Аннотация:The noninvasive method of fundus autofluorescence (FAF) imaging is based on the autofluorescence of lipofuscin granules in retinal pigment epithelium (RPE) cells. Lipofuscin granules accumulate with age, especially in patients with visual diseases including progressive age-related macular degeneration (AMD). Bisretinoids and their photo-oxidation and photodegradation products represent the main sources of lipofuscin granule fluorescence. Investigations of the composition and spectral characteristics of lipofuscin granule fluorophores, as well as their contribution to fundus autofluorescence in normal eyes and in pathologic conditions, provide information on the clinical value of fundus autofluorescence imaging methods.
FAF images are usually obtained with a confocal scanning laser ophthalmoscope, but may also be obtained with a fundus camera. FAF is excited by a wavelength of 488 nm, yielding monochromatic images in the long-wavelength region, starting at 500 nm. Analysis of FAF patterns can provide detailed qualitative information that allows the detection of areas of pathology, thereby differentiating among different types of ocular disease. At present, however, it is not possible to quantify the detected changes. The degree of disease progression must be assessed subjectively by an expert, who compares patterns with those of normal eyes.
Our experimental data showed that the quantitative and qualitative composition of lipofuscin granule fluorophores changes during pathologic development. So there is a possibility to improve the fundus autofluorescence technique to obtain additional information from the total fluorescence patterns. Quantitative determination of increases in photo-oxidation and photodegradation products of bisretinoids in lipofuscin granules may be used to establish quantitative diagnostic criteria for degenerative processes in the retina and retinal pigment epithelium even in the absence of visible signs of disease.
The aim of this work is the determination of quantitative diagnostic criteria based on the spectral characteristics of fundus autofluorescence to detect early stages of degeneration in the retina and retinal pigment epithelium.