Very severe visual loss (hand movements or less) is typical of arteritic anterior ischaemic optic neuropathy (AION) and relatively rare in non-arteritic AION (NAION). This study aimed to report the frequency of very poor visual acuity (VA) in NAION. The authors retrospectively reviewed the medical records of 151 consecutive NAION patients seen in one institution between July 2014 and April 2016. The aim was to evaluate the frequency and characteristics of patients with very poor VA in NAION. Hand movements or worse VA was documented in 17 patients (11%). All 17 patients had at least one vascular risk factor and 14 (82%) had at least two vascular risk factors. All patients seen acutely had severe, pallid disc oedema. The authors conclude that, although severe vision loss at presentation does occur in NAION, an extensive workup should be obtained to rule out another cause, especially arteritic AION.