Prolate shaped corneal reshaping
US6610048B1 · kind B1 · utility
Inventors
Key dates
| Filing date | Oct 5, 2000 |
| Grant date | Aug 26, 2003 |
| Priority date | — |
| Expiry date | May 25, 2021 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61F2009/00882
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Apparatus and techniques for performing prolate shaped corneal reshaping. In accordance with the techniques, an ablation scanning laser system includes fitter modules to fit input refractive or topographical measurement data to a three (3) variable ellipsoid model. This provides pre- and post-operative approximations of a cornea. A desired prolate shaped ablation profile is determined based on a desired prolate ellipsoidal shape. In accordance with the principles of the present invention, the spheroequivalent ellipsoid model has only three degrees of freedom (not four as in a conventional biconic technique) to define a desired ablation profile, providing extremely accurate and predictable long term vision correction. To arrive at an ellipsoid model having only three numbers of freedom, a spheroequivalent (SEQ) value of asphericity QSEQ is generated. The spheroequivalent eccentricity QSEQ value replaces two degrees of freedom (i.e., eccentricities) in an otherwise conventional biconic modeling system, leaving only three (3) variables to determine for a best fit ellipsoid to a corneal surface, to make accurate prolate ellipsoidal modeling of a cornea possible, and to limit results to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.