The pathology of dry eye: the interaction between the ocular surface and lacrimal glands

Tear film secretion and stability in welders

PURPOSE

Welders are prone to ocular injuries and ocular surface problems due to exposure to ultraviolet light. The aim of this study was to evaluate the tear film comprehensively and assess objective and subjective indices of dry eye in welders.

METHODS

In this historical cohort, welders with at least 5 years of experience were compared with controls. A complete evaluation of ocular health was done for all participants. The Schirmer test (invasive and non-invasive) and Invasive Tear Break-Up Time (ITBUT) were applied for objective evaluation and the Ocular Surface Disease Index (OSDI) was used for subjective assessment of the tear film status. The results were compared between the two groups using the SPSS software.

RESULTS

The results of 140 welders (mean age: 46.66 ± 13.01 years) and 172 controls (mean age: 45.05 ± 12.61) were analyzed. The values of the Schirmer test and ITBUT were significantly lower in welders than controls; the difference was more prominent for the Schirmer test as compared to TBUT (Schirmer difference = 4.98 mm, ITBUT difference = 2.23 s). OSDI values were also significantly lower in welders than controls (P < 0.001). Considering a cut-off point of 12, 81.2% of welders had degrees of dry eye which was severe in 46.2% while 35.5% of controls had dry eye.

CONCLUSION

The results indicate that the percentage of dry eye and tear problems is far higher in welders than non-welders. Most of the affected welders have severe dry eye. It seems that the main reason for dry eye in these people is aqueous deficiency.

[Ocular surface aging: Pathophysiology and consequences for management]

All the components of the ocular surface and the lacrimal system are affected by aging. Aging induces lacrimal gland fibrosis, Meibomian gland dysfunction, loss of corneal sensitivity, decreased corneal cell density, impairment of immune defences, increased local inflammation associated with hormonal changes, conjunctivochalasis, lid abnormalities, etc. Furthermore, homeostasis of the ocular surface may be altered by various age-related systemic comorbidities and iatrogenic interventions. Altogether, aging is considered the most predominant risk factor for dry eye disease. The increasing knowledge of the pathophysiology of aging of the ocular surface allows for refinement of the management of ocular surface disease in the elderly.

Compensatory increases in tear volume and mucin levels associated with meibomian gland dysfunction caused by stearoyl-CoA desaturase-1 deficiency

The stearoyl-CoA desaturase (SCD) family of enzymes catalyzes monounsaturated fatty acid synthesis by inserting a cis double bond at the Δ9 position of saturated fatty acids. Disruption of these enzymes has been reported to induce a severe dry skin phenotype. Since lipid abnormalities in the meibomian glands have been associated with dry eye, we analyzed selected eye tissues contributing to tear volume and composition in genetically SCD-1-deficient mice (SCD-1 KO), including the lacrimal glands and conjunctiva. Previous histopathological analysis had revealed atrophy and loss of meibomian glands; taken together with the increased goblet cell and MUC5AC expression in the conjunctiva reported here, these findings suggest that the tear volume and mucin levels secreted are enhanced in the absence of lipid secretion as a compensatory mechanism. The expression of lipid metabolism genes in lacrimal glands was decreased in SCD1 KO mice. Thus, these results provide new pathophysiological mechanisms to pursue with regard to meibomian gland dysfunction. In addition, lack of SCD-1 causes a compensatory increase in the tear volume and mucin levels associated with changes in expression of lipid metabolism genes. These results may be useful as a new concept for dry eye treatment strategies.

Dry Eye Post-Laser-Assisted In Situ Keratomileusis: Major Review and Latest Updates

Dry eye is one of the most common complications occurring after laser-assisted in situ keratomileusis (LASIK), with virtually all patients experiencing some degree of postoperative dry eye symptoms. Enhanced understanding of the pathophysiology and mechanism of dry eye development in addition to preoperative screening of patients who are prone to dry eye is essential for better patient satisfaction and for improving short-term visual outcome postoperatively. This article reviews the latest studies published on LASIK-associated dry eye, including epidemiology, pathophysiology, risk factors, preoperative assessment, and management.

Relationship of Symptomatology with Closed Chamber Infrared Thermometry and Humidity in Dry Eyes

Purpose

To evaluate the relationship of symptoms of dry eye with closed chamber infrared thermometry and humidity measurements.

Methods

The authors studied 54 patients (108 eyes) with dry eye disorders of different grades of clinical severity (mean age 35.75±14.37 years), 31 cases (62 eyes) with normal eyes (mean age 33.68±14.42 years), and 10 cases (20 eyes) with epidemic conjunctivitis (mean age 33.68±14.42 years). The symptoms and the clinical tests (Schirmer-1 test, fluorescein tear break up time, Lissamine green stain; closed chamber infrared thermometry and humidity) were used to establish the diagnosis of dry eyes. The closed chamber humidity difference was used to classify the groups of dry eye.

Results

The authors noted no temperature difference from closed to open eye position in dry eyes as compared to 0.10±0.00 °C difference in normal eyes and epidemic conjunctivitis. Four groups of cases were identified by difference in values of humidity: Group 1 = <0.9 relative humidity (RH)% to 1 RH%; Group 2 = >1 RH% to 1.5 RH%; Group 3 = >1.5 RH% to 2 RH %; and Group 4 = >2 RH%. The symptomatology was measured in the eyes using Oxford scale (0–4) and correlated with the humidity groups. The grading of symptoms with the humidity showed a statistically significant relationship (p<0.0001) in each group. The severity of the symptoms showed an increase in frequency and severity from Group 1 to Group 4, which was statistically significant (p<0.0001). The mean sum total of global symptomatology score was statistically significant (p<0.0001): 3.43±0.31 in Group 1, 4.65±0.42 in Group 2, 8.56±0.78 in Group 3, and 13.35±1.21 in Group 4. However, total symptomatology score in epidemic conjunctivitis did not show a statistically significant value (p=0.20).

Conclusions

The closed chamber humidity and thermometry measurements showed statistical correlation in all four groups of dry eyes to total mean symptomatology score (p<0.001) and showed an increase in value with increasing severity of symptoms. However, all individual symptoms fail to show any conclusive relationship.

Controlled Adverse Environment Chambers in Dry Eye Research

Dry eye disease (DED) is a common condition with signs and symptoms that vary depending on a wide range of environmental factors to which people are exposed in their daily lives. Factors such as variable temperature, airflow velocity, relative humidity, seasonality, and pollutants can alter the rate of tear film evaporation, improving or exacerbating symptoms of DED. Results from currently available clinical tests do not always correlate well with patient-reported symptoms, and the continually changing environment and variability in DED symptoms present challenges for the design and conduct of clinical trials. Controlled adverse environment chambers allow standardization of temperature, humidity, and airflow and may minimize potential confounding factors in clinical investigations. Their use can promote accurate study of the pathophysiology of DED, discovery of disease biomarkers, and assessment of the effect of various therapeutic approaches on patients' symptoms. Controlled adverse environment chambers have been used to simulate indoor surroundings such as airplane cabins and to test their effects on contact lens wearers. This review summarizes how these chambers may be useful for the development, approval, and differentiation of potential new treatments for DED.

Dry eye syndrome: developments and lifitegrast in perspective

Dry eye (DE) is a chronic ocular condition with high prevalence and morbidity. It has a complex pathophysiology and is multifactorial in nature. Chronic ocular surface inflammation has emerged as a key component of DE that is capable of perpetuating ocular surface damage and leading to symptoms of ocular pain, discomfort, and visual phenomena. It begins with stress to the ocular surface leading to the production of proinflammatory mediators that induce maturation of resident antigen-presenting cells which then migrate to the lymph nodes to activate CD4 T cells. The specific antigen(s) targeted by these pathogenic CD4⁺ T cells remains unknown. Two emerging theories include self-antigens by autoreactive CD4 T cells or harmless exogenous antigens in the setting of mucosal immunotolerance loss. These CD4 T cells migrate to the ocular surface causing additional inflammation and damage. Lifitegrast is the second topical anti-inflammatory agent to be approved by the US Food and Drug Administration for the treatment of DE and the first to show improvement in DE symptoms. Lifitegrast works by blocking the interaction between intercellular adhesion molecule-1 and lymphocyte functional associated antigen-1, which has been shown to be critical for the migration of antigen-presenting cells to the lymph nodes as well as CD4⁺ T cell activation and migration to the ocular surface. In four large multicenter, randomized controlled trials, lifitegrast has proven to be effective in controlling both the signs and symptoms of DE with minimal side effects. Further research should include comparative and combination studies with other anti-inflammatory therapies used for DE.

The effects of subconjunctival bupivacaine, lidocaine, and mepivacaine on corneal sensitivity in healthy horses

OBJECTIVE

To compare the efficacy and duration of effect of three local anesthetics on corneal sensitivity when administered subconjunctivally in horses.

ANIMALS STUDIED

Eight healthy adult horses.

PROCEDURE

A randomized, masked, crossover study design was used, with a two-week washout period between trials. The subconjunctival space of the randomly selected eye was injected with 0.2 mLs of bupivacaine (0.5%), lidocaine (2%), mepivacaine (2%), or saline. All horses received each medication once. The contralateral eye served as a control. The corneal touch threshold (CTT) was measured in both eyes with a Cochet-Bonnet esthesiometer prior to sedation with xylazine, after sedation, and at 10-min intervals after subconjunctival injection until corneal sensitivity returned to baseline. The total time of decreased CTT and the maximum decrease in CTT were compared for each medication using a general linear mixed model (P < 0.05).

RESULTS

Total time of decreased CTT was 105.0 min for bupivacaine, 103.8 min for lidocaine, 138.8 min for mepivacaine, and 7.5 min for saline. All local anesthetics decreased CTT longer than saline (P < 0.001) and mepivacaine decreased CTT longer than lidocaine (P = 0.04). The mean minimum CTT was 1.67 cm for bupivacaine, 1.42 cm for lidocaine, and 0.73 cm for mepivacaine, which were all significantly less (P < 0.001) than saline (4.73 cm). No evidence of corneal toxicity was noted with any treatment.

CONCLUSION

Subconjunctival injections of lidocaine, bupivacaine, and mepivacaine effectively and safely reduce corneal sensitivity in eyes of healthy horses for 1.5-2 h, and may be useful for providing perioperative analgesia for equine corneal procedures.

[Novel current and future therapy options for treatment of dry eye disease]

Dry eye disease was redefined by the dry eye workshop (DEWS II) in May 2017. According to the new definition "dry eye is a multifactorial disease of the ocular surface characterized by a loss of homeostasis of the tear film and accompanied by ocular symptoms". The current definition encompasses etiological factors, such as instability and hyperosmolarity of the tear film, ocular surface inflammation and damage as well as a new aspect compared to the former definition, neurosensory abnormalities. Recent and future therapeutic options for dry eye focus on treatment of the aforementioned pathogenetic events. New tear substitutes, medications and devices to stimulate tear production, innovative anti-inflammatory treatment, medications to influence corneal innervation and new methods for treatment of Meibomian gland dysfunction are already available or will be available in the near future.

Sjögren Syndrome: Why Do Clinical Trials Fail?

Sjögren syndrome (SS) comprises glandular and extraglandular manifestations. Double-blind prospective trials of traditional disease-modifying antirheumatic drugs and biologics have failed because they have not improved benign symptoms, the major cause of lowered quality of life. Rituximab has proven effective in SS patients with associated mixed cryoglobulinemia, parotid gland swelling, lymphocytic interstitial pneumonitis, thrombocytopenia, and other manifestations. There were few of these SS patients in the trials required for FDA approval. Most patients had benign symptoms and did not show benefit, leading to failure of the study. This article examines the reasons for these failures and proposes future directions.

Inflammation in Dry Eye Disease: How Do We Break the Cycle?

This article reviews the literature and summarizes the role of inflammation in dry eye disease. A PubMed search was performed using the keywords inflammatory cycle and dry eye. All searches were limited to articles published in or translated into the English language, dating from 1973 through March 2017. There were no restrictions on the study design. Advances in understanding the pathogenesis of dry eye disease has revealed that inflammation is a core driver: the so-called "vicious circle" of inflammation. Researchers continue to analyze the precise mechanisms by which inflammation occurs. This has led to therapeutic options to break the cycle. Continued animal and human studies reveal other potential sites for treatment in this complex host of disorders.

Dynamic Sensitivity of Corneal TRPM8 Receptors to Menthol Instillation in Dry Eye Versus Normal Subjects

PURPOSE

To assess the sensitivity of corneal cold receptors to a known transient receptor potential melastatin 8 (TRPM8) agonist, menthol, in dry eye and normals, and to determine whether factors such as disease duration or age affect responses.

METHODS

Dry eye disease (DED) (N = 33) and normal (N = 15) subjects were randomly assigned to receive Rohto^® Hydra (0.01% menthol) or Systane^® Ultra treatments (OU) in a prospective, double-blind, crossover study. DED subjects had documented disease and symptom response scores >2 on a 0- to 5-point scale. Normals had no history of DED and scores <2 on the same scale. Endpoints included mean cooling score (0 = not cool and 10 = very cool) evaluated at 0, 0.5, 1, 2, 3, and 4 min post-instillation, sum cooling scores (5 time points, range 0-60), and ocular signs and symptoms.

RESULTS

Mean (±SD) ages were similar, 62.2 ± 8.6-year (DED) versus 53.5 ± 7.6-year (normal). Corneal sensitivity scores were not different between groups. Mean cooling scores at 0.5-4 min post-menthol instillation were significantly higher in DED subjects (P ≤ 0.03). Sum cooling scores were significantly higher (P = 0.04) in DED subjects with a disease duration <10 years (N = 18, 28.3 ± 2.58) versus ≥10 years (N = 15, 20.2 ± 2.76). Age did not affect cooling response in either group.

CONCLUSION

DED subjects had greater sensitivity to cold than normal subjects. DED duration, and not age, was critical to cooling sensitivity. The finding that cooling scores were higher in subjects with DED for less than 10 years compared to more than 10 years suggests that corneal cold receptor sensitivity decreases as the duration of DED increases.

Bilateral tear film alterations in patients with unilateral quiescent herpes simplex keratitis

PURPOSE

To evaluate bilateral tear function and corneal sensitivity in patients with unilateral quiescent herpes simplex keratitis (HSK) and determine the correlation between corneal sensitivity and tear secretion in both eyes.

METHODS

Thirty-five patients diagnosed with unilateral quiescent HSK and 35 heathy controls were included in this study. Bilateral tear osmolarity, Schirmer's test, the tear break-up time (TBUT) and corneal sensitivity were measured in all participants.

RESULTS

In the HSK group, both eyes demonstrated a significant increase in tear osmolarity, and a decrease in Schirmer's test and the TBUT compared with healthy controls (All p < 0.001). The bilateral tear osmolarity and Schirmer's test were similar, but the TBUT (4.9 ± 2.1 versus 7.4 ± 2.0 second; p < 0.001) and corneal sensitivity (35.1 ± 1.9 versus 54.3 ± 0.8 mm; p < 0.001) were significantly lower in the affected eyes. The bilateral tear osmolarity, Schirmer's test and the TBUT were significantly correlated with corneal sensitivity of the affected eye (All p < 0.001). When corneal sensitivity of the unaffected eye was treated as a control variable, tear osmolarity (R = -0.626, p < 0.001), Schirmer's test (R = 0.739, p < 0.001) and the TBUT (R = 0.691, p < 0.001) of the unaffected eyes were still significantly correlated with the corneal sensitivity of the affected eyes.

CONCLUSIONS

Unilateral quiescent HSK causes bilateral tear impairment, which depends on the loss of corneal sensitivity in the affected eye. In the affected eye with severe corneal sensitivity loss, bilateral dry eye occurred.

Sodium Hyaluronate in the Treatment of Dry Eye Syndrome: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis compares sodium hyaluronate (HY) with non-HY based artificial tears in the treatment of dry eye syndrome. A literature search for clinical trials comparing HY against non-HY preparations was conducted across PubMed, Cochrane Central Register of Controlled Trials and Scopus databases from inception up to May 2016. Majority of the 18 studies selected for review showed superiority of HY in improving ocular staining and symptoms. Randomized controlled trials (RCTs) examining Schirmer's I (SH) and tear breakup time (TBUT) underwent further meta-analyses with calculation of pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs). 7 RCTs including 383 eyes randomized to HY and 596 eyes to non-HY preparations underwent meta-analysis for SH. 9 RCTs including 458 eyes randomized to HY and 651 eyes to non-HY preparations underwent meta-analysis for TBUT. By fixed-effects modelling, HY demonstrated greater improvement of SH compared to non-HY preparations (SMD, 0.238; 95% CI, 0.107 to 0.369; p < 0.001). By random-effects modelling, HY demonstrated less improvement of TBUT (SMD, -0.566; 95% CI, -1.099 to -0.0336; p = 0.037). In summary, neither preparation was shown to be consistently superior across all outcome measures. The difference in effect between preparations on SH and TBUT was not clinically significant.

Hypersensitivity to Cold Stimuli in Symptomatic Contact Lens Wearers

PURPOSE

To examine the cooling thresholds and the estimated sensation magnitude at stimulus detection in controls and symptomatic and asymptomatic contact lens (CL) wearers, to determine whether detection thresholds depend on the presence of symptoms of dryness and discomfort.

METHODS

Forty-nine adapted CL wearers and 15 non-lens wearing controls had room temperature pneumatic thresholds measured using a custom Belmonte esthesiometer, during Visits 1 and 2 (Baseline CL), Visit 3 (2 weeks no CL wear), and Visit 4 (2 weeks after resuming CL wear). CL wearers were subdivided into symptomatic and asymptomatic groups based on comfortable wearing time (CWT) and CLDEQ-8 score (<8 hours CWT and ≥14 CLDEQ-8 stratified the symptom groups). Detection thresholds were estimated using an ascending method of limits and each threshold was the average of the three first-reported flow rates. The magnitude of intensity, coolness, irritation, and pain at detection of the stimulus were estimated using a 1-100 scale (1 very mild, 100 very strong).

RESULTS

In all measurement conditions, the symptomatic CL wearers were the most sensitive, the asymptomatic CL wearers were the least sensitive, and the control group was between the two CL wearing groups (group factor p < 0.001, post hoc asymptomatic vs. symptomatic group, all p's < 0.015). Similar patterns were found for the estimated magnitude of intensity and irritation (group effect p = 0.027 and 0.006 for intensity and irritation, respectively) but not for cooling (p > 0.05) at detection threshold.

CONCLUSIONS

Symptomatic CL wearers have higher cold detection sensitivity and report greater intensity and irritation sensation at stimulus detection than the asymptomatic wearers. Room temperature pneumatic esthesiometry may help to better understand the process of sensory adaptation to CL wear.

Anti-inflammatory effect of hydroxyproline-GQDGLAGPK in desiccation stress-induced experimental dry eye mouse

The purpose of this study has been the investigation of the effect of novel peptide hydroxyproline-GQDGLAGPK (Hyp-GQDGLAGPK) in desiccation stress-induced dry eye mouse model and compared medicines for dry eye disease including cyclosporine, diquafosol and sodium hyaluronate. Seventy eight NOD.B10.H2^b mice were injected with scopolamine and exposed to an air draft for 10 days, and then the mice were treated with normal saline (n = 13), 1% Hyp-GQDGLAGPK (n = 13), 0.05% cyclosporine (n = 13), 3% diquafosol (n = 13), and 0.1% hyaluronate (n = 13) for 10 days. Thirteen mice were used for histopathologic analysis at DS 10d. The desiccation stress significantly decreased tear production, but the topical treatment of Hyp-GQDGLAGPK recovered to the baseline levels, which was similar to cyclosporine and diquafosol. In addition, Hyp-GQDGLAGPK improved facilitating epithelium stabilization including the corneal irregularity score, fluorescein score and detachment of the corneal epithelium. These improvements in stabilization of the corneal epithelium was superior to that in the cyclosporine and sodium hyaluronate groups. Furthermore, desiccation stress markedly induced expression of autoimmune inflammation-related factors in the lacrimal glands, but it was significantly suppressed by Hyp-GQDGLAGPK treatment. Overall, we found that novel peptide Hyp-GQDGLAGPK has multi-functional effects such as stabilizing the tear film and inhibiting inflammation.

A review on use of botulinum toxin for intractable lacrimal drainage disorders

PURPOSE

To review the published literature on botulinum toxin (BTX) for epiphora secondary to refractory lacrimal drainage disorders.

METHODS

The authors performed a Pub Med search of all articles published in English on BTX injection into lacrimal gland for epiphora secondary to lacrimal drainage disorders. Relevant cross-references were obtained from the resultant studies. Data reviewed included demographics, indications, dose of BTX, number of injections, transconjunctival or transcutaneous route, outcomes and complications. Animal experiments of BTX into lacrimal gland were included and analyzed separately.

RESULTS

Botulinum toxin injection into lacrimal gland, in animal studies, has shown to reduce the tear volume significantly lasting for approximately a month without any histological changes. The major indications have been refractory canalicular obstructions and functional epiphora. The commonly used dose was 2.5 U. Outcomes in the few studies published are encouraging with transient ptosis being the most common complication.

CONCLUSIONS

Botulinum toxin into the lacrimal gland is a minimally invasive alternative in cases of refractory epiphora secondary to lacrimal drainage disorders. In these subsets of patients, the reported concentrations, dosage and outcome measures are variable and need larger studies for standardization.

Corneal confocal microscopy alterations in Sjögren's syndrome dry eye

PURPOSE

To evaluate light backscattering (LB) in corneal layers in patients with primary Sjögren's syndrome dry eye (SSDE) utilizing in vivo corneal confocal microscopy (IVCM) and to determine the eventual association with the lacrimal functional test values.

METHODS

A complete ophthalmic evaluation, Schirmer test with and without stimulation, break-up time (BUT) and IVCM were performed on 55 patients affected by SSDE and in an age- and sex-matched cohort of healthy participants (HP). Light backscattering, measures as light reflectivity unit (LRU), detected by IVCM at Bowman's membrane (BM) at 50 μm, at 100 μm and at 200 μm deeper than BM was compared in the two groups. The correlations between LB values and lacrimal function results were evaluated.

RESULTS

In patients affected by SSDE, LB was significantly higher (p < 0.001) in each corneal layer examined (+14 ± 6.33 LRU at BM), compared with HP. A good reverse correlation between the light reflectivity measures at BM with Schirmer test with (r = -0.91) and without (r = -0.90) stimulation and BUT (r = -0.88) was found. Correlations were lower in the deeper corneal layers.

CONCLUSION

Even if our results should be confirmed in further studies with a larger population, these findings show that IVCM is a device able to detect alterations in corneal layers in SSDE patients related to the lacrimal function. Light backscattering (LB) could be very useful for clinical diagnosis and management of SSDE.

Evaluation of Clinical Efficacy and Safety of a Novel Cyclosporin A Nanoemulsion in the Treatment of Dry Eye Syndrome

PURPOSE

Topical administration of the anti-inflammatory agent cyclosporin A (CsA) is recommended for long-term management of dry eye syndrome (DES), yet standard ophthalmic CsA preparations have been reported to be unstable. In this trial, the efficacy and safety of Clacier™ (based on a phase 3 study developed by Huons Co. Ltd.), a novel 0.05% CsA nanoemulsion formulation, are compared with those of the conventional Restasis^® emulsion.

METHODS

Patients with moderate-to-severe DES were randomly assigned to receive topical 0.05% CsA in the form of Clacier or Restasis, to be administered twice daily for 12 weeks. The primary efficacy outcome was the change from baseline in corneal fluorescein staining scores at week 12; changes at weeks 4 and 8 were secondary endpoints. Additional endpoints included score changes from baseline in nonanesthetic Schirmer's test I, tear breakup time, ocular surface disease index, and conjunctival staining.

RESULTS

At week 12, corneal staining scores were improved in patients treated with Clacier and Restasis, with no significant difference between treatments (P = 0.41). Temporal conjunctival surface damage was significantly more ameliorated with Clacier treatment than with Restasis treatment (P = 0.034). Notably, tear film stability was improved more rapidly in Clacier patients at week 4 (P = 0.005) than in Restasis patients (P = 0.36). Improvements in tear production were comparable with both Clacier and Restasis treatments. Clacier did not increase the risk of adverse events as compared with Restasis.

CONCLUSION

Treatment with Clacier alleviated clinical signs and symptoms of DES comparably to the commercially available Restasis, resulting in improved quality of life for patients. Clacier is an effective and safe therapeutic agent for DES.

TFOS DEWS II Clinical Trial Design Report

The development of novel therapies for Dry Eye Disease (DED) is formidable, and relatively few treatments evaluated have been approved for marketing. In this report, the Subcommittee reviewed challenges in designing and conducting quality trials, with special reference to issues in trials in patients with DED and present the regulatory perspective on DED therapies. The Subcommittee reviewed the literature and while there are some observations about the possible reasons why so many trials have failed, there is no obvious single reason other than the lack of correlation between signs and symptoms in DED. Therefore the report advocates for conducting good quality studies, as described, going forward. A key recommendation for future studies is conduct consistent with Good Clinical Practice (GCP), including use of Good Manufacturing Practice (GMP) quality clinical trial material. The report also recommends that the design, treatments, and sample size be consistent with the investigational treatment, the objectives of the study, and the phase of development. Other recommendations for pivotal studies are a priori selection of the outcome measure, and an appropriate sample size.

Dry Eye Management: Targeting the Ocular Surface Microenvironment

Dry eye can damage the ocular surface and result in mild corneal epithelial defect to blinding corneal pannus formation and squamous metaplasia. Significant progress in the treatment of dry eye has been made in the last two decades; progressing from lubricating and hydrating the ocular surface with artificial tear to stimulating tear secretion; anti-inflammation and immune regulation. With the increase in knowledge regarding the pathophysiology of dry eye, we propose in this review the concept of ocular surface microenvironment. Various components of the microenvironment contribute to the homeostasis of ocular surface. Compromise in one or more components can result in homeostasis disruption of ocular surface leading to dry eye disease. Complete evaluation of the microenvironment component changes in dry eye patients will not only lead to appropriate diagnosis, but also guide in timely and effective clinical management. Successful treatment of dry eye should be aimed to restore the homeostasis of the ocular surface microenvironment.

A novel TRPM8 agonist relieves dry eye discomfort

Background

Physical cooling of the eye surface relieves ocular discomfort, but translating this event to drug treatment of dry eye discomfort not been studied. Here, we synthesized a water-soluble TRPM8 receptor agonist called cryosim-3 (C3, 1-diisopropylphosphorylnonane) which selectively activates TRPM8 (linked to cooling) but not TRPV1 or TRPA1 (linked to nociception) and tested C3 in subjects with mild forms of dry eye disease.

Methods

A set of 1-dialkylphosphoryalkanes were tested for activation of TRPM8, TRPV1 and TRPA1 receptors in transfected cells. The bioactivity profiles were compared by perioral, topical, and intravenous delivery to anesthetized rats. The selected lead candidate C3 or vehicle (water) was applied with a cotton gauze pad to upper eyelids of patients with dry eye disease (n = 30). Cooling sensation, tear film break-up time (TBUT), basal tear secretion, and corneal staining were evaluated. C3 was then applied four times daily for 2 weeks to patients using a pre-loaded single unit applicator containing 2 mg/mL of C3 in water (n = 20) or water only. TBUT, basal tear secretion, and corneal staining, and three questionnaires surveys of ocular discomfort (VAS scale, OSDI, and CVS symptoms) were analyzed before and at 1 and 2 weeks thereafter.

Results

C3 was a selective and potent TRPM8 agonist without TRPV1 or TRPA1 activity. In test animals, the absence of shaking behavior after C3 perioral administration made it the first choice for further study. C3 increased tear secretion in an animal model of dry eye disease and did not irritate when wiped on eyes of volunteers. C3 singly applied (2 mg/ml) produced significant cooling in <5 min, an effecting lasting 46 min with an increase in tear secretion for 60 min. C3 applied for 2 weeks also significantly increased basal tear secretion with questionnaire surveys of ocular discomfort indices clearly showing improvement of symptoms at 1 and 2 weeks. No complaints of irritation or pain were reported by any subject.

Conclusions

C3 is a promising candidate for study of TRPM8 function on the eye surface and for relief of dry eye discomfort.

Trial registration

ISRCTN24802609 and ISRCTN13359367. Registered 23 March 2015 and 2 September 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-017-0495-2) contains supplementary material, which is available to authorized users.

Molecular Profiling of the Developing Lacrimal Gland Reveals Putative Role of Notch Signaling in Branching Morphogenesis

Purpose

Although normal function of the lacrimal gland is essential for vision (and thus for human well-being), the lacrimal gland remains rather poorly understood at a molecular level. The purpose of this study was to identify new genes and signaling cascades involved in lacrimal gland development.

Methods

To identify these genes, we used microarray analysis to compare the gene expression profiles of developing (embryonic) and adult lacrimal glands. Differential data were validated by quantitative RT-PCR, and several corresponding proteins were confirmed by immunohistochemistry and Western blot analysis. To evaluate the role of NOTCH signaling in lacrimal gland (LG) development, we used the NOTCH inhibitor DAPT and conditional Notch1 knockouts.

Results

Our microarray data and an in silico reconstruction of cellular networks revealed significant changes in the expression patterns of genes from the NOTCH, WNT, TGFβ, and Hedgehog pathways, all of which are involved in the regulation of epithelial-to-mesenchymal transition (EMT). Our study also revealed new putative lacrimal gland stem cell/progenitor markers. We found that inhibiting Notch signaling both increases the average number of lacrimal gland lobules and reduces the size of each lobule.

Conclusions

Our findings suggest that NOTCH-, WNT-, TGFβ-, and Hedgehog-regulated EMT transition are critical mechanisms in lacrimal gland development and morphogenesis. Our data also supports the hypothesis that NOTCH signaling regulates branching morphogenesis in the developing lacrimal gland by suppressing cleft formation.

Tear Film Stability in Sjögren Syndrome Patients Treated with Hyaluronic Acid Versus Crosslinked Hyaluronic Acid-Based Eye Drops

PURPOSE

To compare the stability of the tear film after instillation of eye drops containing hyaluronic acid (HA) or crosslinked hyaluronic acid (CLHA)-based in patients with Sjögren syndrome-related dry eye (SSDE).

METHODS

Forty subjects were included in this study and were divided into 2 groups: the first group (control group) consisted of 20 healthy volunteers; the second group (study group) constituted of 20 suffering from SSDE; before and 5, 30, and 60 min after instillation of eye drops the surface regularity index (SRI) and surface asymmetry index (SAI) were registered.

RESULTS

Comparing HA and CLHA, in the control group, SAI show statistically significant difference in the time 0 and in time 5, whereas there is no a statistically significant difference after 30 and 60 min from instillation. For SRI there is no statistically significant difference at any time. In SSDE group there is no statistically significant difference in the time 0 and 5, whereas there is a statistically significant difference after 60 min for SAI, and after 30 and 60 min for SRI from instillation. Both SRI and SAI in dry eyes were significantly greater than in control eyes (P < 0.05).

CONCLUSION

Our study showed a better efficacy of CLHA compared with HA in maintaining the stability of the tear film in a patient suffering from SSDE.

Randomized Controlled Crossover Trial Comparing the Impact of Sham or Intranasal Tear Neurostimulation on Conjunctival Goblet Cell Degranulation

PURPOSE

The aim of the study was to investigate the effects of the Allergan Intranasal Tear Neurostimulator (ITN) on conjunctival goblet cell (GC) degranulation.

DESIGN

A randomized, double-masked, placebo-controlled crossover trial.

METHODS

A total of 15 subjects (5 normal and 10 dry eye) were enrolled in a 3-visit study consisting of 1 screening and 2 separate randomized-masked ITN treatments (sham extranasal or intranasal). Tear meniscus height (TMH) was measured by anterior segment optical coherence tomography before and after applications. Impression cytology (IC) was taken from the bulbar conjunctiva of the right eye for periodic acid-Schiff staining and from the left eye for MUC5AC mucin immunostaining at baseline and after each treatment. The ratio of degranulated to nondegranulated GCs was measured as a marker of secretion.

RESULTS

In all participants, both inferior bulbar (IB) and temporal bulbar (TB) cytology specimens stained for MUC5AC revealed a significantly higher ratio of degranulated to nondegranulated GCs after the ITN (IB: 2.28 ± 1.27 and TB: 1.81 ± 1.01) compared to baseline (IB: 0.56 ± 0.55, P = .015) (TB: 0.56 ± 0.32, P = .003) and extranasal sham application (IB: 0.37 ± 0.29, P = .001) (TB: 0.39 ± 0.33, P = .001). When the same analysis was repeated in the dry eye or control groups, the ratio was significantly higher after ITN than the baseline ratio and ratio after extranasal application in both groups (P < .05). Moreover, although control subjects had a higher ratio of degranulated to nondegranulated GCs at baseline (0.75 ± 0.52) compared with the dry eye group (0.41 ± 0.27), the ratio became slightly higher in dry eye (2.04 ± 1.12 vs 1.99 ± 1.21 in control) after the ITN application. There was no significant difference between the IB or TB conjunctiva locations in terms of the effectiveness of the ITN application on conjunctival goblet cell secretory response.

CONCLUSIONS

These preliminary results document that the Allergan ITN can stimulate degranulation of goblet cells in the conjunctiva, which is a promising new approach for the management of dry eye.

The correct diagnosis and therapeutic management of tear dysfunction: recommendations of the P.I.C.A.S.S.O. board

Purpose

To describe a standard approach to manage tear dysfunction (TD), in order to obtain a clinically favourable outcome. TD is a highly prevalent, yet largely underdiagnosed, condition that affects from 5 to 30% of the population above 50 years old. Left untreated, TD is associated with eye discomfort and ocular surface disease, substantially affecting quality of life. Although the prevalence of this problem is increasing significantly, a standard approach to its prevention and treatment is not available yet.

Methods

In September 2015, a team of Ocular Surface Italian Experts convened for a roundtable to discuss on the latest knowledge about diagnosis and treatments for TD and the real issues in the management of these patients. The discussion centred on the appropriate definition of TD, proposing a new classification of risk factors and how to identify them, how to make a correct diagnosis choosing the rational therapy (questionnaires, symptoms’ time relation, seasonality, low tech diagnostic manoeuvres, specific tests for the detection of tear film disturbances leading to recognition of the level of disease and of the ocular system elements involved), which artificial tear matches the ideal profile for a rational therapy and which questions should be done to the patient.

Results

A multi-item flowchart for tear film dysfunction, with point-by-point explanatory guide, to better identify and manage the patient with this disorder is provided.

Conclusions

The growing prevalence of TD demands increased attention. An appropriate prevention and a treatment pattern for the patient, combined with greater patient–practitioner interaction, and patient education is offered.

Safety and Efficacy of Cortisol Phosphate in Hyaluronic Acid Vehicle in the Treatment of Dry Eye in Sjogren Syndrome

PURPOSE

Evaluation of 0.3% cortisol phosphate eye drops in hyaluronic acid vehicle in the treatment of dry eye in Sjogren Syndrome.

METHODS

This prospective, single-center, masked (single blind), randomized controlled study included 40 female patients divided into 2 groups, group 1 treated with Idracemi, 0.3% cortisol phosphate eye drops twice a day, and group 2 treated with Cortivis, 0.3% cortisol phosphate in hyaluronic acid vehicle, with the same posology. Screening (day -7), randomization (day 0), follow-up (day 7), and termination (day 28) visits were conducted. Symptoms (VAS) questionnaire, tear film breakup time, corneo-conjunctival stain, intraocular pressure (IOP) measurement, and fundus examination were performed at each visit. Conjunctival impression cytology for human leukocyte antigen-DR (HLA-DR) expression at visit 1 and 4 was also performed.

RESULTS

No changes in IOP or fundus examination were observed in either group at each time point. Group 1 showed at day 28 a statistically significant amelioration of symptoms and reduction of HLA-DR expression. Group 2 showed at day 7 statistically significant improvement of corneal and conjunctival stain versus baseline and versus group 1; the symptom score was statistically significantly better than baseline and versus group 1 after 28 days too. The HLA-DR expression and the epithelial cell area were statistically significantly reduced versus baseline and versus group 1 at the same time.

CONCLUSIONS

Cortisol phosphate proved to be safe and effective in treating dry eye in Sjogren Syndrome patients in both formulations. However, the formula with hyaluronic acid vehicle proved to be more effective. Both formulations were very well tolerated.

The analysis of human conjunctival epithelium proteome in ocular surface diseases using impression cytology and 2D-DIGE

Conjunctival impression cytology samples from patients with meibomian gland dysfunction (MGD), dry eye (DE), and healthy subjects (CT) were collected for determination of the degree of squamous metaplasia (SM) by PAS-hematoxylin staining and for comparative proteomic analyses by 2D-DIGE. The protein spots with discriminant expression were identified by MALDI-TOF/TOF mass spectrometry. Three independent statistical studies were conducted: i). Analysis of differential protein expression between study groups: We observed increased expression of proteins S100A4, S100A8, retinal dehydrogenase-1, peroxiredoxin-1, annexin-A1, annexin-A2, α-enolase, and glutathione S-transferase-P in DE, whereas the highest expression of peroxiredoxin-6, actin cytoplasmic-1, peroxiredoxin-2, and heat shock protein HSP-90-α was observed in MGD; ii). Correlation between changes in the proteome profile and the grade of SM: The expression of 5 different cytokeratins (KRT1, KRT4, KRT8, KRT10, and KRT13) correlated with the degree of SM; iii). Proteome profile differences between pathological and CT groups: An overall proteome analysis revealed upregulation of 9 proteins in the pathological groups (Annexin-A1, α-enolase, Annexin-A2, S100A8, cytokeratin-1, Peroxiredoxin-2 and Leukocyte elastase inhibitor) and downregulation of 2 proteins (Galectin-3 and Lipocalin-1). In conclusion, a sensitive proteomic approach to study conjunctival tissue collected from minimally invasive impression cytology was implemented. Differential proteomics analyses showed that in comparison with the MGD, the DE patients presented higher overexpression of proteins related to antimicrobial defense, tissue-damage response, and regulation of body fluid secretions. Changes in MGD proteome were associated with oxidative stress and anti-apoptotic processes. We found a correlation between the grade of SM and expression of proteins associated with cytoskeleton and keratinization. The studied pathological groups shared elements related to the defense and inflammatory responses. Dot blot assays of proteins ANXA1, S100A8, and S100A4 validated the proteomic results obtained from 2D-DIGE experiments and confirmed the correlation between the expression of these proteins and the clinical parameters.

Association Between Serum 25-Hydroxyvitamin D Levels and Dry Eye in Korean Adults: A Study Based on Korean National Health and Nutrition Examination Survey, 2010-2011

BACKGROUND

Dry eye is a common disease. Many patients continue to experience residual symptoms despite optimal treatment. Thus, new treatment options are required. The purpose of this study was to evaluate the association between serum 25-hydroxyvitamin D [25(OH)D] levels and dry eye.

METHODS

This study was performed using data from the fifth Korean National Health and Nutrition Examination Survey, which is a cross-sectional study of the Korean population that was conducted from 2010 to 2011. We included adults aged >19 years who underwent ophthalmologic interviews and examinations. We excluded subjects who had comorbid conditions (rheumatoid arthritis, thyroid disease, chronic kidney disease, or depression) that are associated with dry eye. The subjects were divided into normal and dry eye groups. The dry eye group consisted of those who had clinically diagnosed dry eye syndrome or symptoms. Multiple logistic regression analysis was conducted to determine the association between serum 25(OH)D levels and dry eye.

RESULTS

In the univariate model, the 25(OH)D levels were lower in the dry eye group than in the normal group (P=0.01). A significant association was found between severe vitamin D deficiency (<10 ng/mL) and dry eye (P=0.04). However, after multivariate adjustment, the statistical significance of the association disappeared (P-values= 0.49, vitamin D insufficiency; P=0.33, vitamin D deficiency; P=0.18, severe vitamin D deficiency).

CONCLUSION

Severe vitamin D deficiency was associated with dry eye in an unadjusted model, but the association was not statistically significant after adjustment.

Meibocyte differentiation and renewal: Insights into novel mechanisms of meibomian gland dysfunction (MGD)

This paper reviews our current understanding of age-related meibomian gland dysfunction (MGD) and the role of the nuclear receptor, peroxisome proliferator-activated receptor gamma (PPARγ), in the regulation of meibomian gland function, meibocyte differentiation and lipid synthesis. The studies suggest that PPARγ is a master regulator of meibocyte differentiation and function, whose expression and nuclear signaling coupled with meibocyte renewal is altered during aging, potentially leading to atrophy of the meibomian gland as seen in clinical MGD. Study of meibomian gland stem cells also suggest that there is a limited number of precursor meibocytes that provide progeny to the acini, that may be susceptible to exhaustion as occurs during aging and other environmental factors. Further study of pathways regulating PPARγ expression and function as well as meibocyte stem cell maintenance may provide clues to establishing cellular and molecular mechanisms underlying MGD and the development of novel therapeutic strategies to treating this disease.

Conjunctival impression cytology evaluation of patients with dry eye disease using scleral contact lenses

PURPOSE

To evaluate conjunctival impression cytology and HLADR expression changes after wearing scleral contact lenses (ScCLs) for moderate to severe dry eye disease (DED).

DESIGN

Prospective interventional case series.

METHODS

Forty-one eyes from 25 patients with moderate to severe DED were evaluated for Esclera ScCL treatment. Best-corrected visual acuity (BCVA) and slit-lamp findings were assessed. Impression cytology specimens were obtained from DED patients at the baseline and after wearing ScCLs for 12 months. The impression cytology specimens were analyzed using morphological results score, and HLA-DR positive cells were detected and quantified. The values were compared to assess the IC changes after wearing ScCLs.

RESULTS

Forty-one eyes from 25 patients were fitted with ScCLs to manage DED. The underlying diseases were Stevens-Johnson syndrome (22 eyes), Sjogren's syndrome (11 eyes), graft-versus-host disease (2 eyes), dry eye after keratomileusis (2 eyes) and undifferentiated ocular surface disease (4 eyes). The HE-PAS impression cytology score did not differ significantly before and after wearing ScCLs for 12 months in DED patients (p>0.05). The percentage of eyes expressing the HLA-DR antigen in the temporal conjunctiva after wearing ScCL for 12 months significantly increased in patients with Sjogren's syndrome (11.11% to 66.66%; p=0.0498). In groups with Stevens Johnson syndrome and other ocular surface disorders, we did not observe statistically significant differences (p>0.05).

CONCLUSIONS

The ScCLs did not change the parameters used to evaluate inflammatory processes, which were measured using conjunctival impression cytology and HLA-DR expression, except in Sjogren syndrome, in which there was an unexpected increase in HLA expression.

Dysfunctional tear syndrome: dry eye disease and associated tear film disorders - new strategies for diagnosis and treatment

Dysfunctional tear syndrome (DTS) is a common and complex condition affecting the ocular surface. The health and normal functioning of the ocular surface is dependent on a stable and sufficient tear film. Clinician awareness of conditions affecting the ocular surface has increased in recent years because of expanded research and the publication of diagnosis and treatment guidelines pertaining to disorders resulting in DTS, including the Delphi panel treatment recommendations for DTS (2006), the International Dry Eye Workshop (DEWS) (2007), the Meibomian Gland Dysfunction (MGD) Workshop (2011), and the updated Preferred Practice Pattern guidelines from the American Academy of Ophthalmology pertaining to dry eye and blepharitis (2013). Since the publication of the existing guidelines, new diagnostic techniques and treatment options that provide an opportunity for better management of patients have become available. Clinicians are now able to access a wealth of information that can help them obtain a differential diagnosis and treatment approach for patients presenting with DTS. This review provides a practical and directed approach to the diagnosis and treatment of patients with DTS, emphasizing treatment that is tailored to the specific disease subtype as well as the severity of the condition.

Efficacy of a fixed combination of 0.09 % xanthan gum/0.1 % chondroitin sulfate preservative free vs polyethylene glycol/propylene glycol in subjects with dry eye disease: a multicenter randomized controlled trial

BACKGROUND

Dry eye disease (DED) is multifactorial, affecting 5-34 % of the global adult population and reducing quality of life. The artificial tears or lubricants are the therapy most used for the treatment of DED, due to their low side effect profile, which attempt to modify the properties of the tear film. The aim of the present study was to evaluate the clinical efficacy of a fixed combination of xanthan gum and chondroitin sulfate preservative free on the ocular surface of patients with dry eye disease during 60 days of intervention.

METHODS

A phase III, double-blind, masked, controlled, multicenter, clinical trial of 148 subjects, randomized to either a fixed combination of xanthan gum 0.09 % and chondroitin sulfate 0.1 % (XG/CS) ophthalmic solution (n = 76) or a fixed combination of polyethylene glycol 400 0.4 % and propylene glycol 0.3 % (PEG/PG) (n = 72). Subjects self-dosed four times daily during 60 days. Follow-up was set on days 2, 7, 15, 30 and 60. Assessments of anterior/posterior segment ocular signs were performed. The outcome measures included Schirmer test, tear film break-up time and OSDI score. Security variables included intraocular pressure, lisamine green and fluorescein ocular surface stains.

RESULTS

The primary efficacy endpoints were similar between groups at baseline. After intervention time Schirmer test increased in both groups compared to baseline, XG/CS (6.4 ± 2.2 vs 11.0 ± 6.6; p = 0.002) and PEG/PG (6.5 ± 2.5 vs 10.5 ± 5.6; p = 0.019) respectively. Similar results were reported in the tear film break-up time in XG/CS (5.5 ± 2.1 vs 7.4 ± 2.9; p = 0.027) and PEG/PG (5.2 ± 2.0 vs 7.4 ± 2.7; p = 0.046) respectively. The OSDI score decreased to normal values in both groups, XG/CS (19.3 ± 7.4 vs 7.3 ± 5.9; p = 0.001) and PEG/PG (19.3 ± 7.5 vs 7.9 ± 8.2; p = 0.001) respectively. There was no significant difference between treatments for any parameter. Moreover, both groups decreased the presence of burning sensation, tearing, foreign body sensation, conjunctival hyperemia and photophobia. The adverse events were not related to the interventions.

CONCLUSIONS

Xanthan gum/chondroitin sulfate preservative free showed similar clinical efficacy, evaluated with OSDI score, TBUT and Schirmer test compared to polyethylene glycol/propylene glycol in the treatment of dry eye disease.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01657253 . Date of registration May 19, 2014.

Comparison of self-reported quality of vision outcomes after myopic LASIK with two femtosecond lasers: a prospective, eye-to-eye study

Purpose

To compare self-reported quality of vision (QoV) outcomes after myopic LASIK (laser-assisted in situ keratomileusis) with two femtosecond lasers.

Design

Prospective, randomized, eye-to-eye study.

Methods

Consecutive myopic patients were treated with wavefront-guided LASIK bilaterally. Eyes were randomized according to ocular dominance. The flap of one eye was made with the IntraLase FS 60 kHz femtosecond laser with a conventional 70° side-cut, and the flap of the fellow eye was made with the IntraLase iFS 150 kHz femtosecond laser with an inverted 130° side-cut. Patients completed the validated, Rasch-tested, linear-scaled 30-item QoV questionnaire preoperatively and at Months 1, 3, 6, and 12.

Results

The study enrolled 120 fellow eyes in 60 patients. None of the measured QoV parameters exhibited statistically significant differences between the groups preoperatively or at any postoperative time point.

Conclusion

Creating LASIK flaps with an inverted side-cut using a 150 kHz femtosecond laser and with a conventional 70° side-cut using a 60 kHz femtosecond laser resulted in no significant differences in self-reported QoV assessed by the QoV questionnaire.

Tear biomarkers for keratoconus

Keratoconus is a progressive corneal thinning, ectatic condition, which affects vision. Recent advances in corneal topography measurements has helped advance proper diagnosis of this condition and increased research and clinical interests in the disease etiopathogenesis. Considerable progress has been achieved in understanding the progression of the disease and tear fluid has played a major role in the progress. This review discusses the importance of tear fluid as a source of biomarker for keratoconus and how advances in technology have helped map the complexity of tears and thereby molecular readouts of the disease. Expanding knowledge of the tear proteome, lipidome and metabolome opened up new avenues to study keratoconus and to identify probable prognostic or diagnostic biomarkers for the disease. A multidimensional approach of analyzing tear fluid of patients layering on proteomics, lipidomics and metabolomics is necessary in effectively decoding keratoconus and thereby identifying targets for its treatment.

The Effect of TNF-α Blocker HL036337 and Its Best Concentration to Inhibit Dry Eye Inflammation

Purpose

Dry eye syndrome is commonly thought of as an inflammatory disease, and we have previously presented data showing the effectiveness of topical TNF-α blocker agents for the treatment of this condition. The purpose of this study was to investigate the effectiveness of the TNF-α blocking agent HL036337 compared to cyclosporine A for the treatment of dry eye induced inflammation in order to establish whether HL036337 represents a more effective method for suppressing inflammation. The efficacy of HL036337 and cyclosporine A was determined using an experimental murine dry eye model.

Methods

The TNF-α blocker HL036337 is a modified form of TNF receptor I. Using dry eye induced C57BL/6 mice (n = 45), corneal erosion was measured at day 4 and 7 after topical treatment with cyclosporine A or HL036337. To determine the effective treatment dose, 0.25, 0.5, 1, 2.5, and 5 mg/mL of HL036337 were topically administered twice per day to dry eye induced murine corneas for 1 week.

Results

The optimal concentration of the TNF-α blocker HL036337 for treatment of dry eye induced corneal erosion was determined to be 1 mg/mL. Dry eye induced corneal erosion was improved after 1 week with topically applied cyclosporine A and HL036337 at 1 mg/mL.

Conclusions

HL036337 administered topically at 1 mg/mL effectively improved corneal erosion induced by dry eye. This finding may also suggest that inhibition of TNF-α can improve dry eye syndrome.

Immunomodulation on the ocular surface: a review

The increasing understanding of immune mechanisms changed our perception of the ocular surface, which is now considered a compartment of the common mucosal immune system. It offered the possibility to alter the physiological immune response on the ocular surface and effectively combat inflammation, which impairs stability of the tear film and causes tear hyperosmolarity, causing symptoms of dry eye disease. The paper provides an overview of ocular surface anatomy and physiology, explains the underlying mechanisms of dry eye disease and discusses novel and promising treatment modalities, such as cyclosporine A, biological therapies using autologous serum and various growth factors as well as experimental treatment methods which are currently being investigated.

Tear fluid biomarkers in ocular and systemic disease: potential use for predictive, preventive and personalised medicine

In the field of predictive, preventive and personalised medicine, researchers are keen to identify novel and reliable ways to predict and diagnose disease, as well as to monitor patient response to therapeutic agents. In the last decade alone, the sensitivity of profiling technologies has undergone huge improvements in detection sensitivity, thus allowing quantification of minute samples, for example body fluids that were previously difficult to assay. As a consequence, there has been a huge increase in tear fluid investigation, predominantly in the field of ocular surface disease. As tears are a more accessible and less complex body fluid (than serum or plasma) and sampling is much less invasive, research is starting to focus on how disease processes affect the proteomic, lipidomic and metabolomic composition of the tear film. By determining compositional changes to tear profiles, crucial pathways in disease progression may be identified, allowing for more predictive and personalised therapy of the individual. This article will provide an overview of the various putative tear fluid biomarkers that have been identified to date, ranging from ocular surface disease and retinopathies to cancer and multiple sclerosis. Putative tear fluid biomarkers of ocular disorders, as well as the more recent field of systemic disease biomarkers, will be shown.

PACAP suppresses dry eye signs by stimulating tear secretion

Dry eye syndrome is caused by a reduction in the volume or quality of tears. Here, we show that pituitary adenylate cyclase-activating polypeptide (PACAP)-null mice develop dry eye-like symptoms such as corneal keratinization and tear reduction. PACAP immunoreactivity is co-localized with a neuronal marker, and PACAP receptor (PAC1-R) immunoreactivity is observed in mouse infraorbital lacrimal gland acinar cells. PACAP eye drops stimulate tear secretion and increase cAMP and phosphorylated (p)-protein kinase A levels in the infraorbital lacrimal glands that could be inhibited by pre-treatment with a PAC1-R antagonist or an adenylate cyclase inhibitor. Moreover, these eye drops suppress corneal keratinization in PACAP-null mice. PACAP eye drops increase aquaporin 5 (AQP5) levels in the membrane and pAQP5 levels in the infraorbital lacrimal glands. AQP5 siRNA treatment of the infraorbital lacrimal gland attenuates PACAP-induced tear secretion. Based on these results, PACAP might be clinically useful to treat dry eye disorder.

Prominent Decrease of Tear Meniscus Height With Contact Lens Wear and Efficacy of Eye Drop Instillation

OBJECTIVE

To investigate the change in tear meniscus height (TMH) before and after wearing soft contact lenses (CLs) of different water contents (WCs) and the influence of eye drop instillation on TMH during CL wear.

METHODS

Tear meniscus heights were measured using anterior segment optical coherence tomography in 20 normal subjects wearing a high-WC CL (WC, 69%) in 1 eye and a low-WC CL (WC, 24%) in the other. Tear meniscus height change after eye drop instillation with 3% diquafosol ophthalmic solution or saline with CL wear was evaluated at 5, 15, 30, and 60 min after instillation.

RESULTS

A significant decrease in TMH was observed after lens insertions of both CLs. Tear meniscus height was significantly decreased with high-WC CL wear compared with that with low-WC CL wear. With high-WC CL wear, TMH increased significantly (P<0.001) at 5 min after the instillation of 3% diquafosol ophthalmic solution compared with the baseline values and then returned to the pre-instillation level. No significant TMH changes were found with the instillation of either eye drop (diquafosol or saline) with low-WC CL wear.

CONCLUSIONS

Tear meniscus height decreased with CL wear, especially with high-WC CL wear. Significant increases in TMH were observed at 5 min after the instillation of diquafosol ophthalmic solution with high-WC CL wear. The increases in TMH after diquafosol instillation tended to be greater than those after saline instillation at least for 30 min with both high-WC and low-WC CLs.