In-depth correlation analysis between tear glucose and blood glucose using a wireless smart contact lens.

Tears have emerged as a promising alternative to blood for diagnosing diabetes. Despite increasing attempts to measure tear glucose using smart contact lenses, the controversy surrounding the correlation between tear glucose and blood glucose still limits the clinical usage of tears. Herein, we present an in-depth investigation of the correlation between tear glucose and blood glucose using a wireless and soft smart contact lens for continuous monitoring of tear glucose. This smart contact lens is capable of quantitatively monitoring the tear glucose levels in basal tears excluding the effect of reflex tears which might weaken the relationship with blood glucose. Furthermore, this smart contact lens can provide an unprecedented level of continuous tear glucose data acquisition at sub-minute intervals. These advantages allow the precise estimation of lag time, enabling the establishment of the concept called 'personalized lag time'. This demonstration considers individual differences and is successfully applied to both non-diabetic and diabetic humans, as well as in animal models, resulting in a high correlation.

A surface-engineered contact lens for tear fluid biomolecule sensing.

The eyes provide rich physiological information and offer diagnostic potential as a sensing site, and probing tear constituents via the wearable contact lens could be explored for healthcare monitoring. Herein, we propose a novel adhesive contrast contact lens platform that can split tear film by natural means of tear secretion and blinking. The adhesive contrast is realized by selective grafting of a lubricant onto a polydimethylsiloxane (PDMS)-based contact lens, leading to high pinning zones on a non-adhesive background. The difference in contact angle hysteresis facilitates the liquid splitting. Further, the method offers control over the droplet volume by controlling the zone dimension. The adhesive contrast contact lens is coupled with fluorescent spectroscopic as well as colorimetric techniques to realize its potential as a diagnostic platform. The adhesive contrast contact lens is exploited to detect the level of lactoferrin in tear by sensitizing split droplets with Tb3+ ions. The adhesive contrast contact lens integrated with a fluorescence spectrometer was able to detect the lactoferrin level up to a concentration of 0.25 mg mL-1. Additionally, a colorimetric detection based on the fluorescence of the lactoferrin-terbium complex is demonstrated for the measurement of lactoferrin, with a limit of detection in the physiological range up to 0.5 mg mL-1.

A New Immortalized Human Lacrimal Gland Cell Line.

The lacrimal gland is crucial for maintaining ocular health by producing the aqueous component of the tear film, which hydrates and nourishes the ocular surface. Decreased production of this component results in dry eye disease, a condition affecting over 250 million people worldwide. However, the scarcity of primary human material for studying its underlying mechanisms and the absence of a cell model for human lacrimal gland epithelial cells present significant challenges. Here, we describe the generation of immortalized human lacrimal gland cell lines through the introduction of an SV40 antigen. We successfully isolated and characterized three cell clones from a female lacrimal gland donor, confirming their epithelial identity through genomic and protein analyses, including PCR, RNAseq, immunofluorescence and cultivation in a 3D spheroid model. Our findings represent a significant advancement, providing improved accessibility to investigate the molecular pathogenesis mechanisms of dry eye disease and potential therapeutic interventions. We identified the expression of typical epithelial cell marker genes and demonstrated the cells' capability to form 2D cell sheets and 3D spheroids. This establishment of immortalized human lacrimal gland cells with epithelial characteristics holds promise for future comprehensive studies, contributing to a deeper understanding of dry eye disease and its cellular mechanisms.

Effects of Topical 0.05% Cyclosporine A on Dry Eye Symptoms and Parameters Following Small Incision Lenticule Extraction.

PURPOSE: To evaluate the effects of topical 0.05% cyclosporine A on Ocular Surface Disease Index (OSDI) score and ocular surface parameters after small incision lenticule extraction (SMILE) for myopia. METHODS: In this study, 151 patients who underwent SMILE were randomized into the control group (71 eyes) and the 0.05% cyclosporine A group (80 eyes). Both groups received standard treatment during the 1 month after SMILE. Over the next 3 months, The control group continued standard therapy (0.3% sodium hyaluronate) and the 0.05% cyclosporine A group received additional 0.05% cyclosporine A. OSDI total and subscale scores, non-invasive tear break-up time (NIBUT), tear lipid layer thickness (LLT), and tear meniscus height (TMH) were assessed preoperatively and postoperatively. RESULTS: Compared to baseline, the OSDI scores significantly increased in both groups (P < .001). The 0.05% cyclosporine A group exhibited lower OSDI total scores after administering 0.05% cyclosporine A versus the control group (P = .026). At 1 month of follow-up, NIBUT, LLT, and TMH values significantly decreased in both groups compared to baseline (P < .05). The 0.05% cyclosporine A group exhibited higher NIBUT, LLT, and TMH versus the control group, returning to preoperative values after 2 months. Overall, the OSDI total score and NIBUT values during follow-up were not significantly different between the two groups; however, the LLT and TMH values were significantly different between the two groups (P < .001 and .041, respectively) by repeated measures analysis of variance. CONCLUSIONS: Topical 0.05% cyclosporine A was effective in relieving subjective dry eye symptoms and maintaining ocular surface stability in the early postoperative period of SMILE. [J Refract Surg. 2024;40(4):e229-e238.].

Tear film stability in patients with symptoms of dry eye after instillation of dual polymer hydroxypropyl guar/sodium hyaluronate vs single polymer sodium hyaluronate.

PURPOSE: This study evaluated the tear film stability in patients with symptoms of dry eye after installation of dual polymer hydroxypropyl guar/sodium hyaluronate (DPHG/SH) vs single polymer SH. METHODS: Patients with recently diagnosed mild to moderate dry eye disease (OSDI score 23-32 points) were included. For each patient, the right eye was randomized to receive DPHG/SH or 0.15% SH. Just after the administration of the drop to the right eye, the fellow eye received the other eye drop. The first non-invasive Keratograph first break-up time (NIKBUT), average NIKBUT and tear meniscus height (TMH) were measured before administration of the eye drops, at 1-min, 15 min, 30 min, 60 min, 90 min, and 120 min after instillation. RESULTS: A total of 29 patients aged 22.8 ± 2.2 years participated in the study (21 women). No differences between the eye receiving DPHG/SH and single polymer SH were observed for the first NIKBUT (p = 0.45) and average NIKBUT (p = 0.24) variables at any time point. Both DPHG/SH and single polymer SH increased the TMH (p of time effect < 0.001), but with no difference between groups (p = 0.95). CONCLUSION: Both DPHG/SH and single polymer SH solutions provide lubrication of the eye surface, however, with no difference in NIKBUT and TMH evaluations for up to two hours following administration.

Assessment of tear film parameters in females with refractive errors using a single device: An observational study.

This observational study aimed to evaluate the use of a single portable device to assess the non-invasive tear break-up time (NITBUT), tear meniscus height (TMH), and lipid layer patterns (LLP) in young females with refractive errors (REs). The study was conducted at the College of Applied Medical Science (Female campus), Riyadh, Saudi Arabia between January 5, 2021 to May 15, 2021. Forty young females, with mean age of 23.0± 4.3 years with REs (-2.53 ± 2.05 D) and 40 females, mean age 23.8± 4.5 years with healthy eyes were recruited. The tests were administered in the following order: Ocular Surface Disease Index (OSDI), followed by NITBUT, TMH, and LLP. Significant differences (via Mann-Whitney U test) were noted in the median ocular surface disease index (OSDI; p˂0.001), NITBUT (p=0.035), TMH (p=0.009), and LLP (p˂0.001) scores between the study and control groups. Females with REs have significantly lower lipid layer, TMH, and NITBUT scores than those with healthy eyes.

Effect of upper eyelid blepharoplasty on the ocular surface, tear film, and corneal microstructure.

PURPOSE: This study aimed to investigate the effect of upper eyelid blepharoplasty with the removal of the skin and a strip of orbicularis oculi muscle on the ocular surface, tear film, and dry eye-related symptoms. METHODS: Twenty-two eyes of 22 consecutive patients operated by a single surgeon (21 females; mean age, 61 years; age range, 41-75 years) were included. All subjects completed the Ocular Surface Disease Index questionnaire, underwent in vivo confocal microscopy, tear film breakup time measurements, the Schirmer test with anesthesia, and fluorescein and lissamine green staining measurements before, 1 month, and 6 months after upper blepharoplasty alone with preseptal orbicularis excision. RESULTS: A significant increase in Ocular Surface Disease Index, and corneal fluorescein and lissamine green staining and a significant decrease in tear film breakup time were observed after 1 month (p=0.003, p=0.004, p=0.029, and p=0.024 respectively) and 6 months (p=0.001 for all findings). No significant difference in the Schirmer test score was observed during the follow-up. None of the in vivo confocal microscopy parameters showed significant changes during the study. CONCLUSIONS: An increase in dry eye symptoms and a decrease in tear film stability along with ocular surface staining were observed in patients undergoing upper eyelid blepharoplasty.

Role of Polyunsaturated Fatty Acids (PUFAs) and Eicosanoids on Dry Eye Symptoms and Signs.

Polyunsaturated fatty acids (PUFAs) generate pro- and anti-inflammatory eicosanoids via three different metabolic pathways. This study profiled tear PUFAs and their metabolites and examined the relationships with dry eye (DE) and meibomian gland dysfunction (MGD) symptoms and signs. A total of 40 individuals with normal eyelids and corneal anatomies were prospectively recruited. The symptoms and signs of DE and MGD were assessed, and tear samples (from the right eye) were analyzed by mass spectrometry. Mann-Whitney U tests assessed differences between medians; Spearman tests assessed correlations between continuous variables; and linear regression models assessed the impact of potential confounders. The median age was 63 years; 95% were male; 30% were White; and 85% were non-Hispanic. The symptoms of DE/MGD were not correlated with tear PUFAs and eicosanoids. DE signs (i.e., tear break-up time (TBUT) and Schirmer's) negatively correlated with anti-inflammatory eicosanoids (11,12-dihydroxyeicosatrienoic acid (11,12 DHET) and 14,15-dihydroxyicosatrienoic acid (14,15, DHET)). Corneal staining positively correlated with the anti-inflammatory PUFA, docosahexaenoic acid (DHA). MGD signs significantly associated with the pro-inflammatory eicosanoid 15-hydroxyeicosatetranoic acid (15-HETE) and DHA. Several relationships remained significant when potential confounders were considered. DE/MGD signs relate more to tear PUFAs and eicosanoids than symptoms. Understanding the impact of PUFA-related metabolic pathways in DE/MGD may provide targets for new therapeutic interventions.

Comparative Characterization of Human Meibomian Glands, Free Sebaceous Glands, and Hair-Associated Sebaceous Glands Based on Biomarkers, Analysis of Secretion Composition, and Gland Morphology.

Meibomian gland dysfunction (MGD) is one of the main causes of dry eye disease. To better understand the physiological functions of human meibomian glands (MGs), the present study compared MGs with free sebaceous glands (SGs) and hair-associated SGs of humans using morphological, immunohistochemical, and liquid chromatography-mass spectrometry (LCMS)-based lipidomic approaches. Eyelids with MGs, nostrils, lips, and external auditory canals with free SGs, and scalp with hair-associated SGs of body donors were probed with antibodies against cytokeratins (CK) 1, 8, 10, and 14, stem cell markers keratin 15 and N-cadherin, cell-cell contact markers desmoglein 1 (Dsg1), desmocollin 3 (Dsc3), desmoplakin (Dp), plakoglobin (Pg), and E-cadherin, and the tight junction protein claudin 5. In addition, Oil Red O staining (ORO) was performed in cryosections. Secretions of MGs as well as of SGs of nostrils, external auditory canals, and scalps were collected from healthy volunteers, analyzed by LCMS, and the data were processed using various multivariate statistical analysis approaches. Serial sections of MGs, free SGs, and hair-associated SGs were 3D reconstructed and compared. CK1 was expressed differently in hair-associated SGs than in MGs and other free SGs. The expression levels of CK8, CK10, and CK14 in MGs were different from those in hair-associated SGs and other free SGs. KRT15 was expressed differently in hair-associated SGs, whereas N-cadherin was expressed equally in all types of glands. The cell-cell contact markers Dsg1, Dp, Dsc3, Pg, and E-cadherin revealed no differences. ORO staining showed that lipids in MGs were more highly dispersed and had larger lipid droplets than lipids in other free SGs. Hair-associated SGs had a smaller number of lipid droplets. LCMS revealed that the lipid composition of meibum was distinctively different from that of the sebum of the nostrils, external auditory canals, and scalp. The 3D reconstructions of the different glands revealed different morphologies of the SGs compared with MGs which are by far the largest type of glands. In humans, MGs differ in their morphology and secretory composition and show major differences from free and hair-associated SGs. The composition of meibum differs significantly from that of sebum from free SGs and from hair-associated SGs. Therefore, the MG can be considered as a highly specialized type of holocrine gland that exhibits all the histological characteristics of SGs, but is significantly different from them in terms of morphology and lipid composition.

Is there a relationship between the severity of disease in major depressive disorder patients and dry eye disease?

PURPOSE: To investigate dry eye disease (DED) in newly diagnosed patients with depressive disorder (MDD). METHOD: This observational study included 48 MDD patients in Group 1 and 20 healthy controls in Group 2. Psychiatric and ophthalmic examinations, Beck Depression Inventory (BDI), Ocular Surface Disease Index (OSDI), Schirmer's test, tear breakup time (TBUT), Meibomian gland dysfunction (MGD), and ocular staining were conducted. The results were statistically compared. RESULTS: The participants, comprising 32 men and 36 women, had a mean age of 31.08 ± 11.7 years (18-64 years). Group 1 had a mean BDI score of 30.87 ± 8.56, while Group 2 had a score of 1.3 ± 1.3 (p < 0.001). In Group 1, 28 patients were diagnosed with DED, whereas in Group 2, six subjects were diagnosed with DED. The mean Schirmer's results in Group 1 and Group 2 were (mm/5 min) 10.87 ± 2.44 and 12.70 ± 2.3, respectively, and were significantly lower in Group 1 (p < 0.001). The mean OSDI scores in Group 1 (34.95 ± 15.8) were significantly higher compared to Group 2 (3.2 ± 3.1) (p < 0.001). There was no significant difference in mean TBUT between Group 1 (9.41 ± 2.6 s) and Group 2 (9.8 ± 0.61 s) (p > 0.05). Significant correlations were found between BDI scores and Schirmer's results as well as OSDI scores (p < 0.05, p = 0.02, respectively). No statistically significant correlations were found between BDI scores and TBUT or MGD (p > 0.05). CONCLUSION: DED was found to be more prevalent in the MDD group. The severity of MDD and DED, as indicated by BDI, OSDI, and Schirmer's results, was found to be correlated. It was observed that patients with higher depression scores had more severe dry eye. As a result, we recommend performing ophthalmic examinations in newly diagnosed MDD patients.

New Korean Guidelines for the Diagnosis and Management of Dry Eye Disease.

New Korean guidelines for the diagnosis and management of dry eye disease were developed based on literature reviews by the Korean Dry Eye Guideline Establishment Committee, a previous dry eye guideline by Korean Corneal Disease Study Group, a survey of Korean Dry Eye Society (KDES) members, and KDES consensus meetings. The new definition of dry eye was also proposed by KDES regular members. The new definition by the regular members of the KDES is as follows: "Dry eye is a disease of the ocular surface characterized by tear film abnormalities and ocular symptoms." The combination of ocular symptoms and an unstable tear film (tear breakup time <7 seconds) was considered as essential components for the diagnosis of dry eye. Schirmer test and ocular surface staining were considered adjunctive diagnostic criteria. The treatment guidelines consisted of a simplified stepwise approach according to aqueous deficiency dominant, evaporation dominant, and altered tear distribution subtypes. New Korean guidelines can be used as a simple, valid, and accessible tool for the diagnosis and management of dry eye disease in clinical practice.

Water-Free Cyclosporine Ophthalmic Solution vs Vehicle for Dry Eye Disease: A Randomized Clinical Trial.

Importance: Dry eye disease (DED) is a prevalent eye disorder. Cyclosporine is an effective immunomodulator that is widely used in DED; however, due to its highly hydrophobic nature, delivery of cyclosporine to the ocular surface is challenging. Objective: To evaluate the efficacy and safety of SHR8028, a water-free cyclosporine ophthalmic solution, 0.1%, compared with vehicle in Chinese participants with DED. Design, Setting, and Participants: This was a multicenter, double-blind, vehicle-controlled, phase 3 randomized clinical trial conducted from March 4, 2021, to July 22, 2022. Adult participants with moderate to severe DED were recruited from 12 hospitals in China. Study data were analyzed April 2, 2022, for the primary analysis. Interventions: Following a 14-day run-in period with an artificial tear, participants were randomly assigned (1:1) to receive water-free cyclosporine or vehicle (1 eye drop in each eye twice daily). After a 29-day treatment, participants of both groups were given the option to receive water-free cyclosporine for an additional 12 weeks for longer-term safety assessment. Main Outcomes and Measures: The primary end points were changes from baseline in total corneal fluorescein staining (tCFS) using the National Eye Institute scale and in dryness score on a visual analog scale at day 29. Results: A total of 206 participants (mean [SD] age, 47.8 [14.2] years; 185 female [90%]) were enrolled, with 103 each in the cyclosporine group and the vehicle group. At day 29, the cyclosporine group experienced improved tCFS compared with vehicle (change [Δ] = -1.8; 95% CI, -2.7 to -1.0; P < .001), with a tCFS score decrease from baseline of -4.8 in the cyclosporine group and -3.0 in the vehicle group. Dryness score decreased from baseline in both groups (-19.2 vs -15.4; Δ = -3.8; 95% CI, -9.2 to 1.6; P = .17). During the 29-day treatment, treatment-related adverse events were reported in 15 participants (14.6%) in the cyclosporine group and 11 participants (10.7%) in the vehicle group. Conclusions And Relevance: Results demonstrated superiority of a water-free cyclosporine, 0.1%, eye solution over vehicle in improving tCFS score at day 29 in Chinese participants with DED. However, dryness score (VAS) was not improved at day 29. Trial Registration: ClinicalTrials.gov Identifier: NCT05841043.

Comparison of comfort and tear stability with two novel silicone-hydrogel daily disposable contact lenses.

BACKGROUND: The surface wettability of soft contact lenses (SCLs) affects the wearing comfort. Verofilcon A is a daily disposable silicone hydrogel contact lens with SMARTSURFACE® technology, ensuring high surface wettability. PURPOSE: To evaluate tear stability on the surface of verofilcon A and narafilcon A SCLs and correlate these findings with clinical parameters and patients' discomfort. METHODS: Sixty-two SCL wearers (124 eyes) with SCL discomfort were randomly assigned to use narafilcon A (control SCL) and verofilcon A for 2 weeks each by crossover. The noninvasive tear break-up time (NIBUT) of the naked eye at baseline and pre-lens NIBUT (PL-NIBUT) of the SCL surface after 2 weeks of using each SCL were measured using the DR-1α® dry eye observation device. Corneal superficial punctate keratopathy (SPK) (0-3) and conjunctival hyperemia (0-3), and comfort level of SCL wear (1-10) were also evaluated. RESULTS: NIBUT and PL-NIBUT values were 4.6 ± 2.3 s for the naked eye, 6.6 ± 6.6 s for narafilcon A, and 11.3 ± 3.5 s for verofilcon A. verofilcon A had significantly higher PL-NIBUT than the naked eye and narafilcon A (p < 0.05). SPK (0.16 ± 0.48 vs. 0.00 ± 0.00, p < 0.01) and conjunctival hyperemia (1.15 ± 0.82 vs. 0.49 ± 0.50, p < 0.01) scores were lower when wearing verofilcon A than narafilcon A. The ocular comfort score of wearing SCLs was higher with verofilcon A than with narafilcon A (8.7 ± 1.8 vs. 9.8 ± 0.5, p < 0.01). The ocular comfort score for wearing verofilcon A was higher, regardless of the baseline NIBUT. CONCLUSION: The results of this study showed a consistent surface-wetting advantage of verofilcon A in patients with ocular discomfort. verofilcon A was used comfortably in patients with low NIBUT scores at baseline. The findings suggest that verofilcon A is recommended for SCL wearers experiencing SCL-related dry eye symptoms and discomfort.

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

BACKGROUND: We aimed to check the efficacy of Emustil (oil in water emulsion) drops on tear film index and ocular surface dynamics in dry environments through protection and relief treatment modalities. METHODS: The subjects were exposed to a dry environment using a Controlled Environment Chamber (CEC) where the relative humidity (RH) was 5% and the temperature was 21 °C and screened for ocular symptoms, tear osmolarity, ocular surface temperature (OST) and tear production using ocular Surface Disease Index questionnaire (OSDI), OcuSense TearLab Osmometer, FLIR System ThermaCAM P620 and Schirmer strips/phenol red test respectively. Tear production was calculated by the Tear Function Index test (TFI). RESULTS: The mean tear film osmolarity decreased significantly from 296.8 mOsm/l at 40% RH to 291 mOsm/l at 5%. (p = 0.01). Instillation of Emustil resulted in a significant increase in tear osmolarity in the relief method compared with osmolarity seen at 5% RH when no drop was used. The mean PRT value decreased from 26 ± 9 in normal conditions (40% RH) to 22 ± 4 mm in dry conditions (5% RH). Emustil drops did not induce any significant change in tear production in the PRT test. No significant change was found in OST following exposure to 5% RH. OST did not show a statistically significant change with the emulsion when used for relief (p > 0.05). The mean score of ocular discomfort observed was 70 at 5% RH. Still, the instillation of the oil-in-water emulsion (Emustil) resulted in a noticeable decrease in visual discomfort to 37 (p = 0.00) in protection and 59 in relief (p = 0.05). Emustil drops substantially improved tear film parameters under a desiccating environment, however, tear film parameters respond differently to the management modalities. In the protection method, tear film osmolarity was protected against a dry environment, while in the relief mode, tear production was improved. CONCLUSION: CEC allows for a thorough evaluation of tear film parameters and dry eye treatment protocols in labs, providing greater confidence when applying them to patients. In addition, our study showed that Emustil not only provides protection and relief for dry eyes but also helps to maintain ocular homeostasis in desiccating environments. This indicates a promising potential for improving dry eye treatment protocols.

Efficacy and safety of trigeminal parasympathetic pathway stimulation for dry eye: A systematic review and meta-analysis.

This study aimed to investigate the efficacy and safety of trigeminal parasympathetic pathway (TPP) stimulation in the treatment of dry eye. A comprehensive search for randomized clinical trials was performed in seven databases (MEDLINE, Embase, CENTRAL, etc.) up to 28 February 2023. After screening the suitable studies, the data were extracted and transformed as necessary. Data synthesis and analysis were performed using Review Manager 5.4, and the risk of bias and quality of evidence were evaluated with the recommended tools. Fourteen studies enrolling 1714 patients with two methods (electrical and chemical) of TPP stimulation were included. Overall findings indicate that TPP stimulation was effective in reducing subjective symptom score (standardized mean difference [SMD], -0.45; 95% confidence interval [CI], -0.63 to -0.28), corneal fluorescence staining (mean difference [MD], -0.78; 95% CI, -1.39 to -0.18), goblet cell area (MD, -32.10; 95% CI, -54.58 to -9.62) and perimeter (MD, -5.90; 95% CI, -10.27 to -1.53), and increasing Schirmer's test score (SMD, 0.98; 95% CI, 0.65 to 1.31) and tear film break-up time (SMD, 0.57; 95% CI, 0.19 to 0.95). Compared to inactive or low-activity stimulation controls, it has a higher incidence of adverse events. Therefore, TPP stimulation may be an effective treatment for dry eye, whether electrical or chemical. Adverse events are relatively mild and tolerable. Due to the high heterogeneity and low level of evidence, the current conclusions require to be further verified.

Impact of stress on the tear production of healthy cats.

OBJECTIVES: This study aimed to determine the impact of acute stress on tear production in companion cats to provide a basis for minimizing stress-inducing stimuli during ophthalmic evaluations. METHODS: A total of 24 healthy owned cats (12 males, 12 females) of mixed breed, aged 8 months to 7 years, with no history of ocular diseases, were selected for the study. The cats were housed in individual cages under controlled conditions for 6 days. The Schirmer tear test-1 (STT-1) was performed in the morning (between 9:00 am and 11:00 am) using test strips from the same batch. The first test (without stress) was conducted on the fifth day of acclimation, and the second test (with stress) on the sixth day. The stress stimulus consisted of recordings of barking dogs, cats fighting and the murmuring of people. For both tests, the heart rate was assessed with a stethoscope before, during and after the tests, and the environmental stress level was also evaluated. Results are presented as mean ± SD and 95% confidence interval (CI). RESULTS: The study found that STT-1 values were significantly higher (P = 0.009) with stress (22.2 ± 6.0 mm/min [95% CI 19.9-24.6]) than without stress (17.5 ± 6.9 mm/min [95% CI 14.8-20.2]). Similarly, the heart rate was significantly higher (P = 0.028) in stress vs non-stress conditions (213.4 ± 37.5 beats per minute [bpm] [95% CI 198.7-228.1] vs 171.5 ± 28.6 bpm [95% CI 160.3-182.7], respectively), and the environmental stress score was significantly higher (P <0.001) in stress vs non-stress conditions (3.3 ± 0.5 [95% CI 3.1-3.5] vs 1.2 ± 0.4 [95% CI 1.1-1.4], respectively). CONCLUSIONS AND RELEVANCE: Stress increased tear production in cats. Although the mean STT-1 value obtained under stress conditions was within the normal range, stress can influence the test results. The use of cat friendly handling techniques facilitates execution of the STT-1.

Ocular surface and meibomian gland evaluation in euthyroid Graves' ophthalmopathy.

PURPOSE: Euthyroid Graves' ophthalmology (EGO) refers to the subgroup of thyroid eye disease patients with distinct clinical presentations. This study evaluated the ocular surface and meibomian gland changes in EGO patients. METHODS: A cross-sectional study was conducted at The Chinese University of Hong Kong including 34 EGO patients and 34 age-and sex- matched healthy controls. Outcome measures include anterior segment examination, keratographic and meibographic imaging. RESULTS: Between 34 EGO patients and 34 age and sex-matched healthy controls, EGO was associated with a higher ocular surface disease index (P < 0.01), higher severity of meibomian gland dropout (upper: P < 0.001, lower: P < 0.00001) and higher percentage of partial blinking (P = 0.0036). The worse affected eyes of the EGO patients were associated with corneal staining (P = 0.0019), eyelid telangiectasia (P = 0.0009), eyelid thickening (P = 0.0013), eyelid irregularity (P = 0.0054), meibomian gland plugging (P < 0.00001), expressibility (P < 0.00001), and meibum quality (P < 0.00001). When the two eyes of the same EGO patient were compared, the degree of meibomian gland dropout was higher among the worse affected eyes (upper: P < 0.00001, and lower: P < 0.00001). Tear meniscus height, lipid layer thickness, and noninvasive break-up time were comparable between the two eyes of EGO patients and also between EGO patients and healthy controls. TMH was positively correlated with the degree of exophthalmos (r = 0.383, P < 0.05). CONCLUSION: EGO patients have more ocular surface complications and meibomian gland dropouts than healthy controls. Almost 60% of them had dry eye symptoms, but aqueous deficiency was not apparent. Further studies are warranted to clarify the mechanism of dry eye in EGO. (249 words).