TIME-RESOLVED FLUORESCENCE SPECTROSCOPY OF THE RETINAL-PIGMENT EPITHELIUM - AGE-RELATED STUDIES

Time-resolved fluorescence spectroscopy shows promise as a high-sensitivity, high-discrimination tool for diagnostic purposes. In ophthalmology, the application of this technique to the study and the diagnosis of aging processes within ocular tissues is presently investigation. An age-related study of the pigments (melanin, lipofuscin, and melanolipofuscin) of the retinal pigment epithelium, performed using time-resolved fluorescence spectroscopy with picosecond gating, is herein presented. The study described in the present paper was performed on intact pigment granules, extracted with soft procedures, and the results have been correlated with the ultrastructure of the granules, and with results of continuous wave absorption and fluorescence spectroscopy. Both classes of pigments exhibit age-related fluorescence properties. These changes may be detected using continuous wave fluorescence spectroscopy techniques, but are greatly enhanced when gating techniques are used. Melanin, in particular, exhibits age-related spectral modifications which suggest a progressive accumulation of lipofuscinlike fluorophores in the granule. The implications of this paper in relation to the possibility of monitoring the fluorescence of these pigments in vivo are discussed.