Continuously variable contact lens

A method for fabricating a continuously variable multi-focal soft contact lens from a lens blank having two opposed surfaces, comprising:

• squeezing the lens blank by contacting a first surface with ball means having a spherical surface of radius R to deflect the opposed surface of the lens blank;
• cutting and polishing the opposed surface to a desired concave spherical shape;
• controlling the squeezing by the amount of deflection of the lens blank and the radius R of the ball means so that upon release of the lens blank a lens button is formed having an aspheric concave surface having a sufficient variation of radius of curvature within a dimension less than the maximum pupil opening of a wearer in the dark after expansion of the finished lens;
• and
• finishing the first surface to form a convex surface of the lens to yield a contact lens which when wet and expanded has continuously variable optical power increasing from essentially the optical center point of the lens with the desired distance vision power at the center region of the lens and increasing to the desired near vision power within the dimension of the maximum pupil opening of the wearer in the dark, the optical power of the lens increasing at a rate so as not to create a predominant far vision image, whereby the lens is suitable for creating sharp images of far objects, intermediate objects and near objects simultaneously on the retina of a wearer.

A method for fabricating a lens blank having two surfaces for preparing a soft contact lens having continuously variable optical power at least within a region less than the maximum pupil opening of a wearer in the dark when the lens is finished and ready for use, comprising:

• squeezing a lens blank by contacting a first surface with ball means having a spherical surface of radius R to deflect the opposed surface of the lens blank;
• cutting and polishing the opposed surface to a desired concave shape;
• and
• controlling the squeezing by the amount of deflection of the lens blank and the radius R of the ball means so that upon release of the lens blank, a lens button having an aspheric concave surface from essentially the optical center point of the lens button is formed, whereby the optical power gradient within a dimension less than the maximum pupil opening of a wearer in the dark after the finished soft contact lens is formed, the optical power increasing from essentially the center point at a rate so as not to create a predominant far vision image and is suitable for creating sharp images of far objects, intermediate objects and near objects simultaneously on the retina of a wearer.

A method for fabricating a mold for forming a soft contact lens button having a sufficient amount of continuously variable optical power within a region less than the maximum pupil opening of a wearer in the dark when the lens is finished, expanded and ready for wear, comprising:

• squeezing a metal blank having two opposed planar surfaces by contacting a first surface with ball means having a spherical surface of radius R to deflect the opposed surface of the metal blank;
• cutting and polishing the opposed surface of the metal blank to a desired concave shape;
• controlling the squeezing by the amount of deflection of the blank and the radius R of the ball means so that upon release of the metal blank a metal button having an aspheric concave surface is formed;
• and
• forming a mold from the positive metal shape, whereby a soft contact lens material cast in the mold yields a lens button having an aspherical concave surface having a variable radius of curvature from essentially the optical center point of the lens button to a dimension at least equal to the maximum pupil opening of a wearer in the dark after a finished soft contact lens is formed from the lens button, the optical power of the lens increasing from the center point at a rate so as not to create a predominant far vision image;
• whereby a finished lens formed from the lens button is suitable for creating sharp images of far objects, intermediate objects and near objects simultaneously on the retina of a wearer.