Optic nerve glioma is an entity found almost exclusively in children with a typical age of diagnosis between two and six years old. Optic glioma are generally well differentiated, low-grade astrocytomas which may infiltrate along the optic tracts or nerves. The majority of optic gliomas are found in patients with neurofibromatosis, Type I. Bilateral optic gliomas are virtually pathognomonic for neurofibromatosis, Type I. Computed tomography will demonstrate a well-delineated fusiform enlargement of the optic nerve. A normal optic nerve should not exceed 5 mm in children and 7 mm in adults. MR imaging generally demonstrates the lesion to be isointense on T1 weighted images while usually being hyperintense on T2 weighted images.
Enhancement is variable, but usually moderate to marked.
Clinical Magnetic Resonance Imaging .