Visual Hallucinations

Visual hallucinations are perceptions of seeing something that isn't actually present. They range from simple shapes, colors, or lights to complex images of people, animals, or entire scenes. While the word "hallucination" often suggests psychiatric illness, visual hallucinations have many neurological and ophthalmological causes.

Types of Visual Hallucinations

Simple (Unformed) Hallucinations

• Photopsias—flashes of light
• Phosphenes—spots or patterns
• Colors or shapes—geometric patterns
• Zigzag lines—often migraine-related

Usually indicate problems with the eye, retina, or early visual pathway.

Complex (Formed) Hallucinations

• People—strangers, relatives (living or deceased)
• Animals—insects, pets, wildlife
• Objects—furniture, buildings
• Scenes—landscapes, events
• May be in color or black and white
• May move or be stationary

Usually indicate problems with higher visual processing areas or Charles Bonnet syndrome.

Common Causes

Eye and Visual Pathway Causes

Charles Bonnet Syndrome

• Visual hallucinations in people with significant vision loss
• Brain "fills in" missing visual input
• Hallucinations are recognized as not real
• No psychiatric illness
• Most common cause of complex visual hallucinations in elderly with vision loss

Retinal conditions

• Retinal detachment—flashes, floaters
• Macular degeneration—distortions, hallucinations
• Retinal tears—photopsias

Optic nerve conditions

• Optic neuritis—may cause phosphenes
• Optic nerve tumors—visual phenomena

Neurological Causes

Migraine

• Visual aura—zigzag lines, scintillating scotoma
• Usually precedes headache
• Lasts 20-60 minutes typically

Seizures

• Occipital lobe seizures—simple visual hallucinations
• Temporal lobe seizures—complex hallucinations
• Often brief, stereotyped

Stroke or brain lesions

• Peduncular hallucinosis—vivid hallucinations from brainstem stroke
• Occipital lobe lesions—simple or complex hallucinations

Dementia

• Lewy body dementia—frequently causes visual hallucinations
• Alzheimer's disease—less common but can occur
• Parkinson's disease dementia

Visual snow syndrome

• Persistent visual "static"
• May include palinopsia (afterimages)

Medical and Medication Causes

Delirium

• Acute confusion with hallucinations
• Caused by infection, medication, metabolic disturbance

Medications

• Anticholinergics
• Parkinson's disease medications
• Opioids
• Many others

Substance use

• Alcohol withdrawal (delirium tremens)
• Drug intoxication or withdrawal
• Hallucinogens

Psychiatric Causes

• Schizophrenia (usually auditory, but can be visual)
• Brief psychotic disorder
• Severe depression with psychotic features

Distinguishing Features

Feature	Charles Bonnet	Migraine Aura	Seizure	Psychiatric
Duration	Minutes to hours	20-60 min	Seconds to minutes	Variable
Awareness it's not real	Yes	Yes	Sometimes	Often no
Associated symptoms	Vision loss	Headache	May have other seizure signs	Other psychotic symptoms
Content	Complex, detailed	Geometric, moving	Simple or complex	Variable
Timing	Random	Before headache	Stereotyped	Varies

When to Seek Care

What You'll Be Asked in Clinic

Your doctor will ask detailed questions:

About the hallucinations:

• What do you see? Describe in detail.
• How long do they last?
• How often do they occur?
• Do you know they aren't real?
• Are they distressing?
• Do you see them with eyes open, closed, or both?
• Any triggers?

About your health:

• Do you have vision loss? From what?
• Any history of migraines?
• Any history of seizures?
• Memory problems or cognitive changes?
• Any psychiatric history?
• What medications are you taking?
• Alcohol or drug use?

How Visual Hallucinations Are Diagnosed

Eye Examination

• Complete dilated exam
• Visual acuity and visual field testing
• OCT imaging

Neurological Examination

• Mental status testing
• Cranial nerve examination
• General neurological exam

Additional Testing

• MRI brain—looking for tumors, stroke, lesions
• EEG—if seizures suspected
• Blood tests—checking metabolic causes, vitamin levels
• Cognitive testing—if dementia suspected

Treatment Options

Treatment depends on the underlying cause:

For Charles Bonnet Syndrome

• Reassurance—knowing the cause isn't psychiatric is often helpful
• Optimizing remaining vision—better lighting, magnification
• Treating eye conditions—if possible
• Coping strategies—looking away, blinking, lighting changes
• Medications—rarely needed; low-dose antipsychotics sometimes help

For Migraine

• Migraine treatment and prevention
• Avoiding triggers
• See migraine-specific treatments

For Seizures

• Antiseizure medications
• Treating underlying cause if identified

For Medication-Induced

• Adjusting or stopping causative medication
• Adding protective medication if needed

For Dementia-Related

• Treating underlying dementia
• Low-dose antipsychotics if needed (carefully, due to risks)
• Non-pharmacological approaches—lighting, reassurance

For Psychiatric Causes

• Antipsychotic medications
• Comprehensive psychiatric care

Living with Visual Hallucinations

Coping Strategies for Charles Bonnet Syndrome

• Remind yourself it's not real—reality testing
• Good lighting—can reduce hallucinations
• Eye movements—looking away, blinking
• Social interaction—engaging with others
• Reduce fatigue—hallucinations may worsen when tired
• Join support groups—others understand

When to Worry

• Hallucinations becoming more frequent or distressing
• New types of hallucinations
• Hallucinations with other neurological symptoms
• Difficulty distinguishing hallucinations from reality

Frequently Asked Questions

Do visual hallucinations mean I'm going crazy?

Not necessarily. Many people with visual hallucinations have no psychiatric illness. Charles Bonnet syndrome is a common cause in people with vision loss and is not a mental health condition.

Why do I see things that aren't there when I have poor vision?

When the brain receives less visual input due to vision loss, it can generate its own images—a phenomenon called "release hallucinations." This is Charles Bonnet syndrome and is surprisingly common in people with significant vision loss.

Are my hallucinations dangerous?

The hallucinations themselves aren't dangerous, though they can be startling or distressing. However, they may indicate an underlying condition that needs treatment, which is why evaluation is important.

Will my hallucinations go away?

It depends on the cause. Charles Bonnet syndrome hallucinations often decrease over time as the brain adapts. Medication-induced hallucinations stop when the medication is adjusted. Some causes require ongoing management.

Should I tell people about my hallucinations?

It's important to tell your doctor. Whether to tell others is a personal choice. Many people with Charles Bonnet syndrome find it helpful to explain to family members so they understand the condition.

References