gms | German Medical Science

The retinal pigment epithelium (RPE) plays a key role in the pathogenesis of numerous retinal diseases. With the advent of confocal scanning laser ophthalmoscopy (cSLO) it is now possible to record fundus autofluorescence in vivo, which mainly originates from RPE lipofuscin (LF). In postmitotic RPE cells LF granules accumulate as a common pathogenetic pathway with age and in association with various complex, degenerative diseases such as AMD as well as in monogenetic retinal diseases. LF in the lysosomal compartment is mainly a byproduct of constant phagocytosis of membranous disks shed from distal photoreceptor outer segments and generation of undegradable molecular species and aggregates by various factors including oxidative damage. Within the framework of the DFG Priority Research Program AMD and a prospective, multicenter study (FAM-Study - F undus A utofluorescence Age-related M acular Degeneration) variations in FAF in patients with AMD have been documented and various hypotheses regarding the role of LF accumulation in AMD have been tested. Classifications of heterogenous FAF phenotypes associated with manifestations of early (drusen) and late (geographic atrophy - GA) AMD have been brought forward and prognostic determinants have been identified. Increased FAF levels have been shown to result in impaired retinal sensitivity and to precede the development of GA. High-resoluotion FAF imaging now allows for delineation of individual RPE cells in vivo. FAF imaging is also useful in identifying suitable areas of noncompromised RPE prior to autologous RPE transplantation and demonstration of viable RPE following translocation. In hereditary retinal disorers including stargardt disease, retinitis pigmentosa, LCA and cone dystrophies FAF imaging revealed further insights in the metabolic state of the RPE and allows for more prescise phenotyping as well as for monitoring the natural history. FAF imaging not only improves our understanding of the pathophysiology of retinal diseases but it will also be helpful to monitor current and future therapeutic interventions.