Contact lenses providing improved visual acuity
CA 2272940 C · Owner: Deryke, Kevin J. · Inventors: Cox, Ian G.; Biddle, Graham W.; Chapman, Judith E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for obtaining contact lenses having optimized visual acuity involves providing the anterior surface or the posterior surface of the contact lens with a conic section having a shape factor value within the range of about 0.3 to 2.0, the shape factor value being selected so as to adjust spherical aberration in the central optical zone to a value within the range of about - 0.2 diopter to about -0.6 diopter and to a value that provides optimal visual acuity.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed November 17, 1997 and granted December 23, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 17, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 17, 2019.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.