Abstract
Purpose: :
488 nm fundus autofluorescence is mainly derived from lipofuscin in the RPE cells. Among others causes it can be attenuated by photoreceptor's pigment which can be reduced by retinal bleaching. There are some reports which descibe increased autofluorescence in areas of resolved long-lasting neurosensory retinal serous detachment (RLLSD) such as in choroidal neovascularization and central serous choroidopathy. The introduction of spectral domain OCT imaging (SD-OCT) allowed a side by side comparison between AF and SD-OCT. The purpose of this study was to better understand the origin of these increased AF.
Methods: :
Twenty consecutive eyes with choroidal neovascularization (ChNVM) (16) or central serous choroidopathy (CSC) (4) which showed an increased AF in RLLSD, were analyzed with a combined confocal scanning laser ophthalmoscope and a SD-OCT (Spectralis HRA - Heidelberg Engineering GmbH, Heidelberg, Germany) which allows to acquire simultaneous AF and OCT imaging. To measure photoreceptor's pigment we used AF, the optical and technical principles of which have been described previously (Staurenghi ARVO 2004). In particular for the dark adapted state, AF images were obtained after 20 minutes of dark adaptation and for the light adapted state, after 5 minutes of bleaching at 488 nm.Retinal pigment epithelium cells layer (RPE) was measured on SD-OCT images.
Results: :
AF images show in all dark adapted eyes a sharp demarcation between area of normal and increased AF which exactly correspond to the location of LLSD. Mean photoreceptor's pigment density in the area of normal AF was 0.117+/- 0.007 D.U in CSC and 0.097+/- 0.007 D.U in ChNVM, meanwhile in the area of increased AF was in all cases undetectable. After light bleaching the demarcation almost disappeared.SD-OCT images showed in all 30 eyes a loss of photoreceptor outer segments. Retinal pigment epithelium cells layer did not show any differences in the two areas.
Conclusions: :
These results demonstrated that increased AF in areas of LLSD is related to the loss of photoreceptor outer segments and not to an increase content of lipofuscin in the RPE cells.
Keywords: imaging/image analysis: clinical • retina • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)