There are several eye diseases that cause death of RGCs in the retina and degeneration of the optic nerve.  The most common of these “optic neuropathies” is glaucoma, which affects more than 100 million people worldwide. Glaucoma is caused by eye pressure that is too high for a given patient, and treatments for glaucoma work by lowering the eye pressure which can help prevent further vision loss if it is detected early.  Ischemic optic neuropathy is caused by a blockage in the blood supply to the optic nerve, and is similar to having a stroke in the nerve. Optic neuritis is inflammation of the nerve and can be caused by systemic autoimmune diseases such a multiple sclerosis or neuromyelitis optica, or it can occur in isolation. Infiltrative optic neuropathy causes nerve damage when the body’s immune cells, cancer cells, or infections grow into the nerve and destroy its tissue, as can occur in sarcoidosis, leukemia, metastatic and other cancers, tuberculosis, cryptococcus, and toxoplasmosis. Compressive optic neuropathy is caused by tumors that push on the nerve and damage its fibers, and can be caused by meningioma, pituitary adenoma, optic pathway glioma, and other tumors. Traumatic optic neuropathy can occur following severe head injury. Inherited optic neuropathies include neurodegenerative diseases due to inherited mutations in patient’s DNA that lead to progressive RGC death over time, and include Leber’s optic neuropathy and autosomal dominant optic atrophy.  Toxic and nutritional optic neuropathies can be caused by methanol or antifreeze poisoning, adverse reactions to certain antibiotics, chemotherapeutic medicines or cardiac medications, heavy metal exposure or deficiency of vitamin B12, folate, or copper.  Unfortunately, the sum total of patients affected by these many conditions is large and there are no current treatments capable of restoring vision in patients suffering from these optic neuropathies.  Therefore, innovating treatments capable of regenerating the optic nerve could be transformative.