A patient describes an unusually vivid visual experience. Before revealing the answer, decide what distinguishes eidetic imagery from a visual hallucination.

Ask whether the patient recognises the experience as a memory of something previously seen, or as a current perception of something happening now. Eidetic imagery is specifically recognised by the patient as a memory, however unusually vivid and picture-like, of something they genuinely saw before. A visual hallucination is instead experienced as a current perception, with no accompanying recognition that it is simply a memory being recalled; the patient perceives it as though it is happening now, with no real object present. Whether the experience is anchored to a recognised past event, or presents as a live, current perception, is the key distinguishing detail.