Phenomenological differentiation of delusions into illusions and hallucinations is generally useful. Different forms of visual delusions have typical clinical characteristics, which presumably account for different pathophysiological correlates. All forms of visual perseveration occur paroxysmally, if they are the result of a brain lesion, and are usually unilateral and then contralateral to the lesion. Various casuistic data reveals how different the pathogenesis of visual palinopsia can be: epilepsy, intracranial tumor, cerebral infarction, migraine, traumatic brain injury and so on. Polyopia presents special type of visual perseveration. Photopsias, also called phosphenes or photomes, appear in different diseases. Before a neurological disorder is taken into consideration, diseases of the eye or intoxication and side effects of medicine should be excluded. The pathogenesis of the hallucinations is diverse; the visual hallucinations in epilepsy are most frequently the result of traumatic brain injury, cerebral hemorrhage or, occasionally, cerebral ischemia or tumor.