Adult Optic Neuritis

Updated: May 26, 2016
  • Author: Erhan Ergene, MD; Chief Editor: Edsel Ing, MD, MPH, FRCSC  more...
  • Print
Overview

Practice Essentials

Optic neuritis (ON; see the image below) is a demyelinating inflammation of the optic nerve that often occurs in association with multiple sclerosis (MS) and neuromyelitis optica (NMO). A gradual recovery of visual acuity with time is characteristic of optic neuritis, [1] although permanent residual deficits in color vision and contrast and brightness sensitivity are common. [2]

A case of acute optic neuritis. A. 1.5 Tesla, cont A case of acute optic neuritis. A. 1.5 Tesla, contrast-enhanced spin echo T1-weighted, fat-suppressed coronal MRI through the orbits shows enlargement and contrast enhancement of the left optic nerve in the retrobulbar portion (arrow). B. Coronal spin echo T1-weighted, fat-suppressed MRI of the same patient shows enlargement and contrast enhancement of the nerve in a parasagittal oblique section (arrow).

Signs and symptoms

History

The patient’s history may reveal the following signs and symptoms of optic neuritis:

  • Preceding viral illness
  • Rapidly developing impairment of vision in 1 eye or, less commonly, both eyes: During an acute attack [3]
  • Dyschromatopsia (change in color perception) in the affected eye: Occasionally may be more prominent than the decreased vision [4]
  • Retro-orbital or ocular pain: In association with the vision changes and usually exacerbated by eye movement; the pain may precede vision loss
  • Uhthoff phenomenon, in which vision loss is exacerbated by heat or exercise
  • Pulfrich phenomenon, in which objects moving in a straight line appear to have a curved trajectory: Presumably caused by asymmetrical conduction between the optic nerves

Patients with MS may have recurrent attacks of optic neuritis, [5] which means that a history of previous episodes of decreased vision in the same or fellow eye may be elicited.

NMO is characterized by often severe, bilateral optic neuritis and myelitis in a close temporal relationship. [6, 7, 8, 9] However, optic neuritis can occasionally precede the myelopathy.

Physical examination

Signs and symptoms of optic neuritis may include the following:

  • Decreased pupillary light reaction in the affected eye: A relative afferent pupillary defect (RAPD) or Marcus Gunn pupil commonly is found; in bilateral cases, the RAPD may not be apparent
  • Varying degrees of vision reduction: From a mildly decreased visual acuity to complete vision loss
  • Abnormal contrast sensitivity and color vision: In almost all patients with adult optic neuritis who have decreased visual acuity
  • Altitudinal field defects
  • Arcuate defects
  • Nasal steps
  • Central scotoma
  • Cecocentral scotoma
  • Papillitis (swollen disc): Found in one third of patients with optic neuritis

See Clinical Presentation for more detail.

Diagnosis

The following blood tests can be performed to exclude causes of optic neuropathy other than optic neuritis:

  • Erythrocyte sedimentation rate
  • Thyroid function tests
  • Antinuclear antibodies
  • Angiotensin-converting enzyme
  • Rapid plasma reagin
  • Mitochondrial deoxyribonucleic acid (DNA) mutation studies

Magnetic resonance imaging (MRI) is highly sensitive for and specific in the assessment of inflammatory changes in the optic nerves, and for central nervous system white matter lesions. MRI also helps to rule out structural lesions. [10, 11]

Visual evoked potentials (VEPs) can be considered in patients with suspected optic neuritis. They may be abnormal even when MRI of the optic nerve is normal. VEPs often show a loss of P100 response in the acute phase. P100 recovers with time, but it usually shows a markedly prolonged latency that persists indefinitely, even after clinical recovery.

See Workup for more detail.

Management

For most patients with optic neuritis, treatment and recovery proceed as follows:

  • Visual function begins to improve 1 week to several weeks after onset, even without any treatment
  • Permanent residual deficits in color vision and contrast and brightness sensitivity are common [2]
  • Pharmacologic therapy in optic neuritis (ON) is directed at ameliorating the acute symptoms of pain and decreased vision caused by demyelinating inflammation of the nerve; varying regimens of corticosteroids have been used for this purpose.
  • IV steroids do little to affect the ultimate visual acuity in patients with optic neuritis, but they do speed the rate of recovery; some clinicians advocate IV steroids in patients with either severe or bilateral vision loss [12, 13, 14]

For patients with optic neuritis whose brain lesions on MRI indicate a high risk of developing clinically definite MS, treatment with immunomodulators (eg, interferon [INF] beta-1a, INF beta-1b, glatiramer acetate) may be considered. [15]

See Treatment and Medication for more detail.

Next:

Background

Optic neuritis (ON) is a demyelinating inflammation of the optic nerve that typically first occurs in young adulthood (see the image below). Many cases of optic neuritis are associated with multiple sclerosis (MS) or neuromyelitis optica (NMO), but optic neuritis can occur in isolation. [16] In cases associated with MS, optic neuritis is commonly the first manifestation of the chronic demyelinating process. [17] Long-term follow-up studies have indicated that up to 75% of female patients initially presenting with optic neuritis ultimately develop MS. (See Presentation and Prognosis.)

A case of acute optic neuritis. A. 1.5 Tesla, cont A case of acute optic neuritis. A. 1.5 Tesla, contrast-enhanced spin echo T1-weighted, fat-suppressed coronal MRI through the orbits shows enlargement and contrast enhancement of the left optic nerve in the retrobulbar portion (arrow). B. Coronal spin echo T1-weighted, fat-suppressed MRI of the same patient shows enlargement and contrast enhancement of the nerve in a parasagittal oblique section (arrow).

Occasionally, optic neuritis can result from an infectious process involving the orbits or paranasal sinuses or occur in the course of a systemic viral infection. [18, 19, 20, 21, 22, 23, 24, 25, 26] Certain optic neuropathies, such as anterior ischemic optic neuropathy (AION) and compressive and hereditary optic neuropathies, can resemble optic neuritis. [27]

This article reviews optic neuritis as a primary demyelinating inflammation of the nerve occurring either in isolation or in association with MS or NMO. (NMO is a severe form of a demyelinating disease; it affects the optic nerves and the spinal cord, causing recurrent attacks of blindness and paralysis. [28, 29] ) Much information has been gleaned from the Optic Neuritis Treatment Trial (ONTT), and the reader is encouraged to review the follow-up data from this study. (See Etiology, Treatment, and Medication.) [30, 12, 31, 2]

Patient education

For patient education information, see Multiple Sclerosis.

Previous
Next:

Etiology

Most cases of optic neuritis are associated with MS, even though optic neuritis can occur in isolation. In MS-associated and isolated, monosymptomatic optic neuritis, the cause is presumed to be an autoimmune reaction that results in a demyelinating inflammation of the nerve. Pathologic studies in patients with optic neuritis associated with MS have shown that the demyelinative lesions in the optic nerve are similar to the MS plaques seen in the brain, with an inflammatory response marked by perivascular cuffing, T cells, and plasma cells. However, little is known about the pathology of isolated optic neuritis.

In a single case of chronic, isolated optic neuritis, a biopsy specimen showed the presence of perivascular lymphocytic infiltration, multifocal demyelination, and reactive astrocytosis in the retrobulbar portion of the optic nerve. Abnormal intrathecal immunoglobulin G (IgG) synthesis, reflected as the presence of oligoclonal bands in the cerebrospinal fluid (CSF), is found in 60-70% of patients with isolated optic neuritis, suggesting an immunologic etiology similar to MS.

NMO has been recognized as a distinct inflammatory demyelinating disease consisting of optic neuritis in combination with longitudinally extensive transverse myelitis. NMO is associated with the presence of a specific serum, NMO IgG autoantibody, which targets the water channel aquaporin-4. [32, 33, 34]

As previously stated, optic neuritis can occasionally result from an infectious process involving the orbits or paranasal sinuses or occur in the course of a systemic viral infection. [18, 19, 20, 21, 22, 23, 24, 25, 26]

Previous
Next:

Epidemiology

Studies from Sweden and Denmark have reported an annual incidence of 4-5 cases of new-onset optic neuritis per 100,000 persons. [35] Patients living in temperate climates seem to be predisposed to optic neuritis.

Race-, sex-, and age-related demographics

Optic neuritis appears to affect Caucasians more commonly than it does other races. Women are affected twice as often as men. [30]

Typically, patients with first-time, acute optic neuritis are young adults aged 20-45 years. Atypical cases of optic neuritis may be seen in elderly patients. Bilateral optic neuritis in childhood is not uncommon, and it is believed there is less risk of progression to MS.

Previous
Next:

Prognosis

In contrast to ischemic optic neuropathies and compressive optic neuropathies, a gradual recovery of visual acuity with time is characteristic of optic neuritis. [1] For most patients with optic neuritis, visual function begins to improve 1 week to several weeks after onset, even without any treatment. However, permanent residual deficits in color vision and contrast and brightness sensitivity are common. [2]

Decreased visual acuity secondary to optic neuritis may be permanent. Final visual outcome may be better in patients with an isolated episode of optic neuritis, compared with patients who eventually develop MS. Up to 75% of female patients and 35% of male patients initially presenting with optic neuritis ultimately develop MS. [36, 37, 38]

Patients with silent demyelinative lesions elsewhere in the brain, observed on magnetic resonance imaging (MRI) performed at the initial presentation, are more likely to develop definite MS in the long term than are patients with isolated optic neuritis. In addition, patients who have recurrent episodes of optic neuritis may be more likely to develop MS.

In patients with normal findings on MRI, a 16% risk of progression to clinically definite MS exists at 5-year follow-up.

Most patients with relapsing NMO have an aggressive form of the disease that is associated with frequent and severe exacerbations and poor prognosis.

Previous