Symptoms of Optic Neuritis
Optic neuritis presents with a classic triad of sudden visual loss, periocular pain (especially with eye movement), and dyschromatopsia (color vision impairment), with most patients experiencing good visual recovery with appropriate treatment. 1, 2
Key Clinical Symptoms
- Visual loss: Typically unilateral, subacute onset (hours to days), with central scotomas being the most common visual field defect 1, 3
- Pain with eye movement: Present in approximately 90% of cases, often preceding visual loss 2, 4
- Color vision abnormalities: Red-green color desaturation is particularly characteristic 1, 5
- Photophobia: Common associated symptom that can persist even after visual acuity improves 1
- Relative afferent pupillary defect (RAPD): Present in unilateral or asymmetric cases 2, 6
Clinical Examination Findings
- Optic disc appearance: One-third of patients have mild optic disc edema (papillitis); the remainder have a normal-appearing optic disc (retrobulbar neuritis) 4
- Visual field testing: Typically shows central scotomas, though other patterns may occur 1, 5
- Symptoms that outweigh observable signs: This is a common feature that helps distinguish optic neuritis from other conditions 1
Diagnostic Features on Imaging
- MRI findings: Increased T2 signal, gadolinium enhancement, and optic nerve swelling are key diagnostic features 1, 7
- Optimal imaging technique: Coronal fat-suppressed T2-weighted sequences best visualize optic nerve lesions 1, 7
- Brain MRI: Essential to evaluate for associated demyelinating lesions that may indicate multiple sclerosis 7, 4
Red Flags for Atypical Optic Neuritis
- Bilateral simultaneous involvement: More common in neuromyelitis optica spectrum disorders than in MS-related optic neuritis 1, 7
- Posterior optic nerve involvement: Including the chiasm, suggests anti-AQP4-IgG-seropositive neuromyelitis optica spectrum disorders 1
- Severe visual loss with poor recovery: May indicate neuromyelitis optica rather than MS-related optic neuritis 7, 3
- Painless visual loss: While pain is typical, its absence doesn't rule out optic neuritis but may suggest atypical forms 3
Treatment Approach
- First-line treatment: Intravenous methylprednisolone (typically 1g/day for 3-5 days) provides faster recovery and reduces the chance of recurrence 2, 4
- Contraindicated treatment: Oral prednisolone alone is contraindicated due to increased risk of a second episode 8, 2
- Caution with corticosteroids: Both methylprednisolone and prednisone labels specifically state that "the use of oral corticosteroids is not recommended in the treatment of optic neuritis and may lead to an increase in the risk of new episodes" 9, 8
- Disease-modifying therapies: For patients at high risk of developing MS, immune prophylaxis with interferon β-1a,b or glatiramer acetate may reduce the risk of MS development 2, 4
Prognosis
- Visual recovery: 95% of typical optic neuritis cases show good visual recovery, even without treatment 4
- Residual deficits: Contrast sensitivity, color vision, and visual field abnormalities may persist even after good recovery of visual acuity 2
- Multiple sclerosis risk: The presence of even one clinically silent T2 hyperintense brain lesion in patients with optic neuritis is highly associated with eventual MS diagnosis 1, 4
Differential Diagnosis
- Neuromyelitis optica: Typically presents with more severe vision loss and poorer recovery than MS-related optic neuritis 7
- Anterior ischemic optic neuropathy (AION): Can be mistaken for optic neuritis but typically presents with painless visual loss 2
- Leber's hereditary optic neuropathy: Usually bilateral (sequential rather than simultaneous) with poor visual recovery 2
- Infectious and inflammatory conditions: Various infections and autoimmune disorders can cause optic neuritis 2, 5