PURPOSE To visualize the in vivo structure and to investigate the composition of rat precorneal tear film. METHODS An in vivo cryofixation with freeze substitution method of electron microscopy was used for the study. For light and transmission electron microscopy, a small amount of aluminum powder was used as a tracer spread on the corneal surface. The eyeballs were immediately and quickly f...

Objective(s): Evaluate the effect of topical antiglaucoma drugs on tear film and determine the time taken to develop symptoms and or signs of dry eye in diagnosed open angle glaucoma patients by Schirmer's test I, Schirmer's test II, Tear film break up time. Method(s): This prospective study was carried out in 60 patients attending Ophthalmology outdoor with newly diagnosed patients of primary ...

Tear film lipid layer is a complex lipid mixture forming the outermost interface between eye and environment. Its key characteristics, such as surface tension and structural stability, are governed by the presence of polar lipids. The origin of these lipids and exact composition of the mixture are still elusive. We focus on two minor polar lipid components of the tear film lipid later: sphingom...

The tear film on the front of the eye is critical to proper eyesight; in many mathematical models of the tear film, the tear film is assumed to be on a flat substrate. We re-examine this assumption by studying the effect of a substrate which is representative of the human cornea. We study the flow of a thin fluid film on a prolate spheroid which is a good approximation to the shape of the human...

Purpose To investigate the correlation between the changes in the ocular surface temperature (OST) and tear film stability over soft contact lenses (SCLs). Methods We enrolled 20 eyes of 20 normal SCL wearers (20 men; 24.4 ± 4.1 years). We used four different daily disposable SCLs: one silicone hydrogel lens (delefilcon A) and three hydrogel lenses (etafilcon A with polyvinylpyrrolidone [PVP]...

PURPOSE To develop a safe, noninvasive, noncontact, continuous in vivo method to measure the dehydration rate of the precorneal tear film and to compare the effectiveness of a viscoelastic agent in maintaining the precorneal tear film to that of a balanced salt solution. METHODS Software was designed to analyze the corneal reflection produced by the operating microscope's coaxial illumination...

BACKGROUND Diabetic patients often complain of dry eye symptoms, such as burning and/or foreign body sensation. The aim of the present study was to investigate whether diabetes mellitus is correlated with tear film dysfunction and/or tear hyposecretion. METHODS In 86 consecutive insulin dependent diabetics with retinopathy and 84 non-diabetic controls (age and sex matched) we performed fluoro...

in the current study the effect of casimir force and squeezed film damping on the pull-in instability and dynamic behavior of electrostatically actuated nano and micro electromechanical systems is investigated separately. linear elastic membrane theory is used to model the static and dynamic behavior of system for strip, annular and disk geometries. squeezed film damping effect is modeled using...

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 subjects keeping their eyes open for up to 30...