What to know about cortical blindness

Share on Pinterest

The main symptoms of cortical blindness include:

• Loss of visual perception: The most noticeable symptom is a partial or complete loss of vision despite the physical structure of the eyes being typical.
• Unchanged pupil reflexes: With cortical blindness, the pupils typically react in the usual way to light. This is not usually the case in people with eye damage.
• Visual agnosia: This is a condition where a person cannot recognize familiar objects or faces, even though they may be able to see them.
• Lack of visual fixation and tracking: This describes a difficulty or inability to fixate on visual objects or track moving objects with the eyes.
• Anton syndrome: In some cases, people may deny their blindness, a condition known as Anton Syndrome. They might behave as if they can see, despite having significant visual impairments.
• Visual hallucinations: Some people may experience visual hallucinations.
• Intact eye movements and blinking: Eye movements and blinking often remain typical, which can complicate the diagnosis of cortical blindness.

Learn more about blindness and visual impairments.

The leading causes of cortical blindness in children include:

• occipital lobe irregularities that are present at birth
• perinatal ischemia, which is a restriction in blood flow
• traumatic brain injury to the occipital lobe

Causes of cortical blindness in adults include:

• cardiac embolism
• Creutzfeldt-Jakob disease
• eclampsia
• head trauma
• hyponatremia, or low sodium levels
• infections, such as HIV
• mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS syndrome)
• occipital lobe epilepsy
• severe hypoglycemia, or low blood sugar levels
• stroke

Diagnosing cortical blindness involves a combination of clinical assessments, eye examinations, and neuroimaging studies.

Clinical assessments

Doctors gather a detailed medical history, including any incidents that could have led to brain damage. They typically also ask about symptoms, such as:

• changes in vision
• difficulty recognizing objects
• unusual visual experiences

Eye examinations

An eye specialist, called an ophthalmologist, examines the eyes to rule out any issues, as the eyes are usually physically typical in cortical blindness. Tests may include checking the following:

• visual acuity
• pupil response to light
• eye movements

Neuroimaging studies

A neurologist assesses neurological function, looking for signs that suggest brain involvement.

This can include checking for visual field deficits, assessing cognitive functions, and examining other cranial nerves and neurological reflexes.

Tests may include:

• An MRI scan: An MRI can reveal damage or irregularities in the visual processing areas of the brain, typically in the occipital lobes.
• A CT scan: A CT scan might also quickly assess for brain damage, especially in emergency settings.
• Other diagnostic tests: Doctors may use additional tests such as an EEG to monitor brain activity or a PET scan for more detailed brain imaging.

Treating cortical blindness involves addressing the underlying cause and helping people adapt to the condition.

Since cortical blindness results from damage to the brain’s visual processing areas, the focus is often on rehabilitation and maximizing any remaining vision.

This may involve the following:

• Medical treatment: If the cortical blindness is due to a reversible condition, such as inflammation or an infection, doctors may use medications such as antibiotics or anti-inflammatory drugs.
• Surgical intervention: In cases of brain injury, stroke, or tumors, surgery might be necessary to alleviate pressure or repair damage.
• Visual rehabilitation: This involves training to use any remaining vision effectively. Techniques include learning ways to maximize the use of peripheral vision if a person loses their central vision.
• Orientation and mobility training: Specialists can teach a person navigation skills that involve using other senses, such as hearing and touch.
• Daily living skills: Occupational therapists can help people learn new ways to perform everyday tasks.
• Adaptive techniques and devices: People can participate in training to learn how to use adaptive devices such as text-to-speech programs, screen readers, and other assistive techniques and technologies.

Learn more about mobility aids.

Various complications can occur due to cortical blindness, such as:

• Mobility and navigation challenges: The condition can cause difficulties moving around safely and independently due to the inability to perceive visual cues. This can increase the risk of falls and accidents.
• Challenges in daily living: Difficulties with everyday tasks such as reading, recognizing faces, cooking, or driving may significantly affect a person’s independence and quality of life.
• Cognitive impairments: People can experience other cognitive issues alongside cortical blindness, such as memory problems, difficulty with spatial orientation, or language difficulties.
• Visual hallucinations: Some people may experience Charles Bonnet Syndrome, where they have complex and vivid visual hallucinations despite being blind.
• Learning challenges: In children, cortical blindness can significantly impact learning and development, meaning specialized educational approaches are necessary.

Mental health challenges

Experiencing vision loss may also affect a person’s mental health and could potentially lead to issues such as the following:

• depression
• anxiety
• stress

A loss of independence and difficulty in social interactions may create feelings of isolation and loneliness.

Resources are available to help with any mental health concerns a person might experience.

Managing complications

With rehabilitation and adaptive techniques, many people with cortical blindness can learn to manage the effects of vision loss and maintain a degree of independence.

Managing complications of cortical blindness typically involves a multidisciplinary approach, including:

• vision rehabilitation
• occupational therapy
• psychological counseling
• support from family and caregivers

Addressing these challenges early and comprehensively can significantly improve the quality of life for people with cortical blindness.

The outlook for someone with cortical blindness can vary significantly depending on several factors, including the following:

• the underlying cause
• the extent and location of brain damage
• the individual’s age and overall health
• the timeliness and effectiveness of treatment and rehabilitation

Some people may experience partial vision recovery, especially if the brain damage is not extensive or if it is due to a reversible condition. However, in many cases, vision loss is permanent, especially if the damage to the occipital cortex is severe.

Here are the answers to some common questions about cortical blindness.

What do people with cortical blindness see?

People with cortical blindness may experience a range of visual perceptions, depending on the extent of the damage to the brain. They may have partial vision or see complete darkness, vague shadows, or nothing at all.

Some may have visual hallucinations or a phenomenon called blindsight, where they can respond to visual stimuli without being consciously aware of seeing them.

Can cortical blindness be corrected?

Cortical blindness is typically not fully treatable, especially if the brain damage is extensive.

However, some improvement is possible in cases where the damage is not severe or is temporary. Neuroplasticity, which is the brain’s ability to adapt and reorganize itself, plays a role in recovery.

Learn about neuroplasticity exercises.

Cortical blindness is a type of blindness where the brain cannot process visual information despite the eyes being functional.

Rehabilitation and adaptive techniques and technologies can help many people with cortical blindness manage the effects of vision loss on daily activities and maintain a degree of independence.