A review on recent advances in dry eye: Pathogenesis and management

Optimal acupuncture protocol improving symptoms of typical dry eye syndrome: meta-analysis and systematic review

Previous meta-analyses have shown a superiority of acupuncture over artificial tear for treating typical dry eye syndrome (DES). However, given that the acupuncture protocols were quite diverse in the randomized controlled trials (RCTs) included in the meta-analyses, it is necessary to establish the acupuncture guidelines. Thus, the optimal acupuncture protocol involved in improvements of tear-film breakup time (BUT) or Schirmer tear test (STT) was examined by meta-analyses for RCTs in patients with typical DES. Eight databases until Jun 2018 were searched for 21 RCTs (n = 1542 eyes) comparing effectiveness of acupuncture versus artificial tear control. Indirect comparison of Bucher analysis was used to find specific acupoints (SAPs) improving BUT or STT by comparing the outcomes between subgroups of the RCTs including and excluding certain SAPs. Meta-analysis was examined for the outcomes in subgroups of the RCTs based on the number of SAPs, and network meta-analysis was for multiple pairwise comparisons across the protocols using the SAPs to yield relative effects. The Bucher analyses identified nine SAPs with positive effects on BUT or STT, and the positive relations of two SAPs involved in improvements of both BUT and STT suggested potential combinations of three ('KI3-LI4-SP6' or 'KI3-GB14-ST2') or four SAPs ('KI3-BL1-EX-HN7-SP6'). Subgroup meta-analyses showed the SAP-depending improvements of BUT or STT in the subgroups including more than three SAPs, compared with the artificial tear control. Meta-regression and network meta-analyses revealed significant correlations between the number of SAPs and the improvements of BUT and STT, and demonstrated that acupuncture using four SAPs for 21-30 days, particularly at two-three times per week, can be optimal for improving the symptoms of typical DES. These results provide useful information for guiding acupuncture in clinical trials for DES.

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.

Identified risk factors for dry eye syndrome: A systematic review and meta-analysis

A meta-analytic approach was used to identify potential risk factors for dry eye syndrome. PubMed, Embase, and the Cochrane library were systematically searched for studies investigated the risk factors for dry eye syndrome from their inception until September 2021. The odds ratio (OR) with 95% confidence interval (CI) was calculated using the random-effects model. Forty-eight studies comprising 493,630 individuals were included. Older age (OR: 1.82; P<0.001), female sex (OR: 1.56; P<0.001), other race (OR: 1.27; P<0.001), visual display terminal use (OR: 1.32; P<0.001), cataract surgery (OR: 1.80; P<0.001), contact lens wear (OR: 1.74; P<0.001), pterygium (OR: 1.85; P = 0.014), glaucoma (OR: 1.77; P = 0.007), eye surgery (OR: 1.65; P<0.001), depression (OR: 1.83; P<0.001), post-traumatic stress disorder (OR: 1.65; P<0.001), sleep apnea (OR: 1.57; P = 0.003), asthma (OR: 1.43; P<0.001), allergy (OR: 1.38; P<0.001), hypertension (OR: 1.12; P = 0.004), diabetes mellitus (OR: 1.15; P = 0.019), cardiovascular disease (OR: 1.20; P<0.001), stroke (OR: 1.32; P<0.001), rosacea (OR: 1.99; P = 0.001), thyroid disease (OR: 1.60; P<0.001), gout (OR: 1.40; P<0.001), migraines (OR: 1.53; P<0.001), arthritis (OR: 1.76; P<0.001), osteoporosis (OR: 1.36; P = 0.030), tumor (OR: 1.46; P<0.001), eczema (OR: 1.30; P<0.001), and systemic disease (OR: 1.45; P = 0.007) were associated with an increased risk of dry eye syndrome. This study reported risk factors for dry eye syndrome, and identified patients at high risk for dry eye syndrome.

Efficacy and Safety of Single-Dose OC-02 (Simpinicline Solution) Nasal Spray on Signs and Symptoms of Dry Eye Disease: The PEARL Phase II Randomized Trial

PURPOSE

Dry eye disease is a multifactorial disorder that affects the ocular surface, with symptoms including ocular irritation, impaired vision, and pain. Nicotinic acetylcholine receptor (nAChR) agonists are novel treatments for dry eye disease; this study investigates the nAChR agonist OC-02 (simpinicline solution) as an aqueous nasal spray.

METHODS

PEARL (Clinical Trial to Evaluate the Efficacy of OC-02 Nasal Spray on Signs and Symptoms of Dry Eye Disease) was a Phase II study that evaluated the efficacy and safety of OC-02 (simpinicline solution) nasal spray (OC-02 SNS) in adult patients with dry eye disease. Patients ≥22 years of age were eligible if they had an Ocular Surface Disease Index score ≥23, corneal fluorescein staining score ≥2 in >1 region or ≥4 for all regions, or Schirmer test score (STS) ≤10 mm; there were no restrictions on eye dryness score (EDS). Patients (N = 165) were randomly assigned 1:1:1:1 to vehicle (control; n = 42) or OC-02 SNS (0.11 mg, 0.55 mg, or 1.1 mg; n = 41 per group) and received a single dose of study drug (100 µL using a nasal spray atomizer) at visit 1 and visit 2 (15-19 days after visit 1). Primary efficacy outcomes were change in the STS from baseline to immediately after treatment administration (visit 1) and change in the EDS from before to 5 minutes after treatment during controlled adverse environment exposure (visit 2).

FINDINGS

Baseline demographic and ocular clinical characteristics were similar across all groups. Single-dose OC-02 SNS improved the signs and symptoms of dry eye disease. For the STS, statistically significant and dose-dependent improvements were found from before to after treatment with OC-02 SNS versus vehicle (least-squares mean change from baseline: vehicle, 3.0 mm; 0.11 mg OC-02 SNS, 9.0 mm; 0.55 mg, 17.5 mm; and 1.1 mg, 19.6 mm). For EDS, statistically significant and dose-dependent improvements were found from before to 5 minutes after treatment with higher doses of OC-02 SNS versus vehicle (least-squares mean change from baseline: vehicle, -6.5; 0.11 mg OC-02 SNS, -9.4; 0.55 mg, -17.4; and 1.1 mg, -20.7). OC-02 SNS was well tolerated: only 2 ocular adverse events were reported (eye pruritis and keratitis), and the most common nonocular events were cough and throat irritation.

IMPLICATIONS

Single-dose OC-02 SNS over a range of doses immediately and significantly increased tear production and improved eye dryness. Together with previous studies of OC-01 (varenicline solution) nasal spray, our findings suggest that agonist stimulation of nAChRs in the nasal cavity is a valid and effective mechanism to elicit natural tear production in patients with dry eye disease.

CLINICALTRIALS

gov identifier: NCT03452397.

Development of Lutein-Containing Eye Drops for the Treatment of Dry Eye Syndrome

Dry eye syndrome (DES) is a common ophthalmological disease that decreases tear secretion and causes dryness, photophobia, pain, severe corneal rupture, and even blindness. Ocular and lacrimal gland inflammation is one of the pathological mechanisms underlying DES. Therefore, effective suppression of inflammation is a crucial strategy for the treatment of DES. Lutein, commonly found in healthy foods, has anti-inflammatory effects in corneal or retina-related cells and may be a potential therapy for DES. The addition of lutein to artificial tears (AT) as an eye-drop formulation for DES treatment in a mouse model was studied in the present work. Polyvinyl alcohol (PVA) was used as a thickener to increase the viscosity of eye drops to prolong drug retention on the ocular surface. A WST-8 assay in human corneal epithelial cells (HCE-2) showed that a concentration of <5 μM lutein (L5) and <1% PVA (P1) maintained the cell viability at 80%. A real-time PCR showed that the inflamed human corneal epithelial cells (HCECs) cocultured with L5P1 had downregulated expression of inflammatory genes such as IL-1β, IL-6, and TNF-α. In a benzalkonium chloride- (BAC) induced DES mouse model, AT/L5P1 could repair damaged corneas, elevate tear secretion, increase the number of goblet cells, and inhibit the production of inflammatory cytokines, such as IL-1β, IL-6, and TNF-α, in the cornea. In conclusion, we demonstrate that lutein/PVA as eye drops could prolong the drug ocular retention time and effectively to decrease inflammation in DES mice. Therefore, lutein, obtained from eye drops, has a potential therapeutic role for DES.

[Association of polymorphic markers rs7947461 of the TRIM21 gene and rs33996649 of the PTPN22 gene with the risk of developing exogenous dry eye syndrome]

In this age of technological advancement, an increasing number of people is being exposed to external risk factors of damaging their ocular surface (wearing contact lenses, electromagnetic radiation from computers, mobile devices, etc.). However, the presence of external factors does not lead to a 100% risk of developing the dry eye disease (DED). The trigger mechanism in the development of autoimmune lesions of the ocular environment in some systemic diseases is known to be associated with molecular genetic factors. The search for molecular genetic disorders is based on the analysis of polymorphic markers of a number of genes responsible for the state of the eye surface.

PURPOSE

To study the relationship of polymorphic markers rs7947461 of the TRIM21 gene and rs33996649 of the PTPN22 gene with the risk of developing dry eye syndrome of exogenous etiology.

MATERIAL AND METHODS

The study included 57 people with exogenous risk factors for DED development. The control group included volunteers without a history of ophthalmic pathologies (n=75). Genotyping was done by real-time polymerase chain reaction followed by melting curve analysis. Statistical processing of data was done using the Statistica 6.1 RUS software for statistical analysis.

RESULTS

In the course of the study, 31 patients of the main group were diagnosed with DED and separated into the 1st subgroup; DED diagnosis was not confirmed in 26 patients, who were put into the 2nd subgroup. The 1st subgroup showed a significant increase in the frequency of predisposing genotypes of the TRIM21 and PTPN22 genes. The relative risk of developing DED turned out to be 2.5 and 4.86 times higher, respectively. In the 2nd subgroup, no statistically significant data was found on the presence of predisposing genotypes of polymorphic markers of the TRIM21 and PTPN22 genes (p=0.3).

CONCLUSION

The revealed association of polymorphic markers rs7947461 of the TRIM21 gene and rs33996649 of the PTPN22 gene with the risk of developing DED of exogenous etiology puts these loci as possible markers for diagnosing this pathology.

Therapeutic effects of acupuncture in typical dry eye: a systematic review and meta-analysis

Acupuncture is a treatment option for dry eye syndrome (DES), but its efficacy remains still controversial. We assessed the effectiveness of this treatment for typical DES without specific aetiologies. Eight databases up through June 2018 were searched for randomized clinical trials (RCTs) comparing treatments of acupuncture with artificial tears. The risk of bias was assessed using Cochrane criteria, and a random effects model was used for meta-analyses on tear-film breakup time (BUT), Schirmer test, corneal fluorescein staining (CFS), ocular surface disease index, visual analogue scale and score of symptoms (SOS). Subgroup and sensitivity analyses were conducted to explore the heterogeneity, and publication bias was assessed by funnel plot using Egger's test. Twenty-one RCTs in 19 studies (n = 1542 eyes) met our eligible criteria. The results demonstrated the superiority of acupuncture in improving the symptoms of BUT, Schirmer test, CFS and SOS, compared to artificial tears acting alone. The BUT and Schirmer test were also more improved in acupuncture combination with artificial tears than artificial tears alone. Further subgroup analyses suggest that acupuncture applied at 2.0-3.0 times per week for 21-30 days may be optimal for treating typical DES. This provides useful information for guiding acupuncture in the clinical trials.

Risk of Dry Eye Syndrome in Patients with Orbital Fracture: A Nationwide Population-Based Cohort Study

This study aimed to investigate whether orbital fracture increases the risk of dry eye syndrome (DES) and identified the profile of prognostic factors. We studied a cohort from the Taiwan National Health Insurance Research Database (NHIRD). Overall, 46,179 and 184,716 participants were enrolled in the study and control groups, respectively. Each patient in the case group was age- and gender-matched to four individuals without orbital fracture that served as the control group. Cox proportional hazards analysis regression was used to estimate the risks of incident DES. During the follow-up period, the case group was more likely to develop incident DES (0.17%) than the control group (0.11%) (p = 0.001). Multivariate Cox regression analysis demonstrated that the case group had a 4.917-fold increased risk of DES compared to the controls. In the stratified age group, orbital fracture had the highest impact on patients aged 18–29 years. Furthermore, patients with orbital roof fracture have a greater risk of developing DES. Regardless of whether having received surgery or not, the patients with orbital fracture have higher risks of DES. Our study demonstrated that orbital fracture increases the risk of developing subsequent DES. Early recognition by thorough examinations with raised awareness in the clinical setting could preserve visual function and prevent further complications.

The prevalence, severity, and risk factors for dry eye disease in Dubai - a cross sectional study

Background

The prevalence of dry eye disease is increasing globally and requires the attention of healthcare professionals as it worsens patients’ quality of life. No published studies on the epidemiology of dry eyes have been found in Dubai.

Purpose

To describe the epidemiology, prevalence, severity, and associated factors of dry eyes in Dubai, United Arab Emirates, in 2019.

Methods

This was an analytical, cross-sectional, survey-based study. An online survey was distributed by email to Mohammed Bin Rashid University students, staff, and faculty and to the staff at Mediclinic City and Parkview Hospitals in Dubai, United Arab Emirates, from April–June 2019. The survey included demographic questions and the Ocular Surface Disease Index (OSDI).

Results

The survey was completed by 452 participants; the majority were females (288/452; 63.7 %). The prevalence of dry eyes in Dubai was estimated to be 62.6 % (283/452), with severely dry eyes being the most prevalent (119/283; 42 %). Females, high daily screen time (> 6 h), and the use of contact lenses were found to be associated with dry eyes (P-value < 0.05, 95 % confidence interval). Age was found to be negatively correlated with prevalence of dry eyes. Exposure to smoking/shisha, history of eye injury/surgery, and nationality were not associated with dry eyes.

Conclusions

This is the first cross-sectional study to investigate the prevalence of dry eyes in Dubai (62.6 %). The majority of participants had severe dry eyes symptoms. Severely dry eyes were more common among females and users of contact lenses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01978-4.

Prevalence of dry eye syndrome in association with the use of contact lenses in Saudi Arabia

BACKGROUND

Dry eye disease is a tear film disorder which can cause discomfort to patients and negatively affect vision acuity. A number of risk factors has been reported to affect the incidence and severity of dry eye syndrome (DES). The aim is to study the prevalence of DES in Saudi Arabia and the factors affecting the severity of DES in relation to the use of contact lenses.

METHODS

A cross-sectional questionnaire-based study was conducted on 310 participants using the ocular surface disease index (OSDI) questionnaire and the eye dryness part from contact lens questionnaire-8 (CLDEQ-8). Dry eye OSDI scores were compared across different epidemiological and risk factors with focus on the use of contact lenses. Pearson and Spearman's correlation coefficients were used to analyze the frequency of contact lenses usage in relation to OSDI scores. Student's t-test and one-way analysis of variance (ANOVA) tests were used to compare means of two or more than two groups, respectively.

RESULTS

Forty eight (15.5%) of participants did not have any degree of DES, achieving an OSDI score between 0 and 12. Forty participants (12.9%) scored from 13 to 22, (mild DES), 44 (14.2%) were moderate, scoring 23-32 on the OSDI, while those who scored above 33 were 178 (57.4%) had severe DES. The mean score for all participants was 37.8. A high percentage of participants (84.5%) had some degree of DES. There was a strong positive correlation between OSDI score and the frequency of the feeling of dry eye and a moderate positive correlation between OSDI score and the intensity of dryness feeling. Out of 310 participants, 136 (43.9%) indicated using contact lenses. There was no significant association between the use of contact lenses per se and DES, however, those who used contact lenses more frequently had significantly higher OSDI scores.

CONCLUSIONS

Dry eye syndrome is a widespread, underdiagnosed condition in Saudi Arabia. The frequency of contact lenses use may contribute to the incidence of DES.

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.

GADD34 Function in Protein Trafficking Promotes Adaptation to Hyperosmotic Stress in Human Corneal Cells

GADD34, a stress-induced regulatory subunit of the phosphatase PP1, is known to function in hyperosmotic stress through its well-known role in the integrated stress response (ISR) pathway. Adaptation to hyperosmotic stress is important for the health of corneal epithelial cells exposed to changes in extracellular osmolarity, with maladaptation leading to dry eye syndrome. This adaptation includes induction of SNAT2, an endoplasmic reticulum (ER)-Golgi-processed protein, which helps to reverse the stress-induced loss of cell volume and promote homeostasis through amino acid uptake. Here, we show that GADD34 promotes the processing of proteins synthesized on the ER during hyperosmotic stress independent of its action in the ISR. We show that GADD34/PP1 phosphatase activity reverses hyperosmotic-stress-induced Golgi fragmentation and is important for cis- to trans-Golgi trafficking of SNAT2, thereby promoting SNAT2 plasma membrane localization and function. These results suggest that GADD34 is a protective molecule for ocular diseases such as dry eye syndrome.

Eficácia dos colírios ciclosporina e tacrolimo no tratamento de ceratoconjuntivite seca em cães

RESUMO O objetivo deste estudo foi avaliar os efeitos do tacrolimo e da ciclosporina na produção lacrimal de cães com ceratoconjuntivite seca (CCS) durante 90 dias. Para tanto, foram utilizados colírios de tacrolimo 0,02% (TcL) e ciclosporina 0,1% (CsA) em 14 cães com CCS. Os animais foram distribuídos em dois grupos e avaliados antes do início do tratamento (T0) e aos 15 (T1), 30 (T2), 45 (T3), 60 (T4), 75 (T5) e 90 (T6) dias após o início do tratamento. Na avaliação clínica, observou-se maior redução da secreção ocular, da opacidade e do edema corneano e da vascularização conjuntival. no grupo tacrolimo. No teste de Schirmer, verificou-se produção basal de 6(4,07 e 5,86(2,85mm/min no TcL e CsA, respectivamente, com aumento significativo da produção lacrimal em ambos os grupos, contudo houve aumento significativo da produção lacrimal a partir dos 15 dias de tratamento no grupo TcL (17,88(5,51mm/min), mas apenas a partir dos 45 dias no grupo CsA (11,86(4,74mm/min). Conclui-se que o uso do colírio tacrolimo aumentou em 68,83% a produção lacrimal em 90 dias de tratamento, comparado com a ciclosporina (56,82%), além de diminuir as manifestações clínicas inerentes à CCS, quando comparado à terapia com ciclosporina.

Effect of laser acupuncture on dry eye: A study protocol for a 2-center randomized controlled trial

BACKGROUND

Dry eye is a common ophthalmologic disorder that causes ocular discomfort and has become a worldwide health concern. Patients with dry eye often turn to complementary and alternative medicine (CAM) because of unsatisfactory conventional treatments. Acupuncture is one of the most popular interventions of CAM used, and laser acupuncture (LA) is a noninvasive technique.

METHODS

This protocol is a 2-center randomized controlled trial investigating the effect of laser acupuncture on dry eye. Two hundred participants aged 20 to 65 years will be randomly assigned to the experimental group (LA plus conventional treatment) or the sham control group (LA without laser output plus conventional treatment) at 2 clinical research centers in South Taiwan. The subjects will undergo LA treatment thrice a week for 12 weeks. The subjects in the experimental group will sequentially receive 0.375 J of energy at each of the following acupoints: BL2, TE23, ST2, LI4, ST36, and GB37. The subjects in the control group will also receive a sham LA treatment, without any laser output. Outcome assessments will include evaluation of the ocular surface disease index (OSDI), tear film break-up time (TFBUT), Schirmer-I test finding, and the visual analog scale (VAS) score at 4 and 12 weeks before treatment. The OSDI, TFBUT, Schirmer-I test result, and VAS score of the participants will be analyzed and compared between the experimental and control groups using the paired t test and one-way analysis of variance.

OBJECTIVES

The aim of this protocol is to investigate the efficacy of LA therapy in patients with dry eye.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03204903.

A standardized extract of Rhynchosia volubilis Lour. exerts a protective effect on benzalkonium chloride-induced mouse dry eye model

ETHNOPHARMACOLOGICAL RELEVANCE

In contrast to other leguminous plants generally used as food, Rhynchosia volubilis Loureiro, a small soybean with a black seed coat, has been used as a traditional oriental remedy for various human diseases in Eastern Asia. In this study, we demonstrated the protective effect of R. volubilis against dry eye disease.

AIM OF THE STUDY

We aimed to investigate whether a standardized ethanol extract of R. volubilis (EERV) can protect the cornea in a benzalkonium chloride (BAC)-induced mouse dry eye model.

MATERIALS AND METHODS

Experimental dry eye was induced by the instillation of 0.2% BAC on mouse cornea. A standardized ethanol extract of R. volubilis (EERV) was orally administered following BAC treatment. The positive control group was treated with commercial eye drops. Fluorescein staining, tear break-up time (BUT), and hematoxylin and eosin staining were evaluated on the ocular surface. Squamous metaplasia and apoptosis in the corneal epithelial layer were detected by immunostaining. Furthermore, the protein expression of cytochrome c, Bcl-2, and Bax was determined.

RESULTS

EERV treatment significantly improved fluorescein scoring, BUT, and smoothness in the cornea compared to the vehicle group. In addition, EERV inhibited squamous metaplasia and apoptosis in the cornea. The expression of cytochrome c and Bax was upregulated, while that of Bcl-2 was downregulated in the vehicle group compared with that in the control group. However, EERV treatment inhibited the expression of cytochrome c and Bax, while that of Bcl-2 was improved.

CONCLUSION

Standardized EERV could be a beneficial candidate for the treatment of dry eye disease.

Association of long-term glycaemic control on tear break-up times and dry eye symptoms in Chinese patients with type 2 diabetes

IMPORTANCE

Diabetes mellitus is known to be associated with dry eye syndrome (DES), but the effects of long-term glycaemic control on tear film metrics and dry eye symptoms are not known in the Chinese population.

BACKGROUND

To evaluate tear film stability and dry eye symptoms and their associations with systemic risk factors in Chinese patients with type 2 diabetes mellitus (T2DM).

DESIGN

Cross-sectional study set at the Lo Fong Siu Po Eye Centre (Grantham Hospital), Hong Kong.

PARTICIPANTS

A total of 80 Chinese participants, aged 18 or above, with T2DM recruited from the specialist outpatient setting were included.

METHODS

The Oculus Keratograph 5M (Oculus Inc., Wetzlar, Germany) was used to measure the non-invasive tear break-up time (NITBUT). Ocular symptoms were evaluated using the Ocular Surface Disease Index (OSDI). The association between OSDI, NITBUT and metabolic parameters relating to diabetes were evaluated using multiple linear regression.

MAIN OUTCOME MEASURES

The associations between long-term glycaemic control and NITBUT and OSDI scores.

RESULTS

Stepwise multiple linear regression analysis revealed glycated haemoglobin to be the only significant independent variable for NITBUT (R² = 0.099, P = 0.014) and OSDI (R² = 0.062, P = 0.044) after controlling for potential confounders. The age-adjusted prevalence of DES was 20% (95% confidence interval: 11-30%) in the Chinese T2DM population. The odds of DES for increasing percentage of glycated haemoglobin was 1.49 (95% confidence interval: 1.03-2.17, P = 0.04).

CONCLUSIONS AND RELEVANCE

Our findings highlight the importance of good glycaemic control as a modifiable risk factor for both dry eye symptoms and tear film instability in patients with T2DM.

PERFORMANCE EVALUATION OF DRY EYE DETECTION SYSTEM USING HIGHER-ORDER SPECTRA FEATURES FOR DIFFERENT NOISE LEVELS IN IR THERMAL IMAGES

The enhanced tear film evaporation and diminished tear production causes a dry eye (DE) condition. A non-invasive infrared (IR) thermography is most commonly used as a diagnostic tool for diagnosis of DE. However, the availability of high-quality IR thermal camera at low cost is difficult. Hence, an efficient DE detection system which can perform efficiently by using low-cost and low-quality images instead of conventional IR images would be a significant contribution. Therefore, in this work, we have evaluated the performance of automated non-invasive DE detection system using low-quality images obtained by adding different levels of noise to high-quality IR images. In this work, the performances of two non-linear higher-order spectra (HOS) cumulants and bispectrum features are compared. These features are extracted from the IR images with different levels of Gaussian noise. Principal component analysis (PCA) is performed on these extracted features and they are ranked using [Formula: see text]-value and later fed to different classifiers. We have achieved the accuracies, sensitivities and specificities of: (i) 86.90%, 85.71% and 88.10%, with noise level 0 using 24 bispectrum features, and (ii) 80.95%, 85.71% and 76.19%, with noise level 10 using 15 bispectrum features for right eye IR images. This study exhibits that even in the presence of high levels of noise, the detection of DE is possible and our proposed method performs efficiently using HOS bispectrum features. Thus, our proposed method can be used to detect DE using low-quality and inexpensive cameras instead of high-cost IR camera.

Contact lens to measure individual ion concentrations in tears and applications to dry eye disease

Dry eye disease (DED) affects millions of individuals in the United States and worldwide, and the incidence is increasing with an aging population. There is widespread agreement that the measurement of total tear osmolarity is the most reliable test, but this procedure provides only the total ionic strength and does not provide the concentration of each ionic species in tears. Here, we describe an approach to determine the individual ion concentrations in tears using modern silicone hydrogel (SiHG) contact lenses. We made pH (or H₃O⁺, hydronium cation,/OH^-, hydroxyl ion) and chloride ion (two of the important electrolytes in tear fluid) sensitive SiHG contact lenses. We attached hydrophobic C18 chains to water-soluble fluorescent probes for pH and chloride. The resulting hydrophobic ion sensitive fluorophores (H-ISF) bind strongly to SiHG lenses and could not be washed out with aqueous solutions. Both H-ISFs provide measurements which are independent of total intensity by use of wavelength-ratiometric measurements for pH or lifetime-based sensing for chloride. Our approach can be extended to fabricate a contact lens which provides measurements of the six dominant ionic species in tears. This capability will be valuable for research into the biochemical processes causing DED, which may improve the ability to diagnose the various types of DED.

Effects of Lycium barbarum (goji berry) on dry eye disease in rats

Lycium barbarum (goji berry) has long been used as a food and traditional herbal medicine. This study aimed to investigate the beneficial effect of the goji berry on dry eye disease in rats. Male Sprague-Dawley rats with induced dry eye disease were randomly assigned to four groups: Vehicle (control), low-dose goji berry extract [GBE; 250 mg/kg/body weight (bw)], median-dose GBE (350 mg/kg/bw), and high-dose GBE (500 mg/kg/bw). Three methods, Schirmer's test, tear break-up time (BUT) measurement and keratoconjunctival fluorescein staining, were used to evaluate the effect of GBE on symptoms of dry eye disease experienced by the rats. The results of the present study revealed that both the Schirmer's test score and tear BUT significantly increased following 1 week of GBE administration. Furthermore, the severity of the keratoconjunctival staining decreased significantly. In addition, the results suggested that administration of GBE may ameliorate dry eye disease symptoms in a dose-dependent manner. There were no mortalities and no apparent abnormal histopathology changes in the liver or kidney tissues of rats administered GBE for 21 consecutive days. Polysaccharides and betaine present in GBE may have important effects in alleviating dry eye disease induced by oxidative stress and inflammation. In conclusion, the goji berry is a safe, functional food with beneficial effects in alleviating dry eye disease.

Dry eye disease in patients with metabolic syndrome

OBJECTIVES

To evaluate dry eye disease (DED) in patients with metabolic syndrome (MetS) and compare with healthy individuals.

METHODS

The study was conducted in the Ophthalmology and Endocrinology Department of Bagcilar Education and Research Hospital, a tertiary care center in Istanbul, Turkey, between January and December 2015. In this prospective case-controlled study, dry eye disease tests were performed on 44 patients with MetS and 43 healthy controls. TearLab Osmolarity System, which is a lab-on-a-chip technology, was used to measure tear osmolarity. McMonnies & Ho symptoms questionnaire along with Schirmer I test and tear film break-up time (TFBUT) test were also performed. Statistical evaluation was performed by students' independent test.

RESULTS

There was no statistically significant difference in tear osmolarity, TFBUT, and McMonnies and Ho questionnaire scores between MetS and normal group. However, Schirmer I test was significantly higher in MetS group (14.8±9.4mm versus 20.4±9.4, p=0.007). In women subgroup, tear osmolarity was significantly higher in MetS group compared  to the normal group and over the cut-off score 308 mOsm/L (309.4±13.1 mOsm/L versus 301.2±8.7mOsm/L, p=0.012).

CONCLUSION

Patients with MetS present with lower tear volumes and a higher incidence of lacrimal gland hypofunction than age-matched controls. Especially women with MetS have higher tear osmolarities, which disrupt the normal functioning of the ocular surface and cause inflammation. Clinicians should be aware of higher DED incidence in patients with MetS for early treatment to prevent serious ocular complications.

[Effectiveness of soft contact lenses in severe keratoconjunctivitis sicca treated with local immunosuppressive therapy]

AIM

To study the effectiveness of soft contact lenses in severe keratoconjunctivitis sicca (KCS) treated with local immunosuppressive therapy.

MATERIAL AND METHODS

We have examined 41 patients (60 eyes) with severe KCS, including 3 men (4 eyes) and 38 women (56 eyes) aged from 27 to 76 years. Group 1 consisted of 22 persons (30 eyes) who were prescribed cyclosporine А 0.05% instillations 2 times daily, artificial tears, and soft contact lenses. Group 2 consisted of 19 patients (30 eyes) who received instillations of cyclosporine А 0.05% 2 times daily for no less than 6 months and artificial tears. Apart from the standard ophthalmic examination, the assessment included Schirmer's test, tear break-up time test, fluorescein eye stain test, tear osmometry, Heidelberg tomography of the cornea, optical coherence tomography of the anterior segment with meniscometry, impression cytology of the conjunctiva, tear pH measurement, plating of the content of the conjunctival cavity for its microflora, measurement of the width of the palpebral fissure, and calculation of the ocular surface disease index (OSDI). Treatment outcomes were evaluated at 1, 3, 6, and 12 months.

RESULTS

In group 1, complete re-epithelialization of the cornea (confirmed by all the methods used) was achieved rather shortly, in 1-3 months, while in group 2 - in 6 months.

CONCLUSION

The use of soft contact lenses in addition to cyclosporine A instillation therapy promotes restoration of corneal and conjunctival epithelium, reduces treatment time, and improves quality of life for patients, thus, proving itself a safe and effective treatment of autoimmune KCS.

An Experimental Study on Botulinum Toxin Type A for the Treatment of Excessive Secretion after Submandibular Gland Transplantation in Rabbits

Objectives. To investigate whether botulinum toxin type A (BTXA) could control excessive secretion after submandibular gland (SMG) transplantation in rabbits and its possible mechanisms. Methods. A new SMG transplantation model was established in rabbit. 30 successfully constructed models were randomly assigned to five groups including control group and four experimental groups. Secretion outputs were used to analyze the effect of BTXA injection on excessive secretion. Hematoxylin and eosin (HE) staining, transmission electron microscopy (TEM), Western blot, and immunofluorescence were performed to analyze its possible mechanisms. Results. After BTXA injection, a significant decrease of excessive secretion after SMG transplantation was found in 2 and 4 weeks groups, but no significant effect on 12 and 24 weeks groups. HE and TEM results showed that BTXA led to morphological and ultrastructural changes of acinar cells of transplanted SMG. Western blot results suggested that BTXA decreased the aquaporin-5 (AQP5) protein expression after BTXA injection for 2 and 4 weeks. Immunofluorescence results showed that AQP5 protein was mainly expressed in the cytoplasm after BTXA injection for 2 and 4 weeks, which might indicate that BTXA promoted AQP5 expression from the cell membrane to cytoplasm. Conclusion. BTXA could effectively control excessive secretion after SMG transplantation in rabbits.

[Significance of laser confocal tomography in diagnosis and monitoring of keratoconjunctivitis sicca]

Laser confocal tomography of the cornea enables studying ultrathin sections of corneal layers, which provides additional reliable information on tissue changes in keratoconjunctivitis sicca (KCS).

AIM

To assess the significance of laser confocal tomography of the cornea in the diagnosis and monitoring of KCS.

MATERIAL AND METHODS

We investigated 38 eyes of 30 patients with severe KCS. The patients were divided into two groups. Group 1 (15 patients, 19 eyes) was prescribed cyclosporine А 0.05% instillations 2 times daily, artificial tears, and soft contact lenses. Group 2 (15 patients, 19 eyes) received only instillations of cyclosporine А 0.05% 2 times daily and artificial tears. Besides standard ophthalmic examination, additional tests were performed, namely Schirmer's test, tear break-up time test, fluorescein eye stain test, tear osmolarity test (TearLab System, USA), and Heidelberg retinal tomography of the cornea (HRT, Heidelberg Engineering GmbH, Germany).

RESULTS

HRT findings revealed a 3 times shorter epithelization period and faster recovery of corneal transparency in group 1 as compared to group 2 (1.5 and 4.5 months, respectively). There was also an evident reduction in the number of immune cells in the cornea, most pronounced in group 1 at 3 months, which is indicative of inflammation termination.

CONCLUSION

The use of HRT of the cornea in KCS patients allows real-time cellular level observation of corneal changes, which together with clinical findings and diagnostic tests not only confirms the diagnosis but also determines treatment effectiveness. It has been also found that soft contact lenses accelerate epithelization of the cornea and relieve inflammation of the ocular surface in KCS patients under cyclosporine A 0.05% instillation therapy. Transparency of financial activity: the authors have no financial interest in the submitted materials and methods.

Oral supplementation with a nutraceutical formulation containing omega-3 fatty acids, vitamins, minerals, and antioxidants in a large series of patients with dry eye symptoms: results of a prospective study

Purpose

To assess the benefits and tolerability of a dietary supplement based on omega-3 fatty acids to relieve dry eye symptoms.

Methods

A total of 1,419 patients (74.3% women, mean age 58.9 years) with dry eye syndrome using artificial tears participated in a 12-week prospective study. Patients were instructed to take 3 capsules/day of the nutraceutical formulation (Brudysec^® 1.5 g). Study variables were dry eye symptoms (scratchy and stinging sensation, eye redness, grittiness, painful and tired eyes, grating sensation, and blurry vision), conjunctival hyperemia, tear breakup time (TBUT), Schrimer I test, and Oxford grading scheme.

Results

At 12 weeks, each dry eye symptom improved significantly (P<0.001), and the use of artificial tears decreased significantly from 3.77 (standard deviation [SD] =2.08) at baseline to 3.45 (SD =1.72) (P<0.01). In addition, the Schirmer test scores and the TBUT increased significantly, and there was an increase in patients grading 0–I in the Oxford scale and a decrease of those grading IV–V. Significant differences in improvements of dry eye symptoms were also found in compliant versus noncompliant patients as well as in those with moderate/severe versus none/mild conjunctival hyperemia.

Conclusion

Oral ω-3 fatty acids supplementation was an effective treatment for dry eye symptoms.

Angiogenin for the Diagnosis and Grading of Dry Eye Syndrome

Purpose

To investigate the properties of angiogenin (ANG) as a potential tool for the diagnosis and grading of dry eye syndrome (DES) by analyzing tear protein profiles.

Methods

Tear samples were collected with capillary tubes from 52 DES patients and 29 normal individuals as controls. Tear protein profiles were analyzed with an immunodot blot assay as a screening test. To confirm that the tear ANG levels were in inverse proportion to the disease severity grade, the ANG and lactoferrin (LF) tear contents of normal controls and DES patients were compared in an enzyme-linked immunosorbent assay.

Results

In the immunodot blot assay, the ANG area was lower in patients with grades 3 and 4 DES than in normal controls. The areas of basic fibroblast growth factor, transforming growth factor β2, and interleukin 10 were significantly greater than those of normal controls only in grade 4 DES patients, but these proteins were not linearly correlated with dry eye severity. Upon enzyme-linked immunosorbent assay analysis, the mean concentrations of ANG and LF decreased significantly as dry eye severity increased, except between grades 1 and 2. In addition, the ratios of ANG and LF to total tear proteins were correlated significantly with DES severity.

Conclusions

ANG level was significantly lower in DES patients than in normal controls, and was significantly correlated with the worsening severity of DES, except between grades 1 and 2, as was LF. Therefore, ANG may be a useful measure of DES severity through proteomic analysis.

Corneal and conjunctival sensitivity in rosacea patients

Purpose

To assess corneal and conjunctival sensitivity in rosacea patients.

Methods

A total of 55 patients with rosacea and 37 control subjects participated in the study. Corneal and conjunctival sensitivity was determined by Cochet-Bonnet esthesiometer. Subjective symptoms of ocular dryness were evaluated using Ocular Surface Disease Index (OSDI). Schirmer’s I test (ST), tear breakup time (tBUT) and ocular surface staining with fluorescein were carried out to measure objective signs.

Results

The mean corneal and conjunctival sensitivity did not differ significantly between rosacea patients and controls (all p > 0.05). Schirmer’s I test and tBUT were significantly reduced (p = 0.004 for OD and p < 0.001 for OS) and grade of ocular surface staining was significantly high (p = 0.018 for OD and p = 0.038 for OS) in rosacea patients. Corneal and conjunctival sensitivity did not show significant correlation with ST, tBUT, ocular surface staining (Oxford Schema), duration of rosacea and OSDI score.

Conclusions

Corneal and conjunctival sensitivity did not change significantly in rosacea.

[Ocular surface system integrity]

The interplay of different structures belonging to either the anterior segment of the eye or its accessory visual apparatus, which all share common embryological, anatomical, functional, and physiological features, is discussed. Explanation of such terms, as ocular surface, lacrimal functional unit, and ocular surface system, is provided.

[Treating severe keratoconjunctivitis sicca]

Keratoconjunctivitis sicca is a widespread disease with a complex multifactorial pathogenesis. Current understanding of its pathogenesis and existing treatments are summarized in this literature review.

Acupuncture therapy is more effective than artificial tears for dry eye syndrome: evidence based on a meta-analysis

Background. The efficacy of acupuncture in dry eye syndrome patients remains controversial. Methods. Pubmed, Ovid, Cochrane libraries, CNKI, Wanfang, and CQVIP databases were electronically searched until October 1, 2014. Outcomes including tear break-up time (BUT), Schirmer I test (SIT), and cornea fluorescein staining (CFS) were analyzed. A meta-analysis was performed using both fixed- and random-effects models based on heterogeneity across studies. Results. Seven studies were included in this study; 198 and 185 patients were randomly treated with acupuncture and artificial tears, respectively. The overall BUT of patients in acupuncture group was significantly longer than that of the artificial tears group after treatment (P < 0.00001). The SIT was significantly higher in the acupuncture group than that in the artificial tears group after treatment (P = 0.001). The CFS of patients in acupuncture group was significantly improved compared to that in artificial group (P < 0.0001). Conclusions. Acupuncture therapy is effective for the dry eye patients, partly better than artificial tear treatment.

Evaluation of a community-based participatory farmworker eye health intervention in the "black dirt" region of New York state

BACKGROUND

Eye irritation is a constant hazard for migrant and seasonal farmworkers, but there are few studies of the problem or how to address it. Researchers evaluated the effect of a community-based participatory eye health intervention on farmworker eye symptoms in the Hudson Valley, NY.

METHODS

A randomized pre-post intervention with 2, 4-week follow-up periods was implemented with a sample of 97 farmworkers. Five eye symptoms were measured, along with utilization of protective eyewear and eye drops.

RESULTS

Leading baseline eye symptoms were redness (49%), blurred vision (43%), itching (43%), and eye pain (29%). Significant reductions in eye pain (P = 0.009), and non-significant reductions in redness were observed for the intervention group while controls experienced increases in both.

CONCLUSIONS

The intervention was effective in significantly reducing eye pain, and to a lesser extent, redness. Future eyewear promotion programs should offer a range of eye wear, tailor offerings to local climate and tasks, evaluate eyewear durability, and include eye drops.

Safety and efficacy of cyclosporine in the treatment of chronic dry eye

Dry-eye syndrome (DES) is a multifactorial disease affecting millions of individuals worldwide. Various factors, including age, hormonal status, genetics, sex, immune status, innervation status, nutrition, pathogens, and environmental stress, can alter the cellular and molecular structure or function of components of the ocular surface system. The resulting imbalance increases susceptibility to desiccation and epithelial damage, leading to a vicious circle in which inflammation amplifies and sustains further damage by chronic deregulation of the system. Lubricating agents and steroids have been used as treatment options. However, as the causes of the disease become better elucidated, the more chemically complex cyclosporine A has become an increasingly useful treatment option and in the United States is currently the only Food and Drug Administration (FDA)-approved prescription drug for the treatment of dry eye. The safety and efficacy of cyclosporine have been shown in numerous studies.

Efficacy and safety of chondroitin sulfate/xanthan gum versus polyethylene glycol/propylene glycol/hydroxypropyl guar in patients with dry eye

Purpose:

To evaluate the efficacy and safety of two ophthalmic solutions in patients with mild to moderate dry eye.

Methods:

We performed a prospective, 2-month-long, randomized, double-blind, single-center, parallel clinical trial to compare the efficacy and safety of two ophthalmic solutions for dry eye treatment. Patients were randomly assigned to one of the two treatment groups, study group or active-control group, and received one drop four times a day. The primary efficacy endpoint was to extend the tear film break-up time (TBUT) after 2 months of treatment. The Ocular Surface Disease Index (OSDI) was also evaluated. Safety measures were assessed by the presence of adverse events.

Results:

A total of 28 patients with mild to moderate dry eye were included in the per protocol analysis. TBUT was similar between groups at baseline (chondroitin sulfate and xanthan gum [CS/XG] group, 5.2 ± 2.3; Systane^® group, 4.7 ± 2.6; P = 0.488), after 2 months of treatment, TBUT was still similar in both groups (CS/XG group, 6.1 ± 2.5; Systane^® group, 7.3 ± 2.5; P = 0.088). Baseline OSDI was similar between the groups (CS/XG group, 18.8 ± 5.3; Systane^® group, 19.8 ± 7.1; P = 0.810), but after 2 months of treatment, the OSDI was significantly lower in the CS/XG group (6.7 ± 5.7 versus 10.8 ± 6.4; P = 0.049). An adverse event was present in the CS/XG group, but it was not related to the treatment.

Conclusions:

In this population of patients with mild to moderate dry eye, treatment with CS/XG was as effective as treatment with Systane^® with regard to TBUT; nevertheless, treatment in the CS/XG group was more effective at diminishing OSDI.