Noninvasive Imaging and Monitoring of Retinal Pigment Epithelium Patterns Using Fundus Autofluorescence - Review

Abstract

Non-invasive imaging of the retinal pigment epithelium (RPE) using autofluorescence became recently available with the introduction of confocal laser scanning ophthalmoscopes. Fundus autofluorescence is usually excited at a wavelength of 488nm and the emitted light is detected above 500nm. This intrinsic autofluorescence was shown to derive from the lipofuscin accumulating within the RPE either with age or also due to different hereditary or degenerative diseases of the macula as e.g. age-related macular degeneration. Since a variety of macular diseases correlate with distinct RPE changes, specific patterns of autofluorescence could be evaluated within the recent years for diagnostic and prognostic reasons in those RPE-related diseases. Moreover autofluorescence can also be regarded as a monitoring tool after therapeutic applications as macular surgery or laser treatment. Other new applications try to determine macular pigment density using autofluorescence or use it to evaluate oxygen-dependent cell metabolism. This review summarizes the recent findings of autofluorescent patterns in specific diseases and therapeutic approaches and emphasizes on the tremendous potential of this novel imaging method.

Torpedo maculopathy

“…If the histology of our lesion simply consisted of loss of melanin granules in the RPE as previously suggested, the presence of lipofuscin within such depigmented RPE cells would be expected to result in a near-normal autofluorescence pattern. Lack of autofluorescence indicates a lack of all fluorophores and suggests a significantly abnormal and non-functional or absent RPE 20 24. While this cannot be proven at this time, future histopathological studies will be able to confirm this.…”

Unusual optical coherence tomography and fundus autofluorescence findings of eclipse retinopathy

“…Hyper-autofluorescence might be a sign of increased metabolism. [5] There should be self-repair in process and caused increased metabolism in this area.…”

Electrodiagnostic and two-wavelength fundus autofluorescence imaging investigations in acute idiopathic maculopathy

“…18,19]. Macular pigment occurs normally but can vary greatly in optical density at the fovea and parafovea [17,20] and if dense may confound interpretation of central FAF.…”