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Proceedings Paper

Reflectance feedback control of photocoagulation in vivo
Author(s): Maya Ratna Jerath; Ravi K. Chundru; Steven F. Barrett; Henry Grady Rylander; Ashley J. Welch
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Paper Abstract

Laser induced retinal lesions are used to treat a variety of eye diseases such as diabetic retinopathy and retinal detachment. In this treatment, an argon laser beam is directed into the eye through the pupil onto the fundus where the heat resulting from the absorbed laser light coagulates the retinal tissue. This thermally damaged region is highly scattering and appears as a white disk. The size of the retinal lesions is critical for effective treatment and minimal complications. A real time feedback control system is implemented that monitors lesion growth using two-dimensional reflectance images acquired by a CCD camera. The camera views the lesion formation on axis with the coagulating laser beam. The reflectance images are acquired and processed as the lesion forms. When parameters of the reflectance images that are correlated to lesion dimensions meet certain preset thresholds, the laser is shuttered. Results of feedback controlled lesions formed in vivo in pigmented rabbits are presented. An ability to produce uniform lesions despite variation in the tissue absorption or changes in laser power is demonstrated. This lesion control system forms part of a larger automated system for retinal photocoagulation.

Paper Details

Date Published: 24 June 1993
PDF: 8 pages
Proc. SPIE 1877, Ophthalmic Technologies III, (24 June 1993); doi: 10.1117/12.147537
Show Author Affiliations
Maya Ratna Jerath, Wellman Labs. of Photomedicine (United States)
Ravi K. Chundru, Univ. of Texas/Austin (United States)
Steven F. Barrett, Univ. of Texas/Austin (United States)
Henry Grady Rylander, Univ. of Texas/Austin (United States)
Ashley J. Welch, Univ. of Texas/Austin (United States)

Published in SPIE Proceedings Vol. 1877:
Ophthalmic Technologies III
Jean-Marie A. Parel; Qiushi Ren, Editor(s)

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