Ophthalmic instrument having Hartmann wavefront sensor with extended source
US6595642B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 31, 2001 |
| Grant date | Jul 22, 2003 |
| Priority date | — |
| Expiry date | Aug 31, 2021 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/103
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An improved ophthalmic instrument including an extended source producing light that is formed as an image on the retina of the human eye and reflected there from to produce retinal reflections derived from the extended source, and a wavefront sensor that estimates aberrations in the retinal reflections. The wavefront sensor includes a plurality of subapertures that form a plurality of images of the extended source from the retinal reflections, an imaging device that captures the plurality of images and outputs image data representing the images, and an image processing computer that generates an estimate of the gradient field of the retinal reflections by applying image correlation techniques in the digital domain to the image data. The image processing computer preferably generates an estimate of the local tilt of the retinal reflections incident on a given subaperture by deriving a correlation product for a given image formed by the given subaperture and identifying a peak correlation point of the correlation product. The dimensions of the image of the extended source formed on the retina of the human eye is preferably larger than a diffraction limited spot yet small enough so th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.