Retinal damage from femtosecond to nanosecond laser exposure

The 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 results suggest that nonlinear optical phenomena mitigate the eventual damage threshold of the retina, while the fundamental mechanisms for damage remain unchanged from 100 fs to 10 μs. The result of this research is a recommendation for the establishment of maximum permissible exposure limits in the visible and near infrared that reflect the results of the nonlinear interaction. We review the progress made in determining trends in retinal damage from laser pulses from one nanosecond to one hundred femtoseconds for visible and near-infrared wavelengths including variations in spot size and number of pulses. We discuss the most likely damage mechanisms, including nonlinear optical interactions pertinent in this pulse width regime and discuss relevance to laser safety.

Duke Scholars

Author Cynthia Ann Toth Ophthalmology, Vitreoretinal Diseases & Surgery