Real-time analysis keratometer
US4692003A · kind A · utility
Inventors
Key dates
| Filing date | Nov 7, 1983 |
| Grant date | Sep 8, 1987 |
| Priority date | — |
| Expiry date | Nov 7, 2003 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/107
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A computer assisted keratometer in which a fiducial line pattern reticle illuminated by CW or pulsed laser light is projected on a corneal surface through lenses, a prismoidal beamsplitter quarterwave plate, and objective optics. The reticle surface is curved as a conjugate of an ideal corneal curvature. The fiducial image reflected from the cornea undergoes a polarization shift through the quarterwave plate and beamsplitter whereby the projected and reflected beams are separated and directed orthogonally. The reflected beam fiducial pattern forms a moire pattern with a replica of the first recticle. This moire pattern contains transverse aberration due to differences in curvature between the cornea and the ideal corneal curvature. The moire pattern is analyzed in real time by computer which displays either the CW moire pattern or a pulsed mode analysis of the transverse aberration of the cornea under observation, in real time. With the eye focused on a plurality of fixation points in succession, a survey of the entire corneal topography is made and a contour map or three dimensional plot of the cornea can be made as a computer readout in addition to corneal radius and refractive p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.