Retinal Vascular Abnormalities related to Neurofibromatosis Type 1: Natural History and Classification by OCT Angiography in 473 Patients.

PURPOSE To analyze and classify neurofibromatosis type 1 (NF1) related retinal vascular abnormalities (RVAs), their natural history and correlation with disease severity, in a large cohort of patients. METHODS This was an observational longitudinal study with prospective enrollment. Four hundred and seventy-three patients affected by NF1 and 150 age-matched healthy subjects were consecutively enrolled. RVAs were detected by means of near-infrared reflectance and studied by optical coherence tomography angiography (OCTA). The superficial vascular plexus (SVP) and the deep vascular complex (DVC) were quantitatively and qualitatively analyzed. RESULTS We identified RVAs in 82 of 473 (17%) NF1 patients, but in none of the 150 healthy subjects. A comparison revealed that NF1 patients with RVAs showed a higher number of NF1 diagnostic criteria (4.3 ± 1.5 versus 3.9 ±1.5, respectively; p=0.02) than patients without RVAs. Three different RVA types were identified on OCTA: macrovascular angiomatosis of the sole SVP; macrovascular angiomatosis of the SVP combined with microvascular angiomatosis of the DVC; and combined macrovascular angiomatosis of both SVP and DVC. The prospective analysis of OCTA images showed no significant longitudinal evolution of RVAs (mean follow-up: 3.7 ± 2.8 years). A single patient developed de novo a single RVA, and two RVAs showed detectable changes during follow-up. CONCLUSION In NF1 patients RVAs are a characteristic sign that correlates with a more severe systemic disease expression, usually remaining stable during time. OCTA allows for the identification of different RVAs subtypes.