Non-arteritic anterior ischaemic optic neuropathy (NAION) Non-arteritic anterior ischaemic optic neuropathy (NAION) refers to loss of blood flow to the optic nerve (which is the cable that connects the eye to the brain). This condition typically causes sudden vision loss in one eye, without any pain.  In many cases, the patient notices significant loss of vision in … Continue reading Non-arteritic anterior ischaemic optic neuropathy (NAION)