[A case of various illusion, and hallucination caused by occipital lobe infarction].

A 70-year-old right-handed man noticed that the right side of the screen on his television displayed a time lag compared to the other side. For five days before admission, he had characteristic polyopia, visual photopia, and complex hallucination. Upon neurological examination, he showed no abnormal findings except for right homonymous hemianopia. MRI showed acute infarction of the occipital gyri and part of the lingual gyrus in the left occipital lobe. After admission, he experienced various visual hallucinations and visual illusions, including metamorphopsia and micropia, many times. They gradually disappeared after 2 months. Various hallucination was caused by the release of visual information, and illusion was thought to be due to integration failure of visual information. The appearance of complex hallucination in the blind visual field is known due to the damage of the region on the left occipital gyrus. However, the cases with various symptoms such as visual photopia and micropsia are rare.