The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 22, 1994
Filed:
Apr. 12, 1991
Michael H Freeman, Denbigh, GB;
Pilkington Diffractive Lenses Limited, St. Helens, GB;
Abstract
A method of correcting or alleviating presbyopia in humans comprising (a) fitting a first contact lens to a first eye, and (b) fitting a second contact lens to the other eye. Each of the lenses has a first power provided by the shape, curvature and material of the lens to provide a refractive corrected image and a second power provided by diffractive means to provide a second corrected image, the second power being additive to (or subtracted from) the first power. The lenses are fitted so that one has a refractive near image optical power and the other has a refractive distance image optical power, and the diffractive means of the lenses are arranged so that the amount of the light directed into the near image by one lens is substantially greater than that directed into the far image by that lens, and the amount of light directed into the far image by the other lens is substantially greater than that directed into the near image by that other lens. In this way the wearer sees an image of relatively high intensity and retains a large amount of stereoscopic vision.