Type 1 Neurofibromatosis: Choroidal Involvement and Systemic Disease

Abstract

Purpose: : To study choroidal abnormalities frequency and distribution in patients with type 1 neurofibromatosis (NF1).

Methods: : We examined 112 eyes of 56 consecutive patients (mean age 28.2 ± 16.2 years, range 3-68) diagnosed with NF1 on the basis of stringent National Institutes of Health (NIH) criteria. Confocal scanning laser ophthalmoscopy (HRA II, Retinal Angiograph; Heidelberg Engineering, Heidelberg, Germany) with infrared monochromatic light - 820nm - (IR) was performed for each eye at posterior pole (30°) and at mid-periphery. Using the same instrument, we also captured posterior pole images with near-infrared autofluorescence - excitation 787 nm; emission >800 nm - (NIR AF). Analyzing the images, the fundus of each eye was divided into five regions (one within the vascular arcade and those supero-temporal, infero-temporal, supero-nasal, and infero-nasal to it). The presence of choroidal abnormalities in each region was evaluated and we investigated possible correlations with age and with NIH diagnostic criteria.

Results: : We found peculiar choroidal abnormalities in 43 subjects (77%). Choroidal involvement, when present, was always bilateral and it was more frequent in the region within the arcade (73% of the eyes) than in the other regions (58%, 60%, 49% and 43%, respectively). NIR AF images of good quality were obtained in 84 eyes of 42 patients. In these subjects, we observed a strict correspondence between high IR reflectance choroidal abnormalities and high autofluorescence areas showed by NIR AF. We found significant correlations between patients age and number of fundus regions with choroidal abnormalities (P<0.01, Spearman). No associations were found between choroidal involvement and any NIH criterium.

Conclusions: : NF1 choroidal involvement is frequent and easily detectable with a non invasive and quick procedure. Choroidal abnormalities diffusion tends to increase with age, starting from posterior pole. Peculiar IR detected choroidal alterations seem to be worth thorough study, to investigate their potential as a new NF1 diagnostic criterium.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • choroid • genetics