Variability of Tear Osmolarity in Patients With Dry Eye

Corneal Epithelial Thickness in Sjogren's Disease: A Pilot Study

Purpose

This study was to assess corneal epithelial thickness (CET) in patients with Sjogren's disease (SjD).

Methods

A retrospective chart review was conducted of SjD patients from September 2021 to January 2022. Patient demographics, unanesthetized Schirmer's test, serologic markers, and symptoms as measured by the Ocular Surface Disease Index (OSDI) were reviewed. Epithelial thickness from both eyes was measured using anterior segment OCT at the central 3mm and concentric 5mm, 7mm, and 9mm zones for the superior, temporal, inferior, and nasal corneal quadrants. Associations between corneal epithelial thickness with patient demographics, clinical characteristics, and symptoms were evaluated using regression models.

Results

Fifteen SjD patients (100% female) were included with a mean age of 58.4 years. Patients with Sjogren's disease had a significantly thinner superior corneal epithelium compared to the inferior epithelium (mean 47.7mm vs 53.1mm, p = 0.001). The epithelial thickness mean standard deviation (MSD) was significantly inversely correlated with the unanesthetized Schirmer test (r=-0.39, p = 0.005), suggesting that an overall variability of CET correlates with decreased aqueous tear production. SS-A, SS-B, ANA, and RF positivity were not associated with any measures of CET.

Conclusion

This pilot study suggests that there is significant superior versus inferior thinning of corneal epithelium in Sjogren's patients. There was a significant correlation between variability of corneal epithelial thickness and decreased tear production in Sjogren's patients. Further larger studies are needed to understand the relationship of CET with objective and subjective measurements of ocular surface disease.

Impact of Clinician Subjectivity on the Assessment of Dry Eye Disease Prevalence in a UK Public Health Care Patient Population

Purpose

To understand the impact of subjectivity on diagnosis rates of dry eye disease (DED) in an unbiased population.

Patients and Methods

A multicenter study enrolled 818 subjects with complete report forms (465 females, 67.1 ± 16.7 years, 353 males, 65.0 ± 15.9 years). Subjects were evaluated for staining, TBUT, tear osmolarity, meibomian gland disease, and OSDI.

Results

Physicians diagnosed 48.7% of subjects as having DED, ranging from 42.9% to 62.3% between sites. Positivity rates for staining (≥ grade 1) ranged from 41.3% to 84.1% (mean = 0.8 ± 0.9 grade), TBUT (<10s) ranged from 39.1% to 61.6% (mean = 10.4 ± 6.6 seconds), osmolarity (>308 mOsm/L) ranged from 63.7% to 72.4% (mean = 319.7 ± 20.8), MGD grading ranged from 28.9% to 51.3% (mean = 0.5 ± 0.7), and symptoms measured by OSDI ranged from 57.6% to 71.0% (mean = 23.5 ± 20.5) between sites. Tear osmolarity was the most consistent between sites (max/min positivity = 114%), followed by OSDI (123%), TBUT (158%), MGD (178%), and staining (204%). DED markers were uncorrelated (average r2 = 0.05 ± 0.07). A substantial number of subjects (N = 110) exhibited positive symptoms (OSDI = 32.4 ± 15.7) and hyperosmolarity (338.1 ± 20.1 mOsm/L) but no other obvious signs of DED (MGD grade = 0.2 ± 0.4, TBUT = 13.5 ± 7.0 seconds, staining grade = 0.4 ± 0.5).

Conclusion

Subjective signs of DED varied considerably, whereas objective measurements of OSDI and osmolarity were the most consistent between sites. A large proportion of subjects exhibited high symptoms and hyperosmolarity but no other obvious signs of dry eye disease, most of whom were undiagnosed by clinical assessment without access to the osmolarity measurement.

Patient barriers and facilitators for making environmental and behavioral modifications for dry eye in the United States

BACKGROUND

Managing dry eye disease (DED) is expensive. Often, prescribed treatments improve clinical signs but not patient-reported symptoms. In large surveys, clinicians and patients ranked environmental and behavioral modifications among the most important DED-related research priorities. Our purpose was to investigate the barriers to and facilitators of use of these modifications by patients with DED in the United States and how their use may be impacted by socioeconomic status (SES).

METHODS

Using Qualtrics, we conducted an anonymous online survey of adults with DED living in the United States in August to September 2022. Patients were identified through the Dry Eye Foundation, Sjögren's Foundation, and a DED clinic in Colorado. We used an established index for classifying respondent SES based on education, household income, and employment. Outcomes included use of environmental and behavioral modifications and barriers to and facilitators of their use.

RESULTS

We included 754 respondents (SES: 382 low, 275 high, and 97 unclear). Most were aged 18 to 49 years (67%), female (68%), and White (76%) and reported dealing with DED for ≤5 years (67%). The most frequent modifications were taking breaks to rest eyes (68%), increasing water intake (68%), and using hot/cold compresses (52%). For these three, the biggest facilitators were as follows: belief that the modification works (27 to 37%), being recommended it (24 to 26%), and ease of use/performance (21 to 32%). Across modifications, the biggest barriers were difficulty of use (55%), lack of family/employer/social/community support (33%), and lack of awareness (32%). The data do not suggest discernible patterns of differences in barriers or facilitators by SES.

CONCLUSIONS

Greater emphasis should be placed on explaining to patients how environmental and behavioral modifications might mitigate DED. Employers and members of patients' support systems should be guided regarding how best to support patients in managing DED symptoms.

United States Regulatory Approval of Topical Treatments for Dry Eye

PURPOSE

To report the heterogeneity in methodology of clinical trials submitted to the US Food and Drug Administration (FDA) for approval of topical dry eye treatments.

DESIGN

Comparative analysis of clinical trials' methods.

METHODS

We reviewed the online, publicly available FDA database, application review files, ClinicalTrials.gov registry records, and journal articles for each FDA-approved topical dry eye treatment. For each trial, we extracted information about the study, patient demographics, treatment names and doses, sample size in each arm, and the measurement instrument in a systematic fashion.

RESULTS

Fourteen trials were included that assessed 5 topical treatments for dry eye (cyclosporine 0.05%, cyclosporine 0.09%, lifitegrast 5%, and loteprednol 0.25% eye drops and varenicline 0.03-mg nasal spray). Median treatment duration was 12 weeks (range, 2-24 weeks). In all trials, treatments, including varying concentrations of the same treatment, were compared with vehicle. Twelve trials (85.7%) evaluated a primary clinician-measured clinical sign, and 10 trials (71.4%) evaluated a primary patient-reported symptom. Corneal staining was the most frequently evaluated clinical sign primary outcome, reported in half (6 of 12) of the trials, and was graded using 4 different scoring systems. Conjunctival staining, conjunctival hyperemia, and tear production were each measured using 2 different scoring systems. Ocular discomfort, the only patient-reported symptom primary outcome, was measured using 5 different instruments.

CONCLUSION

A variety of outcome measures were used in these clinical trials. Clinically meaningful dry eye outcome measures and standardized measurements can optimize the assessment of and comparison of therapeutic benefits.

Racial and Ethnic Disparities in Dry Eye Diagnosis and Care

PURPOSE

To investigate health disparities in racial and ethnic minorities with dry eye.

METHODS

Medical records were reviewed for demographics, socioeconomic factors, treatments, and objective dry eye parameters. Race/ethnicity was self-reported as delineated by the U.S. Census. The reference group comprised of randomly selected White patients, with number equal to the largest minority group.

RESULTS

The study included 465 patients (157 Black, 157 White, 85 Asian, and 66 Hispanic). Compared to White (3.2%) patients, larger proportion of minorities used Medicaid or lacked health insurance (Black 8.3%, P = .054; Asian 10.6%, P = .019; Hispanic 18.2%, P < .001). Black and Hispanic patients had lower estimated median household income than Whites (White $98,472, Black $75,554, P < .001; Asian $105,503, P = .088; Hispanic $86,839, P = .030). Prior to presentation, fewer minority patients received prescription treatments or procedures (White 61.8%; Black 30.6%, P < .001; Asian 43.5%, P = .006; Hispanic 43.9%, P = .014). Although at baseline visit minorities had worse mean conjunctival (White, 1.7; Black 2.2, P = .136, Asian 2.4, P = .022; Hispanic 2.6, P = .005) and corneal staining scores (White, 1.6; Black 2.5, P < .001; Asian 2.3, P = .003; Hispanic 2.4, P = .001), no differences were noted at final visit.

CONCLUSION

Minorities presented with worse objective dry eye parameters, and less prior dry eye care. Income and health care access may not fully explain the observed undertreatment at presentation. Differential management by eye care providers and patient attitudes warrant further investigation.

Diagnostic Performance of the Tear Meniscus Osmolarity Measurement for Dry Eye Disease in Rheumatoid Arthritis Patients

BACKGROUND

The aim of our study was to evaluate the diagnostic capacity of the tear meniscus osmolarity measurement for dry eye disease (DED) in patients with rheumatoid arthritis (RA), using a portable osmometer based on electrical impedance and an integrated circuit technology (TearLab® (Escondido, CA, USA)).

METHODS

We included 101 RA patients, 81 patients with DED and 20 without DED (controls). We measured tear osmolarity and assessed other clinical diagnostic tests as suggested by the TFOS DEWS II composite reference standard diagnostic criteria for DED using Ocular Surface Disease Index (OSDI), Five-item Dry Eye Questionnaire (DEQ-5), fluorescein tear break-up time (F-TUBT), ocular surface staining (SICCA score), and other clinical parameters to classify DED subtypes. We analyzed the agreement between osmolarity and the TFOS DEWS II composite reference standard for DED diagnosis. We conducted receiver operating characteristic (ROC) curve analyses using the DED variable and its subtypes as dependent variables and the continuous variable for osmolarity or the inter-eye difference in osmolarity as independent variable. Sensitivity, specificity, and area under the curve for all potential cut-off points were obtained and reported from ROC curves.

RESULTS

We found that tear meniscus osmolarity had a low diagnostic capacity for DED (AUC = 0.57). Tear meniscus osmolarity measurement had a sensitivity of 35% and a specificity of 80% with a kappa level of agreement of 0.08 compared to the TFOS DEWS II composite reference standard. The low diagnostic capacity of the tear meniscus osmolarity was similar for aqueous-deficient DED and for evaporative DED, being only fair for severe DED with a 57% sensitivity and 80% specificity and a kappa level of agreement of 0.36.

CONCLUSIONS

Our findings suggest that in patients with RA, tear meniscus osmolarity measured by the TearLab® showed low sensitivity, low specificity, and limited agreement with the TFOS DEWS II composite reference standard for DED diagnosis.

Effects of physical activity/exercise on tear film characteristics and dry eye associated symptoms: A literature review

PURPOSE

To conduct a review of the literature in order to identify the potential association between physical activity or exercise and the objective signs and/or subjective symptoms of dry-eye disease.

METHODS

A review of PubMed and Web of Science databases was performed, according to the PRISMA guidelines. The papers included in the review addressed the relationship of physical activity or exercise with dry-eye associated signs (changes in tear volume, osmolarity or biochemical composition) and/or subjective symptoms.

RESULTS

A total of 16 papers were included. In eight, the changes in tear film volume, osmolarity and/or biochemical composition were studied after a single, acute bout of aerobic exercise. In another eight, changes in dry-eye associated symptoms were studied in relation to the habitual practice of physical activity or to prescribed exercise programmes. Acute responses of the tear film to exercise included: a) an increase of tear volume, without an increase of the tear break-up time; b) a trend to increase tear osmolarity, although within its physiological range; and c) a reduced concentration of several cytokines, and other molecular markers of inflammation or oxidative stress. Long-term exposure to physical activity or exercise programmes was associated with relief of dry-eye associated symptoms and a trend to increased tear break-up time.

CONCLUSIONS

Despite a high heterogeneity in the studied population, study designs and methods, the current body of evidence suggests a potential role for physical activity as a modulatory stimulus for the proper functioning of the tear film and/or the relief of dry-eye symptoms.

How Can We Best Diagnose Severity Levels of Dry Eye Disease: Current Perspectives

Dry eye disease (DED) is a common ocular condition, but the diagnosis relative to other ocular conditions and the evaluation of severity of the condition has often been difficult. This challenge can be due to clinical signs and symptoms not always correlating with each other. An understanding of the various components which create the condition, as well as the diagnostic measures used to evaluate these components, is useful to the clinician working with DED patients. This review paper will discuss traditional diagnostic options, diagnostic imaging, and Advanced Point of Care testing capabilities to determine the severity level of dry eye disease more adequately.

Efficacy of Topical 0.05% Cyclosporine A for Ocular Surface Disease Related to Topical Anti-Glaucoma Medications

Purpose: We aimed to determine the therapeutic efficacy of 0.05% topical cyclosporine A (CsA) for chronic ocular surface disease (OSD) in patients using benzalkonium chloride (BAK)-preserved antiglaucoma eye drops. Methods: A prospective, randomized, paired-eye, controlled clinical trial was conducted with participants who had been instilling at least one BAK-preserved topical antiglaucoma drug in both eyes for at least 6 months. Topical CsA was only applied in randomly selected unilateral eyes. Visual field (VF) indices, ocular surface parameters, tear meniscus height (TMH), and matrix metalloproteinase-9 (MMP-9) immunoassay were evaluated at baseline and at 2 and 4 months. Results: Seventy eyes from 35 participants were included in the study. The Schirmer I, tear breakup time, and TMH increased by 4.5 ± 8.6 mm (P < 0.01), 5.0 ± 5.3 s (P < 0.001), and 85.4 ± 159.0 μm (P < 0.01) in the treated eyes at 4 months from baseline, respectively. The ocular staining score and MMP-9 positivity in the treated eyes decreased by 2.2 ± 1.3 (P < 0.001) and 0.7 ± 0.9 points (P < 0.001), respectively, at 4 months. In untreated eyes, only TMH increased by 41.4 ± 92.1 μm (P = 0.016) from baseline to 4 months. In VF indices, the tracking failure frequency was 19.09% ± 21.62%, and the test duration was 336.0 ± 79.5 s in the treated eyes at 4 months, which were lower than 34.37% ± 23.13% (P < 0.001) and 375.9 ± 70.7 s (P < 0.05) in the nontreated eyes. Conclusion: Application of topical 0.05% CsA significantly improved the OSD parameters and the reliability indices of VF tests. This study was registered with the Clinical Research Information Service (CRIS) (number KCT0007124).

International survey on dry eye diagnosis by experts

Purpose

To evaluate patterns and opinion from international experts with respect to dry eye disease (DED) diagnosis in clinical practice.

Methods

An online survey was distributed to worldwide DED experts. The use of diagnosis tests was evaluated including: symptoms questionnaires, functional tests, tear stability, tear volume, tear composition, surface damage and inflammation, and eyelid assessment. After the subjective importance of symptoms, tear break up time (TBUT), non-invasive TBUT, Schirmer's test, tear meniscus height, tear osmolarity, tear metalloproteinase 9, blepharitis assessment and non-contact meibography was evaluated according to likert scale.

Results

The survey was sent to 109 experts, and 77 completed the questionnaire (rate of response = 70.6%). Most of the participants were from North America (27%) and Europe (40%). A majority of respondents (73%) diagnose DED using clinical signs and symptoms, but not fulfilling a specific criteria. Seventy-six participants (98.7%) use symptoms questionnaires. All participants evaluate damage to ocular surface, and fluorescein staining is the most frequent method used (92%). Also, all the respondents perform meibomian gland and blepharitis assessment. On the other hand, only 69.8% evaluate tear composition, being osmolarity the most common test used (66.2%). Regarding to the importance of tests, TBUT (p = 0.002) and Schirmer's (p = 0.021) were found to be more important to experts from Europe than North America. No differences were found in any other test (p > 0.05).

Conclusions

This survey offers updated and day-to-day diagnostic clinical practice by DED worldwide experts. The results highlight the importance of symptoms and clinical signs, but not necessarily following a strict criteria.

Evaluation of suitability and detection range of fluorescent dye-loaded nanoliposomes for sensitive and rapid sensing of wide ranging osmolarities

Measurement of osmolarity is critical for optimizing bioprocesses including antibody production and detecting pathologies. Thus, rapid, sensitive, and in situ sensing of osmolarity is desirable. This study aims to develop and assess the suitability of calcein- and sulforhodamine-loaded nanoliposomes for ratiometric sensing of osmolarity by fluorescence spectroscopy and evaluate the range of detection. The detection is based on concentration-dependent self-quenching of calcein fluorescence (sensor dye at 6-15 mM) and concentration-independent fluorescence of sulforhodamine (reference dye) due to osmotic shrinkage of the nanoliposomes when exposed to hyperosmotic solutions. Using mathematical modeling, 6 mM calcein loading was found to be optimal to sense osmolarity between 300 and 3000 mOsM. Calcein (6 mM)- and sulforhodamine (2 mM)-loaded nanoliposomes were produced by thin-film hydration and serial extrusion. The nanoliposomes were unilamellar, spherical (108 ± 9 nm), and uniform in size (polydispersity index [PDI] 0.12 ± 0.04). Their shrinkage induced by exposure to hyperosmotic solutions led to rapid self-quenching of calcein fluorescence (F_Green), but no effect on sulforhodamine fluorescence (F_Red) was observed. F_Green/F_Red decreased linearly with increasing osmolarity, obeying Boyle van't Hoff's relationship, thus proving that the nanoliposomes are osmosensitive. A calibration curve was generated to compute osmolarity based on F_Green/F_Red measurements. As a proof-of-concept, dynamic changes in osmolarity in a yeast-based fermentation process was demonstrated. Thus, the nanoliposomes have great potential as sensors to rapidly and sensitively measure wide-ranging osmolarities.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Intense Pulse Light Combined With Low-Level Light Therapy in Dry Eye Disease: A Systematic Review

OBJECTIVES

To evaluate the improvement in symptoms and signs associated with intense pulse light (IPL) combined with low-level light therapy (LLLT) in the treatment of dry eye disease (DED).

METHODS

A systematic review of full-length original studies reporting the effects of IPL combined with LLLT for DED in two databases, PubMed and Scopus, was performed according to the PRISMA statement. The quality assessment tool for case series studies from the National Heart, Lung, and Blood Institute was used to analyze the quality of the studies selected.

RESULTS

The search provided a total of 393 articles, of which six were included. Significant decreases in the Ocular Surface Disease Index (OSDI) score, meibomian gland dysfunction (MGD) score, MGD grade, and meiboscore and increases in tear film stability, lipid layer thickness, and loss area of the meibomian gland have been reported. Concerning tear volume, tear meniscus height, and Schirmer test remained unchanged. In relation to tear osmolarity and corneal fluorescein staining, contradictory outcomes were found.

CONCLUSIONS

Intense pulse light combined with LLLT for the treatment of dry eye improves OSDI, tear film stability, and meibomian gland function; thus, this treatment may be recommended for DED patients due to MGD.

Assessment of Tear Osmolarity in Smokers Using TearLab and I-Pen Systems

Purpose. Smoking has a negative effect on health and ocular tear film. The purpose of the current study is to investigate the correlation between the TearLab and I-Pen osmolarity scores in smokers and compare them with those of non-smoking healthy males. Methods. Thirty male smokers (25.3 ± 2.2 years) participated in the study. An age-matched (22.9 ± 2.0 years) control group of non-smoking healthy males (N = 30) was also recruited for comparison purposes. The ocular surface disease index (OSDI) was completed first, followed by the TearLab and I-Pen osmolarity measurements. Results. The median TearLab osmolarity score was lower (P < 0.001) than that obtained using the I-Pen in both the study and the control groups. The OSDI scores and osmolality measurements were higher (P < 0.001) in smokers than in the control subjects. In the smoker group, there were moderate correlations between the OSDI scores and the measurements obtained using the TearLab (Spearman’s correlation coefficient, r = 0.463; P = 0.010) and I-Pen (r = 0.449; P = 0.013) systems. In addition, there was a strong correlation between the osmolarity scores obtained from the TearLab and I-Pen systems in smokers (r = 0.911; P < 0.001). Conclusion. The I-Pen scores in smokers were significantly higher than those obtained using TearLab. The TearLab scores showed small variations compared with those obtained using I-Pen. A strong correlation was found between the TearLab and I-Pen scores in smokers. The osmolarity TearLab and I-Pen scores were significantly higher in smokers compared with normal eye subjects.

Evaluation of warm compresses and topical cyclosporine treatment in meibomian gland dysfunction by confocal scanning laser microscopy

PURPOSE

The aim of our study is to confirm the utility of warm compresses (WC) and artificial tears (AT) in meibomian gland dysfunction (MGD) management and to understand if its association with topical cyclosporine A (CsA) improves outcomes.

METHODS

Patients with diagnosis of MGD-related dry eye were evaluated. In this prospective, randomized, double-masked study, patients were randomized in two treatments: AT plus WC (group A), and AT plus WC plus CsA 0.05% ophthalmic emulsion (group B). At baseline and at 1, 3, and 6 months, Ocular Surface Disease Index (OSDI) questionnaire was completed, and tear evaluation (BUT, Schirmer and osmolarity test), ocular surface evaluation (fluorescein and lissamine green staining), clinical (Shimazaki grading) and in vivo confocal microscopy (IVCM) evaluation of rete ridges (RRs) were performed.

RESULTS

A total of 40 eyes, 20 in each group, completed the study. Analysis of OSDI, tear test, ocular surface evaluation and clinical grading of MG showed significant improvement at 6 months, whereas no difference was found between the two groups at 6 months. The analysis of IVCM showed significant improvement in both groups, but significantly better results in group B were found compared to group A at 6 months.

CONCLUSION

WC performed 3 times daily during the 1st month and once daily afterwards, in addition to AT, were useful to manage the obstruction of MG and related signs and symptoms. Additional effects of CsA were visible in IVCM only at 6 months. IVCM is an effective tool to monitor treatments in MGD.

Advances in Dry Eye Disease Examination Techniques

Dry eye-related ocular surface examination is very important in the diagnosis and treatment of dry eye disease. With the recent advances in science and technology, dry eye examination techniques have progressed rapidly, which has greatly improved dry eye diagnoses and treatment. However, clinically, confusion remains about which examination to choose, how to ensure the repeatability of the examination, and how to accurately interpret the examination results. In this review, we systematically evaluate previous examinations of dry eye, analyze the latest views and research hotspots, and provide a reference for the diagnosis and management of dry eye.

Outcomes of Sjögren's versus non-Sjögren's related dry eye in a longitudinal, tertiary clinic-based sample

Purpose

To assess the long-term treatment outcomes of dry eye in patients with and without underlying primary Sjögren’s syndrome (SS).

Design

Retrospective longitudinal cohort.

Methods

SS and non-SS dry eye patients with clinic visits for a minimum of 5 consecutive years at a tertiary, dedicated dry eye clinic were included. Electronic health records were reviewed to collect data regarding demographics, objective dry eye parameters, treatments utilized at baseline and final visit, and corneal complications observed during follow-up.

Results

Two hundred and two patients (101 SS and 101 randomly selected non-SS), with a mean follow-up of 7.1 years were included. At baseline, mean conjunctival lissamine green staining score was 2.9 and mean corneal fluorescein staining score was 2.0. At last visit, notable improvement in staining score for cornea (–1.1, P < .001) and conjunctiva (–1.8, P < .001) was seen equally in both dry eye groups. Most patients (88.1%) had an escalation of treatment by the final visit, with similar rates in both groups (P = .51). Half (48.9%) of the patients had no conjunctival staining, and a third (34.4%) had no corneal staining at their last visit. Twenty (9.9%) patients experienced a vision-threatening corneal complication, including ulcers and melt, with no difference in occurrences between the groups (P = .64).

Conclusions

The majority of patients in this longitudinal, tertiary clinic-based sample demonstrated improvement in their ocular surface staining score by the final visit with escalation in treatment. Treatments used, improvement achieved, and corneal complication rates leading to loss of vision were similar in both SS and non-SS dry eye groups.

Prevalence of Tear Film Hyperosmolarity in 1150 patients presenting for refractive surgery assessment

PURPOSE

To present an analysis of tear film hyperosmolarity in a large, consecutive population and evaluate the correlation of ocular and systemic conditions with tear film osmolarity.

SETTING

Private practice Sydney, Australia.

DESIGN

Single-centre, retrospective, consecutive cohort.

METHOD

1404 patients (n=1357 standard, n=47 post-refractive) undergoing screening for laser refractive surgery from October 2017 to October 2020 were reviewed. Routine examination included tear film osmolarity (TFO) and Ocular Surface Disease Index questionnaire). TFO was conducted prior to further tests and patients refrained from topical eye drops minimum two hours before the appointment.

RESULTS

Mean highest TFO in the standard population was 299.12±11.94mOsm/L with 82.3% of eyes <308mOsm/L indicating normal tear film homeostasis. The mean inter-eye TFO difference was 8.17±8.60mOsm/L with 65.2% of eyes <=8mOsm/L. Mean highest TFO in the post-refractive subgroup was 299.72±11.00mOsm/L with a mean inter-eye difference of 9.02±6.92mOsm/L. Post-refractive surgery patients indicated higher mean OSDI values of 15.28±14.46 compared to the remainder of the population 9.69±10.56 (p=0.012). Significant correlation was demonstrated between TFO scores and OSDI normal classification in the standard population only (p=0.005, r=0.077). The use of contact lens correlated inversely with TFO and OSDI scores (p=0.000, r=-0.136 and p=0.000, r=-0.152 respectively).

CONCLUSION

Our study represents the largest available cohort of TFO scores in a standard population presenting for refractive surgery. We found that although the majority of patients can be expected to fall within normal ranges, a reasonable percentage will be diagnosed with tear hyperosmolarity and therefore at risk of dry eye disease.

Short-Term Impact of FS-LASIK and SMILE on Dry Eye Metrics and Corneal Nerve Morphology

PURPOSE

To analyze the short-term (up to 1 month) clinical outcomes in patients undergoing corneal laser refractive surgery and the impact on dry eye disease (DED) metrics and corneal nerves using in vivo confocal microscopy (IVCM).

METHODS

The unaided distance visual acuity, corrected distance visual acuity, and spherical equivalent refraction (SEQ) were determined in 16 and 13 patients undergoing FS-LASIK and SMILE, respectively. DED metrics assessed were Ocular Surface Disease Index, Dry Eye Questionnaire 5-items (DEQ-5), tear film osmolarity, tear meniscus height, noninvasive keratograph breakup time (NIKBUT), ocular staining, and meibomian gland atrophy. An automated analysis of corneal nerve fiber density, corneal nerve branch density, corneal nerve fiber length (CNFL), and corneal nerve fiber fractal dimension were obtained from the IVCM scans using ACCMetrics software (University of Manchester).

RESULTS

Both surgical techniques provided good refractive and visual outcomes. DED symptoms were found to be higher after FS-LASIK compared with SMILE (P < 0.05). A decrease in tear meniscus height (∼31%) and NIKBUT (∼40%) was reported after FS-LASIK (P = 0.005 and P = 0.001, respectively) but not after SMILE. Both procedures affected corneal nerve fiber density, corneal nerve branch density, CNFL, and corneal nerve fiber fractal dimension, but the impact was significantly greater with FS-LASIK (P = 0.001). Only CNFL correlated with the reported symptoms (DEQ-5) after FS-LASIK (r = -0.545, P = 0.029).

CONCLUSIONS

FS-LASIK and SMILE provided good refractive and visual outcomes. There was an increased impact on DED symptoms after FS-LASIK compared with SMILE, although there were no significant differences between the procedures for most of the other ocular surface metrics assessed. The IVCM findings showed that SMILE had less impact on corneal nerves compared with FS-LASIK.

Evaluation of tear osmolarity measured by I-Pen osmolarity system in patients with dry eye

This retrospective comparative study was to evaluate tear osmolarity measured by I-Pen osmolarity system (I-MED Pharma Inc, Dollard-des-Ormeaux, Quebec, Canada) in healthy subjects without dry eye disease (DED) and patients with DED, and its association with other ocular surface parameters. This study comprised 65 eyes of 65 patients. The ocular surface parameters including tear osmolarity with I-Pen osmometer of the patients who visited the refractive surgery center of Samsung Medical Center between January 1, 2020 and May 31, 2020 were retrospectively collected. The subjects were divided as asymptomatic normal group and symptomatic dry eye group. The distribution of tear osmolarity and its association with other ocular surface parameters were evaluated. Total thirty-two patients (32 eyes) were included in the control group, and 33 patients (33 eyes) were included in the DED group. Tear osmolarity was significantly higher in the DED group. Tear osmolarity was negatively correlated with tear break-up time, and the Schirmer test, and was positively correlated with Ocular Surface Disease Index symptom score. The cut-off value of 318 mOsm/L showed a sensitivity of 90.9% and specificity of 90.6% for diagnosing DED. The I-Pen osmometer can be considered suitable for use in the clinical setting, with good performance in DED diagnosis.

What's new in ocular and oral aspects of Sjögren's syndrome and do new treatments work?

Primary SS (pSS) is a systemic autoimmune disease characterized by lymphocytic infiltration of the exocrine glands leading to glandular dysfunction, resulting in dryness of the eyes, mouth and other mucosal surfaces. Systemic manifestations also occur in the majority of patients. There has been increasing interest in recent years, with a number of publications regarding the classification criteria, diagnostic tools, disease activity, damage, impact and potential treatments. This article reviews recent advances in the diagnosis and treatment of ocular and oral involvement in pSS. Recent stand-out developments include measurement of tear osmolarity as a marker in dry eye disease diagnosis, new devices measuring tear constituents and meibomian gland structure and treatment of its dysfunction. Lip biopsy is still valuable despite emerging evidence of non-invasive diagnostic techniques, notably salivary gland ultrasound.

Tear Film Break-Up Time and Dry Eye Disease Severity in a Large Norwegian Cohort

This study evaluated to what extent tear film break-up time (TFBUT) could discriminate pathological scores for other clinical tests and explore the associations between them. Dry eye patients (n = 2094) were examined for ocular surface disease index (OSDI), tear film osmolarity (Osm), TFBUT, blink interval, ocular protection index (OPI), ocular surface staining (OSS), Schirmer I test, meibomian expressibility, meibomian quality, and meibomian gland dysfunction. The results were grouped into eight levels of break-up time (≤2, ≥3, ≤5, ≥6, ≤10, ≥11, ≤15, and ≥16) with or without sex stratification. Receiver-operating characteristic curve (ROC) analysis and Pearson’s correlation coefficients were used to study TFBUT’s discriminative power and the associations among the tests, respectively. Above and below each TFBUT’s cut-off, all of the parameters indicated significant difference between groups, except OSDI (cut-off 15 s) and Osm (cut-offs 5 s–15 s). At TFBUT cut-off of 2 s, sex difference could be detected for OSDI, Osm, and OSS. OPI presented the strongest discriminative power and association with TFBUT in sharp contrast to Osm, holding the poorest discriminative power with no significant correlation. The remaining parameters were within the poor to very poor categories, both with regard to discrimination and correlation. In conclusion, patients with lower TFBUT presented with more severe DED parameters at all four defined cut-off values.

Ocular Clinical Signs and Diagnostic Tests Most Compatible With Keratoconjunctivitis Sicca: A Latent Class Approach

PURPOSE

To evaluate the ocular signs and tests for keratoconjunctivitis sicca (KCS) in the absence of a gold standard.

METHODS

Cross-sectional study of participants from the Sjögren's International Collaborative Clinical Alliance (SICCA) registry. Participants had oral/ocular/rheumatologic examinations, blood/saliva samples collected, and salivary gland biopsy. Latent class analysis (LCA) identified clusters of patients based on 3 to 4 predictor variables relating to signs or tests of KCS. The resulting model-based "gold standard" classification formed the basis for estimated sensitivity and specificity associated with these predictors.

RESULTS

A total of 3514 participants were enrolled into SICCA, with 52.9% classified as SS. LCA revealed a best-fit model with 2 groups. For the gold standard-positive group, an abnormal tear breakup time, ocular staining score (OSS), and Schirmer I had a sensitivity of 99.5%, 91.0%, and 47.4%, respectively. For the gold standard-negative group, an abnormal tear breakup time, OSS, and Schirmer I had a specificity of 32.0%, 84.0%, and 88.5%, respectively. OSS components (fluorescein and lissamine staining), exhibited a sensitivity of 82.6% and 90.5%, respectively, in the gold standard-positive group, whereas these signs in the gold standard-negative group had a specificity of 88.8% and 73.0%, respectively.

CONCLUSIONS

OSS and its components (fluorescein and lissamine staining) differentiated 2 groups from each other better than other KCS parameters and had relatively high sensitivity and specificity.

Utility of Tear Osmolarity Measurement in Diagnosis of Dry Eye Disease

The prevalence of dry eye disease is high worldwide and poses a great burden on patients' daily lives. Accurate diagnosis of the disease is important, and it requires application of various methods. Hyperosmolarity is believed to be the disease marker and thus measuring it provides useful information. In this study we investigated utility of tear osmolarity measured with TearLab osmometer, along with other diagnostic tests (Ocular Surface Disease Index questionnaire, Tear film break-up time, Ocular Protection Index, Ocular Surface Staining, Schirmer I test, Meibomian gland functionality in 757 patients (1514 eyes) with dry eye disease and 29 healthy controls (58 eyes). Statistical differences between the patient group and the control group were observed for all the tests apart from tear osmolarity, regardless of cut-off value (>308 mOsm/L, >316 mOsm/L, and inter-eye difference >8 mOsm/L). Moreover, in the receiver operating characteristics curve analyses tear osmolarity measurement could not discriminate dry eye disease pathological scores. Therefore, our study suggests that tear osmolarity measured with TearLab osmometer cannot be used as a key indicator of DED.

Scleral Lens Sensor for Ocular Electrolyte Analysis

The quantitative analysis of tear analytes in point-of-care settings can enable early diagnosis of ocular diseases. Here, a fluorescent scleral lens sensor is developed to quantitatively measure physiological levels of pH, Na⁺ , K⁺ , Ca²⁺ , Mg²⁺ , and Zn²⁺ ions. Benzenedicarboxylic acid, a pH probe, displays a sensitivity of 0.12 pH units within pH 7.0-8.0. Crown ether derivatives exhibit selectivity to Na⁺ and K⁺ ions within detection ranges of 0-100 and 0-50 mmol L^-1 , and selectivities of 15.6 and 8.1 mmol L^-1 , respectively. A 1,2 bis(o-aminophenoxy)ethane-N,N,-N',N'-tetraacetic-acid-based probe allows Ca²⁺ ion sensing with 0.02-0.05 mmol L^-1 sensitivity within 0.50-1.25 mmol L^-1 detection range. 5-Oxazolecarboxylic acid senses Mg²⁺ ions, exhibiting a sensitivity of 0.10-0.44 mmol L^-1 within the range of 0.5-0.8 mmol L^-1 . The N-(2-methoxyphenyl)iminodiacetate Zn²⁺ ion sensor has a sensitivity of 1 µmol L^-1 within the range of 10-20 µmol L^-1 . The fluorescent sensors are subsequently multiplexed in the concavities of an engraved scleral lens. A handheld ophthalmic readout device comprising light-emitting diodes (LEDs) and bandpass filters is fabricated to excite as well as read the scleral sensor. A smartphone camera application and an user interface are developed to deliver quantitative measurements with data deconvolution. The ophthalmic system enables the assessment of dry eye severity stages and the differentiation of its subtypes.

Toward better outcomes in Sjögren's syndrome: The promise of a stratified medicine approach

Sjögren's syndrome is a systemic autoimmune disease defined by its targeted inflammation of the salivary and lacrimal glands, resulting in dry mouth and eyes in the majority and persistent or recurrent salivary gland enlargement in a minority of those affected. Involvement of major organs, an increased risk of lymphoma, and autoantibodies against ubiquitous cellular ribonucleoproteins define some of its systemic features. Those affected have a high symptom burden and the development of disease-modifying therapies is thus an urgent need. A stratified medicine approach offers promise as a means of targeting specific therapies to patients for whom the mechanism of action is most relevant. Implementation of this approach will require an understanding of the pathophysiological processes underlying different patient subsets, and then identifying or developing a drug that targets this pathway. Such therapies would be most effective if implemented early in the disease course before the advent of adverse outcomes or glandular damage. This review will provide a disease overview followed by an analysis of the feasibility of a stratified medicine approach, focusing on the disease heterogeneity, predictors of disease progression and adverse outcomes, and recent advances in the development of relevant outcome measures and new therapies.

Multiscale reverse engineering of the human ocular surface

Here we present a miniaturized analog of a blinking human eye to reverse engineer the complexity of the interface between the ocular system and the external environment. Our model comprises human cells and provides unique capabilities to replicate multiscale structural organization, biological phenotypes and dynamically regulated environmental homeostasis of the human ocular surface. Using this biomimetic system, we discovered new biological effects of blink-induced mechanical forces. Furthermore, we developed a specialized in vitro model of evaporative dry-eye disease for high-content drug screening. This work advances our ability to emulate how human physiological systems interface with the external world, and may contribute to the future development of novel screening platforms for biopharmaceutical and environmental applications.

Tear Metabolomics in Dry Eye Disease: A Review

Dry eye disease (DED) is a multifactorial syndrome that can be caused by alteration in the quality or quantity of the precorneal tear film. It is considered one of the most common ocular conditions leading patients to seek eye care. The current method for diagnostic evaluations and follow-up examinations of DED is a combination of clinical signs and symptoms determined by clinical tests and questionnaires, respectively. The application of powerful omics technologies has opened new avenues toward analysis of subjects in health and disease. Metabolomics is a new emerging and complementary research discipline to all modern omics in the comprehensive analysis of biological systems. The identification of distinct metabolites and integrated metabolic profiles in patients can potentially inform clinicians at an early stage or during monitoring of disease progression, enhancing diagnosis, prognosis, and the choice of therapy. In ophthalmology, metabolomics has gained considerable attention over the past decade but very limited such studies have been reported on DED. This paper aims to review the application of tear metabolomics in DED.

Dry eye is matched by increased intrasubject variability in tear osmolarity as confirmed by machine learning approach

OBJECTIVE

Because of high variability, tear film osmolarity measures have been questioned in dry eye assessment. Understanding the origin of such variability would aid data interpretation. This study aims to evaluate osmolarity variability in a clinical setting.

MATERIAL AND METHODS

Twenty dry eyes and 20 control patients were evaluated. Three consecutive osmolarity measurements per eye at 5min intervals were obtained. Variability was represented by the difference between both extreme readings per eye. Machine learning techniques were used to quantify discrimination capacity of tear osmolarity for dry eye.

RESULTS

Mean osmolarities in the control and dry eye groups were 295.1±7.3mOsm/L and 300.6±11.2mOsm/L, respectively (P=.004). Osmolarity variabilities were 7.5±3.6mOsm/L and 16.7±11.9mOsm/L, for the control and dry eye groups, respectively (P<.001). Based on osmolarity, a logistic classifier showed an 85% classification accuracy.

CONCLUSIONS

In the clinical setting, both mean osmolarity and osmolarity variability in the dry eye group were significantly higher than in the control group. Machine learning techniques showed good classification accuracy. It is concluded that higher variability of tear osmolarity is a dry eye feature.

Anti-inflammatory effects of paeoniflorin from Paeonia lactiflora Pall. on human corneal epithelial cells and a mouse model of dry eye disease

Dry eye disease (DED) is characterized by increased osmolality of tears due to a lack of production or increased evaporation of tears. Hyperosmolarity is involved in DED pathogenesis, which damages ocular surface cells and leads to inflammation of the ocular surface. We investigated the anti-inflammatory effect of paeoniflorin (PF) from Paeonia lactiflora Pall. on human corneal epithelial (HCE) cells and its molecular mechanisms, and its therapeutic effects on a mouse model of experimental dry eye (EDE). HCE cells were treated with PF-1 (PF prepared in vitro; 0.01%, 0.1% and 1.0%). Protein production/activity was determined by Western blotting, RT-PCR and immunofluorescent staining. Meanwhile, eye drops containing 0.01%, 0.1% and 1.0% of PF-2 (PF prepared in vivo) were applied to the EDE, and the tear volume, corneal fluorescein-staining score, detachment of the corneal epithelium, and immunohistochemical staining were measured after 28 days of treatment. PF reduced expression of proinflammatory factors such as interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-α in HCE cells, and significantly improved dry-eye signs, including tear volume, desquamation of the corneal epithelium and ocular surface inflammation in mice treated with 1.0% PF-2. Further study showed that PF improved EDE by inhibiting mitogen-activated protein kinase (MAPK), phosphorylated (p)-c-Jun N-terminal kinase (JNK) and pp-38, and nuclear factor kappa B (NF-κB) signaling pathways. These data suggest that PF can improve dry-eye symptoms and reduce expression of proinflammatory mediators. Hence, eye drops containing PF could be used as an adjunctive treatment for DED.

Review of Biomarkers in Ocular Matrices: Challenges and Opportunities

Biomarkers provide a powerful and dynamic approach to improve our understanding of the mechanisms underlying ocular diseases with applications in diagnosis, disease modulation or for predicting and monitoring of clinical response to treatment. Defined as measurable indicator of normal or pathological processes, biomarker evaluation has been used extensively in drug development within clinical settings to better comprehend effectiveness of treatment in ocular diseases. Biomarkers in the eye have the advantage of access to multiple ocular matrices via minimally invasive methods. Repeat sampling for biomarker assessment has enabled reproducible objective measures of disease process or biological responses to a drug treatment. This review describes the usage of biomarkers with respect to four commonly sampled ocular matrices in clinic: tears, conjunctiva, aqueous humor and vitreous. Issues that affect the evaluation of biomarkers are discussed along with opportunities to leverage biomarkers such that ultimately, they can be used for customized targeted therapy.

Variability of Tear Osmolarity Measurements With a Point-of-Care System in Healthy Subjects-Systematic Review

PURPOSE

To assess the variability of osmolarity measured by the point-of-care TearLab system in healthy eyes.

METHODS

A systematic review was performed by searching MEDLINE, Scopus, and the Web of Science Databases until November 2016 and checking reference lists of included articles and reviews. The requirements for inclusion were the availability of TearLab results in healthy subjects and a minimum study sample of 20 eyes. Two reviewers assessed articles against the inclusion criteria, extracted relevant data, and examined the methodological quality. We computed the weighted mean osmolarity using the study size as the weighting factor and calculated the rate of subjects with osmolarity values >308 mOsm/L, the Dry Eye Workshop Report 2017 (DEWS) cut-off value for dry eye disease (DED). We repeated the analysis after excluding reports with a possible conflict of interest or missing description of subject selection.

RESULTS

Searches retrieved 105 nonduplicate articles, and we included 33 studies investigating 1362 eyes of healthy participants who were asymptomatic and showed no clinical signs of DED. Sixty-three percent were female, and mean age was 37.3 years (range: 21.5-69.0 yr). Weighted mean osmolarity was 298 mOsm/L (95% confidence interval, 282-321 mOsm/L). The result of the subgroup analysis was similar. Overall, 386 of 1362 eyes (28.3%) fulfilled the DEWS's definition of DED (>308 mOsm/L).

CONCLUSIONS

There is a high variability of osmolarity measurements with the TearLab system. A substantial number of healthy subjects fulfill the DEWS's definition of DED. We propose interpreting the TearLab osmolarity results cautiously and in the context of other established methods.

Ocular Surface Workup With Automated Noninvasive Measurements for the Diagnosis of Meibomian Gland Dysfunction

PURPOSE

To analyze diagnostic performance of an ocular surface workup based on automated noninvasive measurements in the diagnosis of meibomian gland dysfunction (MGD).

METHODS

Two hundred ninety-eight eyes of 149 patients with MGD and 54 eyes of 27 control patients were analyzed. Ocular Surface Disease Index (OSDI), noninvasive breakup time (BUT), lipid layer thickness, meibomian gland loss, and tear osmolarity were calculated. The correlations among variables in the MGD group were analyzed. The area under the curve (AUC) of receiver operating characteristic curves was calculated.

RESULTS

OSDI, noninvasive BUT, and meibomian gland loss were significantly different between MGD and control groups (respectively, 37.9 ± 19.6 vs. 7.1 ± 2.8; 8.8 ± 3.6 vs. 11.0 ± 3.0; 28.0 ± 17.6 vs. 21.2 ± 13.0; always P < 0.05). Positive correlations were found between lipid layer thickness and noninvasive BUT and between meibomian gland loss and OSDI (respectively, r = 0.169, P = 0.004; r = 0.187, P = 0.004). Noninvasive BUT had the highest diagnostic power as a single parameter, followed by meibomian gland loss (respectively AUC = 0.686, AUC = 0.598). When the diagnosis of MGD was made based on either noninvasive BUT or meibomian gland loss being abnormal, sensitivity was 86.2% and specificity 38.5%. When the diagnosis was made on both noninvasive BUT and meibomian gland loss being abnormal, sensitivity was 39.3% and specificity 85.6%.

CONCLUSIONS

This automated noninvasive ocular surface workup may represent a useful screening tool for the diagnosis of MGD. In case of positivity of either noninvasive BUT or meibomian gland loss, subsequent qualitative clinical tests should be performed to achieve a reliable diagnosis and more precise characterization of MGD.

Tear film evaluation by scanning laser ophthalmoscopy during retinal imaging

Purpose:

Herein, we describe a novel finding which appears as a reticular pattern on multicolor confocal scanning laser ophthalmoscopy image during routine imaging of retina and we aim to show whether there is an association between this pattern and dry eye findings.

Materials and methods:

A total of 162 eyes of 81 patients that were scheduled for a routine retinal imaging by scanning laser ophthalmoscopy at a vitreoretinal practice underwent dry eye evaluation including corneal and conjunctival lissamine green staining, fluorescein staining, tear break-up time, and tear meniscus height measurement before acquiring any images. Then, multicolor images were taken and graded for the severity of reticular pattern.

Results:

Among 150 eyes of 81 patients with gradable multicolor imaging, 45 eyes (30%) had some reticular pattern on multicolor image. Severity of reticular pattern on multicolor imaging was significantly correlated with total lissamine score (rho = 0.378, p = 0.007) and tear meniscus height (rho = −0.408, p = 0.011). Furthermore, they were found to be the best set of predictors for the severity pattern on multicolor imaging (odds ratio = 1.30, 95% confidence interval = 1.01–1.37, p = 0.027 and odds ratio = 0.25, 95% confidence interval = 0.128–0.342, p < 0.001, respectively).

Conclusion:

Reticular pattern seen on multicolor image while acquiring retinal images using scanning laser ophthalmoscopy may be related to tear film instability. Further modulations of the scanning laser ophthalmoscopy instrument will likely improve this indicator of dry eye syndrome.

Influence of Nasal Tear Osmolarity on Ocular Symptoms Related to Dry Eye Disease

PURPOSE

To investigate relationships between local tear osmolarity and tear film characteristics and dry eye disease (DED) symptoms.

DESIGN

Prospective, cross-sectional, observational study.

METHODS

Nasal and temporal tear osmolarity were measured in subjects with DED. The difference between nasal and temporal tears (OSM difference) was then calculated. Ocular symptoms were evaluated and tear break-up time (TBUT), corneal fluorescein staining score (CFSS), eyelid hyperemia, and tear production were measured. Correlations between DED symptoms and nasal tear osmolarity, temporal tear osmolarity, OSM difference, and tear film characteristics were evaluated using Pearson correlation analyses. Subjects were divided into 3 groups based on OSM difference: the temporal group had a temporal osmolarity > nasal osmolarity, the nasal group had a temporal osmolarity < nasal osmolarity, and the equal group had an OSM difference < 10 mOsm/L.

RESULTS

Forty-eight eyes of 48 subjects were included. Eleven eyes were in the temporal group, 17 eyes were in the equal group, and 20 eyes were in the nasal group. Temporal osmolarity, nasal osmolarity, and OSM difference were not correlated with TBUT, CFSS, lid hyperemia, or tear production. Nasal tear osmolarity was correlated with cold sensitivity frequency (r = 0.298, P = .040), foreign body sensation severity (r = 0.293, P = .043), and light sensitivity severity (r = 0.293, P = .043). Additionally, OSM difference was correlated with daily symptom frequency (r = 0.339, P = .019).

CONCLUSIONS

Nasal tear osmolarity and OSM difference play an important role in DED symptoms. Lid hyperemia, TBUT, CFSS, and tear secretion volume are not significantly affected by tear osmolarity. It is important to measure both nasal and temporal tear osmolarity when evaluating patients with DED.

Comparison of Tear Osmolarity in Rheumatoid Arthritis Patients With and Without Secondary Sjogren Syndrome

PURPOSE

To compare tear osmolarity (TO) and other dry eye parameters in rheumatoid arthritis (RA) patients with or without secondary Sjogren syndrome (sSS).

METHODS

Consecutive patients with RA were divided into a sSS group and no-sSS group using conventional diagnostic criteria by rheumatologists using symptomatology, Schirmer test score, and anti-Ro or anti-La autoantibody status. The TO, Ocular Surface Disease Index, dry eye disease (DED) parameters [such as tear breakup time (TBUT) and corneal staining score] and the systemic inflammatory markers [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)] were compared. Correlation analyses between TO and the DED parameters and inflammatory markers were also performed.

RESULTS

A total of 42 cases with mean age 54.8 ± 12.3 were included, with 12 patients (29%) having sSS and 30 (71%) without sSS. TO was increased in both groups (329 ± 20 and 319 ± 25 mOsm/L, respectively), but no statistically significant difference was found between the 2 groups (P = 0.126). RA with sSS had significantly shorter TBUT, higher corneal staining score, and ESR CRP levels (P < 0.05). TO did not correlate with the Schirmer test score, but had significant positive correlations with age, corneal staining score, ESR, and CRP levels, and a significant negative correlation with TBUT.

CONCLUSIONS

TO was increased in RA patients with or without sSS. There was no significant correlation between TO and the Schirmer test score, and the physician could not use TO to diagnose sSS. However, TO correlated well with both DED parameters (TBUT and corneal staining score) and systemic inflammatory markers (ESR and CRP).

Assessments of tear meniscus height, tear film thickness, and corneal epithelial thickness after deep anterior lamellar keratoplasty

OBJECTIVE

To assess the lower tear meniscus height (LTMH), central tear film thickness (CTFT), and central corneal epithelial thickness (CCET) after deep anterior lamellar keratoplasty (DALK).

METHODS

This was a retrospective cross-sectional study of 20 patients who had DALK in one eye over a three-month period. LTMH, CTFT, and CCET of the operated eyes and the unoperated fellow eyes were measured using high-definition optical coherence tomography (HD-OCT). Correlations between three OCT assessments and age, time following surgery, graft size, bed size, and the number of residual sutures were analyzed.

RESULTS

Compared to patients with keratoconus, patients with other corneal conditions had significantly higher CCET in the fellow eye (P=0.024). For all patients, CCET in the operated eye was significantly negatively correlated with the number of residual sutures (R=-0.579, P=0.008), and was significantly positively correlated with time following surgery (R=0.636, P=0.003). In the fellow eye, a significant positive correlation was found between age and CCET (R=0.551, P=0.012), and a significant negative correlation between age and CTFT (R=-0.491, P=0.028). LTMH was found to be significantly correlated between operated and fellow eyes (R=0.554, P=0.011). There was no significant correlation between LTMH and age, bed/graft size, time following surgery, or residual sutures (all possible correlations, P>0.05).

CONCLUSIONS

Patients with keratoconus tend to have a thinner central corneal epithelium. Corneal epithelium keeps regenerating over time after DALK. DALK did not induce a significant change in tear volume compared with the fellow eye. Postoperative tear function might depend on an individual's general condition, rather than on age, gender, bed/graft size, time following surgery, or residual sutures.

Tear Osmolarity and Correlation With Ocular Surface Parameters in Patients With Dry Eye

PURPOSE

To analyze the distribution of tear film osmolarity in patients with dry eye and its association with other ocular surface parameters.

METHODS

Tear osmolarity and other quantitative dry eye parameters were obtained from patients with 1) clinically significant dry eye (significant symptoms and ocular surface staining, n = 131), 2) symptoms-only dry eye (significant symptoms but no significant ocular surface staining, n = 52), and 3) controls (no significant symptoms or staining, n = 42).

RESULTS

Tear osmolarity varied significantly across groups (P = 0.01), with patients with clinically significant dry eye having the highest tear osmolarity (312.0 ± 16.9 mOsm/L), control patients having the lowest tear osmolarity (305.6 ± 9.7 mOsm/L), and patients with symptoms-only dry eye falling in between (307.4 ± 5.6 mOsm/L). Patients with clinically significant dry eye also tended to have a greater intereye difference in osmolarity (12.0 ± 13.4) than did the individuals with symptoms-only dry eye (9.1 ± 12.4) and controls (9.0 ± 7.4) (P = 0.06). In multivariable regression models, higher tear osmolarity was associated with higher Ocular Surface Disease Index, discomfort subscore (P = 0.02), and higher corneal and conjunctival staining scores (P < 0.01 for both). Worse eye tear osmolarity was not correlated with the corresponding tear film breakup time or Schirmer test (P > 0.05 for both).

CONCLUSIONS

Individuals with symptomatic dry eye that is not yet clinically significant seem to have higher and more variable osmolarity measurements than controls, potentially indicating that changes in osmolarity precede clinical findings.

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.

Lack of Agreement among Electrical Impedance and Freezing-Point Osmometers

PURPOSE

To assess the interchangeability of tear osmolarity measurements between electrical impedance and freezing-point depression osmometers and to analyze inter-eye tear osmolarity variability measured with these osmometers in healthy subjects.

METHODS

Tear osmolarity was measured using the TearLab osmometer (OcuSense Inc., San Diego, CA) and the Fiske 210 microsample osmometer (Advanced Instruments Inc., Norwood, MA). We randomly selected one eye in 50 subjects (29 women, 21 men; mean age, 33.16 ± 6.11 years) to analyze whether osmolarity measurements by these osmometers were interchangeable. Both eyes of 25 patients (15 women, 10 men; mean age, 34.32 ± 6.37 years) were included to analyze inter-eye osmolarity variability.

RESULTS

The mean tear osmolarity values measured with the TearLab osmometer were higher (305.22 ± 16.06 mOsm/L) than those with the Fiske 210 osmometer (293.40 ± 12.22 mOsm/L), with the intraclass correlation coefficient being 0.23 (p = 0.051). A Bland-Altman plot showed that the systems were not interchangeable because there was a systematic difference, with the limits of agreement being -17.93 to 41.57 mOsm/L. There were no statistically significant differences (p = 0.5006 and p = 0.6533, respectively) between an individual's eyes measured with either osmometer.

CONCLUSIONS

Because the TearLab tear osmolarity measurements were higher than those of the Fiske 210 measurements and the limits of agreement were too wide, the two osmolarity values cannot be used interchangeably. In healthy subjects, there is no difference in tear osmolarity between right and left eyes of the same individual measured with both instruments.

TFOS DEWS II Tear Film Report

The members of the Tear Film Subcommittee reviewed the role of the tear film in dry eye disease (DED). The Subcommittee reviewed biophysical and biochemical aspects of tears and how these change in DED. Clinically, DED is characterized by loss of tear volume, more rapid breakup of the tear film and increased evaporation of tears from the ocular surface. The tear film is composed of many substances including lipids, proteins, mucins and electrolytes. All of these contribute to the integrity of the tear film but exactly how they interact is still an area of active research. Tear film osmolarity increases in DED. Changes to other components such as proteins and mucins can be used as biomarkers for DED. The Subcommittee recommended areas for future research to advance our understanding of the tear film and how this changes with DED. The final report was written after review by all Subcommittee members and the entire TFOS DEWS II membership.

Estimating the Osmolarities of Tears During Evaporation Through the "Eyes" of the Corneal Nerves

Purpose

A population of corneal neurons in rats preferentially sense and monitor the hyperosmolar conditions of tears when the tears begin to evaporate during corneal dryness. The present study exploited this ability in an effort to estimate tear osmolarities by comparing the responses to corneal dryness to their responses to hyperosmolar stimuli.

Methods

Extracellular recordings were performed from single neurons in the trigeminal ganglia innervating the corneas of rats. To determine the extent to which the corneal neurons' responses to drying of the cornea were induced via the activation by hyperosmolar stimuli, we assessed the responses to ocular instillation of 500 and 600 mOsm/L, and a graded series of hyperosmolar stimuli ranging from 350 to 1000 mOsm/L.

Results

The magnitudes of the responses to drying of the cornea were matched almost exactly to those induced by the ocular instillation of the 600 mOsm/L stimuli but not the 500 mOsm/L solutions. The response magnitudes to a graded series of hyperosmolar solutions were nearly linear from the 350 to the 600 mOsm/L stimuli, but reached a plateau or declined slightly thereafter.

Conclusions

Our results demonstrate that the tear osmolarity in rats could reach 600 to 1000 mOsm/L during ocular dryness. Furthermore, a spontaneous eye blink could be generated at a tear osmolarity of approximately 400 mOsm/L if the blink is solely determined by hyperosmolar tears, but ocular surface cooling also can become a major factor if hyperosmolar tears occurring during ocular dryness lower the threshold of activation of the neurons.

Randomized comparison of in vivo performance of two point-of-care tear film osmometers

PURPOSE

To compare the in vivo precision of two commercially available point-of-care osmometers among normal subjects with no dry eye disease.

METHODS

Twenty healthy adults with healthy ocular surfaces were evaluated by licensed eye care practitioners. All subjects had low Ocular Surface Disease Index score (<5), normal tear breakup time (>10 seconds), and no evidence of corneal fluorescein staining. Five consecutive measurements of tear osmolarity were measured on each eye using each of the two osmometers: the TearLab Osmolarity System (TearLab) and the I-Med i-Pen (i-Pen), for a total of 200 measurements per device. Performance of the osmometers was determined by specificity, estimated by the percentage of osmolarity data at or below the clinical cutoff (308 mOsm/L) and precision, and represented by the standard deviation per subject. In addition, to assess analytical performance, on each day of patient testing, standardized osmolarity quality control solutions (338 mOsm/L) were tested on the TearLab per manufacturer instructions. i-Pen manufacturer instructions do not neither provide for, nor recommend quality control procedures.

RESULTS

The mean age of the 20 subjects was 27±8 years (range: 19-48 years, 16 females, four males). Over 2 months of testing, the TearLab reported analytical performance on quality control solutions of 335.8±4.2 mOsm/L with a coefficient of variation of 1.3%. In the subject cohort, 90.9% of TearLab measurements were in the normal range ≤308 mOsm/L. The i-Pen reported 37.5% of all measurements in the normal range. The average intra-subject osmolarity of the TearLab was 295.4±8.6 mOsm/L, which was significantly lower and less variable than the i-Pen, which reported an average of 319.4±20.3 mOsm/L (P<0.001). When the measurements were grouped by subject, the TearLab accurately identified 100% of subjects as normal while the i-Pen accurately identified only 15% of subjects as normal.

CONCLUSION

In this randomized comparative study of two point-of-care osmometers among normal, healthy non-dry eye subjects, the TearLab Osmolarity System demonstrated accuracy, precision, and agreement with clinical interpretation in line with the manufacturer claims. The i-Pen lacked sufficient performance to delineate subjects with and without dry eye disease.

Sjogren's syndrome from the perspective of ophthalmology

Sjogren's syndrome (SS) is an autoimmune disease affecting the lacrimal glands resulting in dry eye disease (DED). Ophthalmologists may be the first line of detection of Sjogren's syndrome given the frequency of DED in SS and that dry eye is often the presenting symptom. Numerous symptom questionnaires and tests have been developed to help diagnose DED, but as of yet, there is no "gold standard." Minimally invasive objective metrics are needed for a reliable diagnosis of DED. Currently there is no single test to diagnose SS-associated DED. Although there are several approaches to treatment, none are specific for DED in SS, and, generally, several methods need to be tried to find what works best for a specific patient. Treatment for DED continues to be an unmet medical need, especially given that DED in SS is typically on the severe end of the spectrum.

The Growing Need for Validated Biomarkers and Endpoints for Dry Eye Clinical Research

Purpose

Biomarkers with minimally invasive and reproducible objective metrics provide the key to future paradigm shifts in understanding of the underlying causes of dry eye disease (DED) and approaches to treatment of DED. We review biomarkers and their validity in providing objective metrics for DED clinical research and patient care.

Methods

The English-language literature in PubMed primarily over the last decade was surveyed for studies related to identification of biomarkers of DED: (1) inflammation, (2) point-of-care, (3) ocular imaging, and (4) genetics. Relevant studies in each group were individually evaluated for (1) methodological and analytical details, (2) data and concordance with other similar studies, and (3) potential to serve as validated biomarkers with objective metrics.

Results

Significant work has been done to identify biomarkers for DED clinical trials and for patient care. Interstudy variation among studies dealing with the same biomarker type was high. This could be attributed to biologic variations and/or differences in processing, and data analysis. Correlation with other signs and symptoms of DED was not always clear or present.

Conclusions

Many of the biomarkers reviewed show the potential to serve as validated and objective metrics for clinical research and patient care in DED. Interstudy variation for a given biomarker emphasizes the need for detailed reporting of study methodology, including information on subject characteristics, quality control, processing, and analysis methods to optimize development of nonsubjective metrics. Biomarker development offers a rich opportunity to significantly move forward clinical research and patient care in DED.

Overview

DED is an unmet medical need - a chronic pain syndrome associated with variable vision that affects quality of life, is common with advancing age, interferes with the comfortable use of contact lenses, and can diminish results of eye surgeries, such as cataract extraction, LASIK, and glaucoma procedures. It is a worldwide medical challenge with a prevalence rate ranging from 8% to 50%. Many clinicians and researchers across the globe are searching for better answers to understand the mechanisms related to the development and chronicity of DED. Though there have been many clinical trials for DED, few new treatments have emerged over the last decade. Biomarkers may provide the needed breakthrough to propel our understanding of DED to the next level and the potential to realize our goal of truly personalized medicine based on scientific evidence. Clinical trials and research on DED have suffered from the lack of validated biomarkers and less than objective and reproducible endpoints. Current work on biomarkers has provided the groundwork to move forward. This review highlights primarily ocular biomarkers that have been investigated for use in DED, discusses the methodologic outcomes in providing objective metrics for clinical research, and suggests recommendations for further work.

Paper-based microfluidic system for tear electrolyte analysis

The analysis of tear constituents at point-of-care settings has a potential for early diagnosis of ocular disorders such as dry eye disease, low-cost screening, and surveillance of at-risk subjects. However, current minimally-invasive rapid tear analysis systems for point-of-care settings have been limited to assessment of osmolarity or inflammatory markers and cannot differentiate between dry eye subclassifications. Here, we demonstrate a portable microfluidic system that allows quantitative analysis of electrolytes in the tear fluid that is suited for point-of-care settings. The microfluidic system consists of a capillary tube for sample collection, a reservoir for sample dilution, and a paper-based microfluidic device for electrolyte analysis. The sensing regions are functionalized with fluorescent crown ethers, o-acetanisidide, and seminaphtorhodafluor that are sensitive to mono- and divalent electrolytes, and their fluorescence outputs are measured with a smartphone readout device. The measured sensitivity values of Na⁺, K⁺, Ca²⁺ ions and pH in artificial tear fluid were matched with the known ion concentrations within the physiological range. The microfluidic system was tested with samples having different ionic concentrations, demonstrating the feasibility for the detection of early-stage dry eye, differential diagnosis of dry eye sub-types, and their severity staging.

Correlation between Tear Osmolarity and Other Ocular Surface Parameters in Primary Sjögren's Syndrome

PURPOSE

To investigate the relationships between tear osmolarity and other ocular surface parameters and to determine the diagnostic value of tear osmolarity in primary Sjögren's syndrome (SS) using tear film break-up time, Schirmer I test, and cornea/conjunctiva staining.

METHODS

We included 310 eyes of 155 patients diagnosed with dry eye disease (39 primary SS and 116 non-Sjögren dry eye disease) at Seoul St. Mary's Hospital from August 2010 to January 2015. All subjects completed the Ocular Surface Disease Index (OSDI) questionnaire and underwent ocular examinations including tear osmolarity (TearLab Osmolarity System), Schirmer I test, slit lamp examination for tear film break-up time, and corneal and conjunctival fluorescein staining. We used the mean value of both eyes for all parameters. Fluorescein staining was assessed using the Sjögren's International Collaborative Clinical Alliance ocular staining score (OSS).

RESULTS

In primary SS patients (n = 39), the mean subject age was 52.5 ± 11.9 years, and 94.9% of the subjects were women. Mean tear osmolarity in SS was 311.1 ± 16.4 mOsm/L, with 16 (41.0%) subjects having values ≥316 mOsm/L. In SS, there was a positive correlation between mean tear osmolarity and OSDI score (ρ = 0.405, p = 0.011) and OSS (ρ = 0.592, p < 0.001). There was a negative correlation between mean tear osmolarity and the Schirmer I test (ρ = -0.625, p < 0.001). There was no significant correlation between mean tear osmolarity and tear film break-up time in SS (ρ = 0.110, p = 0.505).

CONCLUSIONS

Tear osmolarity measurements using the TearLab Osmolarity System can reflect both symptom severity (OSDI) and objective signs (Schirmer test and OSS) in SS.

The relief of dry eye signs and symptoms using a combination of lubricants, lid hygiene and ocular nutraceuticals

PURPOSE

To determine the combined effect of TheraTears^® Lubricant Eye Drops, TheraTears^® SteriLid Eyelid Cleanser, and TheraTears^® Nutrition on dry eye signs and symptoms.

METHODS

This prospective study enrolled 28 dry eye participants. Participants were instructed to use the Lubricant Eye Drops at least 2-4× a day, SteriLid 1-2× a day, and Nutrition 3 gel caps once a day. Participants were followed up at baseline, 1 month and 3 months. Outcome variables were the Ocular Surface Disease Index (OSDI), Symptom Assessment iN Dry Eye (SANDE) questionnaire, non-invasive tear break-up time (NIBUT), osmolarity, number of meibomian glands blocked (#MG blocked), meibum quality, eyelid margin features, Schirmer's test, tear film lipid layer thickness (LLT), meniscus height, corneal and conjunctival staining.

RESULTS

Twenty participants (mean age=43, from 23 to 66, 17F, 3M) completed the study. Participants reported having used, on average, the Lubricant Eye Drop 2.4×/day, the SteriLid 1.1×/day, and the Nutrition 3 gel caps 1×/day. There was a significant change over time (p<0.05) for OSDI (-21.2 points), SANDE (-32.4 points), NIBUT (+0.43s), eyelid margin features (-1.1 grade), meibum quality (-1.0 grade), and #MG blocked (-4.0 glands).

CONCLUSION

By using a combination of TheraTears^® Lubricant Eye Drop, SteriLid, and Nutrition, patients experience significant relief in both dry eye symptoms and signs.