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In vitro measurements of cytotoxic effects of 193 nm and 213 nm laser pulses at subablative fluences
Author(s) -
Ediger M. N.,
Pettit G. H.,
Matchette L. S.
Publication year - 1997
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/(sici)1096-9101(1997)21:1<88::aid-lsm13>3.0.co;2-5
Subject(s) - laser , photoablation , irradiation , excimer laser , chemistry , electron paramagnetic resonance , spectroscopy , wavelength , materials science , ultraviolet , optics , nuclear magnetic resonance , optoelectronics , physics , quantum mechanics , nuclear physics
Background and Objective The frequency‐quintupled q‐switched Nd:YAG laser is being studied as an alternative to the ArF excimer laser for photorefractive procedures. The present report describes two experiments comparing biologic effects of these laser devices. Study Design/Materials and Methods Bovine corneas were irradiated with subablative laser pulses in liquid nitrogen and analyzed by electron paramagnetic resonance spectroscopy to assess free radical production. Aqueous bacterial suspensions were irradiated with low‐intensity laser pulses and assayed for cell survival. Results Electron paramagnetic resonance spectra were very similar in both amplitude and shape for exposure at the two wavelengths. Bacterial survival was markedly less for 213 nm irradiation than 193 nm exposure and displayed a different dependence on cumulative exposure. Conclusion Free radical production by 213 nm laser exposure is quite comparable to that seen previously for 193 nm irradiation. However, cell lethality appears to be significantly greater at the longer ultraviolet wavelength. This difference may contribute to complications observed after corneal photoablation with the 213 nm device. Lasers Surg. Med. 21:88–93, 1997. © 1997 Wiley‐Liss, Inc.