RON is essentially defined as a diagnosis by exclusion49. Although the pathogenesis of RON is unclear, its microscopic appearance would suggest an initial microvascular injury that results in perivascular inflammation, hyalinization, and fibrosis of vessel walls and also loss of endothelium and consequently infarction with reactive gliosis49. Using MRI with gadolinium, enhancement of the retro-orbital optic nerves and chiasm usually occurs, probably as a consequence of a disrupted blood brain barrier within the optic nerves14,38. This may be used to differentiate RON from optic neuritis due to demyelination. Therefore, this diagnostic approach is currently proposed to improve the diagnosis of RON14,38. A few months after the onset of RON the gadolinium enhancement of the optic nerves on MRI disappears38.
Until now there is no effective treatment for RON69. The effect of high dose corticosteroids and of anticoagulants is unclear69. Hyperbaric oxygen therapy has also been used to treat RON, but its efficacy is uncertain15,69.

Table 2 (click to view)