Dataset Information

Tear film breakup and structure studied by simultaneous video recording of fluorescence and tear film lipid layer images.

ABSTRACT:

Purpose

The thinning of the precorneal tear film between blinks and tear film breakup can be logically analyzed into contributions from three components: evaporation, flow into the cornea, and tangential flow along the corneal surface. Whereas divergent tangential flow contributes to certain types of breakup, it has been argued that evaporation is the main cause of tear thinning and breakup. Because evaporation is controlled by the tear film lipid layer (TFLL) it should therefore be expected that patterns of breakup should match patterns in the TFLL, and this hypothesis is tested in this study.

Methods

An optical system is described for simultaneous video imaging of fluorescein tear film breakup and the TFLL. Recordings were made from 85 subjects, including both with healthy and dry eyes. After instillation of 5 ?L2% fluorescein, subjects were asked to blink 1 second after the start of the recording and try to maintain their eyes open for the recording length of 30 or 60 seconds.

Results

Areas of tear film thinning and breakup usually matched corresponding features in the TFLL. Whereas thinning and breakup were often matched to thin lipid, surprisingly, the corresponding lipid region was not always thinner than the surrounding lipid. Occasionally, a thin lipid region caused a corresponding region of greater fluorescence (thicker aqueous layer), due to convergent tangential flow.

Conclusions

Areas of tear thinning and breakup can generally be matched to corresponding regions of the TFLL as would be expected if breakup is largely due to evaporation. Surprisingly, in some examples, the corresponding lipid area was not thinner and possibly thicker than the surrounding lipid. This indicates that the lipid was a poor barrier to evaporation, perhaps because of deficiency in composition and/or structure. For example, bacterial lipases may have broken down esters into component acids and alcohols, causing a defective TFLL structure with increased evaporation.

SUBMITTER: King-Smith PE

PROVIDER: S-EPMC3720150 | biostudies-literature | 2013 Jul

REPOSITORIES: biostudies-literature

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Publications

Tear film breakup and structure studied by simultaneous video recording of fluorescence and tear film lipid layer images.

King-Smith P Ewen PE Reuter Kathleen S KS Braun Richard J RJ Nichols Jason J JJ Nichols Kelly K KK

Investigative ophthalmology & visual science 20130722 7

<h4>Purpose</h4>The thinning of the precorneal tear film between blinks and tear film breakup can be logically analyzed into contributions from three components: evaporation, flow into the cornea, and tangential flow along the corneal surface. Whereas divergent tangential flow contributes to certain types of breakup, it has been argued that evaporation is the main cause of tear thinning and breakup. Because evaporation is controlled by the tear film lipid layer (TFLL) it should therefore be expe ...[more]

PMID: 23766476

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Project description:Dry eye syndrome is one of the most common ocular diseases, and meibomian gland dysfunction (MGD) is the leading cause of evaporative dry eye syndrome. When the tear film lipid layer becomes thin due to obstructive or hyposecretory meibomian gland dysfunction, the excessive evaporation of the aqueous layer can occur, and this causes evaporative dry eye syndrome. Thus, measuring the lipid layer thickness (LLT) is essential for accurate diagnosis and proper treatment of evaporative dry eye syndrome.We used a white LED panel with a slit lamp microscope to obtain videos of the lipid layer interference patterns on the cornea. To quantitatively analyze the LLT from interference colors, we developed a novel algorithm that can automatically perform the following processes on an image frame: determining the radius of the iris, locating the center of the pupil, defining region of interest (ROI), tracking the ROI, compensating for the color of iris and illumination, and producing comprehensive analysis output. A group of dry eye syndrome patients with hyposecretory MGD, dry eye syndrome without MGD, hypersecretory MGD, and healthy volunteers were recruited. Their LLTs were analyzed and statistical information-mean and standard deviation, the relative frequency of LLT at each time point, and graphical LLT visualization-were produced.Using our algorithm, we processed the lipid layer interference pattern and automatically analyzed the LLT distribution of images from patients. The LLT of hyposecretory MGD was thinner (45.2 ± 11.6 nm) than that of dry eye syndrome without MGD (69.0 ± 9.4 nm) and healthy volunteers (68.3 ± 13.7 nm) while the LLT of hypersecretory MGD was thicker (93.5 ± 12.6 nm) than that of dry eye syndrome without MGD. Patients' LLTs were statistically analyzed over time, visualized with 3D surface plots, and displayed using 3D scatter plots of image pixel data for comprehensive assessment.We developed an image-based algorithm for quantitative measurement as well as statistical analysis of the LLT despite fluctuation and eye movement. This pilot study demonstrates that the quantitative LLT analysis of patients is consistent with the functions of meibomian glands clinically evaluated by an ophthalmologist. This approach is a significant step forward in developing a fully automated instrument for evaluating dry eye syndrome and for providing proper guidance of treatment.

Project description:BACKGROUND:To evaluate the correlations between lipid layer thickness (LLT) and morphology and function of the meibomian glands in patients who were diagnosed as meibomian gland dysfunction (MGD) in different age groups. METHODS:Patients who have diagnosed as obstructive MGD were included in this prospective, cross-sectional study. Patients were divided into three groups: young (ages 20-39?years), middle-aged (ages 40-59?years), and older (aged ?60?years). All patients completed an Ocular Surface Disease Index (OSDI) questionnaire and were evaluated for LLT, tear meniscus height (TMH), noninvasive tear film break-up time (NI-BUT) measurement, invasive TBUT (ITBUT), corneal fluoresceinstaining (CFS) score, eyelid margin abnormalities, Schirmer I test, and MG function and morphology, by using the Keratograph 5 and LipiView interferometer. RESULTS:Two hundred and nine patients (209 eyes) were included. The median LLT of all patient was 57?nm (IQR, 36.5?nm), and the LLT values were significantly different among the young group (median, 51?nm; IQR, 23.5?nm), middle-aged group (median, 59.5?nm; IQR 46.5?nm) and older group (median, 62?nm; IQR, 42.5?nm) (P?=?0.033, Kruskal-Wallis test). In regression analyses controlling for confounder factors sex and MG loss, the LLT was positively correlated with age (??=?5.539, P?=?0.001). There was a negative correlation between LLT and MG dropout in the all (r?=?-?0.527, P?<?0.001), young (r?=?-?0.536, P?<?0.001), middle-aged (r?=?-?0.576, P?<?0.001), and older (r?=?-?0.501, P?<?0.001) groups. LLT was positively correlated with the MG expressibility in the all (r?=?0.202, P?=?0.003), middle-aged (r?=?0.280, P?=?0.044) and older (r?=?0.452, p?<?0.001) groups, but it was no statistical significance in the young group (r?=?0.007, P?=?0.949). CONCLUSIONS:The thickness of LLT was increased with age and significantly correlated with both MG secretion and morphology in middle-aged and older patients with obstructive MGD. LLT measurement is a useful screening tool for detecting obstructive MGD and age as an influential factor should be accounted for when interpreting the meaning of the LLT value. TRIAL REGISTRATION:NCT02481167 ; Registered 25 June, 2015.

Dataset Information

Tear film breakup and structure studied by simultaneous video recording of fluorescence and tear film lipid layer images.

Purpose

Methods

Results

Conclusions

Publications

Tear film breakup and structure studied by simultaneous video recording of fluorescence and tear film lipid layer images.

Similar Datasets

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