The effect of elevated serum cobalt on the human visual system has not yet been established. In light of recent reports of visual problems with elevated cobalt in association with hip prostheses, this review examines the literature for evidence regarding the effects of cobalt on human visual function. A systematic literature review was undertaken in July 2013. The electronic databases of PubMed (1955 to July week 1 2013), Cochrane Library and EMBASE were searched. Only human studies or case reports written in English were included. Eight case reports were identified. Five case reports involved patients with metal hip arthroplasties, two cases involved patients exposed to environmental cobalt, and one case involved a patient treated medically for anaemia with cobalt chloride. No human prospective studies were identified. Several case reports showed that high serum cobalt may be associated with both irreversible and reversible visual loss, optic neuropathy and atrophy, electrophysiological evidence of abnormal retinal and retinal pigment epithelium function and fluorescein angiographic evidence of abnormal choroidal perfusion.