Photoinduction of fluorophores in the retina using a 514-nm argon ion laser.

The purpose of the present study was to elucidate the origin and spectrum of the yellow-orange fluorescence observed during standard argon-ion laser irradiation of the eye. The possibility that the fluorophores were induced by the laser was investigated. The 514.5-nm line of an argon ion laser was used to induce thermal coagulation on frozen sections of human and rabbit eyes. Specifically, the spectrum and retinal site of the fluorescence were analyzed. The fluorescence was measured with a microspectrofluorometer apparatus. The excitation wavelength was 514 nm. At the level of the retinal pigment epithelium (RPE) and choroid a fluorescence was induced that had an emission spectrum that was comparable with that of lipofuscin yet was far more intense. The fluorophores are induced by laser irradiation. Further research to identify the fluorophores and determine their biological behavior is necessary.