Hallucination is defined as perceiving something by the patient without actual presence of external stimulus. Hallucination occurs in patients who are completely conscious and awake. Hallucinations are different from illusions. In illusion the object is present and it is perceived, but it is misinterpreted by the patient as something else from its originality.
Hallucination can be either visual, it can be auditory pertaining to sound and noises, olfactory referring to smell and sometimes taste.
What Is A Visual Hallucination?
Visual hallucination is one such type of sensory misperception, where there is no true existence of any external stimulus to justify the perceived vision.
Here is an example to simplify visual hallucination; a person may see streaks of colors, halos around the light even if there is no true existence of such a thing. In other type of visual hallucination, people see animals and other people or objects which do not exist at all. Seeing and conversing with loved dead ones is common visual hallucination experienced by many elderly individuals.
Causes Of Visual Hallucinations
There are several causes for visual hallucination such as:
Ophthalmic disorders: Cataract, macular degeneration, glaucoma. blindness, total and partial is often associated with visual hallucination. Blindness can be due to any reason, it can be due to cataract formation or due to macular degeneration or any other retinal problem. Most of the time visual hallucination due to blindness is called ‘phantom vision’. Retinal detachment may produce flashes of light, in glaucoma where there is raised ocular pressure, patient may complain of seeing rainbow.
Neurological disorder: In optic nerve disorder, patient may experience bright flash of light momentarily with horizontal movement of eyes. Usually it occurs in dark or when the eyes are closed.
Brain stem lesions: visual hallucination resulting from brain stem lesions occur in the evening which may consist of scenes of flowers, animals and birds. The patient may like these and become amused with these types of hallucinations.
Migraine: often people suffering from migraine complain of visual hallucinations. Patient may see spots and zig zag line in his vision.
Besides this, other brain lesions and epilepsy are also responsible for visual hallucination.
Toxic and metabolic causes:
- Many conditions such as hepatic diseases, endocrine diseases, vitamin deficiencies, infectious diseases, are associated with visual hallucination.
- Intake of recreational drugs such as marijuana, and other is known to cause visual hallucination. These individual know that their ability to perceive things has become distorted by taking this drugs.
- Many other drugs used in the treatment of depression, Parkinsonism, convulsion also manifest visual hallucination.
- Drug and alcohol withdrawal is also responsible for visual hallucination.
Psychiatric disorders:
- Psychiatric disorder such as schizophrenia is known to cause visual and auditory hallucination.
- A person deprived of his sleep may experience visual hallucination.
- Hallucination may also occur in a hypnotic trance or when a person is under mental stress and fatigue.
Treatment Of Visual Hallucinations
Visual hallucination which can affect the person from his real surrounding has to be treated urgently, as reluctance to treatment can be catastrophic for the person and others.
- A person suffering from visual hallucination should not be left alone as it may lead to paronia and fright in an individual.
- Visual hallucination that is chronic, such as seen in schizophrenic and other psychological disorders may need specific medical treatment.
- People may be taught psychosocial therapy, where the person is taught how to cope with visual hallucination.
- In case of glaucoma and other eye disorders, patient is treated for the underlying glaucoma.