficiency.

Conclusions

AQP5 deficiency causes LG nerve abnormalities. Persistent JunB activation, the common denominator for Netrin-1 suppression and Slit2 induction, was found in Aqp5-/- mice LG epithelial cells. This affected sensory and sympathetic nerve fibers' distribution in LGs. Our findings provide insights into preventing, reversing, and treating DED.

Nutritional Factors: Benefits in Glaucoma and Ophthalmologic Pathologies

Glaucoma is a chronic optic neuropathy that can lead to irreversible functional and morphological damage if left untreated. The gold standard therapeutic approaches in managing patients with glaucoma and limiting progression include local drops, laser, and/or surgery, which are all geared at reducing intraocular pressure (IOP). Nutrients, antioxidants, vitamins, organic compounds, and micronutrients have been gaining increasing interest in the past decade as integrative IOP-independent strategies to delay or halt glaucomatous retinal ganglion cell degeneration. In our minireview, we examine the various nutrients and compounds proposed in the current literature for the management of ophthalmology diseases, especially for glaucoma. With respect to each substance considered, this minireview reports the molecular and biological characteristics, neuroprotective activities, antioxidant properties, beneficial mechanisms, and clinical studies published in the past decade in the field of general medicine. This study highlights the potential benefits of these substances in glaucoma and other ophthalmologic pathologies. Nutritional supplementation can thus be useful as integrative IOP-independent strategies in the management of glaucoma and in other ophthalmologic pathologies. Large multicenter clinical trials based on functional and morphologic data collected over long follow-up periods in patients with IOP-independent treatments can pave the way for alternative and/or coadjutant therapeutic options in the management of glaucoma and other ocular pathologies.