A head or brain injury, such as from an accident or stroke, can cause crossed eyes ( strabismus ) and other eye and vision issues. Strabismus is an eye condition that affects the alignment of the eyes and their ability to work together.

The main sign of strabismus is that the eyes are not aligned. There are several types, classified by the direction in which one or both of the eyes is turned:

• Esotropia — Inward-turning (pointing in toward the nose); also called cross-eyed

• Exotropia — Outward-turning (pointing out toward the ears); also called wall-eyed

• Hypertropia — Upward-turning (pointing up toward the forehead)

• Hypotropia — Downward-turning eyes (pointing down toward the chin)

A head or brain injury may also cause other types of vision problems, including partial or total vision loss. If a head injury causes vision changes or symptoms, seekemergency careright away.

A new head injury will not uncross the eyes. The most common treatment for strabismus is strabismus surgery , which may successfully correct the condition in adults or children. Some types of strabismus may also respond to non-surgical treatment such as doctor-supervised vision therapy . In addition, eyeglasses and contact lenses, as well as prism glasses , can be used to manage strabismus.

A traumatic brain injury (TBI) can be caused by an external blow to the head (blunt-force trauma) or by an object penetrating the head (sharp-force trauma), according to the CDC Injury Center . More than 2.5 million Americans visit a hospital emergency department for a brain injury each year, according to the most recent data from the CDC.

In addition to external trauma, a cerebrovascular accident (CVA), or stroke, can also cause a brain injury. This type of brain injury can also cause vision issues.

Between 20% and 40% of people with a brain injury may develop one or more vision problems as a result of the injury. In fact, strabismus often occurs along with hemianopia after a brain injury. Hemianopia is total or partial loss of vision due to optic nerve damage, often from a head injury or stroke .

There are a number of vision problems that can be caused by a head injury. These issues may be caused by injury to the head or eye, or damage to the brain.

Loss of visual acuity

A brain injury can cause visual acuity loss when the nerves that carry signals between the eyes and the brain are damaged. A head injury can also lead to total blindness, although this is very uncommon. For example, blindness may result from an injury such as a gunshot or a blow to the back of the head.

Visual field issues

A brain or head injury may also lead to problems with peripheral vision ( visual field defects ). There are different types of visual field loss named for the part or amount of the field of vision that is missing. For example, hemianopsia is the loss of 50% of the visual field, and quadrantanopia is the loss of 25% of the visual field.

Blurry vision or focusing issues

People who have had a head or brain injury may experience blurry vision or difficulty switching between far and near vision. Vision may seem especially blurry when trying to read or focus on other up-close objects.

Double vision

If vision problems develop after an injury, double vision (diplopia) is often a common symptom. This may happen due to problems with "eye teaming," which is the ability of the eyes to work together to see clearly.

Eye tracking problems

Patients who have a head or brain injury may have issues with eye movements that help them with visual scanning tasks. This may make it difficult to search the environment for specific objects or track text across a page as you read.

Other eye problems

It's common to develop other vision or eye issues after a head or brain injury. These may include:

• Eye pain or headaches

• Dizziness or motion sickness

• Tearing or watery eyes

• Sensitivity to light ( photosensitivity )

These eye issues can cause challenges in daily life that may include issues with reading and computer work, problems participating in athletic activities and difficulty being in public spaces with a lot of light or noise.

Treatment for vision issues caused by a brain or head injury will vary based on the type of injury, the vision issue being experienced and the patient.

In some cases, loss of visual acuity may be corrected with prescription eyeglasses or contact lenses.

Other times, a patient may benefit from vision rehabilitation. This could include learning to use lighting, magnification or ways to “scan" the environment to compensate for peripheral vision loss.

If your pupils are different sizes after a head injury, get emergency medical care right away . You should also go to the ER for a head injury if you experience serious symptoms such as agitation, confusion, convulsions, coordination problems, numbness, slurred speech, weakness or unconsciousness that lasts longer than a minute.

If you experience vision problems after you've received emergency treatment for a head injury, it's important to get a thorough eye exam by an eye doctor with experience treating vision issues from head injuries.