spOPG patients rarely had an intraorbital tumor (pathological optic nerve width in only 13/232 (6%) optic nerves; median 1.7 mm, IQR 1.55; 2.53 mm), whereas the optic nerves were commonly enlarged in NF1 + OPG patients (262/364 (72%) optic nerves; median 4.32 mm, IQR 2.97; 6.08 mm). The gene discussed is NF1; the disease is neoplasm.