Process and arrangement for examining a section of the eye

US6095648A · kind A · utility

Assignee

• Herbert Schwind GmbH & Co. KG · DE

Inventors

• Reginald Birngruber · Taufkirchen, DE
• Christian Scholz · Neustadt an der Weinstraße, DE
• Peter Koch · Wulfen, DE
• Ralf Engelhardt · Bodelshausen, DE

Key dates

• Filing date: Mar 8, 1999
• Grant date: Aug 1, 2000
• Expiry date: Mar 8, 2019

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61B3/1225
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

Systems, methods, and apparatus are provided for deriving the relative position of an eye by tracking a boundary of the eye such as the limbus (i.e., the interface between the white sclera and the colored iris). A technique for tracking the position of the eye of patient comprises directing light to an annular region of the eye between the sclera and the iris and receiving reflected light from that region. The intensity of the reflected light is then measured to determine a relative position of the eye. In some embodiments, the measured region is scanned around the boundary. In other embodiments, a light spot is scanned around a substantially annular trajectory radially outward from the pupil. The signals corresponding to the intensity of the reflected light are then processed and measured to determine the eye's position. A flap of tissue covering the boundary may be automatically detected so as to selectively measure the boundary away from the flap. The invention also provides for integrating the eye tracker into a laser eye surgery system.