US Patent 7052133 Contact lenses

The present invention provides a contact lens having an orientation/stabilization and optionally translation feature that does not provide an prism optical distortion and can effectively maintain a predetermined orientation of the lens on an eye. Like a conventional lens ballast, the orientation feature of the invention works by weighing the lens at its lower half portion, causing it to come to an equilibrium position on the eye. With such orientation feature, the optical zone of the anterior surface can be designed independently to provide an optimal visual performance.