Low Serum 25-Hydroxyvitamin D Levels Are Associated with Dry Eye Syndrome

The efficacy of vitamin D supplementation in dry eye disease: A systematic review and meta-analysis

PURPOSE

Vitamin D (VD) is a vitamin with anti-inflammatory and immunomodulatory effects. Several studies have shown that VD deficiency is associated with the incidence and severity of dry eye disease (DED) in humans. This meta-analysis compared signs and symptoms in patients with DED before and after VD supplementation.

METHODS

Ten databases (PubMed, Cochrane, Web of science, Ovid, Embase, Scopus, CNKI, CSTJ, Wanfang, Sinomed) and four clinical trials registry websites (ISRCTN, CT, ICTRP, ICH GCP) were searched for studies on the efficacy of VD supplement in patients with DED that were published up to 2023 January. A total of 8 studies with 439 cases were included. Two reviewers independently assessed the quality of the literature and extracted data to calculate standard mean differences (SMD) for the Schirmer's test (SH test), tear film break-up time (TBUT), corneal fluorescein staining scores (CFSS, Oxford Scale, 0-5), lid hyperemia, ocular surface disease index (OSDI), and visual analogue pain scale (VAS).

RESULTS

The analysis showed that VD supplementation improved tear production (SMD 1.43, 95% CI 0.81, 2.05, p = 0.000) and tear film stability (SMD 1.19, 95% CI 0.83, 1.55, p = 0.000) and reduced lid hyperemia (SMD -0.71, 95% CI -1.09, -0.32, p = 0.000) and OSDI (SMD -1.10, 95% CI -1.45, -0.74, p = 0.000), which is effective in alleviating the signs and symptoms of DED.

CONCLUSIONS

VD supplementation could be an adjuvant treatment to alleviate the signs and symptoms of dry eye in the future. However, further studies regarding its most appropriate administration and dosage need to be conducted.

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.

Association between systemic medication use and severity of dry eye signs and symptoms in the DRy eye assessment and management (DREAM) study

PURPOSE

Some systemic medications are reported to be associated with dry eye disease (DED), yet their associations with the severity of DED signs and symptoms are not well studied. To evaluate these associations, we performed a secondary analysis of data from the DRy Eye Assessment and Management (DREAM) Study.

METHODS

Participants (N = 535) were assessed for DED signs using tear break-up time (TBUT), Schirmer testing, corneal fluorescein staining, conjunctival lissamine green staining, meibomian gland dysfunction (MGD), and tear osmolarity and DED symptoms using the Ocular Surface Disease Index (OSDI). We derived a composite signs severity score from the 6 DED signs and categorized participant-reported systemic medications into antidepressants, antihistamines, aspirin, corticosteroids, diuretics, nonsteroidal anti-inflammatory drugs, proton pump inhibitors, statins, vitamin D3, and medications for diabetes mellitus, hypertension, hypothyroidism, migraine, and seizure. Generalized linear models were used to compare DED symptom and sign scores between medication users and non-users, with adjustment for factors associated with DED severity.

RESULTS

Compared to non-users, antihistamine users had lower TBUT (p = 0.01) and higher OSDI score (p = 0.02); aspirin users had lower TBUT (p = 0.02); corticosteroid users had lower TBUT (p = 0.02), lower Schirmer test scores (p = 0.03), higher cornea fluorescein staining (p = 0.01), higher composite severity score (p = 0.01), and higher OSDI score (p = 0.03); seizure medication users had higher composite severity score (p = 0.02); vitamin D3 users had lower TBUT (p = 0.001) and greater MGD (p = 0.03); and diuretic users had less MGD (p = 0.03).

CONCLUSIONS

Certain systemic medications may be associated with more severe DED. This may guide prescription practices in patients with DED.

Outcomes of the addition of oral administration of curcumin-phospholipid to hyaluronic acid-based tear substitute for the treatment of dry eye disease

The aim of this study is to report the clinical outcomes of oral supplementation with curcumin-phospholipid in addition to hyaluronic acid-based tear substitute for the management of dry eye disease (DED). Patients with a diagnosis of DED confirmed by pathological values of both NIKBUT <10 s. and OSDI Questionnaire score > 12 were included. Patients were randomized to receive 2 different treatments: 0.25% hyaluronic acid-based tear substitute 3 time daily (Group 1) or as above plus curcumin-phosphatidylcholine complex tablets once a day (Group 2). Patients were evaluated at baseline (T0) and after 90 days of treatment (T1) by means of Keratograph for the measurement of NIKBUT, TMH, meibomian gland dropout and bulbar redness. Overall, data from 90 eyes of 45 patients were included. Group 1 consisted of 48 eyes of 24 patients, while group 2 included 42 eyes of 21 patients. When comparing median values of both groups at T0, no statistically significant differences were found for all parameters; instead for T1, statistically significant differences were found for redness and OSDI compared to Group 1. In group 1, a statistically significant reduction after the treatment was detected for Nikbut average and OSDI questionnaire; while in group 2, a statistically significant reduction after treatment was recorded for Nikbut average, bulbar redness and OSDI questionnaire. The addition of an oral supplement containing curcumin-phospholipid may help in a greater improvement of bulbar redness and subjective ocular symptoms compared to the treatment with tear substitutes alone for the management of DED.

Association Between Vitamin Deficiencies and Ophthalmological Conditions

Vitamin deficiencies can have adverse effects on health, including on the visual system. The ocular manifestations of a vitamin deficiency are related to the underlying biochemical function of the particular nutrient. While vitamin deficiencies are not common in developed counties, they are still prevalent in parts of the developing world and in specific, vulnerable populations. Vitamin deficiencies can cause or contribute to many ophthalmological conditions and eye diseases may even be the first presenting finding of a vitamin deficiency. As such, it is important for ophthalmologists to be aware of the ocular manifestations of vitamin deficiencies, especially given that the complications can be severe and effectively treated if identified early. This review summarizes the literature on the main vitamins known to have characteristic ocular manifestations: vitamins A, B1, B2, B9, B12, C, D, E and K. The function, epidemiology, manifestations, workup, and management of each vitamin is discussed in detail.

TFOS Lifestyle: Impact of nutrition on the ocular surface

Nutrients, required by human bodies to perform life-sustaining functions, are obtained from the diet. They are broadly classified into macronutrients (carbohydrates, lipids, and proteins), micronutrients (vitamins and minerals) and water. All nutrients serve as a source of energy, provide structural support to the body and/or regulate the chemical processes of the body. Food and drinks also consist of non-nutrients that may be beneficial (e.g., antioxidants) or harmful (e.g., dyes or preservatives added to processed foods) to the body and the ocular surface. There is also a complex interplay between systemic disorders and an individual's nutritional status. Changes in the gut microbiome may lead to alterations at the ocular surface. Poor nutrition may exacerbate select systemic conditions. Similarly, certain systemic conditions may affect the uptake, processing and distribution of nutrients by the body. These disorders may lead to deficiencies in micro- and macro-nutrients that are important in maintaining ocular surface health. Medications used to treat these conditions may also cause ocular surface changes. The prevalence of nutrition-related chronic diseases is climbing worldwide. This report sought to review the evidence supporting the impact of nutrition on the ocular surface, either directly or as a consequence of the chronic diseases that result. To address a key question, a systematic review investigated the effects of intentional food restriction on ocular surface health; of the 25 included studies, most investigated Ramadan fasting (56%), followed by bariatric surgery (16%), anorexia nervosa (16%), but none were judged to be of high quality, with no randomized-controlled trials.

Thyroid gland dysfunction and vitamin D receptor gene polymorphism in keratoconus

OBJECTIVES

To detect the serum level of thyroid hormones, vitamin D and vitamin D receptors (VDR) polymorphism in keratoconus (KC) patients and to identify the association between vitamin D deficiency and thyroid dysfunction in KC.

METHODS

This cross sectional study included 177 KC patients with no thyroid disorders compared to 85 healthy controls with normal corneal tomography. Measurements of thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free tetraiodothyronine (FT4) and serum 25-OH vitamin D were done using Enzyme linked immusoassay (ELISA test). VDR polymorphisms were tested including [Taq I (rs731236), Apa I (rs7975232) and Bsm I (rs1544410)] using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

An increase in frequency of thyroid disorders (P = 0.04), decrease in serum 25(OH) vitamin D level (P < 0.001), Taq 1 and tt genotype (P < 0.001) were significantly distributed in KC patients. A significantly higher serum 25(OH) vitamin D level was reported in TT genotype, while insufficient level was more common in Tt genotype (P < 0.001). A deficient serum 25(OH) vitamin D level was predominant in tt genotype (P < 0.001). A 95% confidence interval was in TSH (1.603, 2.946), FT4 (24.145, 77.06), hypothyroidism (1.062, 67.63), insufficient (2.936, 11.643) and deficient vitamin D (5.283, 28.704) and all were significant risk factors for KC with (P < 0.05).

CONCLUSIONS

Both thyroid disorders and low vitamin D are potential factors for KC development. Studying VDR at the molecular level provides interesting avenues for future research toward the identification of new KC cases.

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.

Serum Vitamin D Levels and Status in Thai Optic Neuritis Subjects: A Case-Control Study

Objective

To measure serum total vitamin D or 25-hydroxyvitamin D [25(OH)D] levels and status in immune-based optic neuritis (ON) including neuromyelitis optica spectrum disorder (NMOSD)-ON, myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD)-ON, autoimmune-ON, and idiopathic-ON and compare them with age- and sex-matched healthy controls. The secondary objective was to analyze the association between serum 25(OH)D levels and ON attack severity (nadir best-corrected visual acuity; nadir BCVA).

Materials and Methods

This was a single-center, case-control study. We enrolled 59 subjects (19 NMOSD-ON, 6 MOGAD-ON, 11 autoimmune-ON, 23 idiopathic-ON) diagnosed with acute immune-based ON (any ON attacks) over 11 years. Electronic medical records were reviewed and demographic data (age at sampling, sex, aquaporin-4 immunoglobulin (AQP4-IgG); myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG); other biomarkers of autoimmune disorders), ON attack severity (nadir BCVA), and serum 25(OH)D levels in the acute phase of ON were collected. Serum 25(OH)D levels of 236 age- and sex-matched healthy controls were assessed.

Results

Mean serum 25(OH)D levels were significantly lower in each group of immune-based ON compared with healthy controls (p < 0.001 for each ON group). However, mean serum 25(OH)D levels were not significantly different between four ON groups (NMOSD-ON, 20.18±5.90 ng/mL; MOGAD-ON, 23.07±4.94 ng/mL; autoimmune-ON, 21.14±5.29 ng/mL; idiopathic-ON, 19.56 ±5.12 ng/mL; p = 0.525). All immune-based ON subjects had vitamin D insufficiency or vitamin D deficiency. The prevalences of vitamin D insufficiency and vitamin D deficiency were significantly higher than in healthy controls in each ON group (both p < 0.05 in each ON group). No associations were observed between serum 25(OH)D levels and ON attack severity (nadir BCVA).

Conclusions

Thai immune-based ON subjects had lower serum 25(OH)D levels and higher prevalence of vitamin D insufficiency and vitamin D deficiency compared with age- and sex-matched healthy controls. Serum 25(OH)D levels were not associated with ON attack severity (nadir BCVA). We highly recommend that serum 25(OH)D levels be screened in all subjects with acute immune-based ON.

Conjunctival Histopathological Changes in Children With Vitamin D Deficiency

PURPOSE

The aim of this study was to investigate tear function-associated clinical findings and conjunctival histopathological changes in children with vitamin D (Vit-D) deficiency.

METHODS

This study used a prospective case-control design. Group 1 (n=38) comprised pediatric patients with Vit-D deficiency, and group 2 (n=45) was the control group. Tear break-up times (TBUTs), Schirmer-1 test measurements, ocular surface disease index (OSDI) scores, and conjunctival impression cytology (CIC) results of the groups were compared.

RESULTS

The participant demographic characteristics, including the mean age and the male-to-female ratio, were similar (P>0.05). The median TBUT and Schirmer-1 test measurement were 10 s (5-15) and 12 mm (6-19) in group 1 and 11 s (6-16) and 15 mm (8-21) in group 2 (P=0.004 and P=0.013, respectively). The median OSDI scores were 16 (10-20) in group 1 and 17 (10-21) in group 2 (P=0.092). According to the CIC, 25 samples in group 1 and 40 samples in group 2 were categorized as grade 0, 11 samples in group 1 and 5 samples in group 2 were categorized as grade 1, and 2 samples in group 1 and no sample in group 2 were categorized as grade 2 (P=0.027).

CONCLUSION

Significant conjunctival histopathological changes occur in children with Vit-D deficiency, and these changes have effects on some tear function-associated clinical findings including the Schirmer-1 test and TBUT measurements.

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 Vitamins: A Narrative Literature Review

Dry eye disease (DED) is a major public health problem worldwide that seriously impairs the quality of life, reduces work productivity, and poses significant economic burden. In DED, tear film instability or hyperosmolarity activates a self-perpetuating vicious cycle that may aggravate ocular surface inflammation and damage. Thus, treatment approaches should focus on interrupting this cycle and ameliorating inflammation. In addition to anti-inflammatory medications, such as corticosteroids, cyclosporine, and lifitegrast, nutrients with anti-inflammatory and anti-oxidative properties may also be effective for the treatment of DED. Evidence indicates that vitamin deficiencies may be associated with an increased risk of DED and that vitamin supplementation can be an effective treatment for DED. In the present review, we introduce the results of clinical and experimental studies on the association between vitamin deficiencies and DED. The potential efficacy of systemic and topical supplementation in the treatment of DED is also discussed.

Vitamin D and Ocular Diseases: A Systematic Review

The contributory roles of vitamin D in ocular and visual health have long been discussed, with numerous studies pointing to the adverse effects of vitamin D deficiency. In this paper, we provide a systematic review of recent findings on the association between vitamin D and different ocular diseases, including myopia, age-related macular degeneration (AMD), glaucoma, diabetic retinopathy (DR), dry eye syndrome (DES), thyroid eye disease (TED), uveitis, retinoblastoma (RB), cataract, and others, from epidemiological, clinical and basic studies, and briefly discuss vitamin D metabolism in the eye. We searched two research databases for articles examining the association between vitamin D deficiency and different ocular diseases. One hundred and sixty-two studies were found. There is evidence on the association between vitamin D and myopia, AMD, DR, and DES. Overall, 17 out of 27 studies reported an association between vitamin D and AMD, while 48 out of 54 studies reported that vitamin D was associated with DR, and 25 out of 27 studies reported an association between vitamin D and DES. However, the available evidence for the association with other ocular diseases, such as glaucoma, TED, and RB, remains limited.

A Novel Multi-Ingredient Supplement Reduces Inflammation of the Eye and Improves Production and Quality of Tears in Humans

INTRODUCTION

Dry eye is a multifactorial condition of the eye caused by insufficient tear production and imbalance in tear composition leading to faster evaporation of tear fluid. It is also associated with inflammation that often leads to ocular surface damage. Symptoms of dry eyes include itchiness, soreness, red eyes, a burning sensation, eye fatigue and blurred vision. The objective of this study was to evaluate the efficacy and safety of our multi-ingredient supplement in subjects with dry eye syndrome (DES).

METHODS

We recruited 60 subjects with mild to moderate DES who were randomized in a 1:1 ratio in a single-center study to receive LCD (lutein 20 mg, zeaxanthin 4 mg, curcumin 200 mg curcuminoids, vitamin D3 600 IU) or placebo (soybean oil) capsules for 8 weeks. The primary outcomes evaluated were changes in tear volume by Schirmer's test and ocular symptoms by the Ocular Surface Disease Index (OSDI); secondary outcomes included evaluation of changes in Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire, tear film break-up time (TBUT), corneal and conjunctival staining, tear osmolarity, matrix metalloproteinase-9 (MMP-9), artificial tear use and safety assessments. The outcomes were compared between the LCD and placebo groups at baseline and day 56 of supplementation.

RESULTS

Fifty-nine subjects, 30 from LCD and 29 from placebo group, completed the study. The LCD group showed significant improvements (P < 0.0001) for Schirmer's test, OSDI, TBUT, SPEED, ocular staining scores, tear osmolarity (P = 0.0005), MMP-9 (P = 0.0017) and reduced artificial tear use (P = 0.0004) and its frequency of use (P < 0.0001) in subjects compared to placebo from baseline to day 56. No safety issues were observed in the study.

CONCLUSION

The LCD supplement showed significant improvements in the production, stability and quality of tears by reducing ocular surface damage and tear inflammation and can be used as an adjuvant to artificial tears in subjects with DES.

TRIAL REGISTRATION

Clinical Trials Registry of India (http://ctri.nic.in/) identifier: CTRI/2021/01/030493.

Relation of Dietary Fatty Acids and Vitamin D to the Prevalence of Meibomian Gland Dysfunction in Japanese Adults: The Hirado-Takushima Study

Intervention studies have shown that n-3 polyunsaturated fatty acid (PUFA) supplementation is effective for the treatment of meibomian gland dysfunction (MGD). Ointment containing an analog of vitamin D has also been found to improve symptoms and signs of MGD. We have now evaluated the relation of MGD prevalence to dietary intake of fatty acids (FAs) and vitamin D among a Japanese population. Subjects comprised 300 adults aged 20 to 92 years residing on Takushima Island. MGD was diagnosed on the basis of subjective symptoms, lid margin abnormalities, and meibomian gland obstruction. Dietary FA and vitamin D intake was estimated with a brief-type self-administered diet history questionnaire. MGD prevalence was 35.3%. Multivariate adjusted odds ratios (95% confidence intervals) between extreme quintiles of intake for MGD prevalence were 0.40 (0.16–0.97) for total fat, 0.40 (0.17–0.97) for saturated FAs, 0.40 (0.17–0.97) for oleic acid, 0.52 (0.23–1.18) for n-3 PUFAs, 0.63 (0.27–1.49) for n-6 PUFAs, 1.32 (0.59–2.95) for the n-6/n-3 PUFA ratio, and 0.38 (0.17–0.87) for vitamin D. Total fat, saturated FA, oleic acid, and vitamin D intake may thus be negatively associated with MGD prevalence in the Japanese.

Vitamin D deficiency is associated with dry eye syndrome: a systematic review and meta-analysis

A systematic review and meta-analysis was conducted to determine the association between the serum vitamin D level and dry eye. A systematic literature search was performed using the PubMed, Embase, Web of Science and Cochrane Library databases to identify clinical studies evaluating the association between vitamin D levels and dry eye. The random-effect model was used to combine the results. Possible sources of heterogeneity across studies were determined by meta-regression and sensitivity analysis. Overall, 10 studies (n = 18 919) were included. Patients with dry eye had a mean serum vitamin D level that was lower than that in healthy controls by 3.99 ng/ml (95% CI -6.57, -1.40; p = 0.002). The mean Ocular Surface Disease Index score was higher (mean difference 10.70, 95% CI 1.55-19.86; p = 0.02) and Schirmer's test without anaesthesia result was lower (mean difference 6.38 mm/5 min, 95% CI -10.48, -2.28; p = 0.002) in patients with vitamin D deficiency than in controls. Tear break-up time was comparable in the vitamin D deficiency and control groups (p = 0.15). Sensitivity analyses indicated that the results obtained were robust. This meta-analysis suggested that vitamin D deficiency is associated with worse subjective symptoms and less tear production in patients with dry eye. Vitamin D deficiency may be a risk factor for dry eye syndrome. Prospective cohort and intervention studies are warranted to determine if vitamin D has a protective role in the development of dry eye.

A Novel Integrated Active Herbal Formulation Ameliorates Dry Eye Syndrome by Inhibiting Inflammation and Oxidative Stress and Enhancing Glycosylated Phosphoproteins in Rats

Dry eye syndrome (DES) is a chronic condition of the eye with insufficient production of tears leading to inadequate lubrication of eyes. Symptoms of DES are associated with discomfort and redness of the eye, blurred vision, and tear film instability which leads to the damaged ocular surface. Inflammation and oxidative stress play a significant role in the pathogenesis of the disease. In this study, the protective effect of different doses (100 or 200 mg/kg) of a novel multi-component oral formulation of lutein/zeaxanthin, curcumin, and vitamin D3 (LCD) was evaluated using a rat model with benzalkonium chloride (BAC)-induced dry eye syndrome. The formulation was administered orally to rats for 4 weeks. We observed a significant improvement in tear volume, tear breakup time, tear film integrity, and reduction in overall inflammation in rats fed with the LCD at dose 200 mg/kg performing better than 100 mg/kg. Furthermore, the formulation helped in lowering oxidative stress by increasing antioxidant levels and restored protective tear protein levels including MUC1, MUC4, and MUC5AC with 200 mg of LCD having the most significant effect. The results strongly suggest that the combination of lutein/zeaxanthin, curcumin, and vitamin-D3 is effective in alleviating the symptoms of dry eye condition with a multi-modal mechanism of action.

Ocular Neuropathic Pain: An Overview Focusing on Ocular Surface Pains

Objective

This paper reviews ocular pain with the main focus on ocular surface discomfort and dry eye pain. Anatomy, physiology, epidemiology, assessment, and treatment are discussed in this paper.

Methods

A PubMed search was conducted for studies published from 2000 to 2019 on the anatomy, pathophysiology, epidemiology, assessment, and treatment of ocular pain. Reviews, meta-analyses, and randomized clinical trials were included. Inclusion criteria focused on ocular surface discomfort, dry eye pain and neuropathic pain.

Results

A total of 112 articles were found through searches, 45 of which were selected and studied in this review.

Discussion

Pain in general can be acute or chronic. Acute pain is usually a physiologic response to a serious damage to the tissues and alleviates with pain relief treatments. Chronic pain is defined as the persistence of pain for more than three months. From another point of view, pain has been classified into either nociceptive or neuropathic. Nociceptive pain is a physiologic response to a noxious stimulus. Both central and peripheral nervous systems can be involved in the development of a neuropathic pain, which is characterized by positive or negative sensory signs, a pain perceived disproportionate to a noxious stimulus, and/or not responsive to analgesics. Chronic pain usually has a neuropathic component. Ocular surface pain is a well-known complaint after any corneal surgery. This is mainly due to abnormal regeneration of damaged corneal nerve endings and abnormal connections with adjacent nerve endings which produce spontaneous activity. Tear hyperosmolarity and the resultant ocular surface inflammation can also trigger voluntary activity of corneal nerve endings. Referral pain to the first and second division of the trigeminal nerve has been reported. Interference with vision and even sleep, which is out of proportion to the examination are among patients' complaints. All of these elements proposed the new concept of ocular neuropathic pain syndrome. The first step in conventional evaluation of ocular discomfort is search for tear insufficiency. Pathologies of lid and blinking as well as conjunctival irregularities should be addressed. Anti-inflammatory agents and, in resistant cases, systemic neuromodulators are shown to be helpful. Education on behavioral changes and reassurance are essential steps. Considering the neuropathic origin for the ocular pain, treatment modalities used for such pain in other parts of the body can be considered for this syndrome.

Calcitriol inhibits apoptosis via activation of autophagy in hyperosmotic stress stimulated corneal epithelial cells in vivo and in vitro

BACKGROUND

Previously, calcitriol has been demonstrated as a potential therapeutic agent for dry eye, whilst its role on corneal epithelium death remains unclear. This study aims to investigate the relationship between apoptosis and autophagy on dry eye related scenario, as well as the effect of calcitriol and its potential mechanism.

METHODS

In vitro, immortalized human corneal epithelial cells (iHCEC) were cultured in hyperosmotic medium with or without various concentrations of calcitriol and other reagents. In vivo, Wistar rats were applied with benzalkonium chloride to induce dry eye. Then rats were topically treated with calcitriol (10^-6 M) for 14 days. Autophagy flux (LC3B-II and SQSTM1/P62) was examined by western blotting or immunostaining. To test cell apoptosis, western blotting for cleaved caspase-3, Annexin V/PI double staining and TUNEL assay were used. CCK-8 assay was performed to detect the cell viability. Small interfering RNA was used to knock down the expression of vitamin D receptor in iHCECs.

RESULTS

Autophagy activation could protect iHCECs against HS induced apoptosis in vitro, and calcitriol was able to augment autophagy flux via VDR signaling, shown as the remarkably elevated expression of LC3B-II, as well as the declined p62 expression. In vivo results further supported the protective role of calcitriol on corneal epithelium apoptosis through promoting autophagy in dry eye rats.

CONCLUSION

The current study indicated that autophagy was an adaptive change of corneal epithelial cells in response to hyperosmotic stress and calcitriol could prevent cells from apoptosis via further activation of autophagy through VDR pathway.

A prospective study to assess the role of vitamin D individually and in combination with cyclosporine in the treatment of dry eye in patients with deficient serum 25(OH)D levels

Purpose:

To study the efficiency of vitamin D3 (buccal spray) alone and combination of vitamin D3 with cyclosporine in the treatment of dry eye disease (DED) in patients with deficient serum 25(OH)D levels.

Methods:

Around 90 patients with DED with deficient serum 25(OH)D levels were included and randomized into three groups and were given treatment for dry eye (Group A- 0.5% carboxymethylcellulose (CMC), Group B- 0.5% CMC + 2000 IU vitamin D through buccal spray, Group C- 0.5% CMC + 2000 IU vitamin D through buccal spray + 0.05% cyclosporine). The patients were followed at day-15, day-30, and day-90 for improvement in tear breakup time (TBUT) and Schirmer’s, and ocular surface disease index (OSDI) score. Improvement in serum vitamin D level was assessed at day-90. One way ANOVA test, paired t-test, and Chi-square test were used for analysis.

Results:

Group B and Group C had significantly higher in Schirmer’s test-I values as compared to Group A (P = 0.001, P < 0.001, P < 0.001 at day-15, day-30, and day-90, respectively). Significantly higher values of TBUT and mean serum vitamin D levels were obtained in Group B and Group C as compared to Group A at day-90 (P < 0.05). OSDI scores of patients significantly decreased in all three groups at all follow-up visits (P < 0.05). Overall, Group C and Group B were found statistically better than Group A. Group C showed better results than Group B but they were nonsignificant.

Conclusion:

Vitamin D supplementation leads to earlier and significant improvement in TBUT, Schirmer’s, and OSDI score in patients with vitamin D deficient DED.

Transcription Factor 4 Regulates the Regeneration of Corneal Endothelial Cells

Purpose

Human corneal endothelial cells (hCECs) have limited regenerative capacity in vivo. Reduced hCEC density results in bullous keratopathy requiring corneal transplantation. This study reveals the role of transcription factor 4 (TCF4) in hCEC diseases and suggests that TCF4 may be a molecular target for hCEC regeneration.

Methods

Cell shape, cell proliferation rates, and proliferation-associated proteins were evaluated in normal or senescent hCECs. TCF4 was blocked by siRNA (si-TCF4) or activated using clustered regularly interspaced short palindromic repeats (CRISPR)/dCas9 activation systems (pl-TCF4). The corneal endothelium of six-week-old Sprague-Dawley (SD) rats was transfected by electroporation followed by cryoinjury.

Results

Cell proliferation rates and TCF4 levels were reduced in senescent cells. TCF4 CRISPR activation enhanced corneal endothelial wound healing. TCF4 regulated mitochondrial functions including mitochondrial membrane potential, mitochondrial superoxide levels, and energy production. The percentage of cells in the S-phase was reduced with si-TCF4 and increased with pl-TCF4. Cell proliferation and cell cycle-associated proteins were regulated by TCF4. Autophagy was induced by si-TCF4. In vivo transfection of CRISPR/dCas9 activation systems (a-TCF4) induced regeneration of corneal endothelium.

Conclusions

Corneal endothelial diseases are associated with TCF4 reduction; TCF4 may be a potential target for hCEC diseases. Gene therapy using TCF4 CRISPR/dCas9 may be an effective treatment for hCEC diseases.

The Role of Nutrition and Nutritional Supplements in Ocular Surface Diseases

Dry eye disease (DED) is a multifactorial disease of the ocular surface system whose chore mechanisms are tear film instability, inflammation, tear hyperosmolarity and epithelial damage. In recent years, novel therapies specifically targeting inflammation and oxidative stress are being investigated and used in this field. Therefore, an increasing body of evidence supporting the possible role of different micronutrients and nutraceutical products for the treatment of ocular surface diseases is now available. In the present review, we analyzed in detail the effects on ocular surface of omega-3 fatty acids, vitamins A, B12, C, D, selenium, curcumin and flavonoids. Among these, the efficacy of omega-3 fatty acid supplementation in ameliorating DED signs and symptoms is supported by robust scientific evidence. Further long-term clinical trials are warranted to confirm the safety and efficacy of the supplementation of the other micronutrients and nutraceuticals.

Conjunctival impression cytology and tear-film changes in cases with vitamin D deficiency

PURPOSE

To evaluate conjunctival surface cells and tear-film functions in cases with vitamin D deficiency.

METHODS

Thirty-six patients with serum vitamin D deficiency and 27 control subjects with normal serum vitamin D levels were included in this prospective study. The tear break-up time (TBUT), Schirmer II test, and conjunctival impression cytology tests were performed to all participants.

RESULTS

The mean serum vitamin D levels were 10.5 ± 5.0 µl in the study group and 33.9 ± 11.7 µl in the control group (p < 0.001). The median TBUT scores were 11 s and 17 s and the median Schirmer II values were 7.5 mm and 12 mm in the study and the control groups, respectively (p = 0.003, p = 0.049). According to the Nelson staging system, 69.4% of the patients in the study group had grade 2 or 3 impression cytology, whereas 18.5% of the participants in the control group had grade 2 or 3 impression cytology (p < 0.001).

CONCLUSION

Our study results showed that vitamin D deficiency may lead to dry eye causing conjunctival squamous metaplasia and loss of goblet cells on the ocular surface.

Association between vitamin D and dry eye disease: A systematic review and meta-analysis of observational studies

PURPOSE

A number of studies have examined the association between vitamin D and dry eye disease in different populations, but findings are inconclusive. Herein, available observational studies were systematically reviewed to elucidate the overall relationship between vitamin D and dry eye disease among adult population.

METHODS

PubMed, Scopus, Google scholar and ISI web of science databases were searched until January 2020 for studies assessing the association between vitamin D and dry eye disease. The Newcastle-Ottawa Quality Assessment Scale was used to examine the quality of each study.

RESULTS

A total of 14 studies out of 252 met the inclusion criteria and were included in this systematic review and meta-analysis. Serum 25(OH) D3 was lower in dry eye disease subjects compared to healthy ones (WMD -5.93; 95 % CI, -7.47 to -4.40; P < 0.001) with evidence of significant heterogeneity (I² = 94.6 % p < 0.001). Also, in final analysis, vitamin D correlated significantly with ocular surface disease index (Fisher's Z: -0.26; 95 % CI, -0.48 to -0.04; P = 0.018), with significant heterogeneity between studies (I² = 59.3 %, P = 0.043).

CONCLUSION

It was found that serum vitamin D had a significantly lower level in dry eye disease patients, and correlated with ocular surface disease index but no other dry eye disease parameter. The findings add to the existing literature supporting the concept that nutrition especially vitamin D plays an important role in human eye health. Prospective studies are needed to confirm this relationship.

Dysregulated Tear Fluid Nociception-Associated Factors, Corneal Dendritic Cell Density, and Vitamin D Levels in Evaporative Dry Eye

Purpose

The purpose of this study was to study the status and association among tear-soluble factors, corneal dendritic cell density, vitamin D, and signs and symptoms in dry eye disease (DED).

Methods

A total of 33 control subjects and 47 evaporative dry eye patients were included in the study. DED diagnosis and classification was based on the 2017 Report of the Tear Film & Ocular Surface Society International Dry Eye Workshop (TFOS DEWS II). DED workup, including tear film break-up time (TBUT), Schirmer's test I (STI), corneal and conjunctival staining, ocular surface disease index (OSDI) scoring, and in vivo confocal microscopy (to assess corneal dendritic cell density [cDCD] and subbasal nerve plexus [SBNP] features) was performed in the study subjects. Tear fluid using Schirmer's strip and serum were collected from the subjects. Multiplex ELISA or single analyte ELISA was performed to measure 34 tear-soluble factors levels including vitamin D.

Results

Significantly higher OSDI discomfort score, lower TBUT, and lower STI were observed in DED patients. cDCD was significantly higher in DED patients. No significant difference was observed in SBNP features. Tear fluid IL-1β, IL-17A, MMP9, MMP10, MMP9/TIMP ratio, and VEGF-B were significantly higher in DED patients. Significantly lower tear fluid IL-2, IP-10, NPY, VEGF-A, and vitamin D was observed in DED patients. These dysregulated tear factors showed significant associations with DED signs and symptoms.

Conclusions

Altered tear fluid soluble factors with potential to modulate nociception exhibited a distinct association with ocular surface discomfort status, TBUT, STI, and cDCD. This implies a functional relationship between the various tear-soluble factors and dry eye pathogenesis, indicating new molecular targets for designing targeted therapies.

Conjunctivitis in dupilumab clinical trials

BACKGROUND

Dupilumab blocks the shared receptor component for interleukin (IL)-4 and IL-13. It is approved in the U.S.A. for patients aged ≥ 12 years with moderate-to-severe atopic dermatitis (AD) uncontrolled by topical prescription medicines or who cannot use topical medicines, for patients in Japan whose AD is uncontrolled with existing therapies, for patients with moderate-to-severe AD in Europe who are candidates for systemic therapy and for patients aged ≥ 12 years for maintenance treatment of moderate-to-severe asthma uncontrolled with their current medicines. AD trials have reported increased incidence of conjunctivitis for dupilumab vs. placebo.

OBJECTIVES

To characterize further the occurrence and risk factors of conjunctivitis in dupilumab clinical trials.

METHODS

We evaluated randomized placebo-controlled trials of dupilumab in AD (n = 2629), asthma (n = 2876), chronic rhinosinusitis with nasal polyps (CRSwNP) (n = 60) and eosinophilic oesophagitis (EoE) (n = 47).

RESULTS

In most AD trials, dupilumab-treated patients had higher conjunctivitis incidence than placebo controls. Higher baseline AD severity and previous history of conjunctivitis were associated with increased conjunctivitis incidence. Conjunctivitis was mostly mild to moderate. Most cases recovered or resolved during the treatment period; two patients permanently discontinued dupilumab due to conjunctivitis or keratitis. Common treatments included ophthalmic corticosteroids, antibiotics, and antihistamines or mast cell stabilizers. Most cases were diagnosed by the investigators. In asthma and CRSwNP trials, the incidence of conjunctivitis was lower for both dupilumab and placebo than in AD trials; dupilumab did not increase the incidence compared with placebo. In the EoE trial, no patients had conjunctivitis.

CONCLUSIONS

Conjunctivitis was more frequent with dupilumab treatment in most AD trials. In dupilumab trials in other type 2 diseases, incidence of conjunctivitis was overall very low, and was similar for dupilumab and placebo. In AD, the incidence of conjunctivitis was associated with AD severity and prior history of conjunctivitis. The aetiology and treatment of conjunctivitis in dupilumab-treated patients require further study. What's already known about this topic? Ocular disorders, including allergic conjunctivitis, are common in patients with atopic dermatitis (AD). In most dupilumab AD trials, dupilumab-treated patients had higher conjunctivitis incidence than those receiving placebo. Most cases were mild to moderate and recovered or were recovering during study treatment; study treatment discontinuation due to conjunctivitis was rare. Conjunctivitis incidence was very low and similar for dupilumab and placebo in clinical trials in asthma, chronic rhinosinusitis with nasal polyps and eosinophilic oesophagitis. What does this study add? This analysis confirms and extends the results of the individual clinical trials. Baseline disease-related factors, including AD severity, prior conjunctivitis history and certain biomarkers (thymus and activation-regulated chemokine, IgE, eosinophils), were associated with increased incidence of conjunctivitis. Patients who responded well to dupilumab had reduced incidence of conjunctivitis. Further study is needed to elucidate the aetiology and treatment of conjunctivitis in dupilumab-treated patients with AD.

Rapamycin Rescues Endoplasmic Reticulum Stress-Induced Dry Eye Syndrome in Mice

Purpose

To investigate whether rapamycin protects tear production and the ocular surface during endoplasmic reticulum (ER) stress-induced dry eye syndrome in mice.

Methods

Tunicamycin was injected intraperitoneally in BALB/c mice without or with rapamycin (TM or RM5 group). Peritoneal injection of PBS performed in vehicle group. Group without injection served as control. Blinking rate, fluorescein staining score (FSS), and phenol red thread tear production test were measured at 4 days, 1 week, and 2 weeks after treatment. Levels of inflammatory and angiogenic cytokines were measured by ELISA.

Results

Blinking rate and FSS were elevated, and tear production was decreased in TM group compared with controls (P < 0.05 for all), which was ameliorated by rapamycin at 1 and 2 weeks. Levels of inflammatory and angiogenic cytokines in the cornea and lacrimal glands were higher in the TM group than controls, and lower in the RM5 group than the TM group at 1 and 2 weeks (P < 0.05 for all).

Conclusion

Rapamycin protected tear production and the ocular surface against this dry eye syndrome by ameliorating ER stress-induced vascular damage and inflammation of lacrimal glands and the ocular surface.

Determination of vitamin D in tears of healthy individuals by the electrochemiluminescence method

BACKGROUND

Vitamin D is a fat-soluble steroid hormone which can be converted into various forms and is of extreme physiological importance to our body. However, its functions and local metabolic pathways in some organs, such as the eye, have not yet been well studied. We aimed to verify the correlation between vitamin D levels in blood and tear fluid and the possibility of using tear fluid as a biological material for monitoring eye disorders in the future.

METHODS

The electrochemiluminescence method was used to examine blood and tear samples collected with Schirmer test strips from 21 individuals without ocular disease.

RESULTS

At the 95% confidence interval, mean tear fluid vitamin D = 37.8 ± 3.6 ng/mL, which is higher than the serum level, with a mean of 30.3 ± 7.7 ng/mL; Lin's concordance correlation coefficient = -0.018 (-0.174; 0.139), Pearson's coefficient = -0.070, and the Bland-Altman coefficient = -11.12 (-30.40; 8.16). Results were obtained using the program Stata version 11.0.

CONCLUSION

It is possible to determine vitamin D levels in tear fluid using the electrochemiluminescence method, and as the results do not correlate with blood, there is possibility of using tear fluid as a biological matrix for detection of vitamin D, which may increase the possibilities of new studies in eye disorders.

Factors Associated with Dry Eye Symptoms in Elderly Koreans: the Fifth Korea National Health and Nutrition Examination Survey 2010-2012

Background

Dry eye disease is an aging-related ophthalmic disease that not only affects the daily activities but also causes deterioration in the quality of life. This study aimed to evaluate the factors associated with dry eye symptoms in elderly Koreans.

Methods

We investigated 4,185 subjects (men=1,787 and women=2,398) aged ≥65 years from the fifth Korea National Health and Nutrition Examination Survey 2010−2012. Data were analyzed using multiple logistic regressions to identify the relationships between dry eye symptoms and other factors.

Results

The prevalence of dry eye symptoms was 17.9%. After adjustment for confounding factors, dry eye symptoms were significantly associated with female sex (adjusted odds ratio [aOR], 1.806; 95% confidence interval [CI], 1.410−2.313), a history of cataract (aOR, 1.683; 95% CI, 1.255−2.255), suicidal ideation (aOR, 1.414; 95% CI, 1.070−1.870), hypercholesterolemia (aOR, 1.289; 95% CI, 1.025−1.621), age ≥80 years (aOR, 0.538; 95% CI, 0.337−0.859), and sleep duration ≥9 h/d (aOR, 0.524; 95% CI, 0.330−0.834).

Conclusion

Among elderly Koreans, female sex, a history of cataract, suicidal ideation, and hypercholesterolemia may be the risk factors for dry eye symptoms, whereas sleep duration ≥9 h/d can be a protective factor against dry eye symptoms.

Antioxidant effects of vitamin D on lacrimal glands against high dose radioiodine-associated damage in an animal model

PURPOSE

To evaluate antioxidant effects of active vitamin D (calcitriol) against high-dose radioiodine (RAI) therapy-associated damage of lacrimal gland.

MATERIALS AND METHODS

Wistar albino rats were used and divided into three groups randomly (n = 12/group). The first group was appointed as the negative control group and received no RAI or medication. The second group was appointed as the positive control group that only received 3 mCi/kg (111 MBq/kg) RAI via gastric gavage and the last group was the treatment group that received 3 mCi/kg RAI via same method and calcitriol (200 ng/kg/day) via intraperitoneal administration. Seven days after RAI administration, bilateral intraorbital (IG), extraorbital (EG) and Harderian (HG) glands were removed for the evaluations of histopathologic, tissue cytokine, total oxidant status (TOS) and total antioxidant status (TAS).

RESULTS

RAI led to significant increase in tissue TOS, TNF-α, IL-6 levels and significant decrease in IL-10 and TAS levels (p < 0.05 for each). Addition of adjunctive calcitriol reversed all these parameters significantly (p < 0.05 for each).The following histopathologic parameters were seen more frequently in positive control group than the other groups: Abnormal lobular pattern, perivascular infiltration, periductal infiltration, lipofuscin-like accumulation, acinar atrophy, periductal and periacinar fibrosis in all lacrimal gland types (p < 0.05), acinar fibrosis in EG (p = 0.049), periductal fibrosis in EG and HG (p = 0.049 and 0.038, respectively), abnormal cell outlines in EG and HG (p = 0.020 and 0.011, respectively) and variation in cell size in the IG and the HG (p = 0.003 and 0.049 respectively).

CONCLUSIONS

RAI caused significant oxidative stress and inflammation in lacrimal glands. Vitamin D demonstrated potent anti-inflammatory, antioxidant and radio-protective effects on lacrimal glands in histopathologic, tissue cytokine and oxidant/antioxidant level evaluations.

Are Serum Vitamin D Levels Associated With Dry Eye Disease? Results From the Study Group for Environmental Eye Disease

Objectives

Dry eye disease (DED) is an increasingly important public health problem in Korea. Previous studies conducted in Korea have reported inconsistent results regarding the protective effects of vitamin D on DED, and these discrepancies may be related to the relatively simple questionnaire that has been used. Thus, we evaluated the association of serum vitamin D levels with DED using the ocular surface disease index (OSDI).

Methods

The present study evaluated data from participants in the Study Group for Environmental Eye Disease (2014-2015). This group included data from 752 participants, and data from 740 participants (253 men and 487 women) were analyzed in the present study. DED severity was evaluated using the OSDI.

Results

Higher serum vitamin D levels were associated with a non-significantly reduced risk of DED in the crude analysis (odds ratio [OR], 0.991; 95% confidence interval [CI], 0.971 to 1.011) and in the adjusted analysis (OR, 0.988; 95% CI, 0.966 to 1.010). In the crude analysis of no/mild DED vs. moderate/severe DED, men exhibited a decreased risk with increasing serum vitamin D levels (OR, 0.999; 95% CI, 0.950 to 1.051), while women exhibited an increased risk (OR, 1.003; 95% CI, 0.979 to 1.027). In these analyses, we found no significant associations.

Conclusions

The findings of the present study support previous reports that serum vitamin D levels are not associated with DED.

Ocular Pharmacokinetics of 25-Hydroxyvitamin D3 After Weekly Supplementation in Rabbits Using Ultra Performance Liquid Chromatography-Tandem Mass Spectrometer

BACKGROUND AND OBJECTIVES

The protective role of vitamin D supplementation has recently been shown to be present in various ocular inflammatory diseases. The oral supplementation of vitamin D may take time to achieve adequate levels in intraocular fluids. Therefore, the present study was performed to understand the ocular pharmacokinetics of 25-hydroxyvitamin D3 (25D3) in aqueous humor after weekly supplementation of 25D3 in rabbits.

METHODS

A total of 21 rabbits were fed orally with 25D3 (7.22 µg/kg/week) for 8 weeks and 9th dose was given at the end of 8 weeks. The blood and aqueous humor samples were collected from ear vein and though anterior chamber paracentesis, respectively. The serum and aqueous humor samples were spiked with deuterium labeled internal standard and were extracted using liquid extraction method. Furthermore, the samples were derivatized and 25D3 estimation was performed using ultra performance liquid chromatography-tandem mass spectrometer (UHPLC-MS/MS).

RESULTS

The 25D3 supplementation significantly increased the 25D3 levels in serum (78.5 ± 21.6 ng/ml) (mean ± SD) (p < 0.0001) and in aqueous humor (991.3 ± 180.6 pg/ml) (mean ± SD) (p < 0.0001) compared to baseline levels. The maximum concentration was achieved in serum after the 10th hour of supplementation of 1st and 9th dose, while the same was observed at the 24th hour in aqueous humor.

CONCLUSION

The oral supplementation of 25D3 was found to significantly increase 25D3 levels in aqueous humor; however, the time required to achieve 25D3 concentration in aqueous humor was higher as compared to that in serum. Therefore, weekly oral supplementation of 25D3 may have a beneficial role in ocular diseases.

Vitamin D and regulation of vascular cell function

Vitamin D deficiency is linked to pathogenesis of many diseases including cardiovascular, cancer, and various eye diseases. In recent years, important roles for vitamin D in regulation of immune function, inflammation, angiogenesis, and aging have been demonstrated. Thus, vitamin D and its analogs have been evaluated for the treatment of various types of cancer and chronic diseases. We have previously shown that the active form of vitamin D [1,25(OH)₂D₃] is a potent inhibitor of angiogenesis. This activity is consistent with the important role proposed for vitamin D and its analogs in the mitigation of tumor growth through inhibition of angiogenesis. Here, we review the important nutritional value of vitamin D and the abnormalities linked to its deficiency. We will explore its potential role as a regulator of angiogenesis and vascular cell function and the role vitamin D receptor (VDR) expression plays in these activities during vascular development and neovascularization. Our studies have established an important role for 1,25(OH)₂D₃ and VDR in the regulation of perivascular supporting cell function. In addition, the interaction of 1,25(OH)₂D₃ and VDR is essential for these activities and inhibition of neovascularization. Delineating the signaling pathways involved and identification of genes that are the target of 1,25(OH)₂D₃ regulation in vascular cells will allow us to identify novel pathways that are targets for regulation of vascular function and angiogenesis.

Calcitriol, the Active Metabolite of Vitamin D3, Inhibits Dry Eye Related Corneal Inflammation In Vivo and In Vitro

PURPOSE

To examine the influence of topical administration of calcitriol on dry eye (DE) related corneal inflammation.

METHODS

Benzalkonium chloride (BAC, 0.2%) was applied to induce DE. Then rats were treated topically with calcitriol (10^-6μM). Tear break-up time (TBUT), fluorescein staining score, inflammatory index, and tear volume were measured. Corneal epithelium damage and corneal inflammation were examined by H&E staining or RT-qPCR. In vitro, human corneal epithelial cells (iHCEC) were cultured in hyperosmotic medium (450 mOsM) with various concentrations of calcitriol. Levels of pro-inflammatory mediators were measured by RT-qPCR or ELISA. NF-κB activation was examined by Western blotting and immunofluorescence staining.

RESULTS

Calcitriol significantly ameliorated DE symptoms, attenuating corneal inflammation. In vitro studies showed that calcitriol significantly decreased the expression of pro-inflammatory mediators in iHCECs under hyperosmotic stress, probably through inhibiting NF-κB activation.

CONCLUSION

The results suggest that calcitriol might be a potential therapeutic agent for DE.

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.

Correlation of vitamin D levels with tear film stability and secretion in patients with dry eye syndrome

PURPOSE

To investigate tear film stability and secretion according to serum 25-hydroxyvitamin D3 [25(OH)D] levels in dry eye patients.

METHODS

In this retrospective observational study, the medical charts of 92 patients who visited the Department of Ophthalmology at Hallym University Kangnam Sacred Heart Hospital from April to August 2015 were reviewed. Serum 25(OH)D levels were measured. Subjects were divided into three groups according to serum 25(OH)D levels: sufficient, inadequate or deficient group. Eye discomfort was measured by ocular surface disease index (OSDI). Tear break-up time (TBUT), fluorescein staining score and Schirmer's tear secretion test were measured.

RESULTS

The mean age was 53.38 ± 13.69 years. Mean serum 25(OH)D level was 14.41 ± 5.98 ng/ml. Tear break-up time (TBUT) and tear secretion were positively correlated with serum 25(OH)D levels (r = 0.389, p = 0.001; and r = 0.428, p < 0.001, Pearson correlation test). Tear break-up time (TBUT) and tear secretion were shorter in the vitamin D-deficient group compared to the sufficient group (p = 0.022 and p = 0.004). Fluorescein staining scores and OSDI scores were not different between the three groups.

CONCLUSION

Tear break-up time (TBUT) and secretion were correlated with serum vitamin D levels. Vitamin D status may be an important factor for dry eye syndrome.

Ocular symptoms and tear film break up time (BUT) among junior high school students in Penang, Malaysia - Associations with fungal DNA in school dust

BACKGROUND

There are few studies on ocular effects of indoor mould exposure in schools, especially in the tropics OBJECTIVE: To study associations between eye symptoms and tear film break up time (BUT) in students and demographic data and fungal DNA in schools.

METHODS

A school environment study was performed among randomly selected students in eight randomly selected secondary schools in Penang, Malaysia. Information on eye symptoms and demographic data was collected by a standardised questionnaire. BUT was measured by two methods, self-reported BUT (SBUT) and by the non-invasive Tearscope (NIBUT). Dust was collected by vacuuming in 32 classrooms and analysed for five fungal DNA sequences. Geometric mean (GM) for total fungal DNA was 7.31*10⁴ target copies per gram dust and for Aspergillus/Penicillium DNA 3.34*10⁴ target copies per gram dust. Linear mixed models and 3-level multiple logistic regression were applied adjusting for demographic factors.

RESULTS

A total of 368 students (58%) participated and 17.4% reported weekly eye symptoms the last 3 months. The median SBUT and TBUT were 15 and 12s, respectively. Students wearing glasses (OR 2.41, p=0.01) and with a history of atopy (OR=2.67; p=0.008) had more eye symptoms. Girls had less eye symptoms than boys (OR=0.34; p=0.006) Indoor carbon dioxide in the classrooms was low (range 380-720ppm), temperature was 25-30°C and relative air humidity 70-88%. Total fungal DNA in vacuumed dust was associated with shorter SBUT (4s shorter per 10⁵ target copies per gram dust; p=0.04) and NIBUT (4s shorter per 10⁵ target copies per gram dust; p<0.001). Aspergillus/Penicillium DNA was associated with shorter NIBUT (5s shorter per 10⁵ target copies per gram dust; p=0.01).

CONCLUSION

Fungal contamination in schools in a tropical country can be a risk factor for impaired tear film stability among students.

Vitamin D Supplementation for Patients with Dry Eye Syndrome Refractory to Conventional Treatment

This study investigated the effect of vitamin D supplementation in patients with dry eye syndrome (DES) refractory to conventional treatment with vitamin D deficiency. A total of 105 patients with DES refractory to conventional treatment and vitamin D deficiency that was treated with an intramuscular injection of cholecalciferol (200,000 IU). Serum 25-hydroxyvitamin D (25(OH)D) levels were measured. Eye discomfort was assessed using ocular surface disease index (OSDI) and visual analogue pain score (VAS). Tear break-up time (TBUT), fluorescein staining score (FSS), eyelid margin hyperemia, and tear secretion test were measured before treatment, and 2, 6, and 10 weeks after vitamin D supplementation. Mean serum 25(OH)D level was 10.52 ± 4.61 ng/mL. TBUT, and tear secretion test showed an improvement at 2 and 6 weeks after vitamin D supplementation compared to pretreatment values (p < 0.05 for all, paired t-test). Eyelid margin hyperemia and the severity of symptoms showed improvement at 2, 6, and 10 weeks after vitamin D supplementation (p < 0.05 for all). Compared to pre-treatment values, FSS, OSDI and VAS were decreased at 2 weeks (p < 0.05 for all). In conclusion, vitamin D supplementation is effective and useful in the treatment of patients with DES refractory to conventional treatment and with vitamin D deficiency.

Correlation between tear fluid and serum vitamin D levels

Background

Vitamin D deficiency is associated with a range of systemic diseases including ocular disorders. The objective of this study is to measure tear vitamin D levels and investigate the correlation between serum and tear vitamin D levels.

Methods

A total of 48 healthy volunteers without any systemic and ocular disease were recruited for this observational cohort study. Serum was collected using clot activator coated Vacutainer® Plus tubes. Tear fluid was collected using Schirmer’s strips. Serum and tear total 25-hydroxyvitamin D levels were measured by competitive chemiluminescent ELISA and the correlation between the levels were studied.

Results

The measured serum 25-hydroxyvitamin D level ranged between 3.3 and 27.5 ng/ml (Mean ± SEM, 9.4 ± 0.7 ng/ml; Median 8.4 ng/ml). Significantly (p < 0.0001) higher level of 25-hydroxyvitamin D was detected in the tears (Mean ± SEM, 17.0 ± 1.6 ng/ml; Range 3.2–45.8 ng/ml; Median, 16.3 ng/ml) compared to serum. An average of ~2 fold (Mean ± SEM, 1.9 ± 0.2; Range 0.4–5.8; Median, 1.7) higher 25-hydroxyvitamin D was observed in tears compared to serum in the subjects. In addition, a positive correlation was observed between serum and tear 25-hydroxyvitamin D levels (r = 0.5595; p < 0.0001).

Conclusions

A higher level of 25-hydroxyvitamin D was observed in the tear fluid compared to that of the serum. It would be beneficial to consider tear vitamin D levels to study its role with reference to ocular surface diseases.