Clinicopathologic study of organic dye. Laser in the human fundus

One day before enucleation for choroidal melanoma, four patients consented to experimental laser photocoagulation for the purpose of comparing the histopathologic appearance of acute chorioretinal lesions produced by various dye laser wavelengths with krypton red and argon green laser controls. Three patients had simulated "light" and "heavy" treatment of an extrafoveal choroidal neovascular membrane (CNVM) with wavelengths 577 nm (yellow), 595 nm (orange), and 600 nm (orange). One patient had simulated panretinal photocoagulation (PRP) with four different dye laser wavelengths. Extrafoveal "light" treatment with the three dye wavelengths and both controls spared the inner retina and produced similar effects in the outer retina, pigment epithelium, and choriocapillaris. Choroidal penetration was deepest with the longer wavelengths (590-647 nm) in both "light" and "heavy" treatment groups. "Heavy" treatment gave varying degrees of full-thickness retinal uptake for all dye and both control wavelengths. Both ends of the orange spectrum (590-600 nm) produced the most severe inner retinal uptake. Panretinal photocoagulation produced similar full-thickness retinal uptake for all four dye wavelengths tested. These results indicate that caution should be used when treating "heavily" with 590 and 600 nm in the extrafoveal area.