Identification of phospholipids in human meibum by nano-electrospray ionisation tandem mass spectrometry

Meibum is believed to be the major source of tear film lipids, which are vital in the prevention of excess evaporation of the aqueous phase. The complete lipid composition of meibum has yet to be established. While earlier studies reported the presence of phospholipids in human meibum, recent mass spectrometric studies have not detected them. In this study we use electrospray ionisation tandem mass spectrometry to investigate the presence of phospholipids in meibum and provide comparison to the phospholipid profile of tears.Lipids were extracted from human meibum and tear samples using standard biphasic methods and analysed by nano-electrospray ionisation tandem mass spectrometry using targeted ion scans. A total of 35 choline-containing phospholipids were identified in meibum and the profile of these was similar to that observed in tears, suggesting tear lipids are derived from meibum. The results shown here highlight the need for a combination of optimised techniques to enable the identification of the large range of lipid classes in meibum. © 2011 Elsevier Ltd.

Assessment of conjunctival goblet cell density using laser scanning confocal microscopy versus impression cytology

Purpose To determine the association between conjunctival goblet cell density (GCD) assessed using in vivo laser scanning confocal microscopy and conjunctival impression cytology in a healthy population. Methods Ninety (90) healthy participants undertook a validated 5-item dry eye questionnaire, non-invasive tear film break-up time measurement, ocular surface fluorescein staining and phenol red thread test. These tests where undertaken to diagnose and exclude participants with dry eye. The nasal bulbar conjunctiva was imaged using laser scanning confocal microscopy (LSCM). Conjunctival impression cytology (CIC) was performed in the same region a few minutes later. Conjunctival goblet cell density was calculated as cells/mm2. Results There was a strong positive correlation of conjunctival GCD between LSCM and CIC (ρ = 0.66). Conjunctival goblet cell density was 475 ± 41 cells/mm2 and 466 ± 51 cells/mm2 measured by LSCM and CIC, respectively. Conclusions The strong association between in vivo and in vitro cellular analysis for measuring conjunctival GCD suggests that the more invasive CIC can be replaced by the less invasive LSCM in research and clinical practice.

Visual outcomes in the subfoveal radiotherapy study:A randomized controlled trial of teletherapy for age-related macular degeneration

Objective: To determine whether teletherapy with 6-mV photons can reduce visual loss in patients with subfoveal choroidal neovascularization in age-related macular degeneration. Design: A multicenter, single-masked, randomized controlled trial of 12 Gy of external beam radiation therapy delivered to the macula of an affected eye vs observation only. Setting: Three United Kingdom-based hospital units. Participants: Patients with age-related macular degeneration, aged 60 years and older, who had subfoveal choroidal neovascularization and a visual acuity of 20/200 (logMAR 1.0) or better. Methods: Two hundred three patients were randomly assigned to radiotherapy or observation. Treatment was undertaken at designated radiotherapy centers, and patients assigned to the treatment group received a total dosage of 12 Gy of 6-mV photons in 6 fractions. Follow-up was scheduled at 3, 6, 12, and 24 months. After excluding protocol violators, the data from 199 patients were analyzed. Main Outcome Measures: The primary outcome measure was mean loss of distance visual acuity in the study eye at 12 and 24 months. Other outcome variables analyzed were near visual acuity and contrast sensitivity. The proportions of patients losing 3 or more or 6 or more lines of distance and near acuity and 0.3 or more or 0.6 or more log units of contrast sensitivity at each follow-up were also analyzed. Results: At all time points, mean distance visual acuity was better in the radiotherapy-treated group than in the control group, but the differences did not reach statistical significance. At 24 months, analysis of the proportions of patients with loss of 3 or more (moderate) (P=.08) or 6 or more (severe) (P=.29) lines of distance vision showed that fewer treated patients had severe losses, but there was no statistically significant difference between groups. For near visual acuity, although there was no evidence of treatment benefit at 12 and 24 months, a significant difference in favor of treatment was present at 6 months (P=.048). When analyzed by the proportions of patients losing 3 lines of contrast sensitivity, there was a significant difference in favor of treatment at 24 months (P=.02). No adverse retinal effects were observed during the study, but transient disturbance of the precorneal tear film was noted in treated patients. Conclusion: The results of the present trial do not support the routine clinical use of external beam radiation therapy in subjects with subfoveal choroidal neovascularization in age-related macular degeneration.

Clinical evaluation of long-term users of two contact lens care preservative systems

Purpose: To clinically evaluate long-term users of two different contact lens care preservative systems and to investigate whether prolonged use is associated with an increase in the prevalence of dry eye.

Methods: Eighty-nine wearers of group IV hydrogel or silicone hydrogel lenses participated in this one-visit, investigator-masked study. Subjects were required to have consistently used a polyhexamethylene biguanide (PHMB) or polyquaternium-1 (PQT) based solution for 2 years. Consistent use was defined as 80% for the past 2 years and 100% for the past year. Clinical assessments included: average and comfortable wear time; overall and end-of-day comfort; signs of dryness, discomfort, burning or stinging, grittiness or scratchiness and visual changes; non-invasive and fluorescein break-up-time; pre-ocular tear film lipids, tear meniscus height, Schirmer and fluorescein clearance tests; limbal and bulbar hyperemia; palpebral roughness; corneal and conjunctival staining; lens front surface wetting; and lens film deposits.

Results: Significantly more grittiness or scratchiness was reported by subjects using a PHMB-containing system (67% vs. 44%; P = 0.02). Palpebral roughness and hyperemia were significantly greater in the PHMB group wearing group IV lenses (P = 0.01 and P = 0.05, respectively). Corneal staining was significantly higher in the PHMB users in all four peripheral sectors (P < 0.01). Nasal and temporal conjunctival staining was also significantly higher for users of PHMB-containing systems (P < 0.05). Front surface lens wettability was significantly better for group IV PQT users compared to PHMB users (P = 0.008), with 84% vs. 72%, respectively, with lenses graded by the investigator as having good or excellent wettability. Significantly higher levels of lens front surface film deposits were noted with PHMB users (P = 0.007), with 58% of group IV lenses treated with PHMB compared with 38% of group IV lenses treated with PQT showing some lens front surface film deposition. No significant differences between the two preservative system groups were noted for the range of dry eye evaluations nor the remaining clinical assessments.

Conclusions: Differences in both ocular and lens characteristic were observed between long-term users of two preservative systems used in many contact lens multi-purpose solutions. The findings from this study did not support the hypothesis that prolonged use of PHMB-containing solutions leads to dry eye. Additional studies including a larger sample size and perhaps longer use of the systems could help to further elucidate differences in clinical performance between systems.

In situ osmometry : validation and effect of sample collection technique

Purpose: To compare tear film osmolarity measurements between in situ and vapor pressure osmometers. Repeatability of in situ measurements and the effect of sample collection techniques on tear film osmolarity were also evaluated.

Methods: Osmolarity was measured in one randomly determined eye of 52 healthy participants using the in situ (TearLab Corporation, San Diego, CA) and the vapor pressure (Vapro 5520; Wescor, Inc., Logan, UT) osmometers. In a subset of 20 participants, tear osmolarity was measured twice on-eye with the in situ osmometer and was additionally determined on a sample of nonstimulated collected tears (3 µL) with both instruments.

Results: Mean (SD) tear film osmolarity with the in situ osmometer was 299.2 (10.3) mOsmol/L compared with 298.4 (10) mmol/kg with the vapor pressure osmometer, which correlated moderately (r = 0.5, P < 0.05). Limits of agreement between the two instruments were -19.7 to +20.5 mOsmol/L. Using collected tears, measurements with the vapor pressure osmometer were marginally higher (mean [SD], 303.0 [11.0] vs 299.3 [8.0] mOsmol/L; P > 0.05) but correlated well with those using the in situ osmometer (r = 0.9, P < 0.05). The mean (SD) osmolarity of on-eye tears was 5.0 (6.6) mOsmol/L higher than that of collected tears, when both measurements were conducted with the in situ osmometer. This was a consistent effect because the measurements correlated well (r = 0.65, P < 0.05).The in situ osmometer showed good repeatability with a coefficient of repeatability of 9.4 mOsmol/L (r = 0.8, P < 0.05).

Conclusions: Correlation between the two instruments was better when compared on collected tear samples. Tear film osmolarity measurement is influenced by the sample collection technique with the osmolarity of on-eye tears being higher than that of collected tears. This highlights the importance of measuring tear film osmolarity directly on-eye. The in situ osmometer has good repeatability for conducting this measurement.

The epidemiology of dry eye in Melbourne, Australia

OBJECTIVE: To describe the epidemiology of dry eye in the adult population of Melbourne, Australia. DESIGN: A cross-sectional prevalence study. PARTICIPANTS: Participants were recruited by a household census from two of nine clusters of the Melbourne Visual Impairment Project, a population-based study of age-related eye disease in the 40 and older age group of Melbourne, Australia. Nine hundred and twenty-six (82.3% of eligible) people participated; 433 (46.8%) were male. They ranged in age from 40 to 97 years, with a mean of 59.2 years. MAIN OUTCOME MEASURES: Self-reported symptoms of dry eye were elicited by an interviewer-administered questionnaire. Four objective assessments of dry eye were made: Schirmer's test, tear film breakup time, rose bengal staining, and fluorescein corneal staining. A standardized clinical slit-lamp examination was performed on all participants. Dry eye for the individual signs or symptoms was defined as: rose bengal > 3, Schirmers < 8, tear film breakup time < 8, > 1/3 fluorescein staining, and severe symptoms (3 on a scale of 0 to 3). RESULTS: Dry eye was diagnosed as follows: 10.8% by rose bengal, 16.3% by Schirmer's test, 8.6% by tear film breakup time, 1.5% by fluorescein staining, 7.4% with two or more signs, and 5.5% with any severe symptom not attributed to hay fever. Women were more likely to report severe symptoms of dry eye (odds ratio [OR] = 1.85; 95% confidence limits [CL] = 1.01, 3.41). Risk factors for two or more signs of dry eye include age (OR = 1.04; 95% CL = 1.01, 1.06), and self-report of arthritis (OR = 3.27; 95% CL = 1.74, 6.17). These results were not changed after excluding the 21 people (2.27%) who wore contact lenses. CONCLUSIONS: These are the first reported population-based data of dry eye in Australia. The prevalence of dry eye varies by sign and symptom.

Canine lacrimal and third eyelid superficial glands macroscopic and morphometric characteristics

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Proteomic analysis of dog tears for potential cancer markers

The first reference map of the proteome of pooled normal dog tears was created using 2-dimensional polyacrylamide gel electrophoresis and the identity of a number of the major species determined using matrix-assisted laser desorption time of flight mass spectrometry (MALDI-TOF) and peptide mass fingerprint matching on protein sequence databases. In order to understand the changes in protein expression in the tear film of dogs with cancer, tears from such animals were similarly examined. A number of differences were found between the tears of healthy dogs and the dogs with cancer. Differences were found in levels of actin and albumin and in an unidentified protein which may be analogous to human lacryglobulin. These findings suggest that it may be possible to develop tear film analysis to provide a simple non-invasive test for the diagnosis and/or management of canine cancers. (C) 2007 Elsevier Ltd. All rights reserved.

Eye blink in newborn and preschool-age children

Purpose: To investigate the dynamics of ocular eyelid movements in newborn infants and preschool-age children.Methods: Fifty newborn infants and 200 preschool children aged 4-6 years were examined. Images of each child, with his or her eyes in the primary eye position looking at an object placed at the child's height, were recorded with a digital videocamera for 3 mins. Complete and incomplete blink rates, opening, closing and complete blink times were calculated.Results: Newborn infants presented a lower number of incomplete movements than preschool children. The complete blink rate was lower in newborn infants (6.2 blinks/min) than in preschool children (8.0 blinks/minute). Eyelid closing, opening and compete blink times were longer in newborn infants than in preschool children at all observation times.Conclusions: Newborn infants had a different pattern of eyelid movement compared with preschool children. Specific characteristics that are found in this group of children particularly, such as immaturity of the neural system and more resistant tear film, may explain these findings in part.

Microalterations in the third eyelid gland of dogs with keratoconjunctivits sicca secondary to distemper

Analisaram-se, à microscopia óptica, 28 glândulas da terceira pálpebra de cães, que morreram com cinomose. O diagnóstico de ceratoconjuntivite seca baseou-se nas alterações da superfície ocular e no teste da lágrima de Schirmer. À histologia, visibilizaram-se atrofia tubuloacina, espessamento do tecido conjuntivo e exudação inflamatória de leve a intensa com presença de plasmócitos, de histiócitos e por hipertrofia compensatória de algumas glândulas. O lume das glândulas encontrava-se hipertrofiado contendo células epiteliais descamadas, polimorfonucleares e hemácias, além de muco.

Uso subconjuntival de lipossomas com rapamicina e tacrolimus tópico no tratamento de ceratoconjuntivite seca em cães

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