Near-infrared femtosecond laser damage thresholds in corneal animal model

In recent years, lasers with ultrashort pulse durations have become ubiquitous in a variety of applications, including medical procedures such as laser eye surgery. These sources can generate 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 with pulse durations shorter than 1 ns due to lack of carefully parameterized biological response data. In this study, an in vivo corneal animal model was exposed to femtosecond laser pulses of varying energies at 1318 nm, 1540 nm, and 2000 nm. Optical imaging examined the exposure sites and the presence or absence of a detectable alteration of the surface was noted. Probit analysis evaluated the dose-response data correlating the presence or absence of any alteration to the pulse energy to extract the median effective dose (ED₅₀). The results of this study will guide future in vivo experiments to establish cornea damage thresholds from near-infrared (NIR) lasers with femtosecond pulse durations and contribute to the knowledge base used for setting laser safety exposure limit standards in the NIR range for ocular exposure to ultrashort pulses (< 10 ps pulse duration).