Retinal Injuries From Single and Multiple Picosecond Laser Pulses
Abstract
We investigate laser-induced shock waves from melanin particles as a possible cause of retinal injury from ultrashort pulse laser exposures. Melanin granules were isolated from calf retina and suspended in gels. The melanin particles were irradiated with 100 psec laser pulses from an amplified, mode- locked Nd:YAG laser and shock waves were observed under a microscope using a time-delayed strobe pulse. Spherical shock fronts were observed at incident laser fluences 4J/sq cm and were imaged as close as 20 micrometers from the melanin particles. Multiple shock fronts were resolved when several melanin particles were irradiated simultaneously. Shock front radii were measured as a function of photographic delay time and laser fluence. Average shock from velocities during the first 10 nsec ranged from 2500 to 4000 m/sec. A velocity of 3000 m/sec corresponds to a shock pressure of 11 kbars. These results indicate that shock wave emission from melanin particles in the retinal pigment epithelium is a potential cause of retinal injury from ultrashort laser pulses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 1994
- Accession Number
- ADA284173
Entities
People
- Carmen A. Puliafito