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[Contact cyclophotocoagulation with the continuous wave Nd:YAG laser with quartz fiber. Optimizing coagulation
S Stolzenburg1, N Müller-Stolzenburg, S Kresse
1Universitäts-Augenklinik Steglitz FU Berlin.
Summary
Transscleral cyclo-photocoagulation using a continuous-wave neodymium-doped yttrium aluminum garnet (cw-Nd:YAG) laser was optimized in porcine eyes. Contact delivery via quartz fiber significantly reduced power needs for ciliary body coagulation.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Laser Physics
Context:
- Transscleral cyclo-photocoagulation is a therapeutic option for glaucoma.
- Optimizing laser parameters is crucial for efficacy and safety.
- Previous studies have explored various laser systems and delivery methods.
Purpose:
- To investigate the efficacy of transscleral cyclo-photocoagulation using a cw-Nd:YAG laser in enucleated porcine eyes.
- To compare contact versus non-contact laser delivery methods.
- To determine the optimal application time and power settings for ciliary body coagulation.
Summary:
- Contact delivery via a 600-micron core quartz fiber required 32% less power than non-contact delivery for ciliary body coagulation.
- Focusing fiber tips further reduced the coagulation threshold by a factor of 0.6.
- Energy required for coagulation increased with application time (10 ms to 1.5 s).
- Contact coagulation risks scleral damage due to carbonized tissue buildup.
- Optimal conditions (8 W at 0.2 s) were used in a pilot study on five glaucomatous eyes.
Impact:
- Provides data for optimizing cw-Nd:YAG laser parameters for transscleral cyclo-photocoagulation.
- Highlights the benefits of contact laser delivery for reduced power requirements.
- Identifies potential risks associated with carbonization and suggests mitigation strategies.
- Informs clinical application for secondary glaucoma treatment.