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. Visual illusions are more likely to occur in conditions of dim or poor lighting. Visual illusions may, under circumstances of dim or poor light be normal. Or Visual illusion may be abnormal-a forerunner of visual hallucinations.