(519) 204-7230
Binocular Vision Dysfunction (BVD)
Been told you have BVD? Here's what it means, and how we find out exactly what's going on.
- BVD stands for binocular vision dysfunction: a problem with how the two eyes work together.
- It's a broad term that can cover several different conditions. Testing tells them apart.
- No referral needed. Call (519) 204-7230.
What does BVD mean?
BVD stands for binocular vision dysfunction: a problem with how the two eyes work together as a team. Your eyes need to aim, focus and move together precisely so your brain can combine two images into one. When that teamwork breaks down, the brain has to work harder to keep vision clear and single, and symptoms can follow.
BVD is a broad term rather than a single condition. Some clinics use it for one specific problem, a small vertical misalignment between the eyes. Others use it for any eye-teaming difficulty. Either way, the useful next step is finding out exactly which part of the visual system isn't working as it should.
Common symptoms
- Headaches or eye strain with reading, screens or schoolwork
- Double or blurry vision
- Words that move, blur or run together
- Losing your place, skipping lines or re-reading
- Dizziness or feeling off-balance in busy places like grocery stores
- Discomfort with motion, scrolling or being a passenger
- Head tilt, or neck and shoulder tension
- Avoiding reading or close work
These symptoms overlap with other conditions, which is why a thorough assessment matters. Our assessment looks at whether, and how, your vision is contributing.
Conditions BVD can include
- Convergence insufficiency: the eyes have trouble turning inward together for close work.
- Vertical heterophoria: one eye aims slightly higher than the other.
- Oculomotor dysfunction: trouble with accurate eye movements, including holding fixation, tracking a moving target and jumping from word to word.
- Accommodative dysfunction: trouble focusing and refocusing between distances, such as from the board to the page.
BVD and oculomotor dysfunction: what's the difference?
People told they have BVD are often surprised to learn that a different problem, with eye movements rather than eye alignment, can cause very similar symptoms.
| Comparison | Vertical misalignment (often called BVD) | Oculomotor dysfunction |
|---|---|---|
| What's affected | How the two eyes line up with each other | How accurately the eyes move and hold steady |
| Typical symptoms | Head tilt, dizziness, headaches, double vision | Losing your place, skipping lines, re-reading, trouble copying from the board |
| How it's assessed | Precise eye alignment measurements at distance and near | Testing fixation, tracking and the quick jumps the eyes make when reading |
| Typical management | Often prism lenses, sometimes with vision therapy | Typically vision therapy |
The two can occur together, so we test for both.
How we assess binocular vision
Your assessment is a detailed look at how your eyes work together, not only how clearly you see. We measure:
- Eye alignment at distance and near, both horizontal and vertical
- Eye teaming: how well the eyes turn in and out together
- Focusing: how easily you shift and hold focus
- Eye movements: fixation, tracking and reading eye movements
We explain what we found in plain language, recommend next steps, and send a summary to the practitioner who referred you.
We don't do eye health exams. Please keep seeing your regular optometrist for those.
Treatment options
Your plan depends on what testing shows. It may include:
- Prism lenses: lenses that shift the image slightly so the eyes don't have to work as hard to line up.
- Vision therapy: a doctor-supervised program of in-office sessions and short home activities that trains eye teaming, focusing and eye movements.
- A combination of both, adjusted as your symptoms change.
Already diagnosed with BVD, or wearing prism glasses?
You're welcome to book an assessment. Bring your current glasses and any reports you have. We'll measure how your eyes work together with and without your current lenses, and explain what we find.
Questions about BVD
What does BVD stand for?
Binocular vision dysfunction. "Binocular" means using both eyes together, so BVD describes any problem with how the two eyes work as a team.
Is BVD the same as a lazy eye?
No. A lazy eye (amblyopia) is reduced vision in one eye. With BVD, the eyes usually look straight and see clearly, but they don't work together efficiently.
Do I need a referral?
No. You can book an assessment directly. If another practitioner is involved in your care, we can share our findings with them.
Can children have binocular vision problems?
Yes. They often show up as avoiding reading, losing place or tiring quickly with schoolwork. Dr. Suwala assesses and treats children; see vision therapy for children.
My symptoms started after a concussion or car accident. Can you help?
Yes. Eye-teaming problems are common after a head injury; see concussion vision rehabilitation. For car accident patients, we're licensed with HCAI and communicate directly with your insurer.
Is it covered by insurance?
Vision therapy is not covered by OHIP. Many extended health plans cover part of the cost, and some accident benefit claims may apply. Check with your insurer, and see our FAQ for more on coverage.
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Book a binocular vision assessment
No referral needed. We're at 557 Southdale Road East, Suite 106, London, open Monday to Friday.