Advances in understanding and managing dry eye disease

Evaluation of therapeutic efficacy of Emustil drops for ocular discomfort and tear film osmolarity using different treatment management modes under dry environmental conditions

BACKGROUND

We aimed to check the efficacy of Emustil (oil in water emulsion) drops on tear film index and ocular surface dynamics in dry environments through protection and relief treatment modalities.

METHODS

The subjects were exposed to a dry environment using a Controlled Environment Chamber (CEC) where the relative humidity (RH) was 5% and the temperature was 21 °C and screened for ocular symptoms, tear osmolarity, ocular surface temperature (OST) and tear production using ocular Surface Disease Index questionnaire (OSDI), OcuSense TearLab Osmometer, FLIR System ThermaCAM P620 and Schirmer strips/phenol red test respectively. Tear production was calculated by the Tear Function Index test (TFI).

RESULTS

The mean tear film osmolarity decreased significantly from 296.8 mOsm/l at 40% RH to 291 mOsm/l at 5%. (p = 0.01). Instillation of Emustil resulted in a significant increase in tear osmolarity in the relief method compared with osmolarity seen at 5% RH when no drop was used. The mean PRT value decreased from 26 ± 9 in normal conditions (40% RH) to 22 ± 4 mm in dry conditions (5% RH). Emustil drops did not induce any significant change in tear production in the PRT test. No significant change was found in OST following exposure to 5% RH. OST did not show a statistically significant change with the emulsion when used for relief (p > 0.05). The mean score of ocular discomfort observed was 70 at 5% RH. Still, the instillation of the oil-in-water emulsion (Emustil) resulted in a noticeable decrease in visual discomfort to 37 (p = 0.00) in protection and 59 in relief (p = 0.05). Emustil drops substantially improved tear film parameters under a desiccating environment, however, tear film parameters respond differently to the management modalities. In the protection method, tear film osmolarity was protected against a dry environment, while in the relief mode, tear production was improved.

CONCLUSION

CEC allows for a thorough evaluation of tear film parameters and dry eye treatment protocols in labs, providing greater confidence when applying them to patients. In addition, our study showed that Emustil not only provides protection and relief for dry eyes but also helps to maintain ocular homeostasis in desiccating environments. This indicates a promising potential for improving dry eye treatment protocols.

Awareness About Dry Eye Symptoms and Risk Factors Among Eastern Province Population in Saudi Arabia

Background Dry eye syndrome (DES), also known as keratoconjunctivitis sicca (KCS), is a common cause of patient's visits to the ophthalmologist. It is characterized by a defect in the tear film homeostasis, symptoms of ocular discomfort, and visual disturbance. Also, it increases the risk of ocular surface damage if complicated by tear film hyperosmolarity and ocular surface inflammation. The present study aims to measure awareness about dry eye disease and the risk factors among the Eastern region population in Saudi Arabia via an online questionnaire. Methods This is a cross-sectional community-based study conducted in Saudi Arabia that assessed knowledge and awareness of dry eye among the eastern province population using a self-administered online questionnaire. The minimum sample size was 385 adults. Statistical analysis was performed using SPSS software, version 21.0 (IBM Corp., Armonk, NY), and participants' overall awareness level was evaluated based on correct answers. Results In this study, a total of 522 participants fulfilling the inclusion criteria completed the study questionnaire. Participants ranged from 18 to 65 years, with a mean age of 27.2 ± 14.6 years old. Females represented a higher percentage of the sample, 341 (65.3%). Public awareness regarding dry eye diseases in the Eastern region, Saudi Arabia of 149 participants (28.5%) is overall a good awareness level while 373 (71.5%) of them had poor awareness. Conclusion Participants showed unsatisfactory results in awareness of risk factors of dry eye symptoms, where the most reported causes were prolonged concentration while using electronic devices, climatic factors, and lacrimal gland disorders.

Real Life Impact of Dry Eye Disease

Dry Eye Disease (DED) is an increasingly common condition that affects between 5% and 50% of the global population. Even though DED is most frequently diagnosed in older people, it has also been diagnosed in young adults and adolescents more frequently in recent years (employees, gamers). People can experience different types of symptoms and find it challenging to read, watch TV, cook, climb stairs, and meet friends. Mild and severe dry eye can reduce quality of life similarly to mild psoriasis and moderate-to-severe angina. Furthermore, DED patients experience serious difficulties driving vehicles, especially at night, and show a decrease in work productivity, which, when combined with the relevant indirect cost that this condition produces, poses a serious challenge in our days. In addition, DED patients are more likely to develop depression and suicidal ideations and experience frequent sleep disorders. Finally, it is discussed how lifestyle changes, such as increased physical activity, blinking exercises, and a proper diet, have positive implications for the management of this condition. Our aim is to draw attention to the negative effects of dry eye in real life, which are unique to each patient, especially as they relate to the non-visual symptoms experienced by DED patients.

Evaluation of the Clinical Characteristics of Dry Eye Secondary to Different Types of Liver Diseases

INTRODUCTION

This study compares the clinical characteristics of dry eye secondary to primary biliary cholangitis (PBC), drug-induced liver injury (DILI), and viral hepatitis B(HBV) to evaluate the ocular surface damage caused by different types of liver diseases.

METHODS

Thirty healthy people were included as control group. Sixty patients with dry eye secondary to different types of liver disease were included, including 19 cases of PBC, 18 cases of DILI, and 23 cases of HBV. All patients were evaluated by the SPEED questionnaire, corneal fluorescein staining (CFS), noninvasive tear breakup time (NIBUT), Schirmer I test (SIt), tear meniscus height test (TMH), the area of meibomian glands dropout (MG dropout), partial blinking rate (PBR), lipid layer thickness (LLT), meibum expressibility, and meibum quality.

RESULTS

There are statistical differences in ophthalmic examination results between different types of liver diseases and normal people (P < 0.05). Compared with DILI and HBV groups, the CFS score of PBC group score was higher (P < 0.05), the PBR was higher (P < 0.05), and the SIt was lower (P < 0.01). The TMH of PBC and DILI groups were significantly lower than the HBV group, and the difference was statistically significant (P < 0.05). Compared with the PBC group, the LLT of the DILI group decreased (P < 0.01). The area of meibomian glands dropout of the three groups had mild-to-moderate defects, but there was no significant statistical difference between groups (P > 0.05).The Meibum quality score in the DILI group was significantly higher than the HBV group (P < 0.05).

CONCLUSIONS

The PBC group was more prone to aqueous-deficient dry eye. The DILI group was more prone to obstructive meibomian gland dysfunction (MGD).The HBV group was more prone to nonobstructive MGD. The symptoms of dry eye in the PBC group are mild-to-moderate discomfort, but the degree of corneal damage is higher, indicating that the corneal sensitivity is reduced, which may be related to the high rate of partial blinking.

Evaluation of Therapeutic Capability of Emustil Drops against Tear Film Complications under Dry Environmental Conditions in Healthy Individuals

Background and Objectives: Dry eye disease (DED) is a multifactorial ailment of the tears and ocular surface. The purpose of this study was to assess the tear film physiology under controlled dry environmental conditions and compare the efficacy of oil-in-water emulsion drops on tear film parameters in protection and relief treatment modalities under low-humidity conditions. Emustil eye drops were used after exposure to a low-humidity environment in the relief method, whereas, in the protection method, the drops were applied before exposure to low humidity. Materials and Methods: 12 normal male subjects (mean age 34.0 ± 7.0 years) were exposed to ultra-dry environmental conditions. A number of tear film measurements were carried out under desiccating environmental conditions in a controlled environment chamber (CEC), where the chamber temperature sat at 21 °C with a relative humidity (RH) of 5%. Keeler's TearScope Plus and an HIRCAL grid were used to assess the tear break-up time and lipid layer thickness (LLT), and the evaporation rate was evaluated using a Servomed EP3 Evaporimeter. Results: LLT measurements showed that the dry environment affected LLT significantly (p = 0.031). The median grade of LLT dropped from grade 3 (50-70 nm) at 40% RH to grade 2 (13-50 nm) at 5% RH. A significant increase in LLT was seen after both modes of treatment, with a median LLT grade of 3 when the Emustil was used for both protection (p = 0.004) and relief (p = 0.016). The mean tear evaporation rate in normal environmental conditions (40%) was 40.46 ± 11.80 g/m²/h (0.11 µL/min) and increased sharply to 83.77 ± 20.37 g/m²/h (0.25 µL/min) after exposure to the dry environment. A minimal decrease in tear film evaporation rate was seen in relief; however, statistical tests showed that the decrease in tear film evaporation rate was not significant. Mean NITBUT dropped from 13.6 s at 40% RH to 6.6 s at 5% RH (p = 0.002). All NITBUT measurements at 5% RH (with or without the instillation of Emustil) were significantly lower than those at 40%. The instillation of Emustil at 5% RH resulted in a significant improvement in NITBUT for protection (p = 0.016) but this was not the case for relief (p = 0.0.56). Conclusions: A control environmental chamber (CEC) enables the analysis of tear film parameters comparable to those found in dry eye patients. This enables us to examine the capability of oil in emulsion drops to manage tear film disruption in healthy individuals. This study suggests that using Emustil oil-in-water emulsion before exposure to a dry environment should be advocated for people who work in dry environments.

Tear film instability is associated with weakened colocalization between occludin and MUC5AC in scopolamine-induced dry eye disease (DED) rats

PURPOSE

Dry eye disease (DED) is a disease with tear film instability because of multiple factors. This study was conducted to explore roles of occludin and MUC5AC in tear film instability in DED rat model.

METHODS

A total of 20 SD rats were divided into DED group (n = 10) and normal control (NC) group (n = 10). DED rat model was established by subcutaneously injecting with scopolamine hydrobromide. Clinical examinations, including tear breakup time (tBUT), Schirmer's test and corneal fluorescein staining, were conducted to determine corneal functions. Transmission electron microscopy was used to measure the ultrastructures of corneal epithelial cells. Western blotting assay was used to identify occludin expression in corneal tissues of DED rats. Real-time PCR (RT-PCR) was performed to verify gene transcription of occludin and MUC5AC. Colocalization between occludin and MUC5AC was identified with confocal fluorescence microscopy.

RESULTS

Tear breakup time was significantly shorter, and corneal fluorescein staining score was predominantly higher in DED rats compared to those in normal rats (P < 0.05). Normal rats showed a steady tear secretion throughout the whole experiments, while DED rats showed a dramatic reduction on day 14. DED rats demonstrated ultrastructural damage of Golgi apparatus and endoplasmic reticulum in corneal epithelial cells. Occludin and MUC5AC expressions were significantly downregulated in corneal tissue of DED rats compared with those of normal rats (P < 0.05). Percentage of occludin-MUC5AC-colocalized corneal epithelial cells in DED rats was significantly less compared with those in normal rats (P < 0.01).

CONCLUSIONS

Tear film stability was damaged in scopolamine-induced DED rats because of the weakened colocalization between occludin and MUC5AC molecule. This study would provide a potential clue for the pathogenesis and a promising theoretical basis for clinical work of DED.

Investigating Neutrophil-to-Lymphocyte and C-Reactive Protein-to-Albumin Ratios in Type 2 Diabetic Patients with Dry Eye Disease

BACKGROUND

Patients with Diabetes mellitus (DM) are at risk of developing dry eye disease (DED). We investigated routine laboratory parameters in patients with type 2 DM (T2D) and T2D-DED to identify potential inflammatory markers.

METHODS

A retrospective study of 241 randomly selected patients (30 DED non-diabetic, 120 T2D, and 91 with T2D-DED). The neutrophil-to-lymphocyte ratios (NLR), CRP-to-albumin ratios (CAR), and the glycosylated haemoglobin A1c (HbA1c) results were correlated between groups.

RESULTS

The NLR and HbA1c were significantly higher in the T2D-DED group (p≤0.001 and 0.0001, respectively) when compared with T2D and DED non-diabetic groups. CAR was insignificantly high in the three groups (p=0.192). A positive correlation was identified between CAR and NLR in T2D-DED patients (p= 0.008).

CONCLUSION

In T2D-DED patients, NLR was significantly high and positively correlate with CAR. These results predicate diabetes with dry eye complications, and biomarker-mediated inflammation may have important roles in DED pathogenesis.

Association of Tear Osmolarity With Signs and Symptoms of Dry Eye Disease in the Dry Eye Assessment and Management (DREAM) Study

Purpose

To determine the relationships of (1) tear osmolarity (TO) levels with the severity of signs and symptoms of dry eye disease (DED) and (2) changes in TO with changes in signs and symptoms.

Methods

Patients (N = 405) with moderate to severe DED in the Dry Eye Assessment and Management (DREAM) Study were evaluated at baseline and at six and 12 months. Associations of TO with signs and symptoms were evaluated using Pearson correlation coefficient (r) and regression models.

Results

The mean (standard deviation [SD]) TO was 303 (16) mOsm/L at baseline and 303 (18) mOsm/L at both six and 12 months. TO was higher in older patients (306 mOsm/L for ≥70 years vs. 300 mOsm/L for <50 years; P = 0.01) and those with Sjögren's disease (311 vs. 302 mOsm/L; P < 0.0001). TO did not differ between patients randomized to placebo and omega-3 fatty acid supplementation. TO was weakly correlated with conjunctival (r = 0.18; P < 0.001) and corneal staining scores (r = 0.17; P < 0.001), tear film break-up time (r = 0.06; P = 0.03), and Schirmer test score (r = -0.07; P = 0.02) but not with Ocular Surface Disease Index scores (r = 0.03; P = 0.40). Changes in signs and were not significantly correlated with change in TO at six or 12 months.

Conclusions

Within DREAM, TO was weakly correlated with DED signs, explaining <5% variability in signs. Changes in tear osmolarity were not associated with changes in signs and symptoms of DED, indicating that the association may not be causal.

Factors affecting the prevalence, severity, and characteristics of ocular surface pain

Introduction

Ocular surface pain has been traditionally lumped under the umbrella term "dry eye" (DE) but is now understood as its own entity and can occur in the absence or presence of tear dysfunction. Identifying patients at risk for the development of chronic ocular surface pain, and factors contributing to its severity are important in providing precision medicine to patients.

Areas covered

In this review, we discuss factors linked to the presence and severity of ocular surface pain, including eye related features, systemic characteristics, and environmental findings. We discuss corneal nerves, whose anatomic and functional integrity can be characterized through in vivo confocal microscopy images and testing of corneal sensitivity. We review systemic diseases that are co-morbid with ocular surface pain, including physical and mental health diagnoses. Finally, we identify environmental contributors, including air pollution, previous surgeries, and medications, associated with ocular surface pain.

Expert opinion

Intrinsic and extrinsic factors contribute to ocular surface pain and must be considered when evaluating an individual patient. These factors can inform the suspected etiology of the pain, and guide management decisions such as tear replacement or medications targeting nerve pain.

Acupuncture for the management of dry eye disease

The effectiveness of using acupuncture for dry eye disease (DED) is controversial. Thus, this systematic review investigated the effectiveness and feasibility of using acupuncture for DED in accordance with the 2020 PRISMA statement. The outcomes of interests were (1) to evaluate the efficacy of acupuncture in improving the ocular surface disease index (OSDI), Schirmer I test score, and tear breakup time from baseline to the last follow-up; (2) to determine possible complications of using acupuncture; and (3) to investigate the superiority of acupuncture over other commonly used treatments for DED. Data from 394 patients were collected. Results showed that acupuncture significantly prolonged the tear breakup time (P < 0.0001), significantly increased the Schirmer I test score (P < 0.0001), and significantly reduced the OSDI (P < 0.0001) from baseline to the last follow-up. Compared with the control group, the acupuncture group had significantly greater Schirmer I test score (P < 0.0001), significantly longer tear breakup time (P = 0.0004), and significantly lower OSDI (P = 0.002). These results suggest that acupuncture is effective and feasible in improving symptoms and signs of DED. No severe adverse effects of acupuncture were observed.

Effect of surgical face mask wearing on tear film in women with a high body mass index

PURPOSE

Due to the COVID-19 pandemic, wearing a face mask has become an essential measure to reduce the rate of virus spreading. The aim of the study was to assess the effect of wearing a surgical face mask for a short period on the tear film parameters in subjects with a high body mass index (BMI).

METHODS

Twenty-five females with a high BMI (31.4 ± 5.5 kg/m2) aged 18-35 years (22.7 ± 4.6 years) participated in the study. In addition, a control group consisting of 25 females (23.0 ± 6.7 years) with a high BMI (29.9 ± 4.1 kg/m2) participated in the study in which no mask was worn. The standardized patient evaluation of eye dryness (SPEED) questionnaire was completed first, followed by the phenol red thread (PRT) and tear ferning (TF) tests, before wearing the face mask. The subjects wore the face mask for 1 hour, and the measurements were performed again immediately after its removal. For the control group, the measurements were performed twice with one hour gap.

RESULTS

Significant (Wilcoxon test, p < 0.05) differences were found between the SPEED scores (p = 0.035) and the PRT measurement (p = 0.042), before and after wearing the surgical face mask. The PRT scores have improved after wearing the surgical face mask, while the dry eye symptoms detected by the SPEED questionnaire have increased. On the other hand, no significant (Wilcoxon test, p = 0.201) differences were found between the TF grades before and after wearing a surgical face mask. For the control group, no significant (Wilcoxon test, p > 0.05) differences were found between the two scores from the SPEED questionnaire and the PRT, and TF tests.

CONCLUSIONS

Wearing a surgical face mask for a short duration leads to a change in volume and quality of tears as well as dry eye symptoms in women with a high BMI.

ONSET-1 Phase 2b Randomized Trial to Evaluate the Safety and Efficacy of OC-01 (Varenicline Solution) Nasal Spray on Signs and Symptoms of Dry Eye Disease

PURPOSE

The purpose of this trial was to evaluate the safety and efficacy of OC-01 (varenicline solution), a nicotinic acetylcholine receptor agonist nasal spray, on signs and symptoms of dry eye disease.

METHODS

A phase 2b, multicenter, randomized, double-masked, vehicle-controlled trial (ONSET-1; NCT03636061) was performed. Patients were aged 22 years or older with a physician's diagnosis of dry eye disease and previous use of artificial tears were randomized 1:1:1:1 to control (vehicle nasal spray twice daily [BID]), OC-01 0.006 mg BID, OC-01 0.03 mg BID, and OC-01 0.06 mg BID. The primary end point was the change in the anesthetized Schirmer test score from baseline to day 28 in the study eye. The secondary end points included the change in the eye dryness score from baseline to day 28.

RESULTS

One hundred eighty-two patients were randomized. After 28 days, patients who received OC-01 0.03 or 0.06 mg showed a statistically significant improvement in tear film production relative to vehicle, with least squares mean differences from vehicle of 7.7 mm [95% confidence interval, 3.8-11.7; P < 0.001] with OC-01 0.03 mg and 7.5 mm (95% confidence interval, 3.4-11.6; P < 0.001) with OC-01 0.06 mg. Patients receiving OC-01 0.03 mg showed a significant reduction in the eye dryness score by day 28 versus vehicle (P = 0.021); those receiving the OC-01 0.06 mg dose showed a nonsignificant reduction versus vehicle. OC-01 administration was associated with sneezing (62%-84%) and cough (9%-25%); these were transient and predominantly mild in severity.

CONCLUSIONS

OC-01 nasal spray administered BID at 0.03 and 0.06 mg resulted in significant improvements in signs and symptoms of dry eye disease, was well tolerated, and warrants further clinical investigation.

Dexamethasone attenuates dry eye-induced pyroptosis by regulating the KCNQ1OT1/miR-214 cascade

Dry eye disease (DED) is an inflammatory disorder of the ocular surface seriously affecting the quality of life of patients. Topical dexamethasone (Dex) administration protects the cornea from the hyperosmotic stress (HS) induced by tears. Pyroptosis participates in the activation of epithelial inflammation during DED. However, it remains unclear whether Dex attenuates the progression of DED through pyroptosis. In this study, we aimed to investigate the effect of Dex on DED using both cell and animal models and its underlying mechanism. The inflammatory factors contained in tears were detected using a cytokine assay. The pyroptosis in DED mice and human corneal epithelial cells (HCECs) treated with hyperosmotic medium under various treatments was evaluated by immunohistochemical assays (IHC) or western blotting (WB). RNA expression was manipulated with siRNA or agomir microRNAs and measured using a polymerase chain reaction. The scratch assay was used to assess the migration rate of HCECs. Remaining corneal defects were evaluated using fluorescein staining and photographed using a digital camera. Dex could suppress the release of inflammatory factors and notably attenuate pyroptosis, KCNQ1OT1 expression, and NF-κB activation induced by HS injury in vivo and in vitro. KCNQ1OT1 upregulation could activate pyroptosis by sponging miR-214. Furthermore, KCNQ1OT1 knockdown and miR-214 overexpression reversed the effect of HS, promoted the migration of HCECs, and accelerated corneal wound healing. Dex effectively suppressed HS-induced pyroptosis through the KCNQ1OT1/miR-214/caspase-1 signaling axis by inhibiting the NF-κB activation. Our results provide a novel understanding of the mechanism of Dex as an anti-inflammatory drug in DED.

Capsanthin from Capsicum annum fruits exerts anti-glaucoma, antioxidant, anti-inflammatory activity, and corneal pro-inflammatory cytokine gene expression in a benzalkonium chloride-induced rat dry eye model

Dry eye disease (DED) is a complex ocular surface inflammatory disease. Its occurrence varies widely over the world, ranging from 5% to 34%. The use of preservatives, specifically benzalkonium chloride, in the ocular drops worsens the DED conditions. Furthermore, the Covid-19 pandemic increased screen time and the use of face masks and shields. As a result, the number of people suffering from dry eye disease (DED) has increased significantly in recent years. The main objective of our study is to find a solution to manage the dry eye disease (DED) preferably from natural source without any adverse events. In this study, the beneficial effects of capsanthin from Capsicum annum (CCA) were evaluated on benzalkonium chloride (BAC)-induced dry eye disease (DED) in Albino Wistar rats. Oral supplementation of CCA resulted in a statistically significant decrease in intraocular pressure (IOP) (p < .0001), increase in tear break-up time (TBUT) (p < .01), decline in Schirmer test results (p < .01), and decrease in corneal surface inflammation (p < .01). Capsanthin ameliorated in reducing oxidative stress by increasing serum antioxidant levels such as glutathione peroxidase (GPX), nitric oxide (NO), and lactoferrin (LTF) and inhibiting matrix metalloproteinases 2 and 9 (MMP2 and MMP9) (p < .0001). Capsanthin treatment significantly inhibited the expression of inflammatory cytokines, tumor necrosis factor-alpha (TNF-α), interleukins (IL-2, IL-4, IL-6), and pro-inflammatory mediator, matrix metalloproteinase-9 (MMP9). Furthermore, the lacrimal gland expressed vascular cell adhesion molecule (VCAM-1), and prostaglandin-endoperoxide synthase 2 (PTGS2) was suppressed by CCA treatment. PRACTICAL APPLICATIONS: Benzalkonium chloride (BAC), a preservative widely used in the topical ocular drug delivery system (ODDS), causes undesirable effects such as dry eye disease as well as ameliorating intraocular pressure leading to optical nerve damage and irreversible vision loss. Capsanthin from Capsicum annum (CCA) can be used to treat symptoms related to dry eye disease such as inflammation, eye irritation, visual disturbance, ocular discomfort with potential damage to the ocular surface. The CCA may be beneficial in the treatment of glaucoma, an elevated intraocular pressure. Capsanthin from C. annum can be useful in managing DED by increasing tear break-up time (TBUT), declining in Schirmer test results and decreasing in corneal surface inflammation.

3D Printed Hydrogels for Ocular Wound Healing

Corneal disease is one of the most significant causes of blindness around the world. Presently, corneal transplantation is the only way to treat cornea blindness. It should be noted that the amount of cornea that people donate is so much less than that required (1:70). Therefore, scientists have tried to resolve this problem with tissue engineering and regenerative medicine. Fabricating cornea with traditional methods is difficult due to their unique properties, such as transparency and geometry. Bioprinting is a technology based on additive manufacturing that can use different biomaterials as bioink for tissue engineering, and the emergence of 3D bioprinting presents a clear possibility to overcome this problem. This new technology requires special materials for printing scaffolds with acceptable biocompatibility. Hydrogels have received significant attention in the past 50 years, and they have been distinguished from other materials because of their unique and outstanding properties. Therefore, hydrogels could be a good bioink for the bioprinting of different scaffolds for corneal tissue engineering. In this review, we discuss the use of different types of hydrogel for bioink for corneal tissue engineering and various methods that have been used for bioprinting. Furthermore, the properties of hydrogels and different types of hydrogels are described.

Alleviation of Endoplasmic Reticulum Stress Enhances Human Corneal Epithelial Cell Viability under Hyperosmotic Conditions

Tear hyperosmolarity plays an essential role in the initiation and progression of dry-eye disease. Under a hyperosmotic environment, corneal epithelial cells experience perturbations in endoplasmic reticulum function that can lead to proinflammatory signaling and apoptosis. In this study, we investigated the effect of tauroursodeoxycholic acid (TUDCA), a chemical chaperone known to protect against endoplasmic reticulum stress, on corneal epithelial cells exposed to hyperosmotic conditions. We found that the expression of the genes involved in the activation of the unfolded protein response and the pro-apoptotic transcription factor DDIT3 were markedly upregulated in patients with Sjögren’s dry-eye disease and in a human model of corneal epithelial differentiation following treatment with hyperosmotic saline. Experiments in vitro demonstrated that TUDCA prevented hyperosmotically induced cell death by reducing nuclear DNA fragmentation and caspase-3 activation. TUDCA supplementation also led to the transcriptional repression of CXCL8 and IL5, two inflammatory mediators associated with dry-eye pathogenesis. These studies highlight the role of hyperosmotic conditions in promoting endoplasmic reticulum stress in the cornea and identify TUDCA as a potential therapeutic agent for the treatment of dry-eye disease.

Crocin as a vision supplement

Crocin is a natural ingredient of saffron (Crocus sativus L.) flower that has shown potential for application as a supplement in eye health and preserving vision. Crocin has been examined for its potential to treat various eye diseases such as glaucoma, macular dystrophies, diabetic retinopathy, and age-related macular degeneration. This review briefly discusses the role of crocin in different eye diseases. The underlying pathophysiological pathways involved in the effect of crocin on ophthalmic diseases are also reviewed. Preclinical evidence shows the cytoprotective, antioxidative, anti-inflammatory, and blood-flow enhancing effects of crocin in retinal tissue. Crocin also affects the retinal pathologies by activating PI3K/Akt and inhibiting NF-κB signalling pathways. Clinical evidence suggests that crocin improves outcomes in patients with retinal degenerations, retinal dystrophies, and glaucoma. Overall, crocin can be suggested as a potential vision supplement in healthy populations and patients with eye diseases. However, more clinical studies with larger sample sizes and longer follow-up durations are needed to confirm the current evidence.

Outcome Measures to Assess Dry Eye Severity: A Review

Outcome measures used to assess efficacy of dry eye therapeutics have not been consistently applied in clinical settings, nor have they been shown to correlate with functional outcomes. We propose that corneal staining, a clinically meaningful dry eye parameter, should be used as a standard objective outcome measure across all clinical trials evaluating dry eye treatments. We justify this based on evidence regarding its relationship to vision and vision related quality-of-life. In addition, corneal staining has been shown to correlate with ocular surface inflammation, a well elucidated aspect of dry eye pathophysiology and an active area in therapeutics research. No one outcome measure explored herein correlates perfectly to this heterogenous disease. However, there is mounting evidence showing the correlation between corneal staining and functional visual indices. We hope that future clinical trials will standardize corneal staining as a measure to determine the efficacy of interventions and justify their clinical utility.

Single-Tear Proteomics: A Feasible Approach to Precision Medicine

Lacrimal fluid is an attractive source of noninvasive biomarkers, the main limitation being the small sample amounts typically collected. Advanced analytical methods to allow for proteomics profiling from a few microliters are needed to develop innovative biomarkers, with attractive perspectives of applications to precision medicine. This work describes an effective, analytical pipeline for single-tear analysis by ultrahigh-resolution, shotgun proteomics from 23 healthy human volunteers, leading to high-confidence identification of a total of 890 proteins. Highly reproducible quantification was achieved by either peak intensity, peak area, or spectral counting. Hierarchical clustering revealed a stratification of females vs. males that did not emerge from previous studies on pooled samples. Two subjects were monitored weekly over 3 weeks. The samples clustered by withdrawal time of day (morning vs. afternoon) but not by follow-up week, with elevated levels of components of the immune system in the morning samples. This study demonstrates feasibility of single-tear quantitative proteomics, envisaging contributions of this unconventional body fluid to individualized approaches in biomedicine.

Assessment of a Cationic Emulsion to Control the Tear Film Evaporation Rate

PURPOSE

To investigate the effect of a single application of cationic emulsion in controlling tear film evaporation and improving tear quality and quantity.

MATERIALS A METHODS

Twenty male subjects diagnosed with DE were enrolled in the study with an average age of 45.8 ± 6.37 years. The tear film parameters were observed at several time points post-instillation of the cationic emulsion (10, 20, 30, and 60 min). The tear evaporation rate (TER) was measured with a VapoMeter. Noninvasive tear break-up time and meniscus height were assessed using OCULUS Keratograph.

RESULTS

TER decreased by more than 20% at 20, 30, and 60 minutes time points after instillation of single drop of cationic emulsion. Also, a significant improvement in tear film stability was found at all time points following the instillation of cationic emulsion eye drops. The mean tear break-up time increased from 5.55 ± 2.87 to 6.6 ± 4.2 sec at 60 minutes. The maximum increase in tear break-up time occurred at 30 minutes time point. The TMH was also significantly higher post-instillation of oil emulsion eye drops. There was a significant increase in the TMH post-therapy with oil drop at all time points.

CONCLUSION

The overall study findings of this study illustrate that the single application of a cationic emulsion effectively controls tear film evaporation in patients with mild to moderate DEs. The cationic emulsion efficiently enhanced both the tear film stability and the tear meniscus volume.

Repeatability and Reproducibility of Tear Film Evaporation Rate Measurement using a new Closed-Chamber Evaporimeter

Purpose:

This study evaluates the repeatability and reproducibility of tear film evaporation rate measurement using a commercially available handheld closed-chamber evaporimeter (VapoMeter, Delfin Technologies, Finland).

Study Design:

This was a randomized observational study, in which two visits were required. At visit 1, screening tests were performed on the participants. Subsequently, tear evaporation was measured thrice by examiner 1 (E1). The procedure was then repeated by examiner 2 (E2) at visit 2.

Methods:

40 healthy participants with no ocular diseases were recruited for this study. A closed chamber evaporimeter was used in this study (VapoMeter, Delfin Technologies, Finland). Primary investigations, including slit-lamp examination, tear production test, and ocular discomfort, were performed during the first visit for the purpose of screening.

Results:

The mean of the three measurements of tear evaporation obtained by examiner 1 at visit 1 was 19.38 ± 0.79 g/m2/h, and the mean of the three readings obtained by examiner 2 at visit 2 was 20.49 ± 0.48 g/m2/h. The average Intraclass Correlation Coefficient (ICC) among the three readings of tear evaporation was 0.84 and 0.63 with a 95% confidence interval (CI) at visits 1 and 2, respectively. A comparison of the reliability of the measurements from the two examiners revealed an ICC of 0.69 with a 95% CI.

Conclusion:

The VapoMeter provides repeatable and reproducible measurements of tear film evaporation. This study demonstrates that the VapoMeter could provide clinicians with a readily available method for rapid evaluation of tear film evaporation. By considering the significance of tear evaporation as a diagnostic tool for dry eyes, the VapoMeter may help to diagnose better and manage dry eye syndrome.

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

PURPOSE

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

DESIGN

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

PARTICIPANTS

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

METHODS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

Tear Osmolarity in the Diagnosis of Systemic Dehydration and Dry Eye Disease

Systemic dehydration due to inadequate water intake or excessive water loss, is common in the elderly and results in a high morbidity and significant mortality. Diagnosis is often overlooked and there is a need for a simple, bedside diagnostic test in at-risk populations. Body hydration is highly regulated with plasma osmolality (pOsm) being tightly controlled over a wide range of physiological conditions. By contrast, normal tear osmolarity (tOsm) is more variable since the tear film is exposed to evaporation from the open eye. While plasma hyperosmolality is a diagnostic feature of systemic dehydration, tear hyperosmolality, with other clinical features, is diagnostic of dry eye. Studies in young adults subjected to exercise and water-deprivation, have shown that tOsm may provide an index of pOsm, with the inference that it may provide a simple measure to diagnose systemic dehydration. However, since the prevalence of both dry eye and systemic dehydration increases with age, the finding of a raised tOsm in the elderly could imply the presence of either condition. This diagnostic difficulty can be overcome by measuring tear osmolality after a period of evaporative suppression (e.g., a 45 min period of lid closure) which drives tOsm osmolality down to a basal level, close to that of the pOsm. The arguments supporting the use of this basal tear osmolarity (BTO) in the diagnosis of systemic dehydration are reviewed here. Further studies are needed to confirm that the BTO can act as a surrogate for pOsm in both normally hydrated subjects and in patients with systemic dehydration and to determine the minimum period of lid closure required for a simple, "point-of-care" test.

Dry eye disease symptoms and quality of life in perimenopausal and postmenopausal women

OBJECTIVE

This study aimed to evaluate dry eye disease (DED) symptoms and quality of life (QoL) in a group of perimenopausal and postmenopausal women, based on the Ocular Surface Disease Index (OSDI) questionnaire.

METHODS

An observational study was performed in a group of 1947 perimenopausal and postmenopausal women, aged between 45 and 79 years. The personal data collected were age, menopause status, age at menopause, and OSDI score.

RESULTS

The mean age of the group was 54.18 ± 6.84 years, with a mean age at menopause of 49.45 ± 4.02 years. The average OSDI score was 29.20 ± 19.4. The overall prevalence of DED symptoms was 79%, increasing significantly in postmenopausal women, 76.4% vs. 80.5% (p = 0.029). In our group, 37.7% had severe DED symptoms. Ocular symptoms, vision-related functions, and environmental trigger scores were higher in postmenopausal women, leading to a lower QoL. The severity of OSDI score increases with age (β coefficient: 0.15 [95% confidence interval: 0.02; -0.28]), while the severity of OSDI score decreases with a later onset age of menopause (β coefficient: -0.27 [95% confidence interval: -0.55; -0.01]).

CONCLUSIONS

DED symptoms are highly prevalent in perimenopausal and postmenopausal women. Postmenopausal women had a higher prevalence of symptoms and higher OSDI scores than perimenopausal women. The severity of DED symptoms and vision-related functions leads to poorer QoL.

Study of tear film optics and its impact on quality of vision

Purpose:

To evaluate the relation of the tear film on the quality of vision comparing parameters in normal patients to those having dry eye disease.

Methods:

50 normal and 50 eyes with dry eye disease (DED) were included in the study. Patients were screened for dry eye with Schirmer's test, tear break up time, ocular surface staining, and assessment of meibomian gland disease. Their quality of vision was assessed using the Optical quality analysis system (OQAS). The results of dry eye evaluation were correlated with the parameters on the OQAS especially the mean objective scatter index (OSI).

Results:

Patients with dry eye and unstable tear film were found to have a significantly worse quality of vision and optical scatter (P < 0.05). They were also noted to have fluctuation of vision between blinks.

Conclusion:

Tear film optics can have an important bearing on the quality of vision and quality of life. A detailed assessment preoperatively will help improve surgical outcomes and patient satisfaction.

Dry Eye Disease: Early Recognition with Guidance on Management and Treatment for Primary Care Family Physicians

Primary care presentations of dry eye disease (DED) are common and pose a diagnostic challenge due to the variety of symptoms and the absence of certainty for family practitioners. While there are many published articles on the topic, the 2017 Tear Film and Ocular Surface Society Dry Eye Workshop was a landmark report in distinguishing multifactorial differences. Redefined terms clarified the DED disorder. The ocular surface—the tear/air interface—is the primary refractive component of the eye, which is why DED is so significant and impacts vision. There is a high prevalence of DED in the community, ranging from 5% to 30% of people across multiple studies. Elderly patients have up to 75% increased risk of DED and receive more intensive treatment than younger age groups. DED is also more common in women than men, occurring in 9.8% of postmenopausal women. The causes of DED span defective lacrimal apparatus and systemic disorders. Despite its prevalence, up to one-half of patients with confirmed DED do not receive proper alleviating treatment. Risk factors on functional and environmental bases follow. Tools to elicit a diagnosis more confidently are outlined using the Ocular Surface Disease Index (OSDI) and the Symptom Assessment in Dry Eye questionnaires (SANDE). Lacritin, lutein, vitamin A, and balanced nutrition are essential contributors to maintaining healthy eyes with appropriate management and treatment. The authors hope that this paper will prompt a more accurate and expedient diagnosis of DED in primary care practice and an earlier recognition of specialist referrals.

Dry eye disease (DED) poses a diagnostic challenge to primary care physicians. The condition involves the tear/air interface, at the corneal (ocular) surface, where light enters the eye. Any change in light refraction affects regular sight. Symptoms of DED include itching, grittiness, foreign body sensation, redness, excessive tearing, and visual blurring, the lattermost being the most common presentation. Ultimately, the untreated disease leads to continued discomfort and visual deficit, but when severe, it can result in blindness. Up to 30% of the population suffers from DED, with the elderly, particularly women, more affected. Unfortunately, up to 50% of those affected have inadequate treatment. Questionnaires help in diagnosis. Simple office tests can indicate the severity of eye problems. Technology with smartphone photography can take high-resolution images, which are useful in education and teaching. A multitude of conditions cause DED, including blepharitis, an infection of the eyelids. Environmental risks also abound. Proper nutrition is essential in maintaining eye health. Intermittent eye symptoms are likely to be underrated by the public, by purchasing over-the-counter products such as artificial tears rather than seeking a proper medical check. Newer prescription medications are now available for DED relief before advancing to debility requiring specialist treatment.

A ratiometric electrochemiluminescence resonance energy transfer platform based on novel dye BODIPY derivatives for sensitive detection of lactoferrin

A ratiometric electrochemiluminescence resonance energy transfer (ECL-RET) platform depended on novel dye BODIPY derivatives was proposed for rapid detection of lactoferrin. This ECL-RET platform is composed of aptamer decorated BODIPY composites and C₆₀@BSA, in which BODIPY derivative is the ECL probe and can generate significant resonance energy transfer with K₂S₂O₈. BODIPY derivative and K₂S₂O₈ are used as built-in reference signal and calibration signal respectively to eliminate background signal and abnormal change signal by double signal self-calibration process. At the same time, C₆₀, as the accelerator of K₂S₂O₈, can effectively increase the ECL signal and further transfer as much energy as possible to BODIPY derivative. Under optimal conditions, the constructed ECL-RET platform exhibited sensitive detection of lactoferrin in the wide linear range of 10^-4- 850 ng/mL with a LOD of 42 fg/mL. Meanwhile, the proposed ECL-RET aptasensor demonstrated superior stability, specificity and reproducibility, displaying favorable application value in practical diagnosis of this method.

Evaluation of Tear Protein Markers in Dry Eye Disease with Different Lymphotoxin-Alpha Expression Levels

PURPOSE

To compare tear protein markers between normal subjects and patients with dry eye (DE) and high and low lymphotoxin-alpha (LT-α) levels.

DESIGN

Prospective cross-sectional study.

METHODS

Patients with DE were divided into low (≤700 pg/mL) and high (>700 pg/mL) LT-α groups. Twelve protein markers were measured by microsphere-based immunoassay and ocular surface parameters were determined in right eyes (33 high LT-α DE, 27 low LT-α DE, and 20 control eyes) and left eyes (21 high LT-α DE, 39 low LT-α DE, and 20 control eyes).

RESULTS

In both eyes, tumor necrosis factor-α (TNF-α), interleukin (IL)-10, IL-1β, IL-1 receptor antagonist (IL-1Ra), IL-17A, and IL-12/23 p40 levels in high LT-α DE were significantly higher (P < .01) than in low LT-α DE. Significant correlations identified in high LT-α DE were: Standard Patient Evaluation Eye Dryness with IL-10 (R = 0.43, P = .013), IL-1β (R = 0.48, P = .005), and IL-12/23 p40 (R = 0.50, P = .003), IL-12/23 p40 with ocular surface disease index (R = 0.35, P = .049), and epidermal growth factor with corneal fluorescein staining score (R = -0.36, P = .038). Significant correlations in low LT-α DE were: Standard Patient Evaluation Eye Dryness with IL-10 (R = -0.39, P = .046), TNF-α (R = -0.39, P = .047), and IL-17A (R = -0.48, P = .013), ocular surface disease index with TNF-α (R = -0.47, P = .017) and IL-17A (R = -0.46, P = .018), and IL-6 with tear breakup time (R = -0.40, P = .044). Lastly, IL-1Ra levels significantly increased in DE patients, positively correlated with temporal conjunctival hyperemia index, and negatively correlated with Schirmer I test (P < .05).

CONCLUSIONS

Our study identified tear IL-1Ra level as a potential biomarker to replace the Schirmer I test. Multiple tear protein marker levels increased in high LT-α DE, indicating that high LT-α DE might have a different pathogenesis.

Corneal Sensitivity and Tear Function in Recurrent Corneal Erosion Syndrome

Purpose

To determine the association of corneal sensitivity and tear functions on the prognosis of eyes after posttraumatic recurrent corneal erosion syndrome (RCES).

Methods

Patients were enrolled retrospectively and had unilateral RCES and a history of ocular surface trauma. A corneal sensitivity test and tear function test (tear break-up time and Schirmer test) were performed at three time points (month 1 to month 3, month 3 to month 6, and month 6 to month 12). Depending on the number of recurrences during the follow-up, patients were divided into group A (n > 2) or group B (n = 2). A comparison between diseased and normal fellow eyes in each patient was performed.

Results

A total of 31 patients were enrolled and divided into group A (n = 14) and group B (n = 17). The mean age was 40.3 ± 12.2 years, whereas the mean follow-up was 28.0 ± 3.6 months. During the study period, corneal sensitivity, tear break-up time, and the Schirmer test results were all lower in diseased eyes than in normal fellow eyes in both groups. Compared to the first time point, recovery of corneal sensitivity and the Schirmer test values were observed in diseased eyes in group B at the second and third time points.

Conclusions

Poor corneal sensitivity and tear function are associated with posttraumatic RCES. Recovery of corneal sensitivity and tear function may be associated with a reduction of recurrence in eyes with posttraumatic RCES.

Diagnosis and remediation of blink inefficiency

To examine the role of incomplete blinking in contributing to blink inefficiency, symptoms of dry eye and ocular surface disease. To review methods for diagnosing blink inefficiency (including both reduced overall blink rate and increased incomplete blink rate) and the role of remediation for efficient complete blinking as an essential part of the lacrimal functional unit in maintaining tear homeostasis. Diagnosis and remediation of blink inefficiency appear to have been somewhat misunderstood in the management of dry eye disease. To the extent that a high incomplete blink rate ranks in significance with low blink frequency in contributing to blink inefficiency, measures and remediation of only total blink rate are of reduced usefulness in the diagnosis and treatment of blink inefficiency-related ocular surface exposure, dry eye symptoms and ocular surface disease. In addition, a patient's blink performance during a biomicroscopy or any other clinical assessment of blink efficiency, is unlikely to be characteristic of or relevant to the blink inefficiency that develops and causes symptoms during their various day-to-day activities. There appears to be a strong case for prescribing blink efficiency exercises in the management of many cases of dry eye symptoms and ocular surface disease. Remediation of spontaneous blink inefficiency may require that a motor memory of voluntary complete, rapid, relaxed and natural looking blink formation is established and maintained as the basis for efficient spontaneous blinking. Voluntary forceful blinking may undermine the motor memory of efficient blinking and risk the depletion of any reserves of lipid.

Topical Low Dose Preservative-Free Hydrocortisone Reduces Signs and Symptoms in Patients with Chronic Dry Eye: A Randomized Clinical Trial

PURPOSE

Dry eye disease (DED) is a highly prevalent ocular condition with a significant burden on affected patients. Regardless of the underlying etiology, DED is associated with increased ocular surface inflammation. We investigated the safety and efficacy of a short-term treatment with topical low dose hydrocortisone in patients with chronic DED and ocular surface inflammation.

METHODS

A total of 60 patients (mean age 51 ± 14 years) with chronic DED and conjunctival hyperemia greater than grade 2 on the Efron scale were included. Patients were randomized to receive either preservative-free hydrocortisone 0.335% (Softacort, Laboratories Thea, France) for 12 days four times daily followed by 2 days twice daily instillation (intense treatment group) or 8 days three times daily followed by 3 days twice daily treatment (standard treatment group). Ocular redness was assessed at baseline, day 14, and day 28. Measurement of intraocular pressure (IOP) and clinical tests to assess signs and symptoms of DED were performed.

RESULTS

Conjunctival hyperemia and Ocular Surface Disease Index (OSDI) significantly decreased in both treatment groups (p < 0.001 each) after hydrocortisone treatment. A significant increase in tear film thickness was seen 4 weeks after treatment start (p = 0.03 and p = 0.04, respectively). IOP did not change in either of the two treatment groups (p = 0.45).

CONCLUSION

Treatment with low dose hydrocortisone 0.335% reduced ocular inflammation and decreased OSDI score. No change in IOP was observed in either of the two treatment schedules. Because of its good safety profile, low dose hydrocortisone may be an interesting alternative to standard corticosteroid treatment in DED.

FUNDING

Laboratories Thea.

TRIAL REGISTRATION

Clinicaltrials.gov registry: NCT03907865.

Oculoplastic aspects of ocular surface disease and their management

The normal structure and function of the eyelids, eyelashes, conjunctival fornices, and lacrimal system are essential for the health of the ocular surface, and abnormalities of these structures accompany many cases of ocular surface disease. We describe the role of oculoplastic intervention in the context of ocular surface disease, focusing on blink disorders, lagophthalmos, entropion, lid scarring and keratinization, trichiasis, and punctal and lacrimal sac disease.

Tear electrolyte assessment of diabetic patients in Southern Nigeria

Background

Tears are a critical body extracellular fluid coating the surface epithelial cells of the cornea and conjunctiva, and providing the optically smooth surface necessary for refraction of light onto the retina. The biological and chemical properties of tears change in response to systemic disease.

Objectives

This study assessed the concentration of calcium, magnesium and phosphate levels in tears of diabetics.

Methods

A comparative cross-sectional study involving twenty diabetics visiting Department for Health Services, University of Benin and forty non-diabetics within the University between 35 to 65 years participated in the study. Calcium, magnesium and phosphorous were analysed in tears sample collected with 75mm glass capillary tubes.

Results

The fasting blood sugar (FBS) and age of diabetic patients was 7.48±1.88mmol/l and 56.75±5.82years and non-diabetics was 4.83±0.52mmol/l and 53.58±6.16years respectively. Magnesium showed no differences (P<0.05) between diabetics (0.76±0.45mmol/l) and non-diabetics (0.93±0.59mmol/l). Calcium was elevated (P=0.041) and phosphate (P=0.044) was decreased in diabetics (3.14±1.65mmol/l and 0.074±0.058mmol/l) than non-diabetics (2.41±1.05mmol/l and 0.11±0.081mmol/l).

Conclusion

This study concluded that being diabetic can affect the levels of some tear electrolytes in the tear fluid which may lead to an increased risk of diabetic ocular complications.

Management of meibomian gland dysfunction: a review

Meibomian gland dysfunction is the leading cause of evaporative dry eye disease and is one of the most common conditions encountered by eye care providers. The disorder is characterized by obstruction of the meibomian gland terminal ducts and/or changes in their glandular secretion, resulting in changes in tear film stability, inflammation, and symptoms of irritation. There is no gold standard treatment for meibomian gland dysfunction, but rather a diversity of options. Conservative measures include warm compresses and lid hygiene, but there is growing interest and need for medical treatments and procedures. Potential medical treatments include antibiotics, nonsteroidal and steroidal anti-inflammatory agents, essential fatty acid supplementation, hormone therapy, and control of Demodex infestation. Procedures include intraductal meibomian gland probing, the use of electronic heating devices, intense pulsed light therapy, and intranasal neurostimulation. We provide an update on meibomian gland dysfunction treatments based on recent studies.

Distribution and Characteristics of Meibomian Gland Dysfunction Subtypes: A Multicenter Study in South Korea

PURPOSE

We sought to evaluate the distribution and characteristics of meibomian gland dysfunction (MGD) and the treatment patterns for symptomatic MGD patients in South Korea.

METHODS

One hundred ninety-six right eyes of 196 MGD patients were enrolled. For each patient, meibum expressibility in the central eight glands in both the upper and lower eyelids was examined. Each upper and lower eyelid was separately classified into one of the following three subtypes: nonobvious obstructive (low-delivery without lid margin abnormality), obvious obstructive (low-delivery with lid margin abnormality), and hypersecretory (high-delivery with lid margin abnormality). All treatment plans were also recorded.

RESULTS

The mean number of expressible glands of the central eight glands in the upper eyelids (3.9 ± 2.6) was significantly higher than that in the lower eyelids (2.2 ± 2.4, p < 0.001). Obvious obstructive MGD was the most common subtype, followed by the hypersecretory and nonobvious obstructive subtypes in both the upper and lower eyelids. Of the 196 subjects, 38 (19.4%) had upper and lower eyelids that were assigned to different categories. Eyelid hygiene was the most prescribed treatment (74.5%), followed by lubricant eye drop usage (71.5%). Physicians tended to determine treatment plans based on the subtype of the upper eyelid rather than that of the lower eyelid.

CONCLUSIONS

The majority of subjects were classified as having the obvious obstructive subtype of MGD, and 19.4% had upper and lower eyelids that were different subtypes. Eyelid hygiene was the most prescribed treatment for MGD patients, and treatment patterns were mostly determined based on the subtype of the upper eyelids.

Prevalence and antibiotic susceptibility of bacteria isolated in patients affected with blepharitis in a tertiary eye centre in Spain

PURPOSE

To describe which bacteria can be found on lid margins in patients affected with blepharitis, to show their antibiotic susceptibility pattern, and to evaluate the antibiotic resistance trend of coagulase-negative Staphylococcus through time.

MATERIALS AND METHODS

Consecutive cases of 198 eyes affected with blepharitis between 2012 and 2018 were reviewed. A sample was collected by rubbing a swab against the base of the eyelashes of both the eyes of all patients. The samples were inoculated in blood agar and chocolate agar. The susceptibility of the identified bacteria to common antibiotics was tested. In addition, the antibiotic susceptibility pattern of coagulase-negative Staphylococcus detected from year 2016 to 2018 was compared with that of 4 years before.

RESULTS

The most common isolated bacterium was coagulase-negative Staphylococcus (89%) and Staphylococcus aureus (28%). Coagulase-negative Staphylococcus showed highest susceptibility to vancomycin (100%), neomycin (94%) and chloramphenicol (91%). Coagulase-negative Staphylococcus and Staphylococcus aureus were the most resistant to penicillin and erythromycin (resistance in 92%, 91% for coagulase-negative Staphylococcus, 86% and 43% of eyes for Staphylococcus aureus). Corynebacterium was resistant to oxacillin and erythromycin. Streptococcus viridans showed resistance to gentamycin and tobramycin. Moraxella was susceptible to most antibiotics. Bacillus was resistant to oxacillin. The antibiotic resistance trend of coagulase-negative Staphylococcus showed that the resistance to rifampicin increased through the years 2012-2018.

CONCLUSION

Coagulase-negative Staphylococcus and Staphylococcus aureus were the most isolated bacteria in patients affected by blepharitis in our tertiary eye centre. Both bacteria were resistant to erythromycin. Through the years, it seems that coagulase-negative Staphylococcus gained resistance to penicillin, erythromycin, ciprofloxacin and rifampicin.

Characterisation of corneal impression cytology in dogs and its application in the diagnosis of keratoconjunctivitis sicca

OBJECTIVE

Determine morphological and morphometric parameters of corneal epithelium in dogs, and determine the cellular alterations that occur in canine keratoconjunctivitis sicca (KCS) using impression cytology.

STUDY ANIMALS

60 dogs divided into two groups: dogs with Schirmer tear test (STT) at least 15 mm/minute and absence of ocular disease, and dogs with STT less than 15 mm/minute and clinical signs of KCS.

PROCEDURES

Impression cytology was used to collect corneal samples. The percentage of eyes with cell changes, the number of such cells and the percentage of cells with structural alterations in each group were determined. The possible correlation between corneal epithelium alterations and decreased tear production was evaluated.

RESULTS

A significant positive correlation existed between STT and the area of the cytoplasm and nucleus of corneal cells. A significant negative correlation was found between STT ​​and the nucleus/cytoplasm ratio, and the presence of cellular changes. A significant difference existed between the numbers of pyknotic nuclei, being higher among animals with all stages of KCS.

CONCLUSION

Corneal impression cytology can be used to assess the corneal epithelium in healthy eyes and eyes with KCS, demonstrating its usefulness as a diagnostic tool especially in mild and early cases.

Acupuncture and dry eye: current perspectives. A double-blinded randomized controlled trial and review of the literature

Purpose: Dry eye disease (DED) is a common disorder that negatively impacts quality of life and vision. Prior studies have shown some benefit of acupuncture for dry eye, but very few have included control group to mitigate placebo effect. This study was designed with a sham acupuncture control group to evaluate true acupuncture treatment effect.

Methods: This is a prospective, randomized, double-blinded, sham-acupuncture-controlled trial. Acupuncture treatment for dry eye was performed as per the Niemtzow Protocol. Twenty-four patients received true acupuncture and twenty-five received sham acupuncture. Treatment efficacy was assessed by the Ocular Surface Disease Index (OSDI) Questionnaire, ocular surface staining, tear flow, tear film break-up time (TBUT), and a general questionnaire. Atmospheric data were collected to control for the effect of atmospheric conditions on symptoms of dry eye.

Results: OSDI scores in the treatment group improved compared to baseline (1 week, p<0.01, 1 month p<0.05, 3 months p<0.05, and 6 months p<0.01). OSDI scores in the control group improved, but did not reach significance (p=0.09). Secondary outcome measures showed no significant improvement in TBUT, Schiermer’s Test, ocular surface grading, or artificial tear application. However, at 3 months, a significant reduction in the frequency of eye closing was observed among participants receiving true acupuncture treatment when compared to baseline (p=0.002). Furthermore, intragroup analysis showed significant reduction in symptoms of discomfort (p=0.01), dryness (p=0.001), scratchiness (p=0.001), and redness (p=0.01) in the true acupuncture group at 3 months.

Conclusion: Both true and sham acupuncture improved OSDI at 1 week after treatment, however, the improvement in OSDI was significantly greater in the true treatment groups than the sham group at 6 months after acupuncture. True acupuncture treatment improved many subjective assessments of dry eye symptoms, however, other common indicators used to objectively assess dry eye (tear flow, corneal staining, TBUT) remained unchanged. While there were trends towards improvement in the sham acupuncture group, this did not reach statistical significant during the study period. This suggests a true treatment effect of acupuncture rather than a placebo effect. Acupuncture can, therefore, be an effective adjunct to routine clinical treatment of dry eye.

Incidence and management of symptomatic dry eye related to LASIK for myopia, with topical cyclosporine A

Purpose

To evaluate the incidence of transient dry eye associated with LASIK for myopia and the efficacy of topical cyclosporine A administration.

Methods

Group A was formed from 145 (82 female, 63 male) eyes that developed clinically significant dry eye within 1 month post-LASIK and were subjected to cyclosporine A treatment. A “non-symptomatic for dry eye” and age- and gender-matched group (group B) was formed from the same pool of patients to serve as control. Schirmer’s, tear film break-up time (TBUT) and Ocular Surface Disease Index (OSDI) questionnaire were evaluated. Central corneal epithelial thickness (CET) and topographic epithelial thickness variability (TVT) were evaluated as quantitative dry eye objective markers. Subjective patient survey was also assessed.

Results

Mean age was 39.7±6.2 years for the female and 47.67±9.5 years for the male patients, in group A. Schirmer’s test mean preoperative value was 8.4±3.1 mm; and 4.5±3.6 mm at 1 month post-LASIK. Statistically significant decrease from 1 month post-LASIK baseline was found at 12 months (8.2±2.1 mm; P=0.02). Mean preoperative TBUT value was 7.5±2.5 seconds, 6.5±3.1 seconds at 1 month postoperatively, and 7.6±2.0 seconds at 12 months postoperatively, statistically significant to baseline (P=0.04). Preoperatively, CET was 52.37±3.40 µm and TTV was 1.24±0.57 µm, 59.87±3.89 µm, and 2.74±0.57 µm at 1 month post-LASIK respectively and at 12 months, 55.42±2.75 µm and 1.39±0.96 µm. The differences in CET between 12 months post-LASIK vs baseline were statistically significant (P=0.007). The mean preoperative OSDI scores were 11.47±9.97 for group A and 11.79±10.31 for group B (P=0.782), which changed to 23.03±10.17 and 15.13±9.49 at 12 months postoperatively (P<0.05), respectively. Following commencement of cyclosporine A treatment in group A, statistically significant improvement was noted, greater than the one in group B, in all metrics at the 12-month examination in comparison to the 1-month baseline.

Conclusion

Topical cyclosporine A treatment is an effective alternative in the management of LASIK for myopia-related transient dry eye. Optical coherence tomography epithelial mapping may provide an objective benchmark in diagnosing and monitoring this significant disorder and its correlation with visual symptoms.

Effects of Topical Mucolytic Agents on the Tears and Ocular Surface: A Plausible Animal Model of Mucin-Deficient Dry Eye

Purpose

A topical mucolytic agent, N-acetylcysteine (NAC), has been used to create an animal model without the intestinal mucus layer. In this study, we investigated the effects of topical NAC on the tears and ocular surface.

Methods

NAC-treated models were established by topically administering 10% NAC four times daily for 5 days in male Sprague-Dawley rats. Clinical parameters and the expression of mucin proteins and genes were evaluated. Alterations in the conjunctival epithelium and goblet cells were observed.

Results

The NAC group showed significant decreases in tear secretion, corneal wetting ability, tear MUC5AC concentration, and conjunctival goblet cell numbers as compared with the control group (all P < 0.01). In addition, significant increases in corneal fluorescein score and rose bengal scores were observed in the NAC group versus in the control group (P < 0.05 and P < 0.01, respectively). Hematoxylin and eosin (H&E) staining and scanning electron microscopy clearly showed damage in the epithelial cell layer and microvilli of the NAC group. Although there was no significant difference in MUC16 gene expression, the MUC16 concentration of the tear film and ocular surface tissue was significantly increased in the NAC group versus in the control group (P < 0.01 and P < 0.05, respectively). Five-day treatment with 3% diquafosol had minimal therapeutic effect in NAC-treated rat eyes.

Conclusions

Topical administration of 10% NAC induced ocular surface damage and tear film instability by prompting MUC16 disruption and release from the ocular surface. This animal model could be used to study dry eye disease, especially the mucin-deficiency subtype.

Labial Salivary Gland Transplantation for Severe Dry Eye in a Rhesus Monkey Model

Purpose

To evaluate the effectiveness of autologous labial salivary gland with labial mucous membrane graft in a rhesus monkey model with severe dry eye.

Methods

Eight eyes of eight rhesus monkeys with severe dry eye were included. Four eyes underwent autologous labial salivary gland and mucous membrane graft (group 1) and four eyes served as controls (group 2). The ocular surface was evaluated before and after transplantation surgery (at 1, 4, 8, 12, and 24 weeks). Conjunctival impression cytology was performed before and 24 weeks after transplantation. Finally, a histological analysis of the cornea, conjunctiva, and transplanted grafts was performed.

Results

At inclusion (n = 8) the mean Schirmer test was 1.31 ± 0.53 mm, the mean fluorescein score was 4.7 ± 1.65, and the mean lissamine green staining was 4.38 ± 0.48. After transplantation, a significant increase in tear secretion was observed with the mean Schirmer test results in group 2 significantly higher than those observed for group 1 at all time points (P < 0.05). Similarly, fluorescein and lissamine green scores were significantly lower in group 2 than in group 1 at all time points after transplantation (P < 0.05). Impression cytology specimens showed severe conjunctival squamous metaplasia without goblet cells in both groups. Under light microscopy, no significant difference was observed between the cornea and the conjunctiva of the two groups.

Conclusions

Labial salivary gland transplantation provided a basal secretion of tears and improved ocular surface staining scores during the first 3 months in a severe rhesus monkey model of dry eye. However, this was not accompanied by major improvement of ocular surface tissues.

Chinese Abstract.

Apigenin ameliorates ocular surface lesions in a rat model of dry eye disease

To study the effects of apigenin on dry eye disease (DED) in rats. Rats were divided into six groups: (I) normal control group, (II) DED control group, (III) vehicle control group, (IV) DED + apigenin 10 mg/kg, (V) DED + apigenin 20 mg/kg, and (VI) DED + apigenin 50 mg/kg. Schirmer test, tear film break-up time (BUT), and corneal fluorescein staining were used to evaluate the effects of apigenin on the ocular surface. The related inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). Histopathological examination and inflammatory index were also performed. The results showed that administration of apigenin was shown a significant effect on the recovery of ocular surface function. Compared to the control group, apigenin treatment in DED rats significantly decreased the level of the tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6); however, the interleukin-10 (IL-10) level was increased. Histopathological examination further verified the anti-inflammatory effects of apigenin on DED rats. The results demonstrated that apigenin could protect DED rats via inhibition of inflammation, suggesting that it may have potential as a therapy for DED.

Association between dry eye disease and asthma: a nationwide population-based study

BACKGROUND

Dry eye disease (DED), a chronic ocular disease, is associated with numerous medical issues, including asthma. However, studies on these associations are limited. In this study, we investigated the incidence of DED among patients with asthma and its correlation with other allergic comorbidities.

METHODS

We retrospectively analyzed data from the National Health Insurance Research Database of Taiwan. We compared the data of 41,229 patients with asthma with those of 164,916 sex- and age-matched non-asthma controls. We followed up the patient and control groups from 1998 to 2010, and compared the rate of DED in these two groups. We further analyzed the allergic comorbidities and asthma-related medication use among the patients with asthma to verify whether these factors were associated with DED.

RESULTS

The patients in the asthma group were more likely to have DED than were the controls (6.35% vs. 4.92%, p < 0.0001). In the asthma group, female had a higher risk of DED (odds ratio (OR) = 1.70, 95% confidence interval (CI) [1.57-1.85]) than males did. After adjustment for sex, age, income, urbanization, and the other two allergic comorbidities, patients with allergic rhinitis (adjusted OR = 1.58, 95% CI [1.46-1.72]) and urticaria (adjusted OR = 1.25, 95% CI [1.12-1.38]) were more likely to have DED, but not patients with atopic dermatitis (adjusted OR = 1.17, 95% CI [0.98-1.40]). Patients with asthma who had prescriptions of leukotriene receptor antagonists (LTRAs) (adjusted OR = 1.29, 95% CI [1.01-1.64]), oral antihistamines (adjusted OR = 2.02, 95% CI [1.84-2.21]), and inhaled corticosteroids (adjusted OR = 1.19, 95% CI [1.04-1.36]) exhibited association with DED.

DISCUSSION

Our findings reveal that patients with asthma-particularly females-were more likely to have DED, with comorbidities such as allergic rhinitis and urticaria, and prescriptions including LTRAs, antihistamines, and inhaled corticosteroids. The results suggest that in clinical practice, physicians should pay attention to DED, particularly in patients with a high risk of DED.

The Protective Effect of Polygonum cuspidatum (PCE) Aqueous Extract in a Dry Eye Model

Dry eyes are caused by highly increased osmolarity of tear film, inflammation, and apoptosis of the ocular surface. In this study, we investigated the effect of Polygonum cuspidatum (PCE) aqueous extract in in vivo and in vitro dry eye models. Dry eye was induced by excision of the lacrimal gland and hyperosmotic media. In vivo, oral administration of PCE in exorbital lacrimal gland-excised rats recovered tear volume and Mucin4 (MUC4) expression by inhibiting corneal irregularity and expression of inflammatory cytokines. In vitro, hyperosmotic media induced human corneal epithelial cell (HCEC) cytotoxicity though increased inflammation, apoptosis, and oxidative stress. PCE treatment significantly inhibited expression of cyclooxygenase-2 and inflammatory cytokines (interleukin-6 and tumor necrosis factor-α), and activation of NF-κB p65 in hyperosmolar stress-induced HCECs. Hyperosmolarity-induced increase in Bcl-2-associated X protein (BAX) expression and activation of cleaved poly (ADP-ribose) polymerase and caspase 3 were attenuated in a concentration-dependent manner by PCE. PCE treatment restored anti-oxidative proteins such as heme oxygenase-1 (HO-1), superoxide dismutase-1 (SOD-1), and glutathione peroxidase (GPx) in hyperosmolar stress-induced HCECs. These data demonstrate that PCE prevents adverse changes in the ocular surface and tear fluid through inhibition of hyperosmolar stress-induced inflammation, apoptosis, and oxidation, suggesting that PCE may have the potential to preserve eye health.

Tear instability importance, mechanisms, validity and reliability of assessment

PURPOSE

To examine the factors which contribute to tear stability and the validity and reliability of methods used for assessing tear break up time which is a core part of an examination of tear stability in dry eye patients.

METHODS

A review of publications which are relevant to tear stability and its assessment.

RESULTS

Tear break up time may be more invasive than intended if difficulty avoiding blinking during assessment results in reflex tearing. Notwithstanding control of instilled volume and concentration of fluorescein, on-eye dilution is highly variable according to resident tear volume. Blinking to evenly distribute fluorescein may improve tear and lipid layer thickness so habitual tear function is not assessed. Emphasis on a role for Meibomian gland dysfunction as a cause of tear instability may be appropriate in many cases but ignores the roles for other sources of tear lipid and other non-lipid contributions to tear instability such as aqueous or mucus deficiency, desiccated epitheliopathy or anomalous blinking. Objective less-invasive methods eliminate problems of inter-observer variability and can reliably 'maintain vigilance' over wide areas of the tear layer. However less-invasive results to date include mean tear break up findings which are both shorter and longer than expected for normal controls.

CONCLUSIONS

Fluorescein tear break up time assessments cannot be standardised and less-invasive methods are not yet standardised. Objective less-invasive and subjective fluorescein break up time tests do not appear to be measuring the same tear phenomena although both should be performed before other invasive procedures.

The utility of a normal tear osmolarity test in patients presenting with dry eye disease like symptoms: A prospective analysis

OBJECTIVE

To explore the diagnostic utility of normal tear osmolarity in patients with symptoms suggestive of dry eye disease (DED).

METHODS

Prospective observational cohort study of 100 patients that underwent tear osmolarity testing (TearLab^™) if they endorsed one or more symptoms of potential DED. Patients were included for the study if they had a normal tear osmolarity test (value <308 mOsm/L in each eye, and an inter-eye difference <8 mOsm/L). The main outcome measure was the presence of any alternate diagnosis to explain the patient's symptoms. Results were recorded and descriptive and univariate statistics were employed.

RESULTS

Mean tear osmolarity was 293.40 mOsms/L (±6.82), with a mean absolute difference of 2.85 mOsms/L (±1.98) between the eyes. A possible alternate diagnosis was established in 89% of patients with normal tear osmolarity testing. The most frequent diagnoses included anterior blepharitis (26%) and allergic conjunctivitis (21%).

CONCLUSIONS

Common symptoms of DED overlap significantly with a wide variety of other ocular surface diseases, and a normal tear osmolarity test should increase clinical suspicion for alternate causes of those symptoms. Anterior blepharitis and allergic conjunctivitis were the most common diagnoses made in symptomatic patients with normal tear osmolarity who may have otherwise been misdiagnosed and treated for DED.