Ultrashort laser pulse bioeffects and safety

Recent studies of retinal damage due to ultrashort laser pulses have shown that less energy is required for retinal damage for pulses shorter than 1 n s than that for longer pulses. It has also been shown that more energy is r equired for near-infrared (NIR) wavelengths than in the visible because the light focuses behind the retina, requiring more energy to produce a damagi ng fluence on the retina. We review the progress made in determining the tr ends in retinal damage from laser pulses of 1 ns to 100 fs in the visible a nd NIR wavelength regimes. We have determined the most likely damage mechan ism(s) operative in this pulse width regime. (C) 1999 Laser Institute of Am erica.