The Effects of an Occipital Lobe Stroke

An occipital lobe stroke happens in the back of the brain. This part of our brain helps us recognize what we see. Thet means strokes in the occipital lobe can cause vision changes.

Occipital lobe strokes are not common. Strokes in the frontal, parietal, or temporal lobes happen more often. Strokes almost always affect only one side of the brain. Occipital lobe strokes can happen in one or both occipital lobes.

This article will go over why occipital lobe strokes happen. You will also learn the symptoms of occipital lobe strokes and how strokes in this part of your brain can affect your vision.

Causes

Occipital lobe strokes do not happen often because the blood supply to this part of your brain is set up in a special way.

You have three arteries along the back of your neck. They are called the vertebral arteries, the posterior cerebral arteries, and the basilar arteries.

It's the job of these arteries to get blood with oxygen in it to the occipital lobes of your brain. If the blood supply to one or both the occipital lobes gets stopped, it causes a stroke.

The three arteries connect and create a "backup'" system called a redundant blood supply. This allows the parts to take over for each other if needed. For example, if one small artery is blocked, another can step up to keep the blood flowing. This can help prevent a stroke.

Even with a backup system, strokes still happen. Occipital lobe strokes can also occur at the same time as a cerebellar stroke or a brainstem stroke.

Visual Changes

An occipital lobe stroke can cause visual changes. If you have a stroke in this part of your brain you may experience partial vision loss, complete blindness, and seeing things that are not really there (visual hallucinations). Some people develop other vision syndromes.

The occipital lobe is not the same shape and size all around. Each part of the lobe plays a different role in helping you see. The visual problems caused by a stroke in this lobe depend on which region of it is affected. Strokes in other parts of the brain can also cause vision changes.

Homonomous Hemianopia

When the stroke affects most of the occipital lobe on one side of the brain, you may lose half of the vision in each eye. This condition is called homonymous hemianopia.

A stroke survivor with homonymous hemianopia cannot see objects on one side. It will be the side that is opposite from the side where the stroke happened.

For example, if the stroke was in the left occipital lobe of the brain, the person would have a hard time seeing objects to the right.

This vision problem usually affects both of your eyes. You won't be able to see your right side from your right eye or your left eye.

However, your eyes work together to see. This is called visual integration. If you have homonymous hemianopia, your eyes might not be affected to the same degree.

Central Vision Defect

Central vision is what you see in the middle of your field of vision when you're looking straight ahead. Your central vision is handled by a part of your brain called the occipital pole. While strokes in this part of your brain are rare, they do happen.

An occipital pole stroke can cause a big blind spot in the middle of your vision. The blind spot will be on the same side as the stroke.

This blind spot would make you have trouble seeing the face of a person standing directly across from you.

You might not be able to see the person's nose, upper lip, and the lower half of their eye on the side where you have the blind spot. However, you would still be able to see the person's shoulder and the top of their head.

Cortical Blindness

When the occipital lobes of the brain are completely affected by a stroke, it causes total vision loss. This is called “cortical blindness.” It means the vision loss was caused by damage to the cortex of the brain.

Some stroke survivors know that they cannot see, but others do not. Some people are not aware of their blindness and experience visual hallucinations. The is called Anton syndrome or Balint syndrome.

Some occipital stroke survivors have a condition called visual anosognosia. The condition means that the brain ignores one side of the person's vision.

There are also other symptoms of an occipital stroke, including:

• Visual illusions
• Face blindness (prosopagnosia)
• Inability to read but can still write (alexia without agraphia)

Summary

The occipital lobes of the brain help you see. If a stroke happens in this part of the brain, it can change your vision.

For example, you might not be able to see a person's face well if they're standing right in front of you. You might not be able to see things on one side of your body. Some people see things that are not there. Other people lose their sight completely after a stroke.

Occipital lobe strokes are not common. However, other strokes can also cause vision changes.

A Word From Verywell

If you're a stroke survivor, you might notice changes to your vision. Strokes in different parts of your brain can change your vision, but occipital lobe strokes almost always do.

If you've had an occipital lobe stroke, you might not realize that you've lost your vision. On the other hand, your vision might have changed a lot. These changes can be scary and will affect your life in a major way.

It's also important to know that sudden, intense vision changes can be a sign that you're having a stroke. If you suddenly cannot see or are seeing unusual things, seek medical care right away.