Keratometric illumination system
US5825457A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 1997 |
| Grant date | Oct 20, 1998 |
| Priority date | — |
| Expiry date | Jun 2, 2017 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/107
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A keratometer includes illuminating optics centered along a common measurement axis in alignment with a patient's cornea and with area detection means of the keratometer. A conical reflector is positioned with its apex facing a source of collimated light, such that light incident upon the conical reflector is divided into rays expanding radially outward from the measurement axis. A frusto-conical reflector surrounds the conical reflector to receive the radially expanding rays and redirect them along the measurement axis as an annulus of light large enough to pass around the area detector to a mire ring occluder and refractor which pass a refined converging annulus of light to the cornea.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.