 The first independent variable is the contact lens. Each subject will wear both PureVision TM0 aspheric contact lenses and conventional spherical contact lenses on separate visits. The second independent variable is visibility condition. Subjects will complete the study drive both in clear nighttime conditions and at night under glare conditions. In both cases, the driver will experience oncoming traffic; however, in the glare condition, the simulator will be equipped with a point light source sufficient to provide glare similar to that provided by oncoming traffic in the real world. 