Blink-induced motion of a gas permeable contact lens

The blink-induced dynamics of a gas permeable contact lens are analyzed. The lens is considered to be a planar, circular, porous disk of specified permeability. Specifically, this work investigates the effects of those variables that characterize the porous nature of the lens such as the permeability and thickness of the lens and the effective slip coefficient. The equations governing the dynamics of the tear film and of the lens are solved subject to physical constraints that limit the duration and extent of the lens motion. The motion of a permeable contact lens can be controlled by a proper choice of the lens material microstructure. Analysis of the results indicates that the motion of the lens is enhanced by lower values of the slip coefficient and higher values of the permeability, independent of the lens thickness. In addition, thicker lenses as well as thicker tear films cause the lens to squeeze faster and to slide slower.