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Binocular Vision Dysfunction (BVD)

What Is Binocular Vision Dysfunction?

Binocular vision dysfunction, or BVD, is a general term for problems with how the two eyes work together. Normally, each eye sends a picture to the brain. The brain blends the two pictures into one clear image. This also helps you judge distance and depth. With BVD, the eyes may not line up, focus, move, or work together as they should. The brain may have trouble joining the two pictures into one clear image.

BVD can include several different conditions, such as:

  • Strabismus, sometimes called crossed or wandering eyes
  • Convergence insufficiency, which makes it hard for the eyes to turn inward during close work
  • Problems changing focus between near and far objects
  • Poor depth perception
  • Amblyopia, often called lazy eye, which can develop when the brain favors one eye during childhood

Amblyopia is different from an eye coordination problem, but the two can occur together.

What Is Happening in My Body?

Think of your eyes like two cameras connected to one computer. The cameras must point at the same place and send clear pictures. The computer, or brain, must then blend those pictures into one image.

With BVD, the eyes and brain do not work as a smooth team. One eye may point slightly away from the other. The eyes may also have trouble focusing, tracking an object, or turning inward together.

Your eyes and brain may work harder to keep your vision clear. This extra work can lead to eye strain, headaches, blurred vision, dizziness, or trouble reading. Some people tilt or turn their head to see more clearly. This may cause neck pain or stiffness.

Because of This, You May Have:

Symptoms depend on the type of BVD. Not everyone has the same symptoms.

Eye and Head Symptoms

  • Eye strain or tired eyes
  • Pain around the eyes
  • Headaches
  • Blurry vision
  • Double vision
  • Words or objects that seem to move, jump, or overlap
  • Trouble changing focus between near and far objects
  • Light sensitivity
  • Trouble using a computer, tablet, or phone
  • Closing or covering one eye
  • Squinting
  • Tilting or turning your head

Reading and School Problems

  • Losing your place while reading
  • Using a finger or bookmark to follow a line
  • Skipping words or lines
  • Needing to read the same sentence more than once
  • Words that seem to run together
  • Trouble understanding or remembering what you read
  • Headaches or eye strain during close work
  • Avoiding reading or homework
  • Trouble staying focused on close tasks

These problems may look like a learning or attention problem. However, BVD does not cause every reading or learning problem. A full evaluation may be needed to find the cause.

Balance and Movement Problems

  • Dizziness or lightheadedness
  • Motion sickness
  • Feeling uncomfortable in a moving car
  • Poor depth perception
  • Trouble judging steps or distances
  • Bumping into furniture or doorways
  • Trouble catching or hitting a ball
  • Poor hand-eye coordination
  • Feeling unsteady in busy places

Other inner ear, brain, heart, or medical problems can also cause dizziness and balance problems. An eye problem should not be assumed to be the cause until you have been evaluated.

Problems in Busy Places

Some people feel worse in places with bright lights, crowds, movement, or many objects to look at. Examples include grocery stores, shopping malls, sporting events, and busy classrooms.

You may feel:

  • Overwhelmed by bright or busy places
  • Dizzy when looking at moving objects
  • Uncomfortable in crowds
  • Anxious about driving, sports, or other activities
  • Tired after long periods of reading or screen use

These feelings are real. However, anxiety, migraine, inner ear conditions, and other health problems can cause similar symptoms. More than one condition may be present.

It Is Important to Know:

  • Your symptoms are real.
  • BVD is a group of vision problems, not one specific disease.
  • Symptoms vary from person to person.
  • A regular vision screening may not find every eye coordination problem.
  • Having clear eyesight does not always mean that the eyes work well together.
  • Dizziness has many possible causes. BVD is only one possibility.
  • Treatment depends on the exact cause.
  • Treatment that helps one type of BVD may not help another type.
  • Children should be checked early because vision is still developing.
  • Adults can also develop BVD, especially after a head injury, stroke, eye muscle problem, or other health condition.

How Is BVD Diagnosed?

An optometrist or ophthalmologist can evaluate binocular vision. Children may also be sent to a pediatric ophthalmologist or an eye doctor with training in children’s vision and eye alignment.

The provider may ask about:

  • Blurry or double vision
  • Headaches or eye strain
  • Reading and schoolwork
  • Dizziness or motion sickness
  • Head injuries
  • When symptoms started
  • What activities make symptoms worse
  • Whether closing one eye makes symptoms better

Testing may include:

  • Checking how clearly each eye sees
  • Checking whether the eyes are lined up
  • Watching how the eyes move
  • Testing how the eyes turn inward for close work
  • Testing how the eyes change focus
  • Checking depth perception
  • Testing whether a glasses prescription is needed
  • Checking the health of the eyes

A standard eye chart only measures part of vision. A person may read the eye chart clearly but still have trouble with eye teaming, tracking, or focusing.

An example of a clinician checking how well the eyes line up and work together.

Parents May Be Asked:

  • Does your child close or cover one eye?
  • Does your child squint or tilt their head?
  • Does your child avoid reading or close work?
  • Does your child lose their place while reading?
  • Does your child complain of headaches or tired eyes?
  • Does your child sit very close to books or screens?
  • Does your child bump into objects often?
  • Does your child have trouble catching a ball?
  • Has a teacher noticed reading or attention problems?
  • Did your child’s eyes ever appear crossed or turned?
  • Was your child born early?
  • Is there a family history of crossed eyes, lazy eye, or other vision problems?

Young children may not know that their vision is different. They may not report blurred or double vision. Squinting, closing one eye, head tilting, or poor depth perception may be important clues.

How Is BVD Treated?

Treatment depends on the exact vision problem. There is no single treatment for every type of BVD. Talk with your provider to learn about the best treatment for your BVD.

Possible Treatments

Glasses or Contact Lenses

A new prescription may help the eyes focus more clearly and work together with less effort.

Prism Lenses

Prisms change how light enters the eyes. They may help some people with certain eye alignment problems or double vision. Prisms do not treat every type of BVD.

Patching or Eye Drops

Children with amblyopia may need a patch over the stronger eye or special eye drops. This helps the brain use the weaker eye. Early treatment is important because the vision system is still developing.

Eye Exercises or Vision Therapy

Specific exercises may help some conditions, especially convergence insufficiency. Exercises should be chosen for the diagnosed problem and guided by a neuro-optometrist with specialized training in BVD. Research does not support using the same vision therapy program for every vision, reading, dizziness, or learning problem.

Botox Injections

Botox may be used when BVD is caused by an eye muscle problem that makes the eyes point in different directions. It temporarily relaxes one eye muscle to help the eyes line up better, but it is not used for all types of BVD and is rarely needed.

Surgery

Eye muscle surgery may be needed for some cases of strabismus. Surgery helps improve eye alignment. Some people may still need glasses or other treatment afterward.

Treatment of Another Health Problem

BVD can sometimes develop after a concussion, stroke, nerve problem, thyroid eye disease, or another medical condition. Treatment may need to address both the vision problem and the underlying condition.

What Can I Expect Over Time?

Will It Get Better?
Many binocular vision problems can improve with the right care. Some conditions can be corrected, while others are managed over time. Children with amblyopia or strabismus often have better results when treatment begins early. Adults may also improve, but the result depends on the cause.

How Long Will Treatment Take?
Treatment may take a few weeks, several months, or longer. Glasses or prisms may help some symptoms quickly. Amblyopia treatment, exercises, or recovery after an injury may take more time. Your provider should check your progress and adjust the treatment plan when needed.

Can I Live a Full Life?
Yes. Most people with BVD can attend school, work, drive, exercise, and take part in daily activities. You may need treatment, follow-up visits, or changes to your work and study area.

The outlook depends on:

  • The type of BVD
  • What caused it
  • Your age
  • How long it has been present
  • Whether one or both eyes are affected
  • How early treatment begins
  • How well you follow the treatment plan

Some people improve with glasses or a short course of treatment. Others need long-term care or more than one type of treatment.

Helpful changes may include:

  • Taking short breaks during close work
  • Using larger print
  • Reducing glare
  • Adjusting screen brightness
  • Using good lighting
  • Limiting long periods of screen use
  • Following your glasses or exercise plan

Do not drive if double vision, dizziness, or poor depth perception makes driving unsafe.

When Should I Call My Provider?

Contact an eye care or healthcare provider if you have:

  • Ongoing eye strain or headaches
  • Blurry or double vision
  • Trouble reading or using screens
  • Dizziness that occurs during visual tasks
  • A child who frequently closes one eye or tilts their head
  • An eye that turns inward, outward, upward, or downward
  • New vision symptoms after a concussion or head injury
  • Symptoms that are getting worse
  • Trouble completing school, work, or daily activities

When Should I Get Urgent Medical Care?

Seek Urgent Medical Care for:

  • Sudden or new double vision
  • Sudden loss of vision
  • Severe eye pain
  • New weakness or numbness
  • Trouble speaking or understanding speech
  • A drooping face
  • A new, severe headache
  • Severe trouble walking
  • Fainting
  • A serious head injury
  • Double vision with weakness, numbness, confusion, or trouble speaking

These symptoms are not typical of a long-term binocular vision problem. They may be signs of an eye, brain, nerve, or blood vessel emergency.

Questions to Ask Your Provider

To learn more about your symptoms and any future treatment, it may be helpful to ask your provider questions like:

  • What type of binocular vision problem do I have?
  • What may have caused it?
  • Do I need more testing?
  • Could another condition be causing my dizziness?
  • Would glasses or prism lenses help?
  • Are eye exercises supported for my condition?
  • How often should I do the exercises?
  • How will we know whether treatment is working?
  • How long may treatment take?
  • Is it safe for me to drive?
  • When should I return for another examination?
  • Which symptoms require urgent care?

Key Points to Remember

  • BVD means that the eyes and brain are not working together as well as they should.
  • It is an umbrella term for several different vision problems.
  • Symptoms may include eye strain, headaches, blurred vision, double vision, reading trouble, dizziness, or poor depth perception.
  • Many other health problems can cause similar symptoms.
  • A full eye examination is needed to find the exact cause.
  • Treatment must match the diagnosed condition.
  • Treatment may include glasses, prisms, patching, specific exercises, or surgery.
  • Sudden double vision or vision loss needs urgent medical care.
  • With proper care, most people can continue their usual activities.

Additional Resources