Parkinson patients with dementia, and Parkinson patients suffering from an intellectual decline without dementia, are more likely to experience hallucinations on anti-Parkinson drugs. Visual hallucinations are abnormal. They must be reported. Illusions Visual illusions differ from visual hallucinations. Visual illusions are distortions, misperceptions, or false impressions of real objects.
Visual illusions can consist of seeing an animal's form or shape in a cloud.
Or seeing a person's form or shape in a chair or a coat-rack. Or seeing water shimmering on in the desert. Visual illusions are mirages. Visual illusion are fleeting or transitory. Visual hallucinations usually persist longer.