Fluorescein angiography with an optimized filter combination.

The transmission characteristics of a new filter combination for fluorescein angiography were selected on the basis of in vivo measurements of the excitation and emission spectra of fluorescein dye during its transit in the fundus. This combination of filters was characterized by separation of 530 nm between the spectral ranges of transmission of the excitation and barrier filters. In the standard filter combinations this separation is at about 495 nm. Compared to the standard filters, the new filters enhanced the film exposure for all sites of the fundus, especially for the macular area and choroidal fluorescence. There was an improvement in demonstration of the choroidal vasculature, especially in the macular area, and better visibility of retinal detail in the macular area, but a slight decrease in contrast of the retinal vessels outside the macular region. Improved visibility of the fundus for the observer and reduction of scattering in the ocular media of older subjects improved the overall quality of angiograms made with the new filters.