Two cases of ischaemic optic neuropathy, which occurred as a complication of oncological neck surgery, are reported. These cases are submitted because of the apparent scarcity in the literature of this complication after head and neck surgery. They are also unusual because they presented with different clinical manifestations of ischaemic optic neuropathy after separate forms of bilateral neck dissection. A literature review identifies a small number of similar cases and risk factors and preventative measures are discussed.