You are not logged in to this journal. Log in

Retinal lesions produced with a pulsed laser beam of 1-20 kHz frequency and 10-100% duty cycle were comparedwith lesions produced with a continuous wave (cw) laser of the same peak power and total energy. Photocoagulation wasapplied to the retina of three black pigmented rabbits using krypton red laser (647.1 nm) equipped with an acousto-opticalmodulator to convert cw laser emission to a pulsating beam. An optical fiber fed the laser beam into an optical systemdelivering a collimated beam of predetermined divergence; the animal's eye focused this beam to a 50-pm spot on the retina.Peak power was kept constant at 0.2 W, and energy was kept constant at 20 mJ. After 7 months the animals were sacrificedand retinal tissue examined by light microscopy. The central section of each lesion was identified and photographed. Forlesions with the same energy per pulse and the same pulse duration, the most influential factor, in the frequency range of 1-20kHz, appeared to be the duty cycle: the smaller the duty cycle, the smaller the lesion, and vice versa. In other words, theshorter the time interval between consecutive pulses, the larger were the pulsed laser lesions.

©2005 COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.