Diagnosis of model choroidal malignant melanoma by hematoporphyrin derivative fluorescence in rabbits.

A nonsurgical experimental system for detection of malignant tissue in the posterior ocular segment has been developed. A choroidal amelanotic malignant melanoma in rabbits served as a tumor model. Fluorescence of an hematoporphyrin derivative which is concentrated by malignant tissue was observed and measured simultaneously, using a modified binocular indirect ophthalmoscope. Clinical evaluation and the objective electro-optical measurement were subjected to histopathologic confirmation. Positive correlation of the results of the three different tests was found in 94 per cent of the 84 eyes examined. The problem of interfering lens flourescence was effectively eliminated by the optical design of the instrument. Localization of the suspected tumor is achieved by selective optical filtration. Toxicity to the hematoporphyrin derivative was absent.