Hydrodynamics of a soft contact lens during sliding motion

Tear film thickness and pressure distribution under a tilting soft contact lens with peripheral slopes during the early stage of a blink are calculate d for various flexibility and aspect ratios. The system is modeled as a sli der bearing with the lens behaving as a deformable surface sliding over a r igid eye. The tear is considered to be a linearly viscous (Newtonian) fluid . The velocity pro;file at the edges and the junctions of the slopes are al so calculated for a typical soft contact lens. Back flow at the edges is pr edicted. It is shown that the tilting of the lens has a major affect on the tendency of the pressure distribution. Also important is the lens' flexibi lity for it influences both the film thickness and pressure distribution no ticeably. [S0742-4787(00)01002-X].