Inferior Tear Meniscus Research Articles

Effectiveness and safety of demodecosis blepharitis therapy under dry eye conditions

Purpose: to evaluate the effectiveness and safety of complex therapy in patients with demodex blepharitis and dry eye. Methods. 25 patients with mixed demodex blepharitis and dry eye (50 eyes; 10 men, 15 women; 61.9 ± 5.6 years) were examined before and after treatment with 0.5 % levofloxacin instillation (5 times a day, 5 days); sulfur and metronidazole gel applications (Blefarogel-forte) as part of therapeutic eyelid hygiene (Blepharogel-cleansing, Blepharolotion; starting from day 6, 2 times a day, 45 days); 0.24 % sodium hyaluronate instillation (3 times a day). Therapy effectiveness criteria were as follows: D. folliculorum mite population reduction; positive dynamics of blepharitis objective signs and meibomian gland dysfunction severity (MGD-S, points). Therapy safety criteria included the absence of negative dynamics of OSDI, tear film breakup time (TBUT, s), inferior tear meniscus height (ITMH, µm) and xerosis index (XI, points). Results. As a result of the therapy, statistically significant changes were noted, including mite population reduction (from 9.23 ± 0.81 to 3.54 ± 0.80 imagos); eyelid margins edema intensity decrease (from 3.18 ± 0.39 to 1.30 ± 0.45 points) and hyperemia decrease (from 2.90 ± 0.29 to 0.9 ± 0.3 points); MGD-S decrease (from 2.1 ± 0.3 to 0.95 ± 0.21 points); OSDI decrease (from 43.23 ± 4.70 to 25.10 ± 2.65 points); TBUT increase (from 4.05 ± 0.50 to 5.55 ± 0.50 s); XI decrease (from 5.36 ± 0.49 to 4.04 ± 0.60 points). Conclusion. The treatment of demodex blepharitis and dry eye treatment, including sulfur and metronidazole gel applications, therapeutic eyelid hygiene and 0.5 % levofloxacin and 0.24 % sodium hyaluronate instillation demonstrated a high efficiency and a good safety profile.

High‐intensity physical activity seems to be associated to a higher basal parasympathetic activity and to a reduced OSDI score in young adults

Aims/Purpose: To identify if the habitual practice of physical activity is associated to the basal parasympathetic activity and to dry eye disease‐related symptoms.Methods: Eleven adults (82% women; age: 30.7 ± 4.9 years; BMI 22.2 ± 1.9 kg m−2) responded the Ocular Surface Disease Index (OSDI), the Dry‐Eye 5 (DEQ5) and the International Physical Activity (IPAQ) questionnaires. Subsequently: a) the inferior tear meniscus height (ITMH) and the automated non‐invasive break‐up time (NIBUT) of both eyes; b) the heart rate variability (Polar H10 chest band; Kubios HRV software) and, simultaneously, the Schirmer test; and, c) the tear film break‐up time (BUT) were measured. Correlational analyses were performed among the measured variables.Results: The total weekly physical activity was of 3420 ± 3302 metabolic equivalents (MET) min−1 week−1, with a weekly high‐intensity physical activity (HIPA) of 567 ± 661 MET min−1 week−1. The OSDI score was 14.1 ± 8.3, the DEQ5 score was 7.2 ± 4.8, the ITMH was 229.3 ± 40.7 (OD) and 252.7 ± 51.2 (OS) μm, the NIBUT was 8.5 ± 5.7 (OD) and 8.8 ± 6.1 (OS) s, and the BUT was 9.7 ± 4.1 (OD) and 8.3 ± 3.9 (OS) s. Two surrogates of the parasympathetic activity (the PNS index, and the root‐squared mean of successive standard deviations, RMSSD) showed values of 0.762 ± 1.899 and 60.1 ± 37.8 ms, respectively. The HIPA showed a direct correlation with the parasympathetic activity surrogates (r = 0.784, p = 0.004, PNS index; r = 0.737, p = 0.009, RMSSD). Similarly, the HIPA showed an inverse correlation with the OSDI (r = −0.759, p = 0.006) and the DEQ5 (r = −587, p = 0.07). No other correlations were found, neither among the HIPA nor among the parasympathetic surrogates with the ITMH, the NIBUT, the BUT or the Schirmer test.Conclusions: These preliminary results suggest that in young subjects HIPA seems to be associated to an increased basal parasympathetic activity and to a reduced perception of dry‐eye symptomatology.

Safety and Feasibility of Low Fluence Intense Pulsed Light for Treating Pediatric Patients with Moderate-to-Severe Blepharitis.

To explore the safety and feasibility of low fluence intense pulsed light (IPL) for treating pediatric patients with moderate-to-severe blepharitis and to analyze potential factors associated with the recovery of meibomian glands (MG) dropout, a retrospective, noncomparative study, including 17 blepharitis patients (33 eyes) aged between 5 and 16 years old was conducted. All of the participants were given 4 continuous sessions of low-fluence (9–12 J/cm2) IPL at 3–4 week intervals. Corneal fluorescein staining (CFS), tear breakup time (BUT), inferior tear meniscus height, Demodex presence, and MG morphology were examined before and after the treatment. Results indicated that CFS, BUT and MG morphology (central/total gland area ratio and gland signal index) had significantly improved (p < 0.05). Symptoms and signs such as severe corneal neovascularization, limbal pannus and conjunctival congestion also subsided. Among age, gender, presence of Demodex and interval before diagnosis, age initiating the formal treatment was confirmed as a negatively correlated factor of the recovery of MG dropout (p = 0.032, B = −1.755). No notable adverse events were reported. In conclusion, low fluence IPL seems to be a safe and effective alternative for moderate-to-severe pediatric blepharitis, and MG dropout is prone to recover in younger patients.

Evaluation of Strip Meniscometry and Association with Clinical and Demographic Variables in a Community Eye Study (in Bangladesh).

Strip meniscometry (SM) is a relatively new technique for evaluating inferior tear meniscus. We described SM in an epidemiology study and its potential associations with clinical and tear parameters. This cross-sectional study involved 1050 factory garment workers in Gazipur, Bangladesh. The Ocular Surface Disease Index (OSDI) questionnaire and a standard examination for dry eye and meibomian gland dysfunction (MGD), including the five-second SM, were performed by a single ophthalmologist. The participants’ ages were 35.56 ± 12.12 years (range 18–59), with 53.8% women. The overall SM was 7.7 ± 3.6 mm, with skewness of 0.126 and kurtosis of 1.84 in frequency distribution. SM values were significantly lower in men than women, and significantly correlated with schirmers (r = 0.71) and tear break up time (TBUT) (r = 0.89). A lower SM value was associated with higher OSDI, lower Schirmer test, increased MG severity and lower TBUT. In multivariable analysis, when adjusted by age, SM values remained associated with schirmers and TBUT, and inversely associated with OSDI. In a separate regression model, higher SM was associated with increasing age, reduced severity of MGD grading, and increased TBUT. To conclude, SM is a rapid clinical test associated with dry eye symptoms and signs, with findings affected by both tear secretion and tear stability.

The Effect of 0.01% Atropine Eye Drops on the Ocular Surface in Children for the Control of Myopia-The Primary Results from a Six-Month Prospective Study.

PurposeTo evaluate the effect of 0.01% atropine eye drops on the ocular surface in children for the control of myopia.MethodsA total of 72 participants were recruited for this prospective study. Prior to and after 1, 3, and 6 months of 0.01% atropine administration, an ocular surface disease index (OSDI) questionnaire was obtained, Keratograph 5M was used for the measurement of the tear meniscus height (TMH), noninvasive keratographic tear film break-up time (NK-BUT, the first keratographic break-up time, [NK-BUTfirst] and the average keratographic break-up time, [NK-BUTave]), bulbar redness (BR), meiboscore (MS), and anterior segment optical coherence tomography (AS-OCT) was used to calculate the inferior tear meniscus area (TMA).ResultsAfter using the 0.01% atropine eye drops for 1 month, 9 subjects complained of discomfort immediately after administration, but this quickly subsided, and 1 subject was temporarily dazzled. All the ocular surface symptoms were mild and occurred rarely. After 3 months, these complaints no longer occurred. Compared with the baseline values, the OSDI scores (0.08 ± 0.28), values of TMH (0.23 ± 0.04 mm), TMA (0.0420 ± 0.0444 mm2), NK-BUTfirst (9.39 ± 5.25 s), NK-BUTave (10.49 ± 4.94 s), BR (0.63 ± 0.37), and MS (0.89 ± 0.70) did not change significantly after 6 months of 0.01% atropine eye drop administration (P > 0.05).ConclusionIn this 6-month prospective study, no side effects were observed on the ocular surface after using 0.01% atropine in children.

Influence of eye gaze position on the inferior tear meniscus as measured by OCT

Purpose: Evaluating tear volume, as measured by the inferior central tear meniscus height (TMH), is a valuable clinical measure in the assessment of tear deficient dry eye (DE). A previous study (Bitton, Wittich 2014) found that an inferior gaze position increased the Schirmer score over that of superior gaze. Due to the invasive nature of the Schirmer strip coupled with the enhanced resolution of imaging techniques such as optical coherence tomography (OCT), it would be of clinical value to reassess if gaze position has an influence on the tear meniscus using an anterior segment OCT.

Lower Tear Meniscus Height Measurements Using Keratography and Swept-Source Optical Coherence Tomography and Effect of Fluorescein Instillation Methods

ABSTRACTPurpose: The first aim of this study was to compare inferior tear meniscus height (TMH) measured by keratography and swept-source optical coherence tomography (OCT). Effect of locations of fluorescein instillation and subjects’ subjective sensation, and the TMH results were also investigated.Methods: Forty-one eyes from 41 healthy adults had TMH randomly measured by keratography (K5M, Oculus, Germany) and swept-source OCT (Casia SS-1000, Tomey Corp, Japan) at baseline, followed by touching either the inferior bulbar or inferior palpebral conjunctiva, randomly assigned, with a moistened fluorescein strip. Two-way analysis of variance (ANOVA) was used to compare TMH obtained from the two devices and three measurement conditions. Subjective sensation of conjunctival touch was obtained through a 4-point scale with zero representing no sensation, and one to three representing ocular sensation in an ascending order.Results: Two-way ANOVA revealed no significant difference in TMH between keratography and swept-source OCT (Factor (devices): F = 0.579, p = .451) while there was a significant difference among fluorescein instillations (Factor (conditions): F = 10.146, p < .001). Baseline TMH was around 0.25 mm, and increased to around 0.28 mm after instillation of fluorescein sodium. Ocular sensation was similar between the two conjunctival touch, and TMH was not significantly associated with ocular sensation.Conclusions: Keratography and swept-source OCT provided similar TMH results. Applying fluorescein sodium through moistened fluorescein strip could over-estimate TMH by around 0.03 mm. Applying moistened fluorescein strip at bulbar or palpebral conjunctival led to similar subjective sensations and did not affect TMH measurement.

Shifting the IGF-axis: An age-related decline in human tear IGF-1 correlates with clinical signs of dry eye

ObjectiveThe human corneal epithelium expresses both the insulin-like growth factor type 1 receptor (IGF-1R) and the IGF-1R/insulin receptor (INSR) hybrid. Despite the previous identification of IGF-1 in human tear fluid, little is known regarding the regulation of IGF-1 in tear fluid and its role in corneal epithelial homeostasis. In the present study, we investigated the impact of biological parameters on the concentration of human tear levels of IGF-1. DesignTear levels of IGF-1 were measured in 41 healthy, human volunteers without any reported symptoms of dry eye. All volunteers underwent standard biomicroscopic examination of the cornea and tear film. In a subgroup of volunteers, corneal staining with sodium fluorescein, tear film break up time and tear production using a Schirmer's test strip were measured to assess clinical signs of dry eye. Tears were collected from the inferior tear meniscus using glass microcapillary tubes and IGF-1 levels were measured using a solid phase sandwich ELISA. ResultsTear levels of IGF-1 were highest in young adults and significantly decreased in older adults (P = 0.003). There were no differences in tear IGF-1 between males and females (P = 0.628). Tear IGF-1 levels were correlated with tear film break up time (R = 0.738) and tear production (R = 0.826). ConclusionsThese data indicate that there is a progressive decline in tear IGF-1 due to aging that is associated with clinical signs of dry eye. This effect is likely due to age-related changes in the lacrimal gland.

Comparation on postoperative dry eye between femtosecond laser assisted and conventional phacoemulsification

Objective To compare the postoperative dry eye status between femtosecond laser assisted phacoemulsification and conventional phacoemulsification. Methods It was a prospective study.A total of 106 eyes of 61 patients were collected and they were divided into 2 groups.Group 1: 52 eyes of 34 patients were performed with femtosecond laser assisted phacoemulsification. And group 2: 54 eyes of 27 patients were performed with conventional phacoemulsification.The tear film break up time(BUT) and inferior tear meniscus height(TMH) were examined with keratograph before , 1 week and 1 month after surgery. The parameters were compared at different time between the two groups. Results The BUT and TMH of two groups at 1 week and 1 month after surgery were lower than those before operation (P 0.05). At 1 month after surgery, the TMH in group 1 was significantly higher than that in group 2, the difference was statistically significant (P=0.015). Conclusion Postoperative dry eye is found after the two surgeries, but dry eye after femtosecond laser assisted phacoemulsification has been restored more rapidly. Key words: Phacoemulsification, famtosecond laser, conventional; Keratograph; Dry eye; Tear film; Tear meniscus

Factors that influence tear meniscus area and conjunctivochalasis: The Singapore Indian eye study

ABSTRACTPurpose: Assessment of tear film and conjunctiva is critical to define presence and severity of ocular surface disease. We aimed to characterize tear meniscus area (TMA) and conjunctivochalasis by anterior segment optical coherence tomography (ASOCT) in population-based patients and identify potential factors associated with low TMA and severe conjunctivochalasis.Methods: Study subjects were enrolled from The Singapore Indian Eye Study, a population-based study of Asian Indian in Singapore. Imaging with ASOCT was performed on three ocular regions (nasal, central and temporal). TMA was obtained by measuring the cross-sectional area of the inferior tear meniscus. Severity of conjunctivochalasis was quantified by measuring the conjunctivochalasis ratio (CCR), the ratio of area of redundant conjunctiva to the TMA. Ocular symptoms and demographic factors were assessed by standardized questionnaires.Results: A total of 403 participants (52.9% women) 40 years of age and older were included. TMA centrally was 2818 ± 5308 pixel2. Female sex and the presence of meibomian gland dysfunction (MGD), but not older age, were associated with a lower TMA (p = 0.031, p = 0.031 and p = 0.956 respectively). In this population, 9.2% had severe conjunctivochalasis (CCR>0.7) whereas 39.0% had mild to no conjunctivochalasis (CCR≤0.3). Conjunctivochalasis was more severe in temporal, followed by nasal and central sections. Older age was associated with severe conjunctivochalasis (p < 0.001).Conclusion: MGD and female gender were associated with lower TMA, while older age was associated with increased severity of conjunctivochalasis. Objective measurement of TMA and CCR using ASOCT imaging may be useful in the assessment of tear volume and ocular surface tear function.

Evaluating tear clearance rate with optical coherence tomography.

To assess the early-phase of tear clearance rate (TCR) with anterior segment optical coherence tomography (OCT) and to determine the association between TCR and other clinical measures of the tear film in a group of young subjects with different levels of tear film quality. TCR was classified as the percentage decrease of subject's inferior tear meniscus height 30s after instillation of 5μl 0.9% saline solution. Fifty subjects (32F and 18M) aged (mean±standard deviation) 25.5±4.3 years volunteered for the study. It consisted of a review of medical history, Ocular Surface Disease Index (OSDI) questionnaire, tear film osmolarity measurements, slit lamp examination and TCR estimation based on dynamic measurements of the lower tear meniscus with OCT. Estimates of TCR were contrasted against subject age and tear film measures commonly used for dry eye diagnosis, which includes OSDI score, fluorescein tear film break-up time (FBUT), tear meniscus height (TMH), blinking frequency, tear film osmolarity and corneal staining. The group mean TCR was 29±13% and 36±19% respectively after 30 and 60s margin after saline solution instillation. Statistically significant correlations were found between TCR and FBUT (r2=0.319, p<0.001), blinking frequency (r2=0.138, p<0.01), tear film osmolarity (r2=0.133, p<0.01) and subject's age (r2=0.095, p<0.05). Anterior segment optical coherence tomography allows following changes of tear meniscus morphology post saline solution instillation and evaluating the TCR. OCT based TCR might be used as additional measure of the lacrimal functional unit.

Oxidative Stress Measures of Lipid and DNA Damage in Human Tears.

PurposeWe evaluate feasibility and repeatability of measures for lipid peroxidation and DNA oxidation in human tears, as well as relationships between outcome variables, and compared our findings to previously reported methods of evaluation for ocular sun exposure.MethodsA total of 50 volunteers were seen for 2 visits 14 ± 2 days apart. Tear samples were collected from the inferior tear meniscus using a glass microcapillary tube. Oxidative stress biomarkers were quantified using enzyme-linked immunosorbent assay (ELISA): lipid peroxidation by measurement of hexanoyl-lysine (HEL) expression; DNA oxidation by measurement of 8-oxo-2′-deoxyguinosone (8OHdG) expression. Descriptive statistics were generated. Repeatability estimates were made using Bland-Altman plots with mean differences and 95% limits of agreement were calculated. Linear regression was conducted to evaluate relationships between measures.ResultsMean (±SD) values for tear HEL and 8OHdG expression were 17368.02 (±9878.42) nmol/L and 66.13 (±19.99) ng/mL, respectively. Repeatability was found to be acceptable for both HEL and 8OHdG expression. Univariate linear regression supported tear 8OHdG expression and spring season of collection to be predictors of higher tear HEL expression; tear HEL expression was confirmed as a predictor of higher tear 8OHdG expression.ConclusionsWe demonstrate feasibility and repeatability of estimating previously unreported tear 8OHdG expression. Seasonal temperature variation and other factors may influence tear lipid peroxidation. Support is demonstrated to suggest lipid damage and DNA damage occur concurrently on the human ocular surface.

Temporal Characteristics of Sodium Fluorescein in the Tear Meniscus.

To observe the emission intensity profile of sodium fluorescein in the human tear film as a function of time and concentration. Twenty-two participants with no dry eye signs or symptoms were randomly allocated to receive 1 μL of either a 2 or 10% concentration of fluorescein to one eye. Images of the inferior tear meniscus were captured at regular intervals over 30 minutes and the process repeated for the other eye with the alternate concentration. Fluorescence intensity was quantified on the basis of the grayscale pixel values in the tear meniscus images. The fluorescein-decay profile over time and between concentrations was determined. Peak fluorescence intensity was reached in 3.9 ± 3.0 and 8.7 ± 4.4 minutes after instillation for the 2 and 10% concentrations, respectively. The 10% concentration of fluorescein maintained its peak fluorescence intensity longer than the 2% concentration (about 9 and 2 minutes, respectively). The peak fluorescence intensity was not significantly different between the higher and lower concentrations (44 ± 37 vs. 38 ± 32 units, P = .22). For both concentrations, the observed intensity did not return to baseline levels by the end of the 30-minute observation time. The fluorescence intensity of fluorescein in a clinical setting varies with time such that both the onset and duration of maximum brightness are concentration dependent. At low concentration (2%), maximum brightness occurs almost immediately after instillation and lasts about 2 minutes. With a higher concentration (10%), the effective working window is delayed for about 7 to 8 minutes. Irrespective of initial concentration, observable fluorescence remains in the tear film beyond 30 minutes post-instillation.

Anterior Segment Optical Coherence Tomography for Tear Meniscus Evaluation and its Correlation with other Tear Variables in Healthy Individuals.

Dry eye is one of the most common ocular diseases in this cyber era. Despite availability of multiple tests, no single test is accurate for the diagnosis of dry eye. Anterior segment optical coherence tomography is the recent tool which can be added in the armentarium of dry eye tests. To evaluate tear meniscus with anterior segment optical coherence tomography and its correlation with other tear variables in normal healthy individuals. In this prospective cross-sectional observational study, right eye of 203 consecutive patients were studied. All the patients were divided into three groups Group 1, 2 and 3 according to their age ≤20 years, 21-40 years and >40 years respectively. All patients underwent routine ophthalmologic examinations along with slit-lamp bio-microscopy for tear meniscus height measurement, tear film break up time, Schirmer's I test (with anaesthesia) and optical coherence tomography imaging of inferior tear meniscus height. After focusing of the instrument with a Cross Line (CL) centered on lower tear meniscus at 6'0 clock of cornea, a 6 mm long scan was obtained. The tear meniscus height (μm) and tear meniscus area (mm(2)) were measured manually with help of callipers by joining upper corneo-meniscus junction to the lower lid-meniscus junction and tear meniscus height and area within the plotted line respectively and calculated by using the integrated analysis available in the custom software. There was significant decrease in the all tear variables with the increase in the age. According to age groups in group 1, the mean Schirmer's (24.0±4.9)mm, tear film break up time (11.1±1.9) sec, tear meniscus height on slit lamp (600.2±167.3)mm were higher but decreased in group 2 (21.5±5.4,10.8±1.4, 597.5±186.3) and group 3 (19.8 ± 5.1, 10.2 ± 1.6, 485.6 ± 157.7) respectively. Schirmer's test values and tear film break up time were similar in both sexes (p=0.1 and p= 0.9). Tear meniscus height on slit lamp and Optical coherence based tear meniscus area were similar in both sexes (p=0.5 and p=0.1). However, tear meniscus height on optical coherence tomography was significantly higher in females (p=0.04). Value of Schirmer's and tear film break up time (r =0.2; p= 0.001) and Schirmer's and tear meniscus height on slit lamp (r=0.6; p<0.001) had positive correlation. Tear meniscus height and tear meniscus area on optical coherence tomography had positive correlation (r =.9; p<0.001). On optical coherence tomography tear meniscus height and area significantly correlated. Despite higher values of Schirmer's, tear film break up time, Slit lamp based tear meniscus height in younger age group the tear meniscus height and tear meniscus area with optical coherence tomography were lower.

Conjunctivochalasis Interferes with Tear Flow from Fornix to Tear Meniscus

To determine whether conjunctivochalasis (CCh) interferes with tear flow from the fornix to the tear meniscus and depletes the fornix tear reservoir. Comparative case series. The study group of 24 CCh patients (8 asymptomatic and 16 symptomatic), 9 of whom underwent operative correction, was compared with a control group of 13 normal subjects. After instilling a 5-μl fluorescein drop into the inferior fornix, the inferior tear meniscus was depleted using a capillary tube. The tear meniscus height, with and without blinking, was recorded and calculated by video meniscometer from sequential captured images. The recovery rate of the original meniscus height was compared among groups at each time point after maximal depletion. The recovery rate of the tear meniscus was significantly slower in symptomatic than asymptomatic CCh patients when compared with normal subjects. Blinking 5 times facilitated such recovery in normal subjects and in asymptomatic CCh patients to the same extent as the normal, but not in symptomatic CCh patients. Deepening of the inferior fornix by removing degenerated Tenon's and reconstruction by cryopreserved amniotic membrane improved the recovery rate in symptomatic CCh patients to the same extent as normal subjects. The tear reservoir in the fornix rapidly replenishes the meniscus under normal circumstances. Conjunctivochalasis obliterates tears not only in the meniscus, but also in the reservoir, explaining how symptoms develop in CCh patients. Blinking is an effective compensatory mechanism to distinguish the severity of CCh. Surgical correction should not only restore the tear meniscus, but also deepen the fornix in CCh patients. Proprietary or commercial disclosure may be found after the references.

Tear Film Osmolarity Measurements in Dry Eye Disease Using Electrical Impedance Technology

Tear film hyperosmolarity is recognized as an important pathogenetic factor in dry eye syndrome, but difficulties in its measurement have limited its utility in the recent past. This prospective, nonrandomized, clinical single-center study investigates the osmolarity in tear samples of patients with keratoconjunctivitis sicca compared with healthy controls. One hundred thirty-three patients [aged 58 years (51-64 years), 86 women and 47 men] with moderate to severe keratoconjunctivitis sicca and 95 controls [aged 52 years (48-61 years), 55 women and 40 men] were enrolled in the trial. Tear samples were collected directly from the inferior lateral tear meniscus. Inclusion criteria were a tear breakup time of less than 5 seconds, a Schirmer test with anesthesia less than 5 mm, and positive symptoms (Ocular Surface Disease Index score > 83). Tear film osmolarity was analyzed by the TearLab osmometer. In our study, patients with moderate to severe keratoconjunctivitis sicca showed a tear film osmolarity of 320 mOsmol/L (301-324 mOsmol/L). The results of the control group were 301 mOsmol/L (298-304 mOsmol/L). Our results revealed a significantly higher tear film osmolarity in patients with moderate to severe keratoconjunctivitis sicca compared with the control group. The sensitivity was 87%, and the specificity was 81%. Our results approved the referent value in moderate to severe dry eye of approximately 316 mOsmol/L, as described in the literature. The results showed a significantly higher tear film osmolarity in patients with severe keratoconjunctivitis sicca compared with the healthy controls. Testing tear film osmolarity can be a very effective objective diagnostic tool in the diagnosis of dry eye disease.

Comparison of Human Tear Film Osmolarity Measured by Electrical Impedance and Freezing Point Depression Techniques

Tear hyperosmolarity is diagnostic of dry eye disease (DED), yet difficulty in measurement has limited its utility; development of new instruments could facilitate its clinical application. This study compares the new OcuSense TearLab osmometer (OcuSense, Inc, San Diego, CA), based on electrical impedance "lab-on-a-chip" nanoliter technology, with the freezing point depression Clifton Osmometer (Clifton Technical Physics, Hartford, NY). Thirty-six subjects were recruited: 15 DED (9 women, 6 men age: 41 +/- 16 years) and 21 controls (12 women, 9 men age: 35 +/- 12 years); criteria for DED were noninvasive tear breakup time <10 seconds, Schirmer I test <5 mm, and positive symptoms. Samples were collected from the inferior tear meniscus for testing with both osmometers. Osmolarity values measured with OcuSense TearLab were 308 +/- 6 and 321 +/- 16 mOsm/L for controls and dry eye, respectively, and those measured with Clifton were 310 +/- 7 and 323 +/- 14 mOsm/L for controls and dry eye, respectively; these values were significantly different. Significant correlation was found between OcuSense and Clifton measurements (r = 0.904; P = 0.006). Bland-Altman analysis revealed agreement between techniques; the majority of points fell within the 95% confidence limits, and actual values differed by less than 1%. A cutoff value of >316 mOsm/L, derived from the distribution of osmolarity values, was used to diagnose DED with an effectiveness of 73% sensitivity, 90% specificity, and 85% positive predictive value for the OcuSense and 73% sensitivity, 71% specificity, and 65% positive predictive value for the Clifton in the study samples. Tear film osmolarity measured with the OcuSense TearLab system correlates well with the Clifton Osmometer. The new instrument has the potential to provide clinicians with a readily available clinically applicable measure, which could become the gold standard in DED.

Dynamic Changes in the Lower Tear Meniscus After Instillation of Artificial Tears

To compare the dynamic changes in lower tear meniscus area (TMA) and height after instillation of artificial tears in patients with dry eye and healthy controls. Twenty-two eyes of 11 patients with dry eye and twenty eyes of 10 age- and sex-matched healthy subjects were included. The inferior tear meniscus height and area measurements were taken before and after instillation of 35 μL carboxymethyl cellulose (CMC) 0.5% and 1.0% (Allergan, Irvine, CA) on 2 consecutive days. The measurements were obtained before and 1, 5, 10, 15, and 30 minutes after instillation using anterior segment optical coherence tomography, RTVue-100 (RTVue, Optovue, Inc). The baseline lower TMA and height in the dry eye group were significantly lower than in the control group. A significant increase in TMA and height was found at 1 minute post instillation of 0.5% CMC in both groups, with findings returning to baseline levels at 5 and 10 minutes post instillation in the control group and dry eye group, respectively. The increase in TMA and height persisted for a longer time period in both groups with 1% CMC, versus 0.5% CMC. At 15 and 30 minutes, both tear meniscus parameters were still significantly higher in the control group and dry eye group, respectively. Artificial tears provide a significant yet temporary improvement in the tear meniscus. The anterior segment optical coherence tomography is valuable to measure dynamic changes in the tear meniscus.

Tear ferning in contact lens wearers

Tear ferning (TF) has shown good sensitivity and specificity in the diagnosis of dry eye, but is a relatively uncommon test, especially in contact lens wearers. The aim of this study was to investigate the relationship between TF, ocular comfort and tear film stability amongst contact lens (CL) wearers and non-contact lens (NCL) wearers. Subjects (36 NCL, 24 CL; mean age 23.2 +/- 4.8 years) underwent assessment of non-invasive tear break up time (NIBUT), fluorescein tear break up time (FBUT) and completed the Ocular Comfort Index (OCI) questionnaire. Non-stimulated tears were collected from the inferior tear meniscus with a glass capillary. Samples of 1.5 microL were air dried, observed by light microscopy and the TF pattern quantified according to Rolando's grading scale. Significantly higher grades of TF pattern and discomfort (higher OCI scores) were observed in CL wearers compared to NCL wearers (Mann-Whitney U-test; p < 0.005 and p < 0.05 respectively). Differences in tear film stability were not significant between groups. Even when asymptomatic (low OCI scores) CL and NCL subjects were compared, TF remained significantly different (p < 0.005). In both CL and NCL subjects, TF displayed poor correlation with tear film stability tests and OCI scores. Higher TF grades in CL wearers, even if asymptomatic, indicate an unfavourable ratio of salt to macromolecule concentration within the tear film of such subjects. The lack of significant difference in TF between symptomatic CL and NCL wearers could suggest similar aetiology (tear film hyperosmolarity) in each cohort. The TF technique demonstrates limited sensitivity and specificity for the prediction of ocular surface comfort in both CL and NCL wearers.

Apparent time‐dependent differences in inferior tear meniscus height in human subjects with mild dry eye symptoms

Purpose: The aim of the study was to track the volume of tears contained in the inferior tear meniscus over the course of the day in subjects with symptoms of mild dry eye and a control asymptomatic group.Methods: Forty non‐contact lens‐wearing subjects (aged 27 ± 6 years) were enrolled in this investigator‐masked study. They were divided into ‘dry eye’ (DE) and ‘non‐dry eye’ (NDE) individuals based on their responses to the Allergan Subjective Evaluation of Symptoms of Dryness (SESOD) questionnaire. Measurement of the tear meniscus height (TMH) was undertaken on the centre of the right eye at 9:00 am, noon, 3:00 pm, 6:00 pm and 9:00 pm on the lower lid using a non‐contact, non‐invasive optical coherence tomographer (OCT). The TMH was determined from scanned images using customised software.Results: A monotonous and significant reduction in the central TMH occurred over the course of the day in both groups (p < 0.05), with the values constantly decreasing (NDE = 0.162 to 0.125-mm; DE = 0.154 to 0.121-mm). While the TMH values in the DE group were always lower than the NDE group, these were not significantly different at any time (p > 0.05).Conclusions: A diurnal reduction in tear volume, as assessed by evaluation of the inferior TMH, may be one of the reasons responsible for the common increase in end‐of‐day ocular dryness symptoms reported by many patients in clinical practice.