In vivo fundus autofluorescence in macular dystrophies

Objective: To document the deviation from normal of fundus autofluorescence in patients with inherited macular dystrophies. Methods: The intensity and spatial distribution of fundus autofluorescence was documented in 118 patients with inherited macular dystrophies by means of a confocal laser scanning ophthalmoscope, and the images were compared with the fundus appearance and fluorescein angiograms. Results: Background autofluorescence appears to be elevated in all forms of macular dystrophies examined. The pale deposits at the level of the retinal pigment epithelium in disorders such as Best disease, adult vitelliform macular dystrophy, and fundus flavimaculatus were consistently associated with higher levels of autofluorescence than the background signal. There was no strong correlation between the intensity of autofluorescence and the fluorescein angiographic sign of a dark choroid. Increased levels of autofluorescence were present in a subject with a mutation known to cause macular dystrophy but in whom there were no manifest ophthalmoscopic or functional abnormalities. Conclusions: All dystrophies examined have in common accumulation of autofluorescent material in the retinal pigment epithelium to a greater degree than that seen with age. The abnormal high background autofluorescence associated with inherited macular dystrophies confirms the impression derived from histological studies that these disorders affect the entire retinal pigment epithelium. The lack of correlation between autofluorescence and the presence of a dark choroid implies that there may be different fluorophores in different disorders. The pale deposits at the level of the retinal pigment epithelium-Bruch membrane seen in macular dystrophies have similar autofluorescence characteristics. This technique may be useful in detecting the abnormal phenotype in early disease.