(The three-layered structure of the normal tear film.)

    As shown in the schematic above, the tear film has a intricate structure. Each blink coats the ocular surface with a fresh tear film, which then drains under gravity and may break up. This drainage and breakup process offers clues about the health of the eye. Before an eye infection sets in, for example, bacterial colonies proliferate in the aqueous layer and modify the chemical makeup of the tear film. They may also attack the mucus layer and change the mucin concentration in the tear film. By studying the flow and breakup of the tear film under healthy and pathological conditions, both by computation and optical measurement, we identify abnormalities in the tear-film flow that can serve as indicators of an impending eye infection.

Department of ChBE / Department of Mathematics / Fluids Lab / James J. Feng / Research