Near-infrared imaging: an in vivo, non-invasive diagnostic tool in neurofibromatosis type 1

Only a few reports in the literature have investigated the presence of ocular abnormalities in neurofibromatosis type 1 (NF-1) patients. The aim of this study was to evaluate the prevalence of ocular abnormalities in a large population of NF1 patients, focusing on the choroidal changes. This study was conducted on 160 consecutive patients with NF1 and 106 sex- and age-matched healthy subjects (control). Each patient underwent a complete ophthalmological examination inclusive of best-corrected visual acuity, intraocular pressure measurement, slit-lamp biomicroscopy, indirect fundus biomicroscopy, and near-infrared reflectance (NIR) retinography by using the spectral domain OCT. Moreover, all patients underwent complete dermatological exam and 1.5-Tesla MRI scan of the brain to assess the presence of optic nerve gliomas. Choroidal abnormalities were detected in 97% of patients, with a positive predictive value of 100% and a negative predictive value of 96.4%. Interestingly, a small number of patients (4/160; 2.5%) showed Lisch nodules without choroidal abnormalities, whereas a larger number of patents (22/160; 13.75%) presented choroidal lesions in absence of Lisch nodules. None of the patients showed the absence of both choroidal lesions and Lisch nodules. The number of choroidal lesions increased with age (r = 0.364, p = 0.0001) and with the severity of pathology (r = 0.23, p = 0.003). Any statistically significant correlation between choroidal lesions, visual acuity, and intraocular pressure was observed. NIR imaging represents an in vivo, non-invasive, sensitive and reproducible exam to detect choroidal nodules in NF-1 patients, suggesting that choroidal changes may represent an additional diagnostic criteria for NF1.