[In vivo fundus fluorescence measurements in patients with age related macular degeneration]

This study was performed to measure and characterize the intrinsic fluorescence of the ocular fundus in patients with age-related macular degeneration (AMD).

Fluorescence spectral measurements from discrete retinal locations were made using the fundus spectrophotometer with excitations at 470 and 510 nm. Two normal subjects and seven patients with different stages of AMD were investigated.

The spectral characteristics of fundus fluorescence are consistent with those of lipofuscin in the retinal pigment epithelium (RPE). The fluorescence spectrum is broad, with a maximum at about 620 nm. The shape and intensity of the fluorescence spectra are affected by age, site of measurement, pathology, ocular media absorption, and excitation wavelength. Spectra from areas with drusen reveal an additional fluorophore, with maximum around 560 nm, probably emanating from drusen and Bruch's membrane. Measurements in atrophic reveal a decrease of lipofuscin fluorescence and/or a contribution likely due to choroidal and sclera collagen fluorescence. Fluorescence from lipofuscin is more efficiently excited at 510 nm, whereas that of drusen and subretinal structures is relatively more efficient with 470 nm excitation, allowing for discrimination of various fluorophores.

The spectral characteristics of RPE lipofuscin could be identified and quantified in AMD patients. In addition, the spectra are affected by other fluorophores such as drusen and choroid contributions in atrophy. Fluorescence spectra measurements in AMD patients allow for discrimination of lipofuscin fluorescence, drusen fluorescence, and choroidal or scleral fluorescence. The non-invasive measurement of lipofuscin and drusen fluorescence in AMD may be helpful in monitoring the disease, understanding its evolution, and testing therapeutic concepts.