What is BVD

Have you ever wondered why, despite having two eyes, you only see one image? This is called binocular vision. Our brain is so intricate and complex that it’s able to turn two separate images into one clear image. In order for this to occur, it’s essential for the eyes to be in perfect alignment. In people who have good binocular vision, the eyes work in tandem and are perfectly in sync at all times, which allows them to send one clear, focused picture to the brain.

But when the eyes do not work smoothly together and are not perfectly synchronized, this is called Binocular Vision Dysfunction. People with BVD struggle to see one clear image. This leads to discomfort such as headaches, dizziness, double or overlapping vision, and even problems reading.

For people who have BVD, their eyes are not in alignment (not in sync) so their eyes will transmit two images to the brain that are in slightly different positions to one another. The brain won’t accept this situation and responds by forcing the eye aligning muscles to fix the problem by realigning the eyes. The realignment is only temporary and misalignment then recurs, which is followed closely by realignment.

So there becomes a continuous cycle of image misalignment and realignment, which makes the brain believe things are moving, and as you can imagine, causes a great deal of eye muscle strain. The eyes become tired and sore, which can lead to a variety of unpleasant and sometimes painful symptoms, such as headaches and face and eye pain while making eye movements.

Causes of Binocular Vision Dysfunction

Commonly confused with “sinus” issues and migraines, BVD can develop due to an abnormal visual system as a result of a stroke, brain injury, concussion or similar neurological disorder. It can manifest at any time, with symptoms usually developing around 40-years of age.

Facial asymmetry, where one eye is physically higher than the other one (see figure 1 below) can also be a factor in causing this condition. Facial asymmetry or a nerve or eye muscle abnormality is something many people are born with. Over time, these individuals often start to develop BVD as the eye muscles get weaker with age and become overworked.


Many people with Binocular Vision Dysfunction will try to improve their vision (and reduce their symptoms) by tilting their heads. VICE recently published the article, A Stranger Diagnosed Me With Misaligned Eyes, where the author recounts her experience living with BVD, including this iconic head tilt.

When the head is tilted to the side toward the shoulder, images move down in one eye and up in the other. While tilting the head does help fix the misalignment, it can also lead to chronic neck pain.

Symptoms of Binocular Vision Dysfunction

When you have Binocular Vision Dysfunction, the list of possible binocular vision symptoms can feel endless. Some people experience a handful of symptoms, while for others it’s more like fistfuls, completely disrupting their lives and resulting in disability. Some of the core symptoms are blurred vision, motion sickness, eye pain, light sensitivity, double vision, overlapping vision, and poor depth perception. But many other Symptoms exist and can include:

Misdiagnoses Related to BVD

Doctors cannot diagnose binocular vision dysfunction through standard eye tests because those tests are not sensitive enough to find the very small amount of misalignment that is causing the symptoms. With such tests, both eyes may appear to be functioning correctly. Unless a doctor finds a significant misalignment, they will likely dismiss vision problems as the root cause of symptoms.

But symptoms of BVD plague patients with even slight misalignments. Relying on standard tests alone can lead doctors to diagnose other conditions. As a result, problems will persist following any recommended treatment since those conditions are not the underlying cause of the symptoms.

It’s common for people to have been diagnosed with a myriad of other conditions, then find out that Binocular Vision Dysfunction was the true culprit. These other conditions include:

  • ADD / ADHD

  • Agoraphobia

  • Anxiety / Panic disorders

  • Persistent Post-Concussive symptoms

  • Cervical misalignment

  • Meniere’s Disease

  • BPPV (Benign Paroxysmal Positional Vertigo)

  • Psychogenic dizziness / Chronic Subjective Dizziness

  • PPPD (Persistent Postural-Perceptual Dizziness)

  • Vestibular Migraine / Migraine Associated Vertigo (MAV)

  • Migraines

  • MS (Multiple Sclerosis)

  • Reading & learning disabilities

  • Sinus problems

  • Stroke

  • TMJ disorders

  • Traumatic brain injury (TBI)

How To Distinguish BVD From Other Conditions

It can be challenging to determine if you have BVD, and in many cases, the best approach is to start by ruling out other serious diagnoses. Once that has been accomplished, if the cause of the symptoms is still uncertain, there are questions that should be asked. If the answer is “yes” to one or more of these questions, the primary care physician or ophthalmologist/optometrist should be asked about the possibility of having binocular vision dysfunction:

  1. Have you seen at least one specialist who could not help with your pain, dizziness, poor depth perception, light sensitivity, or other symptoms, or who told you that there is nothing wrong with you despite your persistent symptoms?

  2. Have you been diagnosed with one of the conditions that can often be confused with BVD?

  3. Did you suffer a concussion or traumatic brain injury, and now your symptoms won’t go away?

If you suspect that you have BVD, you should talk to your doctor immediately, as this condition will worsen with time. Make sure you are prepared with a complete list of your symptoms, how long they have persisted, and why you believe the problem is related to BVD and not to another medical condition. Additionally, you may wish to take the Binocular Vision Dysfunction Questionnaire (BVDQ), which has been designed to identify those who may have BVD and who would benefit from a NeuroVisual Evaluation.

Let’s Treat Your Binocular Vision Dysfunction

Are you familiar with some of these symptoms? If so, we provide a free online test to help you learn more about your symptoms and determine whether you should book an appointment for a NeuroVisual exam. At Old Saratoga Eyecare, your detailed and thorough evaluation goes above and beyond a regular eye exam, and is specifically designed to detect Binocular Vision Dysfunction. After the exam, any problems with alignment, far vision or near vision will be treated by Dr. Gardner and corrected using specialized realigning eyeglasses. These specialized microprism lenses fix the misaligned images by bending the light beam entering the eye. With the images realigned, the brain can easily make a single three-dimensional image, relieving the eye strain, eye muscle problems and other BVD symptoms.