It is the infarction of the optic disc, it can be arteritic or non-arteritic. The only constant symptom is a painless loss of vision and the diagnosis is clinical.
Treatment: Of the non-arteritic variety it is ineffective and for the arteritic variety it does not restore vision, but it can help protect the unaffected eye. If the cause is swelling of the arteries in the head (temporal arteritis), steroid pills (prednisone) are indicated. This can prevent it from manifesting in the other eye, you must treat high blood pressure, diabetes, clogged arteries, migraines or other health problems. There is no treatment to improve vision loss, however helpful materials and resources can be suggested to help you see with low vision.