Optic nerves are the second pair of cranial nerves and are unique as they represent an extension of the central nervous system and, hence, are myelinated by oligodendrocytes.
They are the connection between eyes and brain, i.e. they relay visual impulses from retina to brain. Hence, most often, optic nerve abnormalities are associated with brain abnormalities.
A wide variety of benign and malignant conditions may affect the optic nerve resulting in optic neuropathy. Clinical and laboratory findings alone do not always allow to correctly localize a lesion along the course of the optic nerve, nor is it possible to precisely identify the underlying cause. Therefore, optic neuropathy has become a common indication for imaging.
This article provides an overview of the imaging findings of diseases affecting the optic nerve with special emphasis on clinical-radiological correlation and on the latest technical developments in MR imaging deals with tumors, toxic/nutritional and degenerative entities, inflammatory and infectious diseases, compressive neuropathy and vascular conditions involving the optic nerve from its ocular segment to the chiasm.