Department of Mathematical Sciences
Richard Braun, University of Delaware
Friday, March 27th, 2026
11:00AM-11:50AM
Stratton Hall 202
Speaker: Richard Braun, University of Delaware
Title: An Overview of Human Tear Film and Ocular Surface Modeling
Abstract: This talk will briefly survey several approaches to models for the tear film and ocular surface. The tear film is a thin fluid multilayer left on the eye surface after a blink. A good tear film is essential for health and proper function of the eye. Millions of people have a condition called dry eye disease (DED) that is thought to be closely linked to repeated tear breakup (TBU) and hyperosmolarity (elevated saltiness). However, there is little quantitative data about what happens within TBU: for example, there is no technology to directly measure tear osmolarity within areas of TBU. Data from a method that we developed is used to extract data from video of the tear film dyed with fluorescein (for visualization). We have extracted fluorescent intensity data for 15 healthy is subjects resulting in hundreds of instances of TBU. We use parameter identification with a hierarchy of models (PDEs using lubrication models for a few TBU instances, or ODEs from simplified models for all the TBU instances) to fit the data and to estimate which mechanisms are most important in each instance. Using those fits, we determine critical variables such as osmolarity within regions of TBU. Fluorescein dye in the tear film can stain the cornea, which may indicate damage in the corneal epithelium (the surface cells) and the severity of DED in a subject. If time permits, a diffusion model for staining of the corneal epithelium with fluorescein dye will be presented. A simple diffusion model captures a number of aspects of staining seen in vivo. Possible future directions for modeling will be discussed.