Fundus autofluorescence imaging in Best's vitelliform dystrophy.

Abstract

It is well known that with age lipofuscin accumulates in the retinal pigment epithelium (RPE). In many inherited macular dystrophies such as Best's disease abnormally high levels of lipofuscin were found by histopathological studies. In recent years, it has become possible to detect and image fundus autofluorescence in the living eye as an index of lipofuscin accumulation in the RPE. The aim of our study was to document the intrinsic fundus autofluorescence in patients with different stages of Best's disease and to correlate fundoscopic features with visual function in these patients. Images of fundus autofluorescence were obtained from 10 patients with Best's vitelliform dystrophy, using a Heidelberg Retina Angiograph (HRA). Argon laser light (488 nm) was used for illumination, and a wide-bandpass filter with a cutoff of 500 nm was inserted in front of the detector to obtain the autofluorescence images. Images were compared with fundus appearance and fluorescein angiograms as well as with visual acuity, colour vision, visual fields and electrophysiological recordings in these patients. In initial stages of Best's disease, there were localised areas of hyperfluorescence centrally in the fovea, later being replaced by central hypofluorescence (atrophic) areas surrounded by hyperfluorescent rings. The evolution of autofluorescence pattern showed centrifugal spreading of retinal dysfunction from the centre towards periphery. Atrophic regions of the RPE were associated with low levels of background autofluorescence, lower visual acuity, abnormal colour vision (70% of patients), central scotomas (85% of patients) and poorer electrophysiological results (reduced PERG responses in 45% of patients with Best's disease). Fundus autofluorescence imaging provides new information regarding the content and spatial distribution of RPE lipofuscin in eyes with Best's disease, which appears to correspond to retinal function. This may "in vivo" give important clues to the pathogenesis and progression of Best's disease in which non-invasive autofluorescence imaging may replace fluorescein angiography.