Optic Neuritis
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Contents |
Introduction
- Inflammation, demyelination or infection of the optic nerve anterior to the optic chiasm. When the intraocular portion of the optic nerve is involved, the disorder is termed papillitis. If the retina is involved, the disorder is termed optic neuro- retinitis. Otherwise the disorder is termed retrobulbar neuritis.
Etiology
- meningitis
- syphilis
- tuberculosis
- mumps
- chicken pox
- infectious mononucleosis
- Herpes zoster
- Lyme disease
- intraocular keratitis
- endophthalmitis
- chronic uveitis
- orbital cellulitis
- orbital abscess (Rollet's syndrome)
- spread of infection from sphenoid & ethmoid sinuses
- AIDS
- systemic diseases
Clinical-manifestations
- general
- acute monocular loss of vision (over hours to days)
- loss of color vision affected more severely than visual acuity
- afferent pupillary defect ( Marcus Gunn pupil)
- central or paracentral scotoma
- diplopia
- nystagmus
- retrobulbar optic neuritis
- papillitis
- swollen optic disc with blurred margins
- yellow exudate in oval pattern around fovea
- dilated retinal veins
- flame hemorrhages may be present
- inflammatory cells present in vitreous humor
- may progress to optic atrophy with gliosis
Laboratory
- color testing
- visual acuity
- pinhole to assess refractive component
- flashing a light in the eye decreases visual acuity in patients with retinal disease more than in patients with optic neuritis
- visual field testing to identify central or paracentral scotoma
- swinging light test to detect afferent pupillary defect ( Marcus Gunn pupil)
- visual evoked potentials are normal
Radiology
- CT of the orbit may demonstrate diffuse swelling of the optic nerve
Differential-diagnosis
- optic neuropathy - no early loss of visual acuity
- amaurosis fugax - generally resolves after a short time
- cystoid macular edema
- central serous choroidopathy
- painless loss of vision
- central scotoma
- no afferent pupillary defect
- color vision not severely affected
- no early loss of visual acuity
- tends to be bilateral
Management
- remove causative fators
- high dose steroids may help some patients
- retrobulbar neuritis secondary to demyelination usually resolves spontaneously in 2-6 weeks; some residual optic atrophy may remain
More General Terms
References
- Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 829-39
- Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 76-77
- Geriatrics at your Fingertips, 13th edition, 2011 Reuben DB et al (eds) American Geriatric Society
