Retinal dose response from exposure to the supercontinuum generated by a near-infrared femtosecond laser

Ultrashort pulse lasers are currently used in a variety of applications, including laser eye surgery. The 2022 revision to the American National Standards Institute laser safety standards includes maximum permissible exposures for pulses as short as 100 femtoseconds at ultraviolet, visible, and infrared wavelengths. However, the ocular laser safety standards do not consider nonlinear optical effects resulting from the interaction of ocular tissues with femtosecond pulses. The generation of broadband white light, or supercontinuum, is one example of a nonlinear optical effect resulting from the interaction of a femtosecond pulse with water. We have demonstrated supercontinuum generation within the eye of anesthetized porcine subjects and reported the median effective dose for laser-induced in vivo retinal damage from the supercontinuum generated by single femtosecond pulses at central wavelengths of 1325 and 1350 nm. We used a single near-infrared femtosecond pulse to determine the pulse energies that generated a supercontinuum within the eye and resulted in retinal alterations. We are now in a position to report our result for 1375 nm and on the histological analysis of the injuries. The results of this study will inform the laser safety standards’ community about hazards to the eye due to the supercontinuum generated by nonlinear effects in the aqueous media of the eye.