Abstract: In accordance with the disclosure there is described herein a method of designing an anterior curve of a contact lens for the eye of a patient comprising the steps of providing a contact lens material having a posterior, a posterior curve having a predetermined asphericity, an anterior, an index of refraction and a center thickness; providing a geometry of a cornea, a distance power correction for the cornea and a near power correction for the cornea; determining a central distance power of the contact lens in air; calculating a central anterior radius of the contact lens using the posterior curve of the contact lens material, the index of refraction of the contact lens material, the center thickness of the contact lens material and the central distance power of the contact lens in air; calculating a center power of the contact lens on the eye of the patient using the index of refraction of tears at the posterior of the contact lens; and using an on-eye ray trace, said on-eye ray trace having a null lens comp

Abstract: In accordance with the disclosure there is described herein a simultaneous vision lens that incorporates both continuous aspheric and concentric bifocal optics into a single optical lens that may be configured as a contact lens or an intraocular lens.

Abstract: A low vision lens for attachment to the front surface of an ophthalmic lens by an adhesive ring coupling carried by the lens, a method for making such a lens assembly, and a method for attaching such lens to the front surface of ophthalmic lens is described.

Abstract: A machine tool control system in which a programmable controller operates a machine to carry out a plurality of programmable functions. The controller includes a plurality of processor means, a first one of the processor means capable of pre-processing and forwarding control information to a second of said processor means, wherein said second processor means provides control information to control machine movement. Advantageously, the second processor means operates on a periodic time based interrupt method which greatly increases the accuracy of the machine.

Abstract: Signal currents corresponding to a voltage to be converted into current or to a current to be amplified are applied to one input of an operational amplifier and its other input is referenced to ground. Its output is connected via a power amplifier and a small resistance to an output terminal and means are provided for supplying current proportional to the voltage across the resistance to the signal input of the operational amplifier with such polarity as to tend to cancel the signal current present thereat.