A Workflow to Quantitatively Determine Age-Related Macular Degeneration Lesion-Specific Variations in Fundus Autofluorescence

So far, quantitative autofluorescence or QAF, analysis was limited to prefabricated grids analyzing global autofluorescence of the posterior pole of the eye. Our protocol allows the measurement and comparison of autofluorescence intensities of specific regions of interest. QAF revealed reduced autofluorescence intensities in age-related macular degeneration.

As a matter of fact, this important finding contradicted the historical view of pathological lipofuscin accumulations in the AMD. Today, the clinical findings can nicely be confirmed by new histological data on the retinal pigment epithelium at the cellular level. The characteristic autofluorescence levels of the ocular fundus display strong regional differences.

There seems to be a strong relationship between autofluorescence and rod photoreceptor density. For an accurate comparison of autofluorescence, one needs to account for regional differences, which is challenging. We could show for the first time the typical AMD lesions like drusen show further reduced autofluorescence intensities in addition to the generally reduced autofluorescence levels in these patients.

We are currently focusing on spectral analysis of the emitted light from fluorophores from the retinal pigment epithelium in both in vivo and ex vivo settings. With this approach, we hope to get better information on the physiology and pathophysiology of photoreceptors and the retinal pigment epithelium in healthy and deceased eyes.