Optic Neuritis in Multiple Sclerosis, NMOSD and MOGAD: Symptoms, Diagnosis and Treatment
Optic neuritis is an inflammatory disorder of the optic nerve that usually presents with subacute visual loss, impaired color vision and often pain with eye movement. It may occur as an isolated episode, as the first manifestation of multiple sclerosis (MS), or in association with AQP4-IgG-positive NMOSD and MOGAD.
Distinguishing these conditions at the first episode matters because they differ in clinical presentation, MRI and OCT findings, likelihood of visual recovery, relapse risk and the need for long-term preventive treatment.
Main symptoms of optic neuritis
Typical symptoms
- visual loss in one eye, less commonly bilateral involvement;
- progression over several days;
- pain behind the eye or pain with eye movement;
- reduced color saturation, especially red;
- reduced brightness and contrast;
- visual field defects, often central or centrocecal scotoma;
- a relative afferent pupillary defect in unilateral or asymmetric disease.
Features that require broader evaluation
The optic disc may be normal in retrobulbar neuritis or may be swollen. Marked disc edema, hemorrhages, absence of pain, severe bilateral involvement, progression beyond two weeks or poor visual recovery should prompt a broader differential diagnosis.
Optic neuritis in multiple sclerosis
Optic neuritis is one of the most characteristic first manifestations of MS. Typical MS-associated optic neuritis is usually unilateral, is often painful with eye movement and generally has a favorable visual prognosis.
Even after standard visual acuity recovers, some people continue to notice reduced contrast sensitivity, mild color-vision abnormalities, visual fatigue or the Uhthoff phenomenon — transient worsening of vision with increased body temperature or physical exertion.
Brain MRI is important for estimating the probability of MS. Typical demyelinating lesions substantially increase the likelihood that an episode of optic neuritis is related to multiple sclerosis.
McDonald 2024
The optic nerve is included as a fifth anatomical region that may contribute to demonstrating dissemination in space. Objective optic-nerve involvement may be supported by orbital MRI, OCT or visual evoked potentials when there is no more likely alternative diagnosis.
Optic neuritis in NMOSD
AQP4-IgG-positive NMOSD is an antibody-mediated disease of the central nervous system in which optic neuritis is often more severe than in MS.
Typical clues
- severe visual loss;
- bilateral or rapidly sequential involvement;
- long-segment optic-nerve involvement on MRI;
- posterior optic nerve, chiasm or optic tract involvement;
- greater risk of persistent visual disability after an attack.
Testing and prevention
When NMOSD is suspected, serum AQP4-IgG should be tested with a validated cell-based assay. In AQP4-IgG-positive NMOSD, long-term relapse-prevention treatment is usually required after the first clinical attack.
Optic neuritis in MOGAD
MOGAD is a disease associated with antibodies to myelin oligodendrocyte glycoprotein (MOG-IgG). In adults, optic neuritis is one of its most common manifestations.
Typical clues
- pain with eye movement is common;
- marked optic-disc edema;
- bilateral involvement is relatively frequent;
- long segments of optic nerve may be affected on MRI;
- perineural enhancement may be seen;
- visual loss can be severe during the acute attack despite relatively good recovery after treatment.
How the diagnosis is made
MOGAD is not diagnosed from a blood test alone. Diagnosis requires a compatible clinical syndrome together with MOG-IgG detected by a validated cell-based assay. Low-positive results require particularly careful interpretation.
How optic neuritis differs in MS, NMOSD and MOGAD
| Feature | MS | AQP4-NMOSD | MOGAD |
|---|---|---|---|
| Laterality | Usually unilateral | Often bilateral or sequential | Bilateral disease is relatively common |
| Optic-disc edema | Usually absent or mild | May occur | Often prominent |
| Optic-nerve MRI | Often a shorter segment | Often long posterior involvement; chiasm may be affected | Often long anterior involvement; perineural enhancement may occur |
| Visual recovery | Usually good | More often incomplete; severe persistent deficit is more likely | Often good despite a severe acute attack |
Diagnosis of optic neuritis
Neurological and ophthalmological examination
Assessment includes visual acuity, color vision, visual fields, pupillary responses, the optic disc and other signs of dysfunction along the visual pathway. The clinical pattern helps determine whether the episode is typical demyelinating optic neuritis or whether another cause should be sought.
MRI of the brain and orbits
Orbital and brain MRI with contrast is preferred when optic neuritis is suspected. MRI may confirm inflammation, show the length and location of optic-nerve involvement and identify brain lesions suggesting MS or another inflammatory CNS disorder.
OCT
Optical coherence tomography measures the peripapillary retinal nerve fiber layer (pRNFL) and ganglion-cell layers. During the acute phase, marked swelling — particularly in MOGAD — can increase RNFL thickness. Months later, OCT can demonstrate the extent of axonal and neuronal loss.
Visual evoked potentials
Visual evoked potentials can reveal delayed conduction along the visual pathway and are especially useful when previous or subtle optic-nerve involvement is suspected.
AQP4-IgG and MOG-IgG
Testing is particularly important in severe, bilateral, recurrent or atypical optic neuritis, with long-segment MRI abnormalities, marked disc edema or when the presentation is not typical of MS-associated optic neuritis. Validated cell-based assays are preferred.
Cerebrospinal fluid
Lumbar puncture is not required in every case. It may be useful when MS is suspected, the course is atypical or other inflammatory and infectious disorders need to be excluded. Oligoclonal bands and free kappa light chains can support an MS diagnosis.
Treatment of acute optic neuritis
High-dose corticosteroids
Clinically significant demyelinating optic neuritis is usually treated with high-dose corticosteroids. A common regimen is intravenous methylprednisolone 1000 mg daily for 3–5 days; equivalent high-dose oral regimens may be used in selected situations.
In typical MS-associated optic neuritis, corticosteroids primarily accelerate visual recovery.
NMOSD: early escalation
Severe NMOSD attacks should be treated as early as possible. If response to high-dose corticosteroids is inadequate, plasma exchange (PLEX) should be introduced early; in a very severe attack, apheresis may be considered at an early stage.
MOGAD
MOGAD-associated optic neuritis often responds well to corticosteroids, but symptoms may recur during overly rapid tapering. In severe or steroid-resistant attacks, plasma exchange or intravenous immunoglobulin may be considered.
Is long-term preventive treatment needed?
Multiple sclerosis
If the evaluation confirms MS, the choice of disease-modifying therapy depends on disease activity, MRI findings, prognostic factors and individual patient characteristics.
AQP4-positive NMOSD
Because disability in NMOSD accumulates mainly from attacks, long-term preventive immunotherapy is usually recommended after the first attack in AQP4-IgG-positive disease.
MOGAD
MOGAD may be monophasic or relapsing. After a first attack, the decision about long-term treatment is individualized. Recurrent attacks provide a stronger indication for preventive therapy.
Other causes of optic-nerve dysfunction
Acute visual loss with optic-nerve abnormalities is not always demyelinating optic neuritis. The differential diagnosis includes ischemic optic neuropathy, sarcoidosis and other systemic inflammatory diseases, infections, optic-nerve compression, toxic and nutritional optic neuropathies, hereditary disorders, paraneoplastic syndromes and retinal disease.
When to seek medical care urgently
New subacute visual loss in one or both eyes, particularly with pain on eye movement or altered color perception, requires prompt evaluation by an ophthalmologist and neurologist. Severe visual loss, bilateral involvement or rapid deterioration should not be left for a routine appointment.
Dr. Lidiia Prakhova
Neurologist, Doctor of Medical Sciences. Main clinical areas include neuroimmunology, multiple sclerosis, NMOSD, MOGAD, migraine, movement disorders, spasticity and botulinum toxin therapy.
ORCID: 0000-0002-4776-2999
Key references
- Petzold A, Fraser CL, Abegg M, et al. Diagnosis and classification of optic neuritis. Lancet Neurol. 2022;21(12):1120–1134. doi
- Bennett JL, Costello F, Chen JJ, et al. Optic neuritis and autoimmune optic neuropathies: advances in diagnosis and treatment. Lancet Neurol. 2023;22(1):89–100. doi
- Optic Neuritis Study Group. Multiple sclerosis risk after optic neuritis: final optic neuritis treatment trial follow-up. Arch Neurol. 2008;65(6):727–732. doi
- Beck RW, Cleary PA, Anderson MM, et al. A randomized, controlled trial of corticosteroids in the treatment of acute optic neuritis. N Engl J Med. 1992;326(9):581–588. doi
- Banwell B, Bennett JL, Marignier R, et al. Diagnosis of myelin oligodendrocyte glycoprotein antibody-associated disease: International MOGAD Panel proposed criteria. Lancet Neurol. 2023;22(3):268–282. doi
- Wingerchuk DM, Banwell B, Bennett JL, et al. International consensus diagnostic criteria for neuromyelitis optica spectrum disorders. Neurology. 2015;85(2):177–189. doi
