Bioeffects of near-infrared lasers Available to Purchase

Retinal damage thresholds (ED₅₀s) were determined in Rhesus monkey eyes for 100 ms exposures to collimated radiation from a tunable Ti:Sapphire laser at several wavelengths from 690 nm to 900 nm. Prior research using 15 ns duration laser pulses showed a strong variability of ED₅₀ with wavelength for retinal exposure in Rhesus monkeys to laser radiation in the near infrared spectrum. Current studies with the Ti:Sapphire laser show similar variability of ED₅₀ with wavelength for 100 ms retinal exposures. Previously measured light transmission and absorption properties of ocular tissues do not provide a complete or obvious explanation for the significant variations of threshold with small changes in wavelength. Similar wavelength dependencies of ED₅₀ for the two exposure durations in the wavelength range of 750 nm to 830 nm suggest that linear absorption is a cause of the variability. However, differences in the ED₅₀ curves at other wavelengths show that nonlinear mechanisms also contribute.