Occipital Stroke and Anton Syndrome

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Anton syndrome is a rare condition found in patients who have lost their vision after brain damage to the occipital lobes. The main characteristic of Anton syndrome is that these patients do not realize that they are blind.

It occurs most often in patients who have had an occipital stroke. However, Anton syndrome can also be a complication of other diseases that impact the brain.

This article provides more information about the symptoms, causes, diagnosis, and treatment of Anton syndrome.

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Symptoms

Symptoms of Anton syndrome include:

  • Vision loss
  • Visual anosognosia, which means the person is unaware of being blind
  • Confabulations, or presenting false memories of seeing something that wasn't there

Patients with Anton syndrome will deny that they are blind despite evidence to the contrary. They will act as though they are not actually blind.

For example, if you held an object and asked what it is, they would answer confidently with a guess. They would act as though that was the correct answer, even if they are wrong. If you ask them to describe what they are seeing, they will make up a whole visual scenario for you.

Even though this behavior may seem puzzling, they are not lying to you. Their brain is simply unable to figure out that they are blind.

Causes

Anton syndrome is caused by damage to the brain in the occipital lobe, which is in the back of the brain. The occipital lobe allows you to see as well as interpret what you're seeing.

One of the main causes of Anton syndrome is a stroke. This is a medical emergency where blood flow to the brain is interrupted by a ruptured artery or a blood clot. When any part of the brain is deprived of oxygen, brain cells in that area begin to die.

When the occipital lobes of the brain are completely affected by a stroke, the end result is a phenomenon called “cortical blindness.” "Cortical" refers to damage in the brain's visual cortex in the occipital lobe.

When damage to the occipital lobe causes blindness, it could also result in Anton syndrome. However, Anton syndrome is considered a rare condition.

It's unknown exactly how Anton syndrome develops. One theory is that patients with damage to the primary visual cortex also have damage to the visual association cortex. That may cause the lack of awareness of their blindness.

While stroke is the most common cause of Anton syndrome, it can occur with other conditions that cause damage to the occipital lobe. These include:

Diagnosis

To help diagnose your condition, your healthcare provider will typically start with a physical examination. They may see if your eyes can follow a light. They'll talk to you about your sight to get a sense of your awareness of your vision loss.

If they suspect Anton syndrome, they'll likely order imaging tests to help look for damage in the occipital lobe. Tests may include a head computed tomography (CT) scan or magnetic resonance imaging (MRI).

Treatment

Treatment for Anton syndrome will depend on what caused the damage to the occipital lobe. For example, in rare cases where multiple sclerosis causes brain damage, treatment will focus on treating symptoms of MS. This may include intravenous methylprednisolone.

If Anton syndrome was caused by a stroke, therapy would focus on preventing another stroke from causing more damage. This may include medications, such as daily aspirin or statins, and managing risk factors such as blood pressure and glucose (blood sugar) levels.

In some cases, vision may improve with treatment. This often depends on the patient's age and health condition. Someone who's younger than 40, didn't have a stroke, and has no history of hypertension (high blood pressure) or diabetes may be more likely to see improvement.

While improvement of Anton syndrome is less likely after having a stroke, treatment will likely focus on preventing future cardiovascular events.

Summary

Anton syndrome is a rare condition in which the patient loses their sight but doesn't believe they're blind. It's caused by damage in the brain's occipital lobe, usually from a stroke but rarely from other conditions. Treatment focuses on the condition that caused the damage to the brain.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cárdenas G. Cortical blindness (Anton-Babinski syndrome), an unusual manifestation of central nervous system tuberculosisJNSK. 2016;4(6). doi:10.15406/jnsk.2016.04.00157

  2. Ricardo B-AM, Mariana L-IE, AL S-O, Manuel C-CJ, Jesus R-B. Anton syndrome after subarachnoid hemorrhage and delayed cerebral ischemia: A case report. Cerebral Circulation - Cognition and Behavior. 2021;2:100023. doi:10.1016/j.cccb.2021.100023

  3. American Academy of Ophthalmology. Anton syndrome.

  4. Kim N, Anbarasan D, Howard J. Anton Syndrome as a result of ms exacerbation. Neurology: Clinical Practice. 2016;7(2). doi:10.1212/cpj.0000000000000273

  5. Kwong Yew K, Abdul halim S, Liza-Sharmini AT, Tharakan J. Recurrent bilateral occipital infarct with cortical blindness and Anton Syndrome. Case Reports in Ophthalmological Medicine. 2014;2014:1-3. doi:10.1155/2014/795837

Additional Reading
  • Allan Ropper and Robert Brown, Adam's and Victor's Principles of Neurology, 8th Edition McGraw-Hill Companies Inc, United States of America, 2005, pp 417-430.

  • American Stroke Association.