1 research outputs found
Fitting ODE models of tear film breakup
Several elements are developed to quantitatively determine the contribution
of different physical and chemical effects to tear breakup (TBU) in normal
subjects. Fluorescence (FL) imaging is employed to visualize the tear film and
to determine tear film (TF) thinning and potential TBU. An automated system
using a convolutional neural network was trained and deployed to identify
multiple TBU instances in each trial. Once identified, extracted FL intensity
data was fit by mathematical models that included tangential flow along the
eye, evaporation, osmosis and FL intensity of emission from the tear film.
Optimizing the fit of the models to the FL intensity data determined the
mechanism(s) driving each instance of TBU and produced an estimate of the
osmolarity within TBU. Initial estimates for FL concentration and initial TF
thickness agree well with prior results. Fits were produced for
instances of potential TBU from 15 normal subjects. The results showed a
distribution of causes of TBU in these normal subjects, as reflected by
estimated flow and evaporation rates, which appear to agree well with
previously published data. Final osmolarity depended strongly on the TBU
mechanism, generally increasing with evaporation rate but complicated by the
dependence on flow. The method has the potential to classify TBU instances
based on the mechanism and dynamics and to estimate the final osmolarity at the
TBU locus. The results suggest that it might be possible to classify individual
subjects and provide a baseline for comparison and potential classification of
dry eye disease subjects