Retinal damage mechanisms and safety for ultrashort laser exposure

Abstract

For the past several years the US Air Force has led a research effort to investigate the thresholds and mechanisms for retinal damage from ultrashort laser pulses [i.e. nanosecond (10-9 sec) to femtosecond (10-15 sec) pulse widths]. The goal was to expand the biological database into the ultrashort pulse regime and thus to allow establishment of maximum permissible exposure limits for these lasers. We review the progress made in determining trends in retial damage by ultrashort laser pulses in the visible and near infrared, including variations in spot size and number of pulses. We also discuss the most likely damage mechanisms operative in this pulse width regime and discuss relevance to laser safety.