Visual Hallucinations: Causes, Testing, and Treatment

What Are Visual Hallucinations?

A visual hallucination is seeing something that isn’t actually presentanything from simple
lights, shapes, and patterns to detailed people, animals, or scenes. The key idea is that your visual system
(eyes + brain) is generating an image without an external stimulus.

Hallucination vs. illusion vs. “my eyes are messing with me”

• Hallucination: You see something that isn’t there at all (a person in the room who isn’t
  present).
• Illusion/misperception: Something real is misinterpreted (a coat on a chair looks like a
  person in dim light).
• Visual disturbance: Changes like blurriness, floaters, zig-zags, shimmering, or blind spots
  may occur with migraines, eye disease, or neurologic issuesand aren’t always “formed images.”

Simple vs. complex hallucinations

Clinicians often divide visual hallucinations into:

• Simple (unformed): flashes, sparkles, geometric shapes, colored spots, or patterns.
• Complex (formed): faces, people, animals, objects, or whole scenessometimes realistic,
  sometimes cartoonish.

This distinction matters because different causes tend to cluster in different “styles” of visuals.

Why Visual Hallucinations Happen: The Big Picture

Visual hallucinations usually show up when one of these systems is disrupted:

• Input problem: the eyes/retina aren’t sending clear signals (vision loss).
• Processing problem: the brain’s visual centers are irritated, injured, or degenerating.
• Chemistry problem: medications, substances, infections, metabolic changes, or withdrawal alter brain signaling.
• Sleep-state overlap: dreaming “bleeds” into wakefulness during falling asleep or waking up.

Translation: this isn’t automatically a psychiatric issueand in many cases, it’s not. In fact, purely visual
hallucinations often point toward neurologic, eye, medication, or sleep-related causes.

Common Causes of Visual Hallucinations

1) Vision loss–related hallucinations (Charles Bonnet syndrome)

Charles Bonnet syndrome (CBS) is one of the most misunderstood causes. People with partial
vision lossoften from age-related macular degeneration, glaucoma, diabetic retinopathy, retinal disease, or
other eye conditionsmay experience vivid visual hallucinations while otherwise thinking clearly.

The simple explanation: when the brain gets less visual input, it sometimes “fills in the gaps,” like a
screensaver turning on when your monitor goes idle. CBS hallucinations can be patterns, faces, animals,
or detailed scenes. Many people maintain insight that the images aren’t real, especially once it’s explained.

Clue: hallucinations are visual only (no voices), and they occur in the setting of reduced
visionoften with preserved attention and memory.

2) Migraine aura and other migraine-related visual phenomena

Migraine isn’t just “a bad headache.” In migraine with aura, visual symptoms can appear before or during the
headacheor sometimes without headache at all. Classic descriptions include shimmering zig-zag lines,
sparkles, blind spots, or “fortification” patterns that slowly expand or move across the field of vision.

Clue: aura symptoms often evolve over minutes and typically resolve within an hour. If visual
changes are new, unusually severe, or paired with weakness, trouble speaking, or confusion, they need urgent
medical evaluation to rule out stroke or other emergencies.

3) Delirium (acute confusion from illness, medications, or metabolic changes)

Delirium is a sudden change in attention and thinkingoften fluctuating over hours to dayscommonly triggered
by infection, dehydration, medication effects, hospitalization, intoxication/withdrawal, or metabolic problems.
Visual hallucinations can occur, especially alongside confusion, disorientation, or sleep-wake cycle changes.

Clue: the person seems “not themselves,” has trouble focusing, and symptoms can vary
throughout the day. Delirium is a medical problem that needs prompt evaluation.

4) Dementia with Lewy bodies and Parkinson’s disease–related hallucinations

In Lewy body dementia (LBD), recurrent visual hallucinations can be an early feature. People
may see well-formed figuresoften people or animalssometimes with remarkable detail. Parkinson’s disease can
also involve hallucinations (especially later in the disease or with medication changes), sometimes referred
to as Parkinson’s disease psychosis.

Clue: hallucinations occur alongside other features such as changes in attention/alertness,
movement symptoms, REM sleep behavior disorder (acting out dreams), or progressive cognitive changes.

5) Seizures involving visual brain regions (occipital lobe seizures)

Seizures starting in the occipital lobe (the brain’s visual processing area) can produce brief, stereotyped
visual phenomenaoften colored flashes, shapes, or moving spots. These episodes may be seconds to a few minutes
and can sometimes be followed by other neurologic symptoms.

Clue: episodes are short, repetitive, and similar each time. A clinician may recommend an EEG
and brain imaging depending on the presentation.

6) Sleep-related hallucinations (hypnagogic/hypnopompic)

Hypnagogic hallucinations happen as you’re falling asleep, and hypnopompic
hallucinations happen as you’re waking up. They’re common, often visual, and frequently benign. Stress, sleep
deprivation, irregular sleep schedules, and conditions like narcolepsy can increase the odds.

Clue: the timingright at sleep transitionsplus otherwise normal daytime thinking.

7) Medications and substances

Some prescription medications can trigger or worsen hallucinations, especially in older adults or at higher
doses. Examples often discussed in clinical references include certain anticholinergic medicines, some
Parkinson’s medications, steroids, and sedatives. Substance intoxication or withdrawal can also play a role.

Important: never stop a prescribed medication suddenly without talking to a clinician. The
goal is a careful medication review and a safe plan.

8) Psychiatric conditions (less commonly “visual only”)

Psychiatric disorders can involve hallucinations, but visual hallucinations by themselves are less typical as
the only symptom. If hallucinations occur with paranoia, major mood changes, disorganized thinking, or loss of
reality testing, a mental health evaluation may be part of the workupespecially after medical causes are
considered.

When Visual Hallucinations Are an Emergency

Some situations should be treated as urgentespecially if hallucinations are new, sudden, or paired with other
concerning symptoms. Seek emergency care or call local emergency services if any of the following are present:

• Stroke-like symptoms: face drooping, arm weakness, speech difficulty, severe imbalance.
• Sudden major vision change: sudden loss of vision, new double vision, or severe visual disturbance.
• Severe confusion or agitation (possible delirium).
• New seizure or repeated brief episodes with impaired awareness.
• Severe headache with neurologic symptoms, especially if it’s the “worst headache” of your life.

If you’re unsure, it’s safer to be evaluatedbecause timing matters for conditions like stroke and serious
infections.

How Clinicians Evaluate Visual Hallucinations

A good evaluation is less about one magic test and more about matching clues. Expect a clinician to ask:

Key questions that shape the diagnosis

• What do you see? (patterns vs. formed images; people/animals; moving vs. still)
• How long does it last? seconds, minutes, hours?
• How often? once, daily, clustered?
• Insight: do you recognize it isn’t real?
• Timing: only at sleep transitions? after medication changes? during illness?
• Other symptoms: headache, weakness, confusion, tremor, memory changes, fever?
• Vision status: any known eye disease or recent vision loss?
• Medication/substance review: new meds, dose changes, interactions?

Typical exam components

• Vision and eye exam: visual acuity, visual fields, retinal/optic nerve assessment.
• Neurologic exam: strength, sensation, coordination, reflexes, eye movements.
• Cognitive screening: attention, orientation, memoryespecially if delirium or dementia is suspected.

Testing: What May Be Ordered (and Why)

Not everyone needs every test. Testing is usually targeted based on the story and exam. Common categories
include:

Eye-focused testing

• Comprehensive eye exam (often the first step if vision loss is present).
• Visual field testing if there’s concern for optic nerve or neurologic field loss.
• Retinal imaging depending on suspected eye disease.

Blood and urine tests

These can help identify reversible triggers such as infection, dehydration, electrolyte imbalance, low oxygen,
thyroid issues, vitamin deficiencies, or metabolic problems.

Brain imaging

• CT or MRI may be used to look for stroke, tumor, inflammation, bleeding, or structural lesions.

EEG (brain wave testing)

If seizures are suspectedespecially with brief, stereotyped visual episodesan EEG may help support the
diagnosis.

Neuropsychological or dementia-focused evaluation

If symptoms suggest Lewy body dementia or another neurodegenerative condition, clinicians may use cognitive
testing, detailed history, and sometimes specialty referrals to guide diagnosis and care.

Treatment: What Actually Helps (Depends on the Cause)

There isn’t one universal “anti-hallucination” fixbecause hallucinations are a symptom, not a standalone
disease. Treatment works best when it targets the underlying driver.

For Charles Bonnet syndrome (vision-loss related)

• Education and reassurance: simply knowing CBS is a known phenomenon can reduce fear.
• Optimize vision: update glasses, treat reversible eye issues where possible, use low-vision aids.
• Practical tricks: improve lighting, blink or shift gaze, change the environment, or briefly close/open eyes.
• Address stress and sleep: anxiety and fatigue can make hallucinations more frequent or intense.

Medication is not routinely required for CBS, and responses can varyso the focus is usually on vision support,
reassurance, and quality-of-life strategies.

For migraine-related visual symptoms

• Acute migraine treatment (as recommended by a clinician) and trigger management.
• Prevention for frequent attacks (sleep regularity, hydration, stress reduction, preventive meds when appropriate).
• Rule-out when new: a first-time aura or major change in aura pattern often warrants medical evaluation.

For delirium

• Treat the trigger: infection, dehydration, medication toxicity, metabolic imbalance, etc.
• Support the brain: sleep hygiene, reorientation (clocks/lights), glasses/hearing aids, pain control, mobility, hydration.
• Medication caution: sedating medications can sometimes worsen delirium; decisions are individualized.

For Lewy body dementia and Parkinson’s-related hallucinations

• Review meds: sometimes hallucinations worsen after medication changes.
• Non-drug strategies: reduce shadows, maintain routine sleep, simplify overstimulating environments.
• Targeted medications: in some cases, clinicians consider specific options designed to reduce psychosis symptoms while minimizing movement side effects.

Because people with Lewy body conditions can be sensitive to certain antipsychotic medications, treatment
choices should be handled carefully by clinicians familiar with these disorders.

For seizure-related visual hallucinations

• Anti-seizure treatment (if epilepsy is diagnosed).
• Address underlying lesions if imaging reveals a treatable structural cause.
• Safety planning for episodes (avoid risky activities until evaluated).

For sleep-related hallucinations

• Fix the sleep schedule (consistent bed/wake times).
• Reduce sleep debt and manage stress.
• Evaluate for narcolepsy if there are additional symptoms (excessive daytime sleepiness, sleep paralysis, cataplexy).

For medication/substance-related hallucinations

• Medication review to identify recent additions, dose increases, or interactions.
• Gradual adjustments under supervision to avoid withdrawal problems or symptom rebound.
• Treat underlying medical issues that raise sensitivity (dehydration, kidney issues, infection).

What You Can Do While You’re Getting Answers

If you or someone you care about is experiencing visual hallucinations, these steps can help you prepare for a
medical visit and reduce distress:

Track patterns (without turning your life into a spreadsheet)

• Time of day (especially sleep-related timing)
• Duration and frequency
• What the images look like
• Triggers (fatigue, stress, dim lighting, headaches)
• New medications or dose changes
• Associated symptoms (confusion, fever, tremor, headaches)

Environment tweaks that often help

• Increase lighting and reduce shadows (especially in the evening).
• Reduce visual clutter if scenes feel overwhelming.
• Use glasses/hearing aids if neededbetter sensory input can reduce misperceptions.
• Prioritize sleep (sleep deprivation can make the brain extra “creative”).

If someone is scared by what they’re seeing

Calm reassurance helps: “I believe you that this feels real. Let’s check the room together.” If the person has
insight, you can gently validate: “That sounds like a visual hallucinationlet’s note it and tell the doctor.”
In dementia-related hallucinations, arguing about “real vs. not real” can backfire; focusing on safety and
comfort is usually more effective.

Real-World Experiences: What People Often Describe (and What It Feels Like)

The medical definitions are tidy. Real life is not. People describe visual hallucinations in surprisingly
consistent waysyet the emotional impact can vary widely depending on insight, context, and how unexpected the
experience is.

The “pattern generator” experience (often migraine or sleep-related)

Many people report simple visuals: shimmering zig-zags, sparkles, geometric grids, or waves of distortion.
Migraine aura is commonly described as slowly expanding shapes or shimmering edges that move across the visual
field. Sleep-transition hallucinations can feel like quick flashes, shapes, or shadowy impressions as the brain
shifts gears between wakefulness and dreaming.

People often say the most stressful part isn’t the visual itselfit’s the uncertainty: “Is this a migraine?
Am I about to pass out? Is this something worse?” Once a clinician confirms a benign pattern and helps set a
plan for when to worry, the fear often drops dramatically.

The “movie overlay” experience (common in vision loss and Lewy body conditions)

With vision loss–related hallucinations (like Charles Bonnet syndrome), people sometimes describe detailed,
silent imagesfaces, animals, or scenesappearing like a transparent film layered over the real world. A person
might see a row of tiny figures marching along the carpet, or a dog sitting quietly in a corner. The images can
fade when lighting changes or when attention shifts.

In Lewy body dementia or Parkinson’s-related hallucinations, the images are often well-formed and can be
persistent. Some people describe seeing children, pets, or unfamiliar visitors in the home. When the person has
insight, they may say, “I know it sounds strange, but I keep seeing someone by the window.” When insight is
reduced, the experience can be more frightening and may lead to distrust or anxietyespecially in unfamiliar
environments or during times of stress.

How emotions change the experience

A consistent theme is that stress, fatigue, illness, and dim lighting tend to make visual
hallucinations more frequent or intense. People also report that the first few episodes are the hardest. After
learning what’s happeningand seeing that episodes passmany feel more in control.

What people say helps “in the moment”

• Changing the scene: turn on lights, open curtains, move to a different room.
• Resetting attention: blink, look away and back, stand up, take a sip of water.
• Grounding cues: name real objects in the room, focus on textures, sounds, or breathing.
• Reducing overstimulation: lower background noise, step away from busy visual patterns.
• Sleep and routine: consistent sleep and predictable daily rhythm often reduce episodes over time.

These strategies don’t replace medical evaluation, but they can make the experience less distressing while
you’re working on diagnosis and treatment.

What people wish clinicians asked sooner

Many people hesitate to mention hallucinations because they fear being judged or misunderstood. In reality,
clinicians see hallucinations across many medical contextseye disease, migraine, delirium, medication effects,
dementia, sleep disordersand the details are useful, not shameful. People often say they felt immediate relief
when a clinician normalized the conversation: “Thank you for telling me. Let’s figure out what category this
fits into.”

If you’re preparing for an appointment, bringing a short description (“what I saw,” “how long,” “how often,”
“what else was happening,” and “medication changes”) can speed up the path to answersand make the whole thing
feel less like your brain is freelancing without a contract.