Optic neuritis and papillitis are broad terms denoting inflammation, degeneration, or demyelinization of the optic nerve due to a wide variety of diseases.
The optic nerve may be affected by inflammation in any part of its course. The clinical term optic neuritis implies involvement of any part of the optic nerve by an inflammatory disease process.
Papilledema is the most common differential diagnostic problem. In papilledema, there is often greater elevation of the optic nerve head, nearly normal visual acuity, normal pupillary response to light, associated intracranial pressure, and an intact visual field defect except for an enlarged blind spot.
The most frequent cause of retrobulbar neuritis is multiple sclerosis. When the disk is affected, the term papillitis is used.
The ophthalmoscopic appearance of the disk in papillitis and papilledema may be similar, but papillitis often causes significant vision loss, and usually a faint vitreous haze caused by cellular and fluid exudation from the inflamed area, with some opacification of the inner surface of the disk.
Typically, nerve conductivity is impaired, with loss of visual acuity and visual field changes. When the retrobulbar portion of the nerve is affected, ophthalmoscopic examination initially reveals no significant alteration, and the disease is called retrobulbar neuritis.
Ideally, treatment is directed toward the underlying cause. Systemic corticosteroids are helpful in retrobulbar neuritis by shortening the course of the disease. Their value in influencing the final outcome is under investigation.
In papillitis with minimal evidence of collagen vascular disease or other signs of multiple sclerosis, pulsed intravenous methylprednisone therapy continued over days to weeks may be indicated as the visual loss is often more extensive.
Optic neuritis in demyelinating disease has a favorable prognosis without treatment for an individual attack, but over a period of years significant visual loss is the rule since permanent damage results from recurrent attacks.