Optic Perineuritis.

Optic perineuritis (OPN) is now defined as "a form of idiopathic orbital inflammatory disease, in which the specific target tissue is the optic nerve sheath". It may be idiopathic or may occur as part of an underlying systemic inflammatory disease. It is a rare disorder and information regarding its presentation and management is only available in case reports and small case series. This review will discuss the contribution of these recent articles to what is known about idiopathic and secondary OPN. Suggestions will also be made as to how to investigate and treat a patient presenting with OPN.