Method and system for canceling system retardance error in an ophthalmological polarimeter
US6704106B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 2002 |
| Grant date | Mar 9, 2004 |
| Priority date | — |
| Expiry date | Jul 13, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J4/04
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A polarimeter system that averages multiple retardance measurement samples to cancel the effects of system birefringence in the diagnostic path. The retardance measurement errors arising from system birefringence have a symmetry that repeats over each complete cycle of optical signal rotation cycle. This symmetry is such that averaging the four retardance measurements collected over one complete rotation cycle cancels the effects of system birefringence, leaving a mean retardance measurement free of residual polarization bias. Apparatus is provided for determining the birefringence, thickness, and fiber orientation of the nerve fiber layer at the fundus of the eye by measuring the polarization bias induced in a return beam of polarized light that is reflected at the ocular fundus from an incident beam of a known polarization state. A corneal polarization compensator cancels the birefringent effects of the cornea and other portions of the eye anterior to the fundus.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.