Instrumentation for feedback-controlled retinal photocoagualation

Steven F. Barrett, Maya R. Jerath, Henry G. Rylander, Ashley J. Welch

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

10 Scopus citations


Laser induced retinal lesions are used to treat a variety of eye diseases. The size and location of these retinal lesions are critical for effective treatment and minimal complications. An automated system is under development for retinal photocoagulation to improve the accuracy of this treatment. Separate instrumentation systems have been developed to monitor and control lesion growth in real time to compensate for tissue inhomogeneity, and to track and compensate for retinal movement during irradiation. A real time lesion feedback control system is implemented on a UNIX based workstation. A CCD camera (30 frames/second) and coagulating laser are coaxially aligned such that images of the lesion can be acquired during laser irradiation. Parameters of these reflectance images are extracted by an image processor in real time and when certain preset thresholds are exceeded, the laser is shut off. The camera and laser legs are alternately shuttered during irradiation by a high speed spinning wheel to prevent the reflected light from the laser from interfering with the reflectance signal. This system is coupled to a fundus camera for delivery to the eye.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsDavid M. Harris, Carl M. Penney, Abraham Katzir
PublisherPubl by Society of Photo-Optical Instrumentation Engineers
Number of pages10
ISBN (Print)0819411191
StatePublished - Dec 1 1993
EventMedical Lasers and Systems II - Los Angeles, CA, USA
Duration: Jan 17 1993Jan 22 1993

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceMedical Lasers and Systems II
CityLos Angeles, CA, USA


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