[Confocal scanning laser indocyanine green angiography with the Heidelberg retinal angiograph]

Indocyanine-green angiography (ICG) has been shown to be a valuable adjunctive technique to fluorescein angiography including further delineation of choroidal neovascularization in age-related macular degeneration. We report on initial clinical experiences with a newly developed infrared confocal scanning laser ophthalmoscope.

Fundus and fluorescein angiography photographs were obtained in 20 patients with various fundus changes. Confocal laser scanning ICG-angiography using the Heidelberg Retina Angiograph (Heidelberg Engineering GmbH, Germany) was performed after injection of 25 mg ICG. The confocal principle ensures that only light reflected from a defined focal plane is detected by the integrated photomultiplier. Excitation wave-length was 795 nm, and emission was recorded above 810 nm. About 60% of the emission is detected. An additional built-in diode laser (830 nm) allowed fundus visualization prior to dye injection.

ICG angiography using the scanning laser angiograph showed typical findings as previously reported with other systems. The images were characterized by high contrast. In addition, the retinal vessels were readily visualized in the late phase. By means of the confocal mode different layers of the circulation could be visualized.

The findings indicate that the confocal scanning angiograph is a useful alternative tool for ICG angiography and that it offers similar information obtained by other imaging systems. Advantages compared with previous techniques may include high image contrast, visualization of retinal vessels in the late phase, lower amount of light exposure, direct digital image acquisition and easy practical operation.