Etiology of Optic Neuritis
Optic neuritis is most common among adults 20 to 40 years. Most cases result from demyelinating disease, particularly multiple sclerosis Multiple Sclerosis (MS) Multiple sclerosis (MS) is characterized by disseminated patches of demyelination in the brain and spinal cord. Common symptoms include visual and oculomotor abnormalities, paresthesias, weakness... read more , in which case there may be recurrences. Optic neuritis is often the presenting manifestation of multiple sclerosis. Other causes include:
Infectious diseases (eg, viral encephalitis Encephalitis Encephalitis is inflammation of the parenchyma of the brain, resulting from direct viral invasion. Acute disseminated encephalomyelitis is brain and spinal cord inflammation caused by a hypersensitivity... read more [particularly in children], sinusitis Sinusitis Sinusitis is inflammation of the paranasal sinuses due to viral, bacterial, or fungal infections or allergic reactions. Symptoms include nasal obstruction and congestion, purulent rhinorrhea... read more , meningitis Overview of Meningitis Meningitis is inflammation of the meninges and subarachnoid space. It may result from infections, other disorders, or reactions to drugs. Severity and acuity vary. Findings typically include... read more , tuberculosis Tuberculosis (TB) Tuberculosis (TB) is a chronic, progressive mycobacterial infection, often with a period of latency following initial infection. TB most commonly affects the lungs. Symptoms include productive... read more [TB], syphilis Syphilis Syphilis is caused by the spirochete Treponema pallidum and is characterized by 3 sequential clinical, symptomatic stages separated by periods of asymptomatic latent infection. Common manifestations... read more , human immunodeficiency virus Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection results from 1 of 2 similar retroviruses (HIV-1 and HIV-2) that destroy CD4+ lymphocytes and impair cell-mediated immunity, increasing risk of certain... read more [HIV])
Tumor metastasis to the optic nerve
Chemicals and drugs (eg, lead, methanol, quinine, arsenic, ethambutol, antibiotics)
Neuromyelitis optica Neuromyelitis Optica Spectrum Disorder (NMOSD) Neuromyelitis optica spectrum disorder is a demyelinating disorder that predominantly affects the eyes and spinal cord but can affect other structures in the central nervous system (CNS) that... read more (NMO;  General references Optic neuritis is inflammation of the optic nerve. Symptoms are usually unilateral, with eye pain and partial or complete vision loss. Diagnosis is primarily clinical. Treatment is directed... read more )
Myelin oligodendrocyte glycoprotein autoantibody (MOG-IgG) disease (2 General references Optic neuritis is inflammation of the optic nerve. Symptoms are usually unilateral, with eye pain and partial or complete vision loss. Diagnosis is primarily clinical. Treatment is directed... read more )
Rare causes include diabetes Diabetes Mellitus (DM) Diabetes mellitus is impaired insulin secretion and variable degrees of peripheral insulin resistance leading to hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia... read more , pernicious anemia Autoimmune Metaplastic Atrophic Gastritis Autoimmune metaplastic atrophic gastritis is an inherited autoimmune disease that attacks parietal cells, resulting in hypochlorhydria and decreased production of intrinsic factor. Consequences... read more , systemic autoimmune diseases, Graves ophthalmopathy Etiology Hyperthyroidism is characterized by hypermetabolism and elevated serum levels of free thyroid hormones. Symptoms are many and include tachycardia, fatigue, weight loss, nervousness, and tremor... read more , bee stings Insect Stings Stinging insects are members of the order Hymenoptera of the class Insecta. Hymenoptera venoms cause local toxic reactions in all people and allergic reactions only in those previously sensitized... read more , and trauma. Often, the cause remains obscure despite thorough evaluation.
1. Chen JJ, Pittock SJ, Flanagan EP, et al: Optic neuritis in the era of biomarkers. Surv Ophthalmol 165(1):12-17, 2020. doi: 10.1016/j.survophthal.2019.08.001
2. Chen JJ, Bhatti MT: Clinical phenotype, radiological features, and treatment of myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG) optic neuritis. Curr Opin Neurol;33(1):47-54, 2020. doi: 10.1097/WCO.0000000000000766
Symptoms and Signs of Optic Neuritis
The main symptom of optic neuritis is vision loss, frequently maximal within 1 or 2 days and varying from a small central or paracentral scotoma to complete blindness. Most patients have mild eye pain, which often feels worse with eye movement.
If the optic disk is swollen, the condition is called papillitis. If the optic disk appears normal, the condition is called retrobulbar neuritis. The most characteristic findings include reduced visual acuity, a visual field deficit, and disturbed color vision (often out of proportion to loss of visual acuity). An afferent pupillary defect is usually detectable if the contralateral eye is unaffected or involved to a lesser degree. Testing of color vision is a useful adjunct, although 10% of males have congenital color blindness, producing false-positive results. In about two thirds of patients, inflammation is entirely retrobulbar, causing no visible changes to the optic nerve head. In the rest, disk hyperemia, edema in or around the disk, vessel engorgement, or a combination is present. A few exudates and hemorrhages may be present near or on the optic disk.
Diagnosis of Optic Neuritis
Magnetic resonance imaging (MRI)
Optic neuritis is suspected in patients with characteristic pain and vision loss, particularly if they are young. Neuroimaging, preferably with gadolinium-enhanced MRI of the brain and orbits, is usually done and may show an enlarged, enhancing optic nerve. MRI may also help diagnose multiple sclerosis, myelin oligodendrocyte glycoprotein autoantibody (MOG-IgG) disease, and neuromyelitis optica (NMO). Fluid attenuating inversion recovery (FLAIR) MRI sequences may show typical demyelinating lesions in a periventricular location if optic neuritis is related to demyelination. Spinal cord involvement can be seen in NMO or MOG-IgG disease.
Pearls & Pitfalls
Prognosis for Optic Neuritis
Prognosis depends on the underlying condition. Most episodes resolve spontaneously, with return of vision in 2 to 3 months. Most patients with a typical history of optic neuritis and no underlying systemic disease, such as a connective tissue disease, recover vision, but > 25% have a recurrence in the same eye or in the other eye (1 Prognosis reference Optic neuritis is inflammation of the optic nerve. Symptoms are usually unilateral, with eye pain and partial or complete vision loss. Diagnosis is primarily clinical. Treatment is directed... read more ). MRI is used to determine future risk of demyelinating disease.
1. Beck RW, Cleary PA, Backlund JYC, Optic Neuritis Study Group: The course of visual recovery after optic neuritis: Experience of the optic neuritis treatment trial. Ophthalmology 127(4S):S174-S181, 2020. doi: 10.1016/j.ophtha.2020.01.027
Treatment of Optic Neuritis
Corticosteroids are an option, especially if multiple sclerosis or neuromyelitis optica are suspected. Treatment with methylprednisolone (500 mg to 1000 mg intravenously once a day) for 3 days followed by prednisone (1 mg/kg orally once a day) for 11 days may speed recovery, but ultimate vision results are no different from those with observation alone. Intravenous corticosteroids have been reported to delay onset of multiple sclerosis for at least 2 years. Treatment with oral prednisone alone does not improve vision outcome and may increase the rate of recurrent episodes. Low-vision aids (eg, magnifiers, large-print devices, talking watches) may be helpful. Other treatments, such as those used to treat multiple sclerosis, can be given if multiple sclerosis is suspected.
Optic neuritis is most common among adults 20 to 40 years.
The most common causes are demyelinating diseases, particularly multiple sclerosis, neuromyelitis optica (NMO), and myelin oligodendrocyte glycoprotein autoantibody (MOG-IgG) disease, but infections, tumors, drugs, and toxins are other possible causes.
Findings include mild pain with eye movement, visual disturbances (particularly disproportionate loss of color vision), and afferent pupillary defect.
Consider gadolinium-enhanced MRI.
Corticosteroids and other treatments can be given, particularly if multiple sclerosis is suspected.