Method and apparatus for mapping a corneal contour and thickness profile
US6382794B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1999 |
| Grant date | May 7, 2002 |
| Priority date | — |
| Expiry date | Sep 27, 2019 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/107
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Method and apparatus is disclosed for mapping a corneal contour and thickness profile. In accordance with one aspect of the present invention, a set of narrow, collimated, parallel beams is projected onto a corneal surface at an angle with respect to a predetermined axis (“an instrument axis”) that is substantially aligned with a visual axis of an eye. The set of beams is rotated about the instrument axis. A CCD camera is disposed to view the cornea along the instrument axis. Traces of the rotating set of beams form a set of rings in images obtained by the CCD camera; wherein outer and inner edges of the rings correspond to intersections of the set of beams with anterior and posterior surfaces of the cornea, respectively. Next, a direct triangulation algorithm is used to determine spatial positions of data points along the outer edges of the rings, and these spatial positions are used to reconstruct the anterior surface profile of the cornea. Next, using the anterior surface profile of the cornea, a ray tracing triangulation algorithm is used to determine spatial positions of data points along the inner edges of the rings, and these spatial positions are used to reconst…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.