ИСТИНА

The noninvasive method of fundus autofluorescence 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. Comparative analysis of fluorescence spectra of RPE cell suspensions from cadavers with normal eyes and those with AMD showed a significant difference in fluorescence intensity at 530–580 nm in response to fluorescence excitation at 488 nm. The fluorescence intensity was notably higher in eyes with visual pathology than in normal eyes regardless of the age of the eye donor. The increase in fluorescence intensity is a consequence of the increase in the content of bisretinoid photo-oxidation and photodegradation products in RPE of pathological eye compared to the norm. Because these bisretinoid products are markers of photodestructive processes, which can cause RPE cell death and initiate degenerative processes in the retina, quantitative determination of increases in bisretinoid photo-oxidation and photodegradation products in lipofuscin granules may be used to establish quantitative diagnostic criteria for degenerative processes in the retina and RPE, even in the absence of visible signs of disease.