Optic neuritis describes any condition that causes inflammation of the optic nerve; it may be associated with demyelinating diseases, or infectious or inflammatory processes.It is also known as optic papillitis (when the head of the optic nerve is involved), neuroretinitis (when there is a combined involvement of optic disc and surrounding retina in the macular area) and retrobulbar neuritis (when the posterior part of the nerve is involved). Prelaminar optic neuritis describes involvement of the non-myelinated axons in the retina. It is most often associated with multiple sclerosis, and it may lead to complete or partial loss of vision in one or both eyes. Other causes include:
Hereditary optic neuritis (Lebers disease)
Parainfectious optic neuritis (associated with viral infections such as measles, mumps, chickenpox, whooping cough and glandular fever)
Infectious optic neuritis (sinus related or associated with cat scratch fever, tuberculosis, lyme disease and cryptococcal meningitis in AIDS patients
Autoimmune causes (sarcoidosis, systemic lupus erythematosus, PAN, MOG Antibody disease, granulomatosis with polyangiitis)
Diabetes Mellitus
Low phosphorus levels
HyperkalaemiaPartial, transient vision loss (lasting less than one hour) can be an indication of early onset multiple sclerosis. Signs and symptoms
Major symptoms are sudden loss of vision (partial or complete), sudden blurred or "foggy" vision, and pain on movement of the affected eye. Early symptoms that require investigation include symptoms from multiple sclerosis (twitching, lack of coordination, slurred speech, frequent episodes of partial vision loss or blurred vision), episodes of "disturbed/blackened" rather than blurry indicate moderate stage and require immediate medical attention to prevent further loss of vision.
Demyelinating recurrent optic neuritis and non-demyelinating (CRION)
The repetition of an idiopathic optic neuritis is considered a distinct clinical condition, and when it shows demyelination, it has been found to be associated to anti-MOG and AQP4-negative neuromyelitis opticaWhen an inflammatory recurrent optic neuritis is not demyelinating, it is called "Chronic relapsing inflammatory optic neuropathy" (CRION)When it is anti-MOG related, it is demyelinating and it is considered inside the anti-MOG associated inflammatory demyelinating diseases. Some reports point to the possibility to establish a difference via OCT

Treatment
In most MS-associated optic neuritis, visual function spontaneously improves over 2–3 months, and there is evidence that corticosteroid treatment does not affect the long term outcome. However, for optic neuritis that is not MS-associated (or atypical optic neuritis) the evidence is less clear and therefore the threshold for treatment with intravenous corticosteroids is lower. Intravenous corticosteroids also reduce the risk of developing MS in the following two years in patients with MRI lesions; but this effect disappears by the third year of follow up.Paradoxically, oral administration of corticosteroids in this situation may lead to more recurrent attacks than in non-treated patients (though oral steroids are generally prescribed after the intravenous course, to wean the patient off the medication). This effect of corticosteroids seems to be limited to optic neuritis and has not been observed in other diseases treated with corticosteroids.A Cochrane Systematic Review studied the effect of corticosteroids for treating people with acute optic neuritis. Specific corticosteroids studied included intravenous and oral methylprednisone, and oral prednisone.