A person with a concussion may have dilated pupils, droopy eyelids, or difficulty tracking objects. Sometimes, these symptoms are obvious, but not always. Assessment tools can help a doctor check for concussions.

Around 90% of people experience eye symptoms after a concussion. They may also have difficulty concentrating, light sensitivity, depth perception issues, memory loss, or blurry vision.

In some cases, vision problems are symptoms of serious complications. Anyone with these symptoms needs to seek medical advice.

This article looks at the most common vision-related concussion symptoms, along with treatment options.

Vision symptoms are common following a concussion. Some symptoms may be visible externally, such as:

  • dilated pupils, or pupils of uneven size
  • misaligned eyes
  • difficulty tracking objects with the eyes
  • atypical eye movements
  • droopy eyelids

However, not all concussion-related eye symptoms are outwardly visible. Additionally, not everyone with a concussion will have the same symptoms.

There is no conclusive at-home test that can diagnose a concussion. However, online questionnaires can help rate a person’s symptoms following a head injury.

These tests can help guide someone’s decision to seek medical attention. However, they should not replace a medical diagnosis.

Anyone who suspects a person could have a concussion needs to seek medical help. If a person has any of the following symptoms, they should dial 911 right away:

  • one pupil larger than the other
  • a headache that worsens and does not go away
  • drowsiness or difficulty staying awake
  • nausea or repeated vomiting
  • seizures, convulsions, or twitching
  • unusual behavior
  • confusion, agitation, or restlessness
  • slurred speech
  • weakness or numbness
  • decreased balance and coordination

In babies and children, inconsolable crying or refusal to eat or nurse can also be signs they need emergency medical attention.

If a person loses consciousness, even if only for a short time, they should receive urgent medical care as soon as possible.

Vision-related activities occupy more brain territory than any other body function. Additionally, the eyes are particularly vulnerable to the effects of concussions because of their proximity to the brain. When the brain becomes injured, the force of the impact can affect the eyes. This can cause a range of issues that can vary in how long they persist.

Double vision

Double vision, or diplopia, is when a person sees two images of an object instead of one. It may result from trauma to the delicate orbital bones, the extraocular muscles that direct eye gaze, or injury to the optic nerve.

Often, it is due to fourth nerve palsy, meaning paralysis of the fourth cranial nerve that can lead to a misalignment of the eye muscles.

Light sensitivity

Photophobia is very common following a head injury, which is why hospitals keep lights dimmed in rooms where people with concussions are staying.

Light sensitivity can cause significant discomfort and trigger a range of other symptoms, including nausea and headaches. It is not always clear why it occurs. Experts believe it is neurological in origin and involves the trigeminal nerve pathway, which has a role in sensory input and pain sensation.

Altered eye movements

Altered eye movements are a common symptom of concussion. This can include difficulty tracking or following objects with the eyes, loss of range of motion in the eyes, and sudden jerking movements known as ocular flutter or opsoclonus. A person may also experience nausea and dizziness due to disorientation.

Diagnosing a concussion typically involves taking a medical history and performing a physical exam. Doctors may also use assessment tools, such as medical questionnaires and criteria, to make a diagnosis.

In some cases, they may perform a CT scan of the head to exclude other serious causes of the symptoms such as intracranial hemorrhage.

Treatments for a concussion are primarily supportive. They involve limiting activities that are likely to worsen symptoms and resting for an initial 24–48 hours. The person can then gradually return to activity but watch how their symptoms respond.

Certain over-the-counter pain medications may help relieve headaches. People with persistent visual symptoms may also need vision rehabilitation. This involves exercises to improve eye alignment, focusing, and coordination. It can also include light sensitivity therapies.

Although there is no specific treatment for concussion, there are some things people can do to help their recovery, including:

  • resting
  • avoiding overstimulating environments, such as noisy places or loud music
  • avoiding using digital screens for the first 48 hours, as this may slow recovery

After 24–48 hours, a person can try gradually increasing their physical activity as long as it does not cause symptoms. Some gentle aerobic exercise, such as walking, may help with recovery. If symptoms occur, they need to continue resting.

If a person experiences visual symptoms, they may find wearing sunglasses helpful to reduce light sensitivity. They should also limit screen use and prolonged periods of close work, such as reading. It is important to take frequent breaks until these symptoms go away.

Adults often recover from concussion after 10–14 days, while children generally need 4 weeks. If symptoms persist beyond this time, people can seek medical help. They should also seek emergency help if new symptoms suddenly appear or become severe.

Learn more about concussion recovery.

A concussion often affects the eyes and may cause double vision, eye tracking issues, or light sensitivity, among other symptoms.

There are some external signs that can indicate a concussion, such as atypical pupils or altered eye movements. However, people cannot rely on this as a way of self-diagnosing. Not everyone with a concussion will have the same symptoms, and some visual symptoms require urgent medical care.

A person needs to speak with a doctor if they suspect they or someone else has had a concussion. A doctor will be able to make a diagnosis and monitor for any signs of complications.

Treatment involves rest and limiting activities, such as using screens. If visual symptoms persist, a person may need vision rehabilitation.