Visual disorders occur after lesions of brain areas involved in visual processing. Bilateral lesions located in occipital, temporal or parietal lobes leads to cerebral blindness, visual agnosia, prosopagnosia, alexia or visuospatial disorders. These visual disorders are difficult to understand by the patient. They see but do not recognise, or they can't see but their eyes are normal, spectacles can not improve their disorders. The diagnosis will be done after a systematic ophthalmologic, neurologic and neuropsychologic examination.