Optic glioma
A benign tumor on an optic nerve or the optic chiasm (the crossing of the two optic nerves).
Optic gliomas are derived from glial cells and are classified as low-grade astrocytomas.
They cause symptoms both by pressure and by destruction of normal optic nerve tissue.
They may result in proptosis (protrusion of the eye) and progressive loss of vision.
Optic gliomas are associated with neurofibromatosis (NF1)