Optic Neuritis

Introduction And Definition

Represents any inflammation or demyelinization of the optic nerve causing attendant impairment of function.
Manifests as an acute process featuring rapidly progressive loss of vision.
Develops in childhood as an isolated condition or as a manifestation of a broader neurologic or systemic disease.

Clinical Terminology	Ophthalmoscopic Findings
Retrobulbar Optic Neuritis	Affects the retrobulbar portion of the nerve without ophthalmoscopically visible signs of inflammation at the disc. Fundus appears normal.
Papillitis (Intraocular Optic Neuritis)	Displays ophthalmoscopically visible evidence of inflammation of the nerve head. Characterized by inflammatory swelling of the optic disc.
Optic Neuroretinitis	Involves both the retina and the papilla. Features inflammatory swelling of the optic disc accompanied by retinal edema and/or exudates.

Disease Category	Specific Associated Triggers And Disorders
Demyelinating Disorders	Multiple Sclerosis, Acute Disseminated Encephalomyelitis, Neuromyelitis Optica (Devic disease).
Inflammatory Diseases	Systemic lupus erythematosus, sarcoidosis, Behçet disease.
Infectious Agents	Tuberculosis, syphilis, Lyme disease, meningitis, viral encephalitis, Human Immunodeficiency Virus, postinfectious disease.
Toxic Or Nutritional	Methanol, ethambutol, vitamin B12 deficiency, lead poisoning. Complication of long-term high-dose chloramphenicol or vincristine.

Presents with a rapid drop in vision.
Occurs usually in one eye, although it may be unilateral or bilateral.
Pain on movement or palpation of the globe frequently precedes or accompanies the onset of visual symptoms.
Produces decreased visual activity, diminished color vision, and reduced contrast sensitivity.
Demonstrates a relative afferent pupillary defect (Marcus Gunn pupil).
Macula and peripheral retina typically remain normal.
Paradoxical constriction of the pupils in reduced light occasionally presents as a sign of optic neuritis.

Bilateral optic neuritis in children may associate with Acute Disseminated Encephalomyelitis or Neuromyelitis Optica.
Neuromyelitis Optica features rapid and severe bilateral visual loss.
Neuromyelitis Optica is consistently accompanied by transverse myelitis and paraplegia.

Diagnostic Entity	Distinguishing Clinical Features
Acute Papilledema	Distinguishable by the preservation of good central vision and the absolute absence of an afferent pupillary defect, unless macular hemorrhage or edema is present.
Leber Hereditary Optic Neuropathy	Differentiated by peripapillary angiopathy, lack of short-term remission, absence of inflammation on Magnetic Resonance Imaging, and a high degree of symmetry.

Requires extensive pediatric neurologic and ophthalmic investigation.
Magnetic Resonance Imaging is usually required to assess central nervous system involvement.
Lumbar puncture is frequently indicated to rule out infectious or inflammatory central nervous system processes.
Neuromyelitis Optica-specific immunoglobulin G (directed to the aquaporin 4 water channel) serves as the diagnostic test of choice for Devic syndrome.
Antibody-negative Neuromyelitis Optica patients may test positive for anti-Myelin Oligodendrocyte Glycoprotein antibodies, suggesting an alternate demyelinating form.
Brain stem and cortical involvement may occasionally be visualized on Magnetic Resonance Imaging in Neuromyelitis Optica patients.

Visual acuity better than no light perception.
Presence of periocular pain.
Acutely normal-appearing optic nerve.
Complete absence of retinal abnormalities.
Abnormal Magnetic Resonance Imaging findings suggesting underlying demyelinating disease.

Patients mandate immediate treatment in direct consultation with a neuro-ophthalmologist.
A treatment trial demonstrates that high-dose intravenous methylprednisolone helps speed visual recovery in young adults.
Intravenous methylprednisolone may actively prevent the subsequent development of Multiple Sclerosis in high-risk individuals.
Initial improvement in vision typically begins within 1 to 4 weeks following onset.
Visual acuity may improve to normal or near-normal baseline within weeks or months.
Central vision frequently recovers fully.
Permanent residual defects in contrast sensitivity, color perception, brightness sense, and motion perception commonly persist despite central vision recovery.
Disease recurrences happen frequently, especially in patients who ultimately develop Multiple Sclerosis.