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Vascular effects on ciliary tissue from endoscopic versus trans-scleral cyclophotocoagulation
  1. S C Lin1,
  2. M J Chen2,
  3. M S Lin1,
  4. E Howes1,
  5. R L Stamper1
  1. 1Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
  2. 2Department of Ophthalmology, Taipei Veterans General Hospital, National Yang-Ming University, Taiwan, Republic of China
  1. Correspondence to: Shan Chi Lin MD, Department of Ophthalmology, University of California, San Francisco, 10 Koret Way, San Francisco, CA 94143, USA; lins{at}vision.ucsf.edu

Abstract

Aim: To determine the acute and chronic vascular effects of endoscopic cyclophotocoagulation (ECP) versus trans-scleral cyclophotocoagulation (TCP) in a rabbit model.

Methods: 20 rabbits underwent ECP in one eye and another 20 rabbits had unilateral TCP. Five treated eyes from each group underwent endoscopic fluorescein angiography (EFA) of the treated ciliary processes at each of the following time points: immediate, 1 day, 1 week, and 1 month. Five untreated rabbits were used as controls. The NIH Image software program was used to trace ciliary processes in order to determine their mean intensity, as a measure of their perfusion. Histopathology was also performed on eyes from each time point.

Results: Immediately and 1 day after laser, both TCP and ECP eyes demonstrated severely reduced or non-existent blood flow in the areas of treatment. TCP treated processes essentially remained non-perfused at the 1 week and 1 month time points. ECP treated processes showed some reperfusion at 1 week and greater reperfusion by 1 month. Histopathology confirmed the overall greater vascular occlusion seen with TCP.

Conclusions: Chronic poor perfusion of the ciliary body after TCP may account, in part, for its efficacy, as well as the significant complications including hypotony and phthisis. Late reperfusion of this region after ECP may provide some insight into the differences in efficacy and complication rates compared to TCP.

  • ECP, endoscopic cyclophotocoagulation
  • EFA, endoscopic fluorescein angiography
  • IOP, intraocular pressure
  • TCP, trans-scleral cyclophotocoagulation
  • endoscopic cyclophotocoagulation
  • trans-scleral cyclophotocoagulation
  • glaucoma laser surgery
  • ciliary process histology
  • rabbit model
  • ECP, endoscopic cyclophotocoagulation
  • EFA, endoscopic fluorescein angiography
  • IOP, intraocular pressure
  • TCP, trans-scleral cyclophotocoagulation
  • endoscopic cyclophotocoagulation
  • trans-scleral cyclophotocoagulation
  • glaucoma laser surgery
  • ciliary process histology
  • rabbit model

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Footnotes

  • Grant support: That Man May See, Inc, San Francisco, CA; Research to Prevent Blindness, Los Angeles, CA, USA.

  • Competing interests: SL has received honoraria for speakerships for Medtronics, Inc.

  • The authors do not have a financial/proprietary interest in any of the devices, equipment, instruments, or drugs discussed in this article.

    The results of this study have been presented at the Association for Research in Vision and Ophthalmology (ARVO) meeting in Fort Lauderdale, FL, USA, May, 2002.

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