Autofluorescence distribution associated with drusen in age-related macular degeneration

PURPOSE. TO determine whether drusen in patients with age-related maculopat hy and macular degeneration (ARM/AMD) are associated with focal changes in retinal pigment epithelium (RPE) lipofuscin fluorescence. METHODS. A new autofluorescence imaging device was used to study lipofuscin distribution associated with individual drusen in 20 patients with ARM/AMD . Paired monochromatic and autofluorescence fundus images were used for der ailed analysis of the topography of autofluorescence at specific sites cont aining drusen. In four eyes, image analysis was used to compare the spatial distribution of the autofluorescence with the location of drusen and to qu antify the autofluorescence distribution over individual drusen (54 drusen) . RESULTS. A specific pattern of autofluorescence was frequently found to be spatially associated with hard drusen and soft drusen between 60 and 175 mu m in size. The pattern is characterized by a central area of decreased aut ofluorescence surrounded, in most cases, by an annulus of increased autoflu orescence. The location of this pattern was highly correlated with the posi tion of individual distinct drusen. The central low autofluorescence focus was on average 16% below the surrounding background, and the annulus, when present, was on average 6% more fluorescent than the background. Soft druse n larger than 175 mu m and confluent soft drusen show either multifocal are as of low autofluorescence or a more heterogeneous distribution. CONCLUSIONS. Autofluorescence imaging permits measurement of RPE lipofusein at specific sites. RPE overlying drusen hale altered autofluorescence, sug gesting changes in RPE health.