Hemianopia is the loss of half of a person’s field of vision. This can occur due to a variety of factors, but it most commonly results from a stroke.

Hemianopia means a person loses half of their visual field in one or both eyes. In some cases, a person may only lose a quarter of their vision. It is only temporary in some cases.

In this article, we explore hemianopia. We describe the different types, symptoms, causes, diagnoses, treatments, and outlook for people with the condition.

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Hemianopia is a condition that affects a person’s eyesight. It means someone cannot see half of their field of vision. This can occur in either the right or left side of someone’s vision. In many cases, it can occur in both eyes at once.

It is usually the result of damage to the brain. This can then damage the visual pathways, such as the optic nerve, within the central nervous system, resulting in the loss of field of vision.

There are several different types of hemianopia.


Partial hemianopia is when a person loses less than half of their field of vision. If someone loses a quarter of their vision in both eyes, this is known as quadrantanopia.

The term for when a person loses half of their field of vision is complete hemianopia.


This is a type of hemianopia where a person loses vision on the same side in both eyes.

Homonymous hemianopia can affect a person’s quality of life, ability to drive, and ability to navigate. It can result in injuries due to falls.


This is where a person loses half of their field of vision in both eyes but on different sides. If they lose vision on the outer sides of the eyes, experts call this bitemporal hemianopia. If vision loss occurs on the inner sides, experts call this binasal hemianopia.


Superior hemianopia is where a person loses their vision in the top half of each eye.


This is a type of hemianopia where a person loses their vision in the bottom half of each eye.

A person may experience a variety of symptoms, which can be mild or severe. Some of these symptoms include:

  • difficulty seeing objects on the side of the vision disturbance
  • bumping into obstacles
  • having spatial awareness problems
  • double, blurred, or distorted vision
  • visual hallucinations, such as light flashes and shapes that are not actually there
  • difficulty seeing color
  • loss of depth perception
  • difficulty moving around crowds
  • reading difficulties
  • difficulty seeing in the dark or at night
  • driving difficulties, particularly with changing lanes

The most common cause of homonymous hemianopia is a stroke.

It may occur after a stroke if the area of the brain that controls the vision becomes affected.

Any form of brain injury can also result in hemianopia if it affects the part of the brain that controls vision.

Additional possible causes of hemianopia include:

Despite the condition occurring due to brain injury, a doctor will diagnose hemianopia by looking at the eyes and discussing a person’s symptoms.

Performing a vision test will help the doctors rule out any additional eyesight problems and ocular causes of visual field loss.

Within this eye examination, a person may be subject to a visual field test. This involves them expressing when they can no longer see an object within their peripheral vision. Research suggests that a doctor usually bases a hemianopia diagnosis on a person’s visual field test results.

Doctors may also look at the back of the eye using an imaging test or check eye pressure by shooting bursts of air into the eye.

Following these eye examinations, a doctor may order brain scans or blood tests to rule out any other brain conditions.

Visual field testing can also help monitor changes if there is a progressive condition, such as pituitary tumors.

Doctors may treat hemianopia by first treating the underlying cause of the condition. For example, if hemianopia is the result of a stroke, doctors will focus on treatment for the stroke.

This treatment approach may help relieve and improve the symptoms of hemianopia.

In some cases, symptoms may disappear completely once a person receives treatment for the cause. However, research showed that only 17–18% of individuals with homonymous hemianopia got their vision back after 28–30 days.

Treatment will usually involve adapting to the vision loss rather than curing it. Doctors can help by discussing techniques for rehabilitation and adapting to the impaired field of vision.

Possible methods a person may adopt to help them adapt include:

  • Reading aids: These include using line guides, color markers, magnifiers, or a dark ruler. It may also be helpful for people to learn to read vertically rather than horizontally to keep the words in a person’s field of vision.
  • Mobility changes: A person may need to change how they would usually sit or move so they can see as much as possible in their field of vision. For example, they may need to turn their body or head to get a wider view of their surroundings.
  • Visual aids: A person may be able to receive glasses containing prisms or mirrors. This can help expand a person’s field of vision.
  • Support from friends and family: An individual should make their friends and family aware of what they can or cannot see so that they can support the individual. For example, they can advise them not to approach from the individual’s blind side to avoid frustration.
  • Eye coordination activities: People may wish to participate in exercises to help strengthen their eye coordination. These exercises could include crosswords, word searches, and computer games.

A vision specialist may also prescribe vision aids, such as prism or mirror glasses.

Hemianopia may take some adjustment time before a person adapts to it.

In some cases, it can resolve itself, particularly when a person receives treatment for the underlying cause.

However, some cases may be permanent. Although hemianopia is not a life threatening condition, it may affect a person’s quality of life and result in the need for lifestyle changes.

Hemianopia is a condition that causes the loss of half of a person’s field of vision. It usually occurs in both eyes at the same time.

The most common cause of hemianopia is a stroke. However, it can also occur due to brain injury, neurological diseases, infection, seizures, and many other reasons.

Treatment would usually involve the treatment of the underlying cause. Hemianopia symptoms may reduce with this treatment and can eventually disappear. In some cases, hemianopia is permanent. There is no treatment, but a person can adapt to it with lifestyle changes.