Early versus late staining of microaneurysms in fluorescein angiography.

PURPOSE: To analyze the appearance and disappearance of microaneurysms in different phases of fluorescein angiography.

METHODS: Three fluorescein angiograms were taken at 13-month intervals during a 26-month follow-up period from 13 patients with type I diabetes and mild background retinopathy. Two frames of the angiogram were analyzed: one from the transit phase and the other from the late phase of the angiogram. Individual microaneurysms were identified and localized from each frame using a computerized system for retrieval of the coordinates for each microaneurysm. Microaneurysms identified by their location then were analyzed in relation to the phase of the angiogram in which they were visualized and their disappearance during follow-up study.

RESULTS: Thirty-three percent of the microaneurysms were visualized only in the early phase, 31% in only the late phase, and 36% in both phases of the fluorescein angiogram. The microaneurysms frequently changed their phase of appearance in the angiogram during follow-up study.

CONCLUSION: During the 26-month follow-up period, between 55% and 80% of the microaneurysms present at baseline disappeared. The phase of the baseline angiogram in which the microaneurysms were visualized did not determine their disappearance rate.