Table 1:

Type of hallucination

Feature	Possible Cause
Monocular	Eye disease or optic nerve proximal to optic chiasm
Limited visual field	Focal lesion in visual pathway
Simple, brief, unformed	Eye disease, migraine, seizure, calcarine lesions
Visual distortion	Seizures, CJD
Lilliputian	Delirium, intoxication, withdrawal
Frightening	Delirium, hallucinogens, psychosis
Unconcerned/preserved insight	Charles Bonnet syndrome, peduncular hallucinosis