Apparatus for dose measurement upon photocoagulation in the fundus of the eye

US4644948A · kind A · utility

Assignee

• Carl Zeiss Stiftung · DE

Inventors

• Walter Lang · Oberkochen, DE
• Gerhard Mueller · Freilassing, DE
• Eugen Weimer · Oberkochen, DE

Key dates

• Filing date: May 22, 1984
• Grant date: Feb 24, 1987
• Expiry date: May 22, 2004

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61F2009/00863
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

For determining the proper dose of therapy radiation for photocoagulation at the fundus of the eye, the fluorescent radiation excited by the therapy radiation (laser light) in the fundus of the eye is utilized. The fluorescence intensity passes through a characteristic minimum upon the termination of the coagulation process. Apparatus is disclosed for the detection by measurement of this effect. Optical beam splitters are provided to separate the fluorescent radiation from the therapy radiation. An electronically controlled shutter is provided for the passage and blocking off of the therapy radiation. The shutter is closed when the fluorescence intensity reaches a minimum after commencement of coagulation, or when the radiation reaches a predetermined amount, if this occurs before the fluorescence reaches its minimum.