Ultrashort Pulse Laser Effects in the Primate Eye.

Minimum visible lesion MVL threshold measurements at the retina for rhesus monkey eyes are reported for femtosecond, picosecond, and nanosecond single laser pulses using visible wavelengths. Estimates of the dose causing 50 probability for damage ED50 are calculated for 1-hour and 24-hours postexposure as well as the 95 fiducial intervals for ED. The ED values are found to be dependent on both wavelength and pulsewidth, and for a single wavelength are, in general, lower for short pulsewidths, with the exception of values at the shortest pulsewidth of 90 fs at 580 nm. At 90 fs the ED50 dosages were noted to increase slightly when compared with the 3-ps and 600-fs values, all three delivered at 580-nm wavelength. The 4-ns ED50 value was more than double the value at 60 ps delivered at 532-nm wavelength. Fluorescein angiography was accomplished at 1-hour and 24-hours postexposure and did not demonstrate lower threshold for damage, which has been the case for MVLs created with longer pulse duration greater than 1 ns or for rabbit eyes at the same pulse-widths as measured in our laboratory.