gms | German Medical Science

Background: To investigate the potential of near-infrared autofluorescence (AF-787) imaging in assessing pathological changes in patients with retinal dystrophies.

Methods: 16 patients with Stargardt’s macular dystrophy (STGD), 8 patients with Best dystrophy (BD) and 7 patients with retinitis pigmentosa (RP) were included in this retrospective study. AF-787 images were obtained with an HRAc using the excitation wavelength of 787 nm and detecting fluorescence above 800 nm. For all subjects lipofuscin autofluorescence (AF-488) images, and digital color images were also recorded.

Results: The distribution of AF seen for AF-787 excitation does not correspond with the distribution of AF-488. Flecks of high AF-488 in STGD revealed low AF-787 properties in most cases. Single flecks at the periphery of the lesion also revealed high AF-787. Lack of correspondence in the distribution for the two AF types was also marked in BD. AF-787 is low at the site of high AF-488 accumulations of yellow lipofuscin-like material. High AF-787 is linked to areas of brownish material in the color image, often observed at the edge of the lesion. In RP, concentric contraction of the normal central bright area in AF-787 was observed. Later, the combined observation of perifoveal atrophy and preservation of central retinal structures lead to a ring-like configuration in both AF modalities. Characteristic bone spicules neither revealed high AF-488 nor high AF-787.

Conclusions: Melanin and/or melanolipofuscin in the RPE appear to be in large part responsible for the AF-787. Its distribution differs from that of lipofuscin particularly in degenerating RPE cells. The observation that extracellular deposition of melanin such as in cases of bone spicules in RP does not fluoresce in AF-787 and AF-488 requires further investigation. Long time observations will be necessary to determine the change of AF properties during the progression of the diseases.