In vitro measurements of cytotoxic effects of 193 nm and 213 nm laser pulses at subablative fluences

✍ Scribed by Ediger, M. N.; Pettit, G. H.; Matchette, L. S.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 72 KB
• Volume: 21
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/(sici)1096-9101(1997)21:1<88::aid-lsm13>3.0.co;2-5

✦ Synopsis

Background and Objective:

The frequency-quintupled qswitched 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.