PURPOSE: A fundus video camera and a nonconfocal scanning laser ophthalmoscope (SLO) detect direct light and indirect light, whereas a confocal SLO detects mostly direct light. Differences in confocal and nonconfocal SLO images and fundus video camera images are most likely due to their different optical systems. These differences were examined in indocyanine green (ICG) angiograms of a choroidal nevus. METHODS: A confocal SLO, a nonconfocal SLO, and a high resolution digital fundus video camera were used to obtain ICG angiograms of pigmented choroidal nevi in 4 patients for 30 minutes following dye injection. RESULTS: All the angiograms showed a hypofluorescent region in the nevus until 10-14 minutes after dye injection, except in 1 patient in whom no hypofluorescent region was seen in an early confocal-SLO angiogram. From 20 minutes to 30 minutes postinjection, the hypofluorescent regions were still visible in all fundus video camera angiograms and nonconfocal SLO angiograms but not in confocal SLO angiograms. CONCLUSIONS: Early angiograms taken with the three angiography systems showed a similar appearance of the choroidal nevus. However, late ICG angiograms with a confocal SLO showed different images from those taken with a nonconfocal SLO or a fundus video camera. It is suggested that the angiography system and the aperture size of an SLO should be selected according to the aspect of the pigmented choroidal nevus that is of interest in late-phase ICG angiography.
PURPOSE: A fundus video camera and a nonconfocal scanning laser ophthalmoscope (SLO) detect direct light and indirect light, whereas a confocal SLO detects mostly direct light. Differences in confocal and nonconfocal SLO images and fundus video camera images are most likely due to their different optical systems. These differences were examined in indocyanine green (ICG) angiograms of a choroidal nevus. METHODS: A confocal SLO, a nonconfocal SLO, and a high resolution digital fundus video camera were used to obtain ICG angiograms of pigmented choroidal nevi in 4 patients for 30 minutes following dye injection. RESULTS: All the angiograms showed a hypofluorescent region in the nevus until 10-14 minutes after dye injection, except in 1 patient in whom no hypofluorescent region was seen in an early confocal-SLO angiogram. From 20 minutes to 30 minutes postinjection, the hypofluorescent regions were still visible in all fundus video camera angiograms and nonconfocal SLO angiograms but not in confocal SLO angiograms. CONCLUSIONS: Early angiograms taken with the three angiography systems showed a similar appearance of the choroidal nevus. However, late ICG angiograms with a confocal SLO showed different images from those taken with a nonconfocal SLO or a fundus video camera. It is suggested that the angiography system and the aperture size of an SLO should be selected according to the aspect of the pigmented choroidal nevus that is of interest in late-phase ICG angiography.
Authors: Kai Yuan Tey; Kelvin Teo; Anna C S Tan; Kavya Devarajan; Bingyao Tan; Jacqueline Tan; Leopold Schmetterer; Marcus Ang Journal: Eye Vis (Lond) Date: 2019-11-18