Paper
2 March 2022 Femtosecond laser corneal damage thresholds at 1540 nm and 2000 nm
Author Affiliations +
Abstract
Recently, pulsed lasers with ultrashort pulse durations have become ubiquitous in a variety of applications, including medical procedures such as laser eye surgery. These sources are capable of generating extremely high peak powers that can cause laser-induced tissue breakdown upon exposure. However, current laser safety standards do not provide exposure limits for wavelengths longer than 1400 nm and pulse durations shorter than 1 ns due to a lack of biological data. Instead, the recommendation is to limit the peak irradiance to the maximum permissible exposure (MPE) limits applicable to 1 ns pulse durations. We applied femtosecond laser pulses of varying energies at 1540 nm and 2000 nm to corneas of anesthetized rabbits. We used slit lamp biomicroscopy and optical coherence tomography to examine the exposure sites and determine the presence or absence of visible lesions 1 h and 24 h post-exposure. The dose-response data correlating the presence or absence of any alteration of the corneal surface to the pulse energy 1 h post-exposure was evaluated using probit analysis to extract the median effective dose (ED50) corresponding to the cornea damage threshold. We compared our results to the MPE limits applicable to 1 ns pulse durations and determined that the current safety standard procedures are not adequate to evaluate small diameter single pulse femtosecond exposures at 1540 nm and 2000 nm. The results of this study contribute to the knowledge base used for setting laser safety standards in the near infrared range for ocular exposure to ultrashort pulses.
© (2022) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Xomalin G. Peralta, Joseph E. Clary, Amanda M. Peterson, Michelle A. Jefferson, Amanda J. Tijerina, Brian J. Lund, Wesley T. Kinerk, Francesco J. Echeverria, and Benjamin A. Rockwell "Femtosecond laser corneal damage thresholds at 1540 nm and 2000 nm", Proc. SPIE 11958, Optical Interactions with Tissue and Cells XXXIII; and Advanced Photonics in Urology, 1195807 (2 March 2022); https://doi.org/10.1117/12.2608295
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KEYWORDS
Cornea

Femtosecond phenomena

Near infrared

Laser damage threshold

Standards development

Laser safety

Eye

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