Optic neuritis
Optic neuritis is predominately an autoimmune condition most common in middle-aged females producing demyelination of the optic nerve. Swelling of the optic nerve head ensues and may be visible on fundoscopy as papillitis. An acute and often progressive visual loss results.
Optic neuritis is a common presentation (approximately 15-20% of cases) in multiple sclerosis. [9]
Monocular optic neuritis is the presenting finding in up to 20% of patients with multiple sclerosis.
Acute ischaemic optic neuropathy
Acute ischaemic optic neuropathy is most commonly caused by giant cell arteritis, but can also be seen with other conditions such as polyarteritis nodosa and systemic lupus erythematosus (SLE).
In giant cell arteritis, vascular wall inflammation leads to lumen narrowing and eventual occlusion, resulting in ischaemia and infarction of the optic nerve. [10] The underlying cause of this inflammation remains uncertain, with autoimmune and infective mechanisms thought to be the main contributors.