Ablation of intraocular tissue with fiber-optic probe-delivered 266-nm and 213-nm laser energy.

摘要

PURPOSE: To explore the tissue ablation properties of pulsed 266-nm and 213-nm laser radiation in porcine retina and the potential for 213-nm laser radiation to cut through human trabecular meshwork. METHODS: Segments of porcine retinas were used, and localized areas of tissue were exposed to 266-nm or 213-nm laser. Human trabecular meshwork from donor eyes was also ablated using pulsed 213-nm laser. Ocular tissue was bathed in fluid to mimic the intraocular environment. Single or multiple pulses at various fluence levels were delivered with a tapered fiber-optic probe. The tissue was then fixed for histologic examination. Ablation depth and extent of damage were measured and related to fluence level and number of pulses applied. RESULTS: Ablation of the inner retina was achieved by single pulses at fluence levels of 0.6 J/cm(2) and higher with 266-nm laser radiation and 0.2 J/cm(2) and higher with 213-nm laser radiation. At the same fluence, ablation depth was greater (P < 0.001) with 213-nm than 266-nm laser, with less collateral damage. Ablation of human trabecular meshwork using 213-nm laser was highly dependent on fluence after exposure to single and multiple pulses, allowing good control of ablation depth. CONCLUSIONS: Laser radiation at 213 nm has greater ablation efficiency, less collateral damage, and a more linear dose-response than ablation at 266 nm. Precise removal of human trabecular meshwork was demonstrated using pulsed 213-nm laser radiation.