Clinical application of digital indocyanine green angiography in choroidal neurofibromatosis

Indocyanine green angiography (ICGA) was used to investigate 2 cases of type 1 systemic neurofibromatosis that had appeared at birth with cafe-au-lait skin spots, gradually developing into multiple cutaneous neurofibromas. Patients underwent periodical visual acuity examinations, the fundus was checked and fluorescein angiography (FA) was done; all findings appeared extremely stable. In 1995 these 2 patients underwent ICGA to check for pathological choroidal involvement. In both cases the initial examination stages showed multiple extensive areas of hypofluorescence, their morphology and extension coinciding with the retinal pigment epithelium (RPE) lesions shown by FA and by ophthalmoscopic examination. In later stages the hypofluorescent areas became smaller, generally shrinking to small isolated dots in the middle of the original areas. These initially hypofluorescent areas appeared to be due to slow focal choroidal filling caused by deep alterations to the walls of the choroidal arterioles induced by the disease. Chronic hypoperfusion of the choriocapillaris results in impairment of the overlying RPE, causing it to atrophy. The late hypofluorescent areas could be either persistent nonperfused lobules of choriocapillaris or neurofibromatose choroidal nodules. ICGA examination showed that the FA lesions described in the literature as choroidal nodules are in fact alterations to the RPE secondary to areas of hypoperfusion in the choriocapillaris.