Shiraz Qureshi Shafi
Introduction
Optic perineuritis is an uncommon cause of optic nerve dysfunction resulting from inflammation of the optic nerve sheath. Historically considered a variant of optic neuritis, it is now recognised as a distinct condition with unique clinical and radiological features. Unlike typical demyelinating optic neuritis, optic perineuritis often affects older individuals, responds dramatically to corticosteroids, and carries a high risk of relapse if treatment is tapered prematurely. Awareness of optic perineuritis is crucial in ophthalmic and neuro-ophthalmic practice, as misdiagnosis may lead to some optimal treatment and preventable visual loss (1).
Epidemiology
Optic perineuritis is rare, with most data derived from small case series and retrospective studies (2,3). It typically presents in middle-aged or older adults, contrasting with demyelinating optic neuritis, which more commonly affects younger patients (4). The condition may be idiopathic or associated with systemic inflammatory or infectious diseases. Reported associations include granulomatous conditions, autoimmune disease, vasculitis, and infections such as syphilis and tuberculosis (5–7).
Pathophysiology
The pathological hallmark of optic perineuritis is inflammation confined primarily to the optic nerve sheath, with relative sparing of the optic nerve axons, particularly in early disease. This distinguishes it from optic neuritis, in which the nerve itself is inflamed and demyelinated. Inflammation of the sheath leads to compression of the optic nerve and disruption of axoplasmic floor, resulting in visual dysfunction. Chronic or recurrent inflammation may cause secondary optic nerve damage, explaining why delayed treatment or repeated relapses can result in permanent visual loss (8).
Clinical presentation
Patients with optic perineuritis typically present with subacute visual loss, often accompanied by periocular pain that is exacerbated by eye movement (1). Visual acuity may be mildly to moderately reduced at presentation, but visual field defects are common and may be more prominent than acuity loss. Unlike demyelinating optic neuritis, optic perineuritis may present with a relatively preserved colour vision early in the disease, mild or absent relative afferent pupillary defect, and optic disc oedema. Symptoms may progress over days to weeks, and spontaneous recovery without treatment is uncommon. Bilateral involvement is rare, but it has been reported (9).
Diagnosis
MRI scans with contrast of the orbit is central to diagnosis (10). The characteristic radiological feature is circumferentially enhancement of the optic nerve sheath, often described as the “tram track” or the “doughnut” sign on the coronal view (4,11). Importantly, the optic nerve itself typically shows little or no enhancement. These imaging findings alone differentiate optic perineuritis from optical neuritis. Neuroimaging can also help identify associated orbital or intracranial pathology. Laboratory investigations should be guided by clinical suspicion and may include inflammatory markers, autoimmune screening, and infectious serology. Lumbar puncture is not routinely required but may be considered if central nervous system inflammatory disease is suspected (1).
Management
Systemic corticosteroid therapy is the mainstay of treatment for optic perineuritis. Patients typically demonstrate rapid and dramatic improvement in symptoms following initiation of high-dose oral or intravenous steroids. A key management consideration is the duration and tapering of steroid therapy (8,9). Unlike optic neuritis, short courses of corticosteroids are associated with a high risk of relapse. Prolonged treatment with a slow taper over several weeks to months is often required to achieve sustained remission.
Prognosis
When recognised early and treated appropriately, the visual prognosis in optic perineuritis is generally favourable. Many patients experienced significant improvement in visual acuity and visual fields. However, recurrent inflammation and delayed diagnosis are associated with worse outcomes due to cumulative optic nerve damage. Long term follow-up is recommended to monitor for relapse, assess visual function, and manage complications of prolonged corticosteroid therapy. Patients should be counselled regarding the risk of recurrence and the importance of adherence to treatment regimens (1).
Conclusion
Optic perineuritis is a rare but important inflammatory optic neuropathy that can closely mimic optic neuritis while requiring a fundamentally different management approach. Distinctive imaging findings and a marked steroid responsiveness are key diagnostic tools. Early recognition and appropriately prolonged corticosteroid therapy are essential to prevent relapse and preserve vision. Increased awareness of this condition among ophthalmologists and neurologists is critical to optimising patient outcomes.
References
1. Gupta S, Sethi P, Duvesh R, Sethi HS, Naik M, Rai HK. Optic perineuritis. BMJ Open Ophthalmol. 2021 May 21;6(1).
2. Bergman O, Andersson T, Zetterberg M. Optic perineuritis: a retrospective case series. Int Med Case Rep J. 2017 June 8;10:181–8.
3. Xie JS, Donaldson L, Margolin E. Optic perineuritis: A Canadian case series and literature review. J Neurol Sci. 2021 Nov 15;430:120035.
4. Purvin V, Kawasaki A, Jacobson DM. Optic perineuritis: clinical and radiographic features. Arch Ophthalmol Chic Ill 1960. 2001 Sept;119(9):1299–306.
5. Meehan K, Rodman J. Ocular perineuritis secondary to neurosyphilis. Optom Vis Sci Off Publ Am Acad Optom. 2010 Oct;87(10):E790-796.
6. Delaney P. Neurologic manifestations in sarcoidosis: review of the literature, with a report of 23 cases. Ann Intern Med. 1977 Sept;87(3):336–45.
7. McClelland C, Zaveri M, Walsh R, Fleisher J, Galetta S. Optic perineuritis as the presenting feature of Crohn disease. J Neuro-Ophthalmol Off J North Am Neuro-Ophthalmol Soc. 2012 Dec;32(4):345–7.
8. Hickman SJ. Optic Perineuritis. Curr Neurol Neurosci Rep. 2016 Jan 11;16(2):16.
9. Hykin PG, Spalton DJ. Bilateral perineuritis of the optic nerves. J Neurol Neurosurg Psychiatry. 1991 Apr;54(4):375–6.
10. Dutton JJ, Anderson RL. Idiopathic inflammatory perioptic neuritis simulating optic nerve sheath meningioma. Am J Ophthalmol. 1985 Sept 15;100(3):424–30.
11. Kanamalla US. The optic nerve tram-track sign. Radiology. 2003 June;227(3):718–9.