Streptococcus thermophilus iHA318 Improves Dry Eye Symptoms by Mitigating Ocular Surface Damage in a Mouse Model.

Dry eye is a complicated ocular surface disease that causes discomfort, visual disturbance, and frequently observed ocular surface damage. Emerging hypotheses suggest probiotics may help relieve dry eye symptoms by modulating inflammation and oxidative stress. This study aimed to investigate the therapeutic effects of Streptococcus thermophilus iHA318 probiotics on dry eye using in vitro assays and an in vivo murine model of ultraviolet B (UVB) radiation-induced dry eye. In vitro analyses revealed that S. thermophilus iHA318® exhibited antioxidant activity and anti-inflammatory effects by inhibiting reactive oxygen species production and suppressing inflammatory cytokines. For the in vivo study, female ICR mice were assigned to normal control, UVB-induced dry eye, and UVB+iHA318 treatment groups. UVB exposure significantly decreased tear volume and tear film breakup time (TBUT) compared to normal controls. Supplementation with S. thermophilus iHA318® via oral gavage markedly improved tear production and TBUT on day 7 post-UVB exposure. Ocular surface photography demonstrated improved gradings of corneal opacity, smoothness, and lissamine green staining in the iHA318 group versus the UVB group. Topographical analysis further revealed improvement in the UVB-induced corneal irregularities by iHA318 treatment. Collectively, these results indicate that S. thermophilus iHA318 exerts a protective effect against dry eye symptoms by mitigating oxidative stress and inflammation, thereby preserving tear film stability and ocular surface integrity. This probiotic strain represents a promising therapeutic approach for managing dry eye syndrome.

A novel multi-ingredient supplement significantly improves ocular symptom severity and tear production in patients with dry eye disease: results from a randomized, placebo-controlled clinical trial.

Introduction: Dry eye disease (DED) is multifactorial and characterized by a loss of tear film homeostasis that causes a cycle of tear film instability, tear hyperosmolarity, and inflammation. While artificial tears are the traditional mainstay of treatment, addressing the underlying pathophysiology could relieve symptoms and prevent progression. Increasing evidence indicates a role for oral nutritional supplementation in multiple ophthalmic diseases, including DED. Lutein, zeaxanthin, curcumin, and vitamin D3 have demonstrated protective and anti-inflammatory properties in ocular models. This prospective, randomized, double-blind, parallel, placebo-controlled study evaluated the efficacy and safety of a proprietary blend of lutein, zeaxanthin isomers, curcumin, and vitamin D3 (LCD) as a daily supplement in adult participants with DED. Methods: Participants were randomized to receive one LCD supplement capsule (lutein 20 mg, zeaxanthin isomers 4 mg, curcumin 200 mg curcuminoids, and vitamin D3 600 IU) or placebo per day for 8 weeks (LCD, n=77; placebo, n=78). Primary outcomes were changes in tear volume (Schirmer's test) and ocular symptoms (Ocular Surface Disease Index [OSDI]). Results: The study met its primary endpoints: the LCD group demonstrated significantly better Schirmer's test scores and improvement in overall OSDI score, versus placebo, at Day 56 (p<0.001 for both). Scores for total OSDI, and symptoms and vision domains, significantly improved by Day 14 for LCD versus placebo, (p<0.05 for all) and were maintained to Day 56 (p<0.001). In addition, the LCD group demonstrated significantly improved tear film break-up time (TBUT) and tear film osmolarity, versus placebo, by Day 56 (p<0.001), along with significant improvements in corneal and conjunctival staining (p<0.001 for both), and inflammation (matrix metalloproteinase-9; p<0.001 for each eye). Total Standard Patient Evaluation of Eye Dryness (SPEED) score, and scores for the frequency and severity domains, were significantly improved by Day 14 for LCD versus placebo (p<0.05 for all) and maintained to Day 56 (p<0.001). There was no difference between groups for artificial tear usage. The supplement was well-tolerated. Discussion: Once-daily LCD supplementation significantly improved tear production, stability and quality, reduced ocular surface damage and inflammation, and improved participants' symptoms. LCD supplementation could offer a useful adjunct to artificial tears for patients with DED (NCT05481450).

A Standardized Extract of Green-Cotyledon Small Black Soybean (EYESOY®) Ameliorates Dry Eye Syndrome in an Animal Model.

PURPOSE: Dry eye syndrome is a common ocular disease that causes morbidity, high healthcare burden, and decreased quality of life. In this study, we evaluated the beneficial effects of a standardized extract of small black soybean (EYESOY®) in a benzalkonium chloride (BAC)-induced murine model of dry eye. METHODS: Experimental dry eye was induced by instillation of 0.02% BAC on the right eye of the Sprague-Dawley rats. Saline solution or EYESOY were administered orally every day for 8 weeks. RESULTS: EYESOY significantly improved tear volume in the cornea compared with that in the BAC group. Moreover, EYESOY inhibited damage to the corneal epithelial cells and lacrimal glands by suppressing the oxidative and inflammatory responses in a mouse dry eye model. It also increased the goblet cell density and mucin integrity in the conjunctiva. CONCLUSIONS: Our results suggest that EYESOY has the potential to alleviate dry eye syndrome.

Evaluation methods using tear volume in a conjunctivitis mice model.

Allergic conjunctival disease is an immune-mediated inflammatory disease of the conjunctiva. To develop clinically useful drugs, it is necessary to develop quantitative evaluation methods that reflect the clinical symptoms in experimental animal models. Allergic conjunctivitis model mice were systemically sensitised with ovalbumin (OVA) administered intraperitoneally and locally sensitised with OVA eye drops between day 14-28. Next, conjunctivitis induced by ocular administration of OVA solution to sensitised mice was evaluated based on tear volume. Additionally, we evaluated increase in tear volume induced by direct ocular instillation of histamine, compound 48/80, and carrageenan. An increase in antigen-induced tear volume was observed in the mice model. Additionally, direct instillation of histamine, compound 48/80, and carrageenan increased tear volume. Furthermore, levocabastine inhibited the increase in tear volume in antigen-induced allergic conjunctivitis and histamine- and compound 48/80-induced conjunctivitis models. In contrast, betamethasone suppressed carrageenan-induced tear volume but not histamine- or compound 48/80-induced tear volume. Histamine may be involved in increased tear volume in allergic conjunctivitis. Betamethasone is not directly involved in the action of histamine and is thought to suppress increase in tear volume. Evaluation of tear volume in a conjunctivitis mice model is highly quantitative; therefore, it is possible to evaluate drug efficacy. This is considered a useful index compared with conventional methods.

The role of endothelial growth factor and tear levels in diabetic retinopathy in type 2 diabetes.

PURPOSE: To evaluate the tear level of VEGF and the quantity of tear film in type 2 diabetic patients. METHODS: Thirty patients with diabetic retinopathy (DR group) and 30 patients with no DR (NDR group), and 30 healthy subjects with age and gender matching were enrolled in this prospective comparative study. The tear samples were collected using the Schirmer strips, and the amount of moisture absorbed by the strips was used to determine the quantitative level of the tear film. The concentration of VEGF in the tear samples was measured using the enzyme-linked immunosorbent assay method. The variables were compared with an independent t-test and covariance analysis. RESULTS: Mean tear level of VEGF was significantly higher in DR group (235.42 pg/ml) compared to NDR (75.11 pg/ml) and control (58.77 pg/ml) groups (P ≤ 0.001). There was no significant difference in the mean of VEGF between NDR and control patients (P = 1.00). Mean quantitative tear film levels were 7.15%, 9.72%, and 15.11% in DR, NDR, and healthy subjects, respectively (P < 0.05). The pairwise analysis showed significant differences in the level of VEGF between DR and both NDR (P = 0.001) and normal (P = 0.017) groups. However, there was no significant difference observed between NDR and normal eyes (P = 0.743). CONCLUSION: The VEGF level in tear was higher in diabetic patients with DR, independent of tear volume. The tear VEGF measurement can be used as a valuable predictor to prevent DR in diabetic patients.

Validation of the phenol red thread test in a Chinese population.

BACKGROUND: To investigate the validation of phenol red thread (PRT) test in a Chinese population by evaluating the intraobserver repeatability and interobserver reproducibility, determining correlations between the PRT test and other dry eye disease (DED) parameters including tear meniscus height (TMH) and Schirmer I test, and testing the accuracy of diagnosing DED when using the PRT test alone. METHODS: A total of 108 eyes were involved in this prospective and diagnostic study, and were divided into two groups (with and without DED). Each subject underwent a series of ocular surface examinations, including Ocular Surface Disease Index (OSDI) questionnaire, non-invasive tear breakup time (NIBUT), tear meniscus height (TMH) assessment, PRT test, fluorescein tear breakup time (FBUT), corneal fluorescein staining and Schirmer I test. RESULTS: In the experimental group and the control group, the intra-class correlation coefficients (ICCs) of the repeatability were 0.747 and 0.723, respectively (all P < 0.05). The ICCs of the reproducibility in both groups were 0.588 and 0.610, respectively (all P < 0.05). The PRT test correlated weakly with the Schirmer I test and the tear meniscus height, with Spearman coefficients of 0.385 and 0.306, respectively (all P < 0.05). The PRT test is available to diagnose DED, with an area under the curve of 0.806 and a Youden index of 0.556 at the cutoff point of 8.83 mm. CONCLUSIONS: The PRT test can provide patients a comfortable, timesaving and less irritating approach to screening and diagnosing DED compared to Schirmer I test.

Klotho Null Mutation Indirectly Leads to Age-Related Lacrimal Gland Degeneration in Mutant Mice.

The Klotho null mutation is known to lead to accelerated aging in many organs, but its effects on tear secretion and lacrimal gland (LG) senescence have not been addressed. This study investigated whether the Klotho null mutation would lead to a dry eye status and the outcome of LG without Klotho function. The Klotho (-/-) mutant mice showed reduced LG size and tear volume on the 8th week, as compared to their littermates (+/+, +/-). Hematoxylin-Eosin and Masson's trichrome staining were performed to determine morphological changes and collagen deposition. Traits of LG aging, including acinar atrophy, thickened capsules, and more collagen depositions, were observed. Immunohistochemical detections for Klotho, α-SMA, MDA, 8-OHdG, vasoactive intestinal polypeptide (VIP), tyrosine hydroxylase (TH), MMP-2, MMP-9, and FGF-23 were performed and compared among the three genotypes (+/+, +/-, -/-) at 6 and 8 weeks of age for mechanism analyses. Unexpectedly, the Klotho protein was not detected in the LG of all the three genotypes, indicating indirect effects from the Klotho null mutation. Further analyses showed abundant MDA and 8-OHdG detected in the Klotho (-/-) LG on the 8th week, indicating elevated oxidative stress. In addition, both sympathetic and parasympathetic neural transducing activities, as represented by TH and VIP expression, respectively, and α-SMA were increased in LGs with Klotho mutations. Furthermore, MMP-2 and MMP-9 expression were elevated, with FGF-23 expression being decreased on the 8th week in the Klotho (-/-) LG. In conclusion, characteristics of age-related LG degeneration were found in the Klotho null mutant mice. These traits support the use of Klotho mutant mice as a model of age-related dry eye disease.

Effect of Diquafosol Ophthalmic Solution on Airflow-Induced Ocular Surface Disorder in Diabetic Rats.

PURPOSE: To examine the effect of 3% diquafosol ophthalmic solution (DQS) on ocular surface disorders in diabetic model rats maintained in a continuous airflow condition. METHODS: Goto-Kakizaki (GK) rats, a spontaneous model of type 2 diabetes, were exposed to constant airflow for 8 weeks. After the establishment of the animal model in this environment, DQS or saline was instilled six times a day into GK rat eyes for 6 weeks. Schirmer's test was performed before and after 6-week instillations. Corneal fluorescein staining was scored at 2-, 4-, and 6-week instillations. Touch thresholds for the cornea were also determined using a Cochet-Bonnet esthesiometer before and after 6-week instillations. RESULTS: The mean Schirmer's test score after instillation of DQS was twice higher than that recorded for saline alone. DQS significantly decreased corneal staining scores at 4- and 6-week instillations. No changes in touch thresholds were observed before and after 6-week instillations. CONCLUSION: These results suggest that DQS improves corneal epithelial damage by stimulating tear secretion without influencing corneal sensation in diabetic keratopathy. Thus, DQS may have potential for treatment of diabetic patients with dry eye.

[Observation on therapeutic effect of needle-knife for dry mouth and eyes symptoms of primary Sjögren's syndrome].

OBJECTIVE: To compare the clinical efficacy of needle-knife and hydroxychloroquine sulfate in the treatment of dry mouth and eyes symptoms of primary Sjögren's syndrome. METHODS: A total of 60 patients with primary Sjögren's syndrome were randomly divided into an observation group and a control group, 30 cases in each group. In the observation group, needle-knife was used in the range of 2 cm and 2-3 cm below the occipital protuberance, the left and right lateral bone edges of the C2 spinous process, between and within the range of 1.5-3 cm beside the C3 and C4 spinous processes, points between the left and right mandibular angle and the mastoid, the treatment was given 1 time a week for 8 times. The hydroxychloroquine sulfate was applied 0.2 g each time, 2 times daily, 4 weeks as a course and a total of 2 courses in the control group. The changes of salivary flow rate, tear volume, serum immunoglobulin IgG, IgA, IgM contents and Chinese medicine symptom score were observed before and after treatment in the two groups, and the efficacy was evaluated. RESULTS: The total effective rate in the observation group was 86.7% (26/30), which was better than 70.0% (21/30) in the control group (P<0.05). The salivary flow rates, tear volume, serum IgG contents and Chinese medicine symptom scores in the two groups were significantly improved after treatment (all P<0.05), and the improvement degree in the observation group was better than the control group (all P<0.05). There was no significant difference in IgA and IgM between the two groups and before and after treatment (all P>0.05). CONCLUSION: Needle-knife is superior to hydroxychloroquine sulfate in improving dry mouth and eyes symptoms and reducing serum IgG content in patients with primary Sjögren's syndrome.

A novel strip meniscometry method for measuring aqueous tear volume in dogs: Clinical correlations with the Schirmer tear and phenol red thread tests.

OBJECTIVES: The strip meniscometry test (SMT) is a novel method for quantitative measurement of tear volume with only five seconds. We aimed to evaluate clinical correlations of SMT with the gold standard Schirmer tear test (STT) and phenol red thread test (PRT) in dogs, including normal and tear-deficient eyes. ANIMALS STUDIED: Left eyes from 621 outpatient dogs with and without ocular disorders were evaluated. PROCEDURES: Each subject underwent SMT, PRT, and STT without topical anesthesia in the described order with five-minute intervals. The total population was divided into four groups by classifying tear deficiency severity based on STT results: "severe" (0-5 mm/min), "moderate" (6-10 mm/min), "subclinical" (11-14 mm/min), and "normal" (15 or more mm/min). RESULTS: The strongest correlation coefficient was found between SMT-STT (0.676), followed by PRT-STT (0.637) and SMT-PRT (0.600) pairs. Mean(SD) scores of SMT, PRT, and STT in total population were 9.47 (4.08) mm/5 s, 33.30 (8.52) mm/15 s, and 16.47 (7.01) mm/min. Significant differences were found among STT-classified groups, both using SMT and PRT results. Receiver operating characteristic (ROC) curves revealed that SMT better agreed with STT than PRT; agreement increased with increasing STT severity. A cutoff for SMT was identified at 10 mm/5 s to discriminate normal eyes from tear-deficient eyes, yielding high sensitivities and acceptable specificities. CONCLUSIONS: SMT could be superior to PRT for discriminating tear-deficient eyes. The high sensitivity of SMT could be useful as an initial diagnostic tool to rule out normal eyes with the short testing time.

Influence of Conjunctival Folds on Calculated Tear Meniscus Volume Along the Lower Eyelid.

PURPOSE: In calculating tear meniscus volume (TMV), tear meniscus height (TMH), radius (TMR) and cross-sectional area (TMA) are usually measured at the center of the lower lid margin, but lid-parallel conjunctival folds (LIPCOFs) are known to influence the tear meniscus regularity. The aim of this study was to analyze the influence of LIPCOFs on TMA measured by optical coherence tomography (OCT) and consequently, the calculated tear meniscus volume (TMV). METHODS: Using OCT (Cirrus-HD; Carl Zeiss Meditec, Jena, Germany), the TMH, TMR and TMA in 42 subjects (13M, 29F; mean age 27.3 SD±8.4 years) were measured directly below the pupil center, plus at temporal and nasal locations perpendicularly below the limbus, where LIPCOFs were also evaluated and graded. TMV for the different locations was calculated. Correlations between LIPCOFs and the tear meniscus parameters were analyzed using the Spearman Rank-Order coefficients. Differences between tear meniscus parameters at the different locations were evaluated by the paired t-test. RESULTS: Central TMV (5.30±1.42 x10(-2)µl/mm) was significantly positively correlated to LIPCOF sum (grade 2.4±1.2) (r=0.422; P<.05). The calculated temporal TMV was greater by 0.53x10(-2)µl/mm compared to the central TMV (P=.037), while there was no significant difference in tear volume between the other locations. CONCLUSIONS: Using OCT it was possible to investigate the influence of LIPCOFs on TMH, TMR, and for the first time on TMA, at central and paracentral positions along the lower lid margin. The presence of LICPOF results in an irregularity of tear meniscus with a difference in the amount of predicted tear volume while measuring TMH or TMR at the different locations.

Long-term tear volume changes after blepharoptosis surgery and blepharoplasty.

PURPOSE: To evaluate long-term changes in tear volume by using video meniscometry following blepharoptosis surgery and upper blepharoplasty. METHODS: Forty-three eyes of 27 patients with blepharoptosis and 29 eyes of 18 patients with dermatochalasis without lacrimal duct obstruction or other eyelid diseases underwent anterior approach levator advancement or blepharoplasty. Tear volume was evaluated by measurement of tear meniscus radius (R), using video meniscometry preoperatively and at 1.5, 3, and 6 months postoperatively. Margin reflex distance-1 (MRD-1) was measured before and after surgery by using photographs. RESULTS: After blepharoptosis surgery, the mean MRD-1 was significantly increased: 0.45 mm preoperatively, 3.64 mm at 1.5 months, 3.56 mm at 3 months, and 3.57 at 6 months postoperatively (P < 0.001), and the average R value was significantly decreased: 0.29 mm preoperatively, 0.22 mm at 1.5 months, 0.23 mm at 3months, and 0.24 mm at 6 months postoperatively (P < 0.05). Preoperative R was significantly correlated to the reduction rate of R (ΔR). A higher preoperative R was more likely to be decreased (P < 0.01). Postoperative MRD-1 and change in MRD-1 were not correlated to ΔR. After blepharoplasty, the preoperative mean MRD-1 (3.11 mm) was significantly decreased at 1.5 months (2.47 mm; P < 0.01) and 3 months (2.71 mm; P < 0.05) but recovered at 6 months (3.14 mm). However, the average R was not changed: 0.31 mm preoperatively, 0.34 mm at 1.5 months, 0.31 mm at 3 months, and 0.33 mm at 6 months postoperatively. CONCLUSIONS: Long-term tear volume was not changed after blepharoplasty but was decreased after blepharoptosis surgery, and even more so in cases with an initial high tear volume.

Does estrogen deficiency cause lacrimal gland inflammation and aqueous-deficient dry eye in mice?

Researchers have proposed that estrogen deficiency will lead to a Sjögren's syndrome (SjS)-like lacrimal gland inflammation, aqueous tear deficiency and dry eye. The purpose of this study was to determine whether this proposal is correct. Lacrimal glands were obtained from adult, age-matched wild type (WT) and aromatase knockout (ArKO) mice, in which estrogen synthesis is completely eliminated. Tissues were also obtained from autoimmune MRL/Mp-lpr/lpr (MRL/lpr) mice as inflammation controls. Tear volumes in WT and ArKO mice were measured and glands were processed for molecular biological and histological evaluation. Our results demonstrate that estrogen absence does not lead to a SjS-like inflammation in lacrimal tissue or to an aqueous-deficient dry eye. There was no upregulation of genes associated with inflammatory pathways in lacrimal glands of male or female ArKO mice. Such inflammatory activity was prominent in autoimmune MRL/lpr tissues. We also found no evidence of inflammation in lacrimal gland tissue sections of estrogen-deficient mice, and tear volumes of ArKO males were actually increased as compared to those WT controls. Interestingly, our study did show that estrogen absence influences the expression of thousands of lacrimal gland genes, and that this impact is sex- and genotype-specific. Our findings demonstrate that estrogen absence is not a risk factor for the development of SjS-like lacrimal gland inflammation or for aqueous-deficient dry eye in mice.

Time course of changes in tear meniscus radius and blink rate after instillation of artificial tears.

PURPOSE: Using a novel digital meniscometer (PDM), alterations in tear meniscus radius (TMR) were measured simultaneously with blink rate (BR) following the instillation of artificial tears. METHODS: Central TMR and BR of 22 subjects (11 male and 11 female; mean age, 24.3 ± 2.6 SD years) were measured at baseline, and 0, 1, 5, 10, and 30 minutes after instillation of an artificial tear containing hydroxypropyl-guar and glycol (SYS) or saline (SAL). A dose of 35 µL was applied in one eye in a randomized order with a washout period between each drop. RESULTS: For SAL, compared to baseline TMR (0.33 ± 0.08 mm), TMR significantly increased with drop instillation (1.55 ± 0.69 mm) and at 1 minute (0.66 ± 0.36 mm; P < 0.05), but returned to baseline after 5 minutes. For SYS, TMR (0.32 ± 0.07 mm) remained significantly increased after application (1.62 ± 0.81 mm), and at 1 minute (0.81 ± 0.43 mm) and 5 minutes (0.39 ± 0.08 mm; P < 0.05). Compared to baseline BR with SAL (14.8 ± 7.7) and SYS (14.9 ± 9.4), values were significantly increased upon drop instillation (22.5 ± 11.8; 21.3 ± 11.8; P < 0.05), but returned to baseline after 1 minute. Dry eye symptoms were correlated with baseline BR (r = 0.550, P = 0.008). CONCLUSIONS: Results indicate that PDM can detect changes in TMR following instillation of artificial tears. Difference in residence time reflects the different viscosity of each drop. An overload with a large drop may result in an initially increased BR.

Comparison of a new portable digital meniscometer and optical coherence tomography in tear meniscus radius measurement.

PURPOSE: Non-invasive measurement of tear meniscus radius (TMR) is useful in the assessment of tear volume for dry eye diagnosis. This study investigates the agreement between a new, portable, slit-lamp mounted, digital meniscometer (PDM) and optical coherence tomography (OCT) in the measurement of human TMR. METHODS: Images of the tear meniscus at the centre of the lower lid of 30 normal subjects (8M, 22F; mean age 27.5 SD ± 9.6 years) were taken using the PDM and the OCT. On the PDM and OCT images, TMR was measured using imagej 1.46b software. The meniscus on the OCT images was subdivided vertically into three equal sections and the radius calculated for each: bottom (BTMR), centre (CTMR) and top (TTMR). The relationship between PDM and OCT measurements was analysed using Spearman's rank coefficient, and differences between PDM and OCT subsection measurements were evaluated using Bland-Altman plots. RESULTS: Tear meniscus radius measured with the PDM (0.25 ± 0.06 mm) and OCT (0.29 ± 0.09 mm) was significantly correlated (r = 0.675; p < 0.001). The mean differences between TMR using the PDM and the subsections from OCT showed that TMR measured with PDM was greater for BTMR (0.07 mm; CI 0.05-0.10; p < 0.001), similar for CTMR (-0.01 mm; CI -0.04 to 0.02; p = 0.636) and steeper for TTMR (-0.07 mm; CI -0.10 to -0.04; p < 0.001). CONCLUSIONS: Portable digital meniscometer and OCT measurements of the TMR are significantly correlated, suggesting that the new PDM is a useful surrogate for OCT in this respect. The PDM appears to measure the radius of the central section of the tear meniscus.