Experimental Validation of Thermal Retinal Models of Damage from Laser Radiation

摘要

This research concerns the validation of a model for the mathematical prediction of laser-radiation thermal damage on the eye. The model developed by IITRI for the Air Force has four distinct steps: (1) The laser image at the retina is computed. (2) The amount of heat generated by absorption of light in the pigment epithelium, choriocapillaris, and choroid is computed. (3) This heat is used in the linear heat-conduction equation to calculate the laser-induced temperature rise in the eye. (4 ) The potential of damage for any point of the fundus is found with a sequence of first-order rate process equations which use the computed temperature-time histories. The University of Texas conducted a seris of dye cell and animal experiments for the purpose of validating the IITRI model. In the dye cell experiments, retinal absorption was modeled as a single homogeneous absorbing layer with known optical, thermal, and geometric parameters. In the second set of experiments we measured the retinal intensity profile, temperature rise, threshold power, and extent of damage as a function of wavelength, beam radius, intensity distribution, and exposure duration in the monkey eye. (Author)