Revisiting laser exposure guidelines to prevent retinal damage

In 2022, the American National Standards Institute (ANSI) updated its safety criteria for short laser pulses, relaxing the maximum permissible exposure (MPE) guidelines for wavelengths between 1200 and 1400 nanometers. In response to these changes, Peralta et al. measured the retinal damage lasers within these relaxed parameters can cause in Yucatan mini pigs to determine whether the new safety standards are sufficient.

Author Emily Boice describes a pig’s eye as a “heavy-duty blueprint of the human eye.” They come in similar sizes and follow similar compositions of blood vessels and retinas consisting of rods and cones.

But despite their increased durability, the researchers found the pig retinas could not properly withstand the ANSI MPE guidelines: Single, 100-femtosecond laser pulses of wavelengths above 1300 nanometers caused retinal lesions that appeared as small spots in the eye.

“Because the swine retina is less sensitive to laser damage than a human’s, any safety threshold based on a pig model will likely underestimate human risk,” Boice said.

Based on their findings, the researchers hope the ANSI will modify its MPE standards for lasers with wavelengths between 1300 and 1400 nanometers and pulse durations less than 10 picoseconds. These types of advanced laser systems are commercially available but not widely mass-produced like less complex lasers. However, they are used in micromachining, medical imaging, surgery procedures, scientific research, and more — so exposure guidelines affect a wide range of safety protocols.

“Our hope is that this recommendation will be adopted by the standards committee and implemented swiftly in the next revision,” Boice said. “By proactively updating these safety guidelines, laser safety officers and researchers will have the correct information to implement appropriate safety controls — such as using the right protective eyewear and proper enclosures — and support the continued safe use of these powerful and valuable laser systems.”

Source: “Retinal damage thresholds from exposure to nonlinear optical effects generated within the eye by a single near-infrared femtosecond pulse,” by Xomalin G. Peralta, Joseph E. Clary, Amanda M. Peterson, Amanda J. Tijerina, Francesco J. Echeverria, Robert Aldrich, Clifton D. Clark, Benjamin A. Rockwell, and Emily N. Boice, Journal of Laser Applications (2026). The article can be accessed at https://doi.org/10.2351/7.0002157 .