Femtosecond laser pulses in the near-Infrared produce visible lesions in the primate eye

Single pulses in the near-Infrared (1060 & 1064 nanometers) were used to measure ophthalmoscopically minimum visible lesion (MVL) thresholds in the rhesus monkey eyes for pulsewidths of 7 nanoseconds(ns), 20 picoseconds(ps), and 150 femtoseconds(fs). MVL thresholds for 1 hour reading and 24 hour reading are reported as the 50% probability for damage (ED50) together with their fiducial limits. These measured thresholds are compared with previously reported thresholds for near-IR and visible wavelengths for the complete range of pulsewidths(ns, ps, and fs). Threshold doses were lower at the 24 hour reading than at the 1 hour reading and both ED50 for the fs pulsewidths were less than 25% of those for ns pulsewidths. MVL thresholds ranged from 19 μJ at 7 ns down to 1 μJ at 150 fs. Thresholds measured for the nanosecond and picosecond pulsewidths using infrared laser pulses were an order of magnitude larger than for the visible wavelengths at similar pulsewidths while the 150 fs threshold was only about double the value for the 580 nm visible wavelength at 90 fs.

Duke Scholars

Author Cynthia Ann Toth Ophthalmology, Vitreoretinal Diseases & Surgery