Fluorescein angiography is one of the most commonly used diagnostic techniques in modern ophthalmology. Prior to this study, recommendations on the phototoxicity of this technique were based on light levels alone (i.e., without fluorescein present). Using a rabbit model to demonstrate retinal damage, intravenous sodium fluorescein was found to reduce the amount of blue light needed to cause a phototoxic retinal lesion almost a log unit (from 1.6 to 0.2 W/cm(2)). Intravenous fluorescein also reduced the threshold for light damage to iris and cornea in the rabbit. The results suggest that blue light exposure should be minimized when sodium fluorescein is present in ocular tissue.