Related articles: Neurite optics
Definition
Optic neuritis is the inflammation of the optic nerve.
The optic nerve is the structure that carries visual information, coming from the retina, to the visual cortex located in the occipital lobe (area of the brain responsible for processing electrical stimuli in vision).
When the optic nerve becomes inflamed, its function is compromised. The inflammatory process, in fact, causes swelling and degeneration of the myelin sheath; this structure covers the optic nerve and normally guarantees the correct conduction of electrical impulses. Myelin damage thus alters the transmission of signals from the retina to the brain; for this reason, optic neuritis causes a reduction in vision.
The most common cause of optic neuritis is multiple sclerosis, a demyelinating disease of which it often represents the initial symptom. Other causes include infectious diseases (eg Lyme disease, syphilis, meningitis, TB, viral encephalitis, etc.), autoimmune disorders (eg systemic lupus erythematosus, Behçet's disease, sarcoidosis) and any process that causes direct damage to the optic nerve ( compression, tumors or ischemia).
Optic neuritis can also be favored by trauma, nutritional deficiencies, radiotherapy, temporal arteritis, pernicious anemia, Graves' disease, diabetes and drug and chemical poisoning (eg lead, methanol, arsenic and antibiotics). Other times, the cause remains unknown.
Most common symptoms and signs *
- Halo around the light
- Altered color vision
- anisocoria
- Night Blindness
- Movable bodies
- Ocular pain
- Fotofobia
- Narrowing of the visual field
- Reduced vision
- Intraocular bleeding
- scotomas
Further indications
In most cases, optic neuritis is unilateral, although both eyes may be involved simultaneously. Onset of the disease is typically characterized by a triad of clinical signs: reduction in visual acuity, eye pain (often intensified with eye movement) and changes in the visual field. Other characteristic symptoms include an altered color vision (dyschromatopsia), reduced sensitivity to contrast and appearance of visual phenomena such as the perception of light flashes in the absence of light, flashing lights and spots.
Optic neuritis can lead to partial or complete loss of vision. The diagnosis is based on ophthalmological and neurological evaluation. The characteristic findings on examination may include reduced peripheral vision, alteration of the pupillary reflex and swelling of the head of the optic nerve (papilla), sometimes associated with surrounding bleeding.
Therapy is directed at the underlying disease (for example, corticosteroids are an option in the case of neuritis associated with multiple sclerosis); most of the time, however, inflammation resolves spontaneously.
