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Proceedings Paper

Fiber-delivered mid-infrared (6-7 µm) laser ablation of retinal tissue under perfluorodecalin
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Paper Abstract

The Er:YAG laser (λ=2.94μm) is an effective tool in vitreo-retinal surgery. Pulsed mid-infrared (λ=6.45μm) radiation from the Free Electron Laser has been touted as a potentially superior cutting tool. To date, use of this laser has been limited to applications in an air environment. The goal of this study was: 1) determine feasibility of fiberoptic delivery of λ= 6.45μm using silverhalide fibers (d=700μm); 2) use infrared transparent vitreous substitute (perfluorodecalin) to allow non-contact ablation of the retina at λ= 6.45μm. Fiber damage threshold=7.8J/cm2 (0.54GW/cm2) while transmission loss=0.54dB/m, allowing supra-ablative radiant exposures to the target. FTIR measurements of perfluorodecalin at λ=6.45μm yielded μa=3 mm-1. Pump-probe imaging of ablation of a tissue-phantom through perfluorodecalin showed feasibility of non-contact ablation at λ=6.45μm. Ablation of the retinal membranes of enucleated pig eyes was carried out under perfluorodecalin (2 Hz, 1.3 J/cm2). Each eye was cut along its equator to expose the retina. Vitreous was replaced by perfluorodecalin and laser radiation was delivered to the retina via the silverhalide fiber. The eye was rotated (at 2 rpm) to create an ablation circle around the central axis of the retina. Histological analysis of the retina in a limited number of eyes shows that retina ablation using this method is feasible and can be accomplished with minimal collateral damage. Remote structures are shielded, as the radiation exposure falls below the ablation threshold owing non-negible absorption of perfluorodecalin at λ=6.45μm. This may optimize efficacy and safetly of laser-based vitreoretinal surgery.

Paper Details

Date Published: 14 July 2003
PDF: 9 pages
Proc. SPIE 4951, Ophthalmic Technologies XIII, (14 July 2003); doi: 10.1117/12.482369
Show Author Affiliations
Mark A. Mackanos, Vanderbilt Univ. (United States)
Karen Margaret Joos, Vanderbilt Univ. (United States)
E. Duco Jansen, Vanderbilt Univ. (United States)

Published in SPIE Proceedings Vol. 4951:
Ophthalmic Technologies XIII
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

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