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Treatment of Optic Neuritis

European Ophthalmic Review, 2013;7(1):52–5 DOI: http://doi.org/10.17925/EOR.2013.07.01.52

Abstract:

Optic neuritis (ON) is a self-limiting condition caused by inflammation-driven demyelination process affecting the optic nerve. Main clinical features are sudden, unilateral worsening of visual acuity, colour vision disturbance, visual field defects and motion-induced ocular pain. Spontaneous recovery appears usually within up to 8 weeks. It is a frequent initial manifestation of multiple sclerosis. Treatment of optic neuritis remains controversial, although many clinical trials have been conducted to establish firm therapeutic guidelines. The most relevant clinical trial is the Optic Neuritis Treatment Trial (ONTT), proving three days’ intravenous methylprednisolone therapy is not able to change the long-term prognosis, however improving visual recovery, what became a therapeutic option in monocular patients, patients with significant visual field loss, as well as those with professional requirements of fast visual recovery. The ONTT showed that 15-year risk of developing multiple sclerosis was 50 % regardless of the treatment regimen. Oral corticosteroids are recommended for treatment of acute optic neuritis.
Keywords: Optic neuritis, multiple sclerosis, treatment, corticosteroids, Optic Neuritis Treatment Trial, ONTT
Disclosure: The authors have no conflicts of interest to declare.
Received: October 08, 2012 Accepted: November 20, 2012
Correspondence: Andrzej Grzybowski, Department of Ophthalmology, Poznan City Hospital, 3 Szwajcarska St, 361-285 Poznań, Poland. E: ae.grzybowski@gmail.com

Optic neuritis (ON) is an acute inflammatory condition affecting the optic nerve in young adults predominantly.1–4 It is caused by idiopathic inflammatory demyelination of the optic nerve, although there is also evidence of axonal loss.4,5 Its incidence amounts to 1–5 per 100,000 per year, being more frequent in Caucasians, countries at high latitudes and in spring.2,3,4,6 The patient’s complaints include both sudden, unilateral worsening of visual acuity ranging from mild visual disturbance to visual loss and movement induced ocular pain. Substantial female predominance among the patients is noted. ON is found to be a frequent initial manifestation of multiple sclerosis (MS), as up to 50 % of ON cases are likely to progress into MS within 15 years.1–4

Diagnostic Criteria
ON is a self-limiting condition, progressing over hours to 10 days and spontaneously improving within up to 8 weeks. Such a condition not presenting recovery within 8 weeks should require further investigation and may impose other diagnosis implementation.4ON can usually be diagnosed taking only clinical features in to consideration.2,3 Although, typical ON requires no further laboratory studies visual evoked potentials (VEP) testing,2,7,4 magnetic resonance imaging (MRI) is recommend for prognostic purposes.4 It was recently shown that patients with normal VEP and MRI had a 96 % probability of a normal lumbar puncture, thus both tests are suggested in all patients before deciding on a lumbar puncture.8

The most common presentation is a unilateral, subacute, painful visual loss, which is not associated with any systemic disease or other neurological symptoms. Visual acuity might deteriorate to zero light perception in the affected eye, but also can be as minor as blurry vision only. Other frequent clinical characteristics of ON include colour vision disturbance of a non-specific pattern, contrast sensitivity reduction, photopsias, relative afferent pupillary reflex (RAPD) and visual field loss presence.2,4,9 Pau et al. divided ON into four clinical categories, depending on the anatomic localisation:
  • retrobulbar neuritis characterised by normal disc appearance;
  • papillitis with swollen optic disc;
  • perineuritis involving mainly the optic nerve sheath with or without optic disc oedema; and
  • neuroretinitis with swollen optic disc and a ‘star figure’ of macular exudates.
The two first forms are most commonly associated with MS ON. Retrobulbar neuritis accounts for two-thirds of acute demyelinating ON. Temporal optic disc atrophy as well as other residual clinical findings are often seen after ON resolution.4 The ON recurrence ratio is described to reach 28 and 35 % at 5- and 10-year follow up respectively.10,11 Differential diagnosis encompasses hereditary, ischaemic, compressive, toxic and other inflammatory optic neuropathies.3

Treatment Trials
In the decades since its first clinical implementation in the 1950s, corticosteroids proved useful in dealing with ON as well as MS.12 Many clinical trials have been conducted to establish an optimal therapeutic regimen and asses treatment efficacy and its indications.1,7,9,10,12–22 The trial including greatest number of patients, which became leading treatment guideline, was the Optic Neuritis Treatment Trial (ONTT), carried out in 1988–2006.1,2,9–12,15,18

Table 1: Treatment Trials of Optic Neuritis

Optic Neuritis Treatment Trial
The ONTT was a prospective randomised trial enrolling 389 patients with acute ON, presenting up to 8 days after onset of the initial episode. The trial evaluated MS risk after an episode of ON and factors predicting of high and low risk under three corticosteroid concerning therapeutic approaches: 3-day course of methylprednisolone given intravenously in a dose of 250 mg every 6 hours followed by 2 weeks of daily oral prednisolone in a dose of 1 mg/kg/day, oral prednisolone alone in a dose of 1 mg/kg/day for 2 weeks and placebo. Yearly neurological and ophthalmological examinations were conducted within the first 5 years after inclusion, then 5 and 10 years later. Visual acuity, contrast sensitivity, colour vision and visual field were tested during the ophthalmological exam.1,2,12,15,18 The final follow-up evaluation showed that intravenous corticosteroids followed by oral corticosteroids ensured lower risk of MS occurrence as well as improved visual recovery period but had no impact on final visual outcome.1,7,9,12 Interestingly, a smaller rate of recurrence within first 2 years following the first episode of ON wasdescribed in above-mentioned treatment group compared to oral corticosteroids assigned group as well as placebo group. The beneficial effect of intravenous methylprednisolone treatment on the development of MS lessened after 2 years.1,7,9,10,12 By five years, the treatment had no significant effect on the development of MS, reported Beck et al.12

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  22. Roed HG, Langkilde A, Sellebjerg F, et al., A double-blind, randomized trial of IV immunoglobulin treatment in acute optic neuritis, Neurology, 2005;64:804–10.
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Keywords: Optic neuritis, multiple sclerosis, treatment, corticosteroids, Optic Neuritis Treatment Trial, ONTT