The authors review the latest evidence regarding how the optic nerves are affected by idiopathic intracranial hypertension (IIH), possible pathophysiology and methods of assessment. IIH is described as a clinical syndrome of raised intracranial pressure of unknown aetiology. A systematic review was conducted to identify studies dealing with 1) idiopathic intracranial hypertension 2) the effects on the optic nerve and 3) relevant optic nerve evaluation methods. Key terms used for the search were: ‘idiopathic intracranial hypertension’, ‘optic nerve’, ‘perimeter’, ‘optical coherence tomography (OCT)’, ‘magnetic resonance imaging (MRI)’ and ‘ultrasound (US)’. Results showed that papilloedema and visual disturbance are the two main clinical manifestations related to the optic nerve in IIH. Available evidence favours axoplasmic stasis as the cause of papilloedema rather than increased venous pressure. Methods of assessment found to aid in the assessment of papilloedema include slit-lamp, stereoscopic fundus photography, fluorescein angiography, perimetry, US, OCT and MRI.