Characteristics of RPE-autofluorescence in different lesions of the late age-related macular degeneration

Background Lipofuscin is the main fluorophore of the human fundus. Because lipofuscin is the result of the accumulation of metabolic debris in pigmentepithelial cells (RPE), the autofluorescence can be interpreted as a clinical sign for the metabolic activity of the RPE. In order to get informations of RPE-function in different types of late AMD, the autofluorescence patterns in patients with late AMD were analyzed. Material and method A prospective examination of the fundus-autofluorescence of 64 eyes of 52 patients with different types of late AMD was performed using a confocal scanning-laser-opthalmopscope. The autofluorescence images were categorized in respect to the type of late AMD according to the opthalmoscopic and fluoresceine-angiographic Results Reduced autofluorescence was found in the centre of occult (78.6%) and classic (100%) choroidal neovascularisations (NV) as well as in the occult NV of RPE detachments. A loss of autofluorescence was related to the RPE free area of RPE-tears (100%) and to RPE-atrophy (58.9%) with sometimes increased autofluorescence at the rim. Increased autofluorescence could be seen at the surface of RPE-detachments (71.4%), in the area of the shrink age of RPE in RPE-tears (100%) as well as at RPE-proliferations in small occult NV (100%). Disciforme scars showed variable patterns of autofluorescence. Conclusion The autofluorescence of the RPE can be analyzed clinically with the described method. Different patterns of autofluorescence could be revealed in different types of late AMD. Increased autofluorescence was found in lesions with proliferative or phagocytotic metabolic activity of the RPE like RPE-detachments, shrinked RPE in RPE-tears or occult NV with RPE-proliferations. The reduced autofluorescence in occult or classical choroidal NV can be interpreted as a sign of decompensation of the RPE and was also seen in areas with RPE-loss.