What is Anton Syndrome (Anton’s Blindness)?
Cortical blindness is a rare neurological disorder that causes loss of vision in both eyes because of damage to a specific part of the brain called the occipital cortex. Another term associated with this condition is Anton-Babinski syndrome (ABS) which involves two main symptoms: the person is unaware of their loss of vision and they create memories of experiences that never happened, despite clearly suffering from visual loss.
This type of blindness does not stem from problems in the eyes, but rather from issues in the brain. The first mention of a case resembling ABS traces back to the Roman era. A philosopher named Seneca wrote about a slave who suddenly went blind and denied the fact, insisting that the room was dark. This incident outlines the critical characteristics of ABS: sudden blindness, denial of vision loss, yet generally unaffected thinking abilities.
Another historical account related to ABS was documented by a French writer named Michel de Montaigne during the Renaissance era, who mentioned a nobleman denying his blindness. Later in 1895, an Austrian neurologist, Gabriel Anton discovered similar cases, including patients who were objectively blind and deaf but refused to acknowledge their condition. In 1914, French-Polish neurologist Joseph François Babinski coined the term “anosognosia” to describe this denial of deficiency in stroke patients that affected one side of their body.
The cause of ABS was proposed in 1920 by a researcher named Meyer. It was suggested that the condition resulted from blockages in the branches of the artery that supplies the back of the brain, specifically the region involved with vision.
What Causes Anton Syndrome (Anton’s Blindness)?
There can be many reasons why certain medical conditions occur, including:
1. A type of stroke where the back part of the brain isn’t getting enough blood (this is the most common cause)
2. Having heart surgery
3. An X-ray test to look at the blood vessels in your brain
4. A rare genetic disorder known as MELAS, which stands for mitochondrial myopathy, encephalomyopathy, lactic acidosis, and stroke-like episodes
5. Having high blood pressure during pregnancy (preeclampsia)
6. Severe bleeding during birth (obstetric hemorrhage)
7. Trauma or injury to the head
8. A rare inherited disorder called adrenoleukodystrophy
9. A sudden increase in blood pressure affecting the brain, known as hypertensive encephalopathy
10. Having inflammation of your brain and spinal cord’s blood vessels due to an overreaction of the immune system.
Other causes could include a condition where multiple parts of the brain are damaged in patients with HIV, a disease that affects the nervous system called multiple sclerosis, and a condition that temporarily affects the brain and is often related to high blood pressure, known as posterior reversible encephalopathy syndrome (PRES), which can also occur because of COVID-19 pneumonia. Conditions like fat embolism syndrome, which is a blockage of an artery caused by a fat globule, and Trousseau syndrome, a condition where blood clots form in veins usually related to cancer, can also lead to these medical issues.
Risk Factors and Frequency for Anton Syndrome (Anton’s Blindness)
Anton-Babinski syndrome is an extremely rare condition. Only 28 cases were reported between the years 1965 and 2016.
Signs and Symptoms of Anton Syndrome (Anton’s Blindness)
Cortical blindness is diagnosed when the following characteristics are present:
- No ability to see anything, even differences between light and dark
- Absence of reaction to threatening gestures
- Ability to respond normally to light and pupil reflexes
- No abnormalities in a close examination of the back of the eye
- Ability to move their eyes normally
Patients with cortical blindness tend to behave as if they can see completely fine. However, they may run into furniture, trip over objects, and struggle to navigate around. They may even try to walk through walls or closed doors. It becomes clear something is not right when they start talking about people or things that aren’t there. Additionally, they may appear confused at times. Some individuals with cortical blindness may deny that they’re unable to see. They might blame their vision problems on poor lighting, and insist that they’re not blind. This denial can sometimes lead to dangerous situations.
Testing for Anton Syndrome (Anton’s Blindness)
If you find yourself faced with certain neurological concerns, your doctor will likely follow a very specific process to understand your condition better:
First, they will conduct a thorough examination of your overall health and ask about your medical history. Afterwards, they’ll perform a detailed check of your eyes using a neuroophthalmological evaluation. This includes tests for your vision sharpness or ‘visual acuity’, and ‘field of vision’, which is all the area you can see without moving your eyes or head.
Next, they could conduct a Magnetic Resonance Imaging (MRI) scan of your brain. This is a type of imaging technology that can create detailed pictures of the structures within your brain to identify any potential issues.
To exclude the possibility of a stroke caused by heart or major blood vessel issues, your doctor may conduct an echocardiogram, which is a type of ultrasound for your heart, and a carotid Doppler. The Doppler is a special ultrasound technique that captures images of your carotid arteries responsible for carrying blood from your heart to your brain.
In certain tricky situations and for young patients, your doctor might also order a visual evoked potential test. This test measures the electrical signals to your brain that are triggered by visual stimuli to further understand your condition.
Treatment Options for Anton Syndrome (Anton’s Blindness)
The treatment for ABS, or Alien Hand Syndrome, depends on what caused it. If a stroke caused it, doctors usually prescribe medicine to prevent blood clots. It’s also important to check if there’s any heart-related condition that might have led to the stroke.
What else can Anton Syndrome (Anton’s Blindness) be?
When diagnosing ABS syndrome, there are several other conditions that doctors need to consider due to their similar symptoms. These conditions include:
- Problems with brain-related vision (Cerebral visual impairment)
- Delayed development of vision
- Blindness in one half of the visual field (Homonymous hemianopia)
- Difficulty recognizing faces (Lack of facial recognition)
- Challenges identifying objects, although they can be seen (Visual agnosia)
- Ignoring half of the visual field (Visual neglect)
- Problems perceiving visual information (Visual perceptual disorders)
It’s very important for the doctor to consider these possibilities and perform the necessary tests to arrive at the right diagnosis.
What to expect with Anton Syndrome (Anton’s Blindness)
There have been cases where people recover their eyesight in conditions that result in corticosteroid Anterior Basement Membrane Dystrophy (ABMD), like hypertensive encephalopathy and cortical hypoperfusion. In such circumstances, addressing the root cause might help to clear the symptoms.
The likelihood of regaining sight after cortical blindness varies. It can depend on the patient’s age, the initial cause and severity of the blindness, how long they’ve been blind, how quickly they begin to recover, and their previous medical history.
Possible Complications When Diagnosed with Anton Syndrome (Anton’s Blindness)
People with ABS, who often pretend to see, are at risk of getting hurt as they continue to move around.
Preventing Anton Syndrome (Anton’s Blindness)
Advice can be given to patients depending on the cause of their condition. However, managing confabulation, which means making up stories unconsciously, might be challenging with counseling alone.
