Quantification and anatomic distribution of choroidal abnormalities in patients with type I neurofibromatosis

Background: Choroidal abnormality manifesting as a bright patchy lesion under infrared monochromatic light has previously been described in neurofibromatosis type I patients in whom the choroid appears normal under conventional ophthalmoscopic examination or on the fluorescein angiogram. We investigated the correlation between patient age and the number of choroidal abnormalities, as well as the anatomic distribution of choroidal abnormalities in the fundus. Methods: We examined the fundus of 28 eyes in 14 patients with neurofibromatosis type I. Patients ranged in age from 2 to 38 years and were examined between April 2001 and April 2002 by confocal scanning laser ophthalmoscopy with infrared monochromatic light (780 nm wavelength). We divided the fundus into five regions (one within the retinal vascular arcade and those supero-temporal, infero-temporal, supero-nasal, and infero-nasal to it), and lesions on the border between regions were assigned to the region containing the greater part of the lesion. We studied the total number of choroidal abnormalities and the correlation between the total number and age. Results: A positive correlation was found between the total number of choroidal abnormalities and age (Spearman rank correlation coefficient, r=0.6209, P=0.0178). There was a significantly greater number of choroidal abnormalities in the arcade region than in the other four regions (ANOVA, P < 0.001). Conclusions: Choroidal abnormalities tend to increase with age and are most often observed within the vascular arcade.