Optic neuritis, symptomology and medical management.

Abstract

By definition optic neuritis is an inflammatory lesion of the optic nerve which is located somewhere between the optic disk and the optic chiasm. The process can be purulent and acutely destructive or it can involve interstitial tissue proliferation and degeneration of the nerve fibers. If it affects the nerve sheaths it is actually a perineuritic meningitis. When the inflammation involves the disk a papillitis is produced. It is often difficult to distinguish this reaction from a papilledema caused by increased intracranial pressure. However in papillitis the swelling is rarely more than (two) diopters, neighborhood hemorrhage and venous engorgement is less, there is a central scotoma rather than an enlarging blind spot, the scotoma is pronounced for colors, and vision loss is sudden and acute. When the lesion is located beyond the disk it is called retrobulbar neuritis. The functional findings are the same but the ophthalmoscopic examination is negative. Chiasmal neuritis presents the same symptoms but the visual and field defects are usually bilateral. Any of the preceding conditions can result in disk changes and pallor which constitute a type of optic atrophy.