Amaurosis is an organic loss of visual acuity which can attain blindness and which occurs suddenly in the absence of other ophthalmological changes. It constitutes an ophthalmologic emergency requiring a careful aetiologic work-up in order to determine therapy. We will discuss various aetiologies of amaurosis and its treatment. Amaurosis can be of ophthalmologic origin, i.e., retinal vascular occlusion of neuro-ophthalmologic origin, or ischaemic and inflammatory neuropathy, or it can present as transient unilateral blindness in carotid pathology, during cardiac embolism and in some haematologic disorders. Such unilateral transient blindness can at any time become complicated by definitive ischaemia; it is thus urgent to detect the mechanisms in order to institute treatment. Since the causes of amaurosis are varied, the importance of history taking must be underlined in order to determine the circumstances of the loss of vision, its characteristics and the existence of accompanying signs.