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PURPOSE The purpose of our study was to test the prediction that if the tear film thins due to evaporation, rather than tangential flow, a high concentration of fluorescein in the tear film would show a greater reduction in fluorescent intensity compared to a low concentration of fluorescein due to self-quenching at high concentrations. METHODS Tear film(More)
PURPOSE Tear evaporation should increase fluorescein concentration, causing fluorescence dimming from self-quenching for high but not low fluorescein concentration. This prediction was tested and compared to the predicted effect of "tangential flow" that fluorescence dimming should be similar for high and low concentrations. METHODS A custom optical(More)
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(More)
PURPOSE To evaluate an interferometric method for measuring the thickness of the pre- (PLTF) and postlens tear film (POLTF) in subjects wearing hydrogel contact lenses. The precision and accuracy of measuring postlens tear thickness is compared with a previous method based on optical pachymetry and mechanical measurement of contact lens thickness. METHODS(More)
PURPOSE To investigate whether the tear film thinning between blinks is caused by evaporation or by tangential flow of the tear film along the surface of the cornea. Tangential flow was studied by measuring the movement of the lipid layer. METHODS Four video recordings of the lipid layer of the tear film were made from 16 normal subjects, with the(More)
PURPOSE To apply interferometry as an in vivo measure of tear film thinning between blinks. METHODS Wavelength-dependent interference was used to measure the tear film thinning rates in 20 normal contact lens wearers, and spectra were captured at a rate of 4.5 per second for 20 seconds. Four recordings of precorneal tear film (PCTF) thinning were made,(More)
PURPOSE To examine tear film, contact lens, medical, and patient-related factors associated with self-reported contact lens-related dry eye. METHODS Four hundred fifteen contact lens wearers were recruited and enrolled in this phase of a larger cross-sectional study. A variety of tear film (e.g., interferometry, osmolality, phenol red thread, meibography,(More)
PURPOSE To determine the contribution of evaporation to the thinning of the precorneal tear film between blinks. METHODS The rate of tear film thinning after a blink was measured using spectral interferometry from the right eyes of 37 subjects. Data were obtained under two different conditions: free air and air-tight goggles. RESULTS The mean (±SD) tear(More)
PURPOSE The complex superficial lipid layer of the tear film functions to prevent evaporation and maintain tear stability. Although classes of lipids found in the tear film have been reported, individual lipid species are currently being studied with more sophisticated. METHODS The purpose of this work was to show the identification of fatty acids and the(More)