Purchase this article with an account.
Kara L. Maki, Gregory Barron, Richard J Braun, Peter Ewen King-Smith; The Effect Of A Polar Lipid Reservior Near The Lids On Tear Film Dynamics. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):346.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The purpose of this study is to use mathematical models to examine the tear film flow during a blink cycle in the presence of a reservoir of lipid near the lids. In the prior modeling efforts of Aydemir et al. (Bull Math Bio 2011; 73: 1171-1201) and Jones et al. (Bull Math Bio 2006; 68: 1355-1381), the amount of lipid is not fixed at the lid margins but rather decreases in concentration during the upstroke phase of the blink. Therefore, it is not fully understood what effect a reservoir of lipid distributed at the lid margin has on tear film dynamics and potentially dry eye.
In this study, we explore mathematical models to simulate the tear film thickness and the concentration of polar lipid during a blink. By implementing a new set of boundary conditions, fixing the polar lipid concentration at the lid margins, we mimic the presence of a lipid reservoir and the possible continual secretion of lipid from the meibomian gland orifices during a blink cycle. We implement a moving overset grid method to numerically approximate the models (Maki et al. MMB 2008; 25:187-214).
The polar lipid distribution near the moving upper lid is sensitive to the lid motion, building up dramatically near the lid margin during downstroke and then later removed during upstroke. The reservoir prevents the polar lipid from being starved too much as may happen when the amount of lipid is hypothesized to be fixed as in other math models for the tear film with polar lipid. Our results will be compared and contrasted with prior modeling results as well as experimental observations. In addition, we will explore the effect of different tear volumes and lid speeds.
A mathematical model was formulated to mimic a reservoir of lipid at the lids and its influence on the tear dynamics during a blink was studied. Our model may be more appropriate for normal and pseborrheic MGD subjects, where lipid expression may approach continuous release, and not as applicable for MGD subject who are lipid deficient.
This PDF is available to Subscribers Only