Binocular Vision

A Binocular Vision Assessment with Advanced Vision Therapy Center is specifically designed to assess several visual skills that are typically overlooked during a routine eye exam.

Several areas of visual performance will be evaluated using age-normed, standardized tests. This allows the doctor to identify visual deficits in a developing child as well as adults. The information gathered during the Binocular Vision Assessment is used by our team to identify areas of visual deficits in order to develop a customized treatment plan for improvement. 


Vision is a very complex process that serves as our dominant sense. In fact, 80% or more of classroom learning occurs through the visual system. While being able to see 20/20 is important, it is only a small portion of overall visual performance. In addition to seeing clearly in the distance, one must have an efficient visual system with the ability to sustain clear, comfortable, single-image vision while scanning and interpreting the visual environment.

An inefficient visual system can result in a number of symptoms, including:

  • Blurred vision
  • Difficulties performing visual tasks (such as reading or computer work)
  • Double vision
  • Eye strain
  • Fatigue
  • Poor working memory
  • Processing speed deficits
  • Tracking difficulties

Unfortunately, the eye chart fails to identify many vision conditions that impact daily visual functioning. Vision conditions that affect one's visual performance include:

  • Accommodative dysfunction (eye focusing deficits)
  • Binocular vision dysfunction (difficulties with eye teaming - including strabismus)
  • Oculomotor dysfunction (eye tracking deficits)
  • Prolonged visual processing speed (slow to extract visual information)
  • Visual perceptual deficits (difficulties interpreting visual information)

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Who Should Have a Binocular Vision Assessment?

A Binocular Vision Assessment is designed for both children and adults.


A Binocular Vision Assessment is recommended for children who struggle with visual tasks or who are symptomatic. The types of vision conditions identified during a Binocular Vision Assessment can affect both academic and athletic performance. It is estimated that 1 in 4 children have a vision problem significant enough to affect academic performance. This occurs because the child has difficulties efficiently taking in and interpreting visual information. In the classroom, vision conditions commonly affect reading, computer or other screen-time activities, and taking notes from the board. These tasks are extremely visually-demanding and require efficient eye tracking, eye teaming and eye focusing.

Symptoms of these vision conditions vary greatly. An underlying vision problem should be suspected by the parents and teacher if a child complains of:

  • Blurred or fluctuating vision
  • Double vision (even intermittent)
  • Eye strain, discomfort or soreness
  • Headaches after visual tasks
  • Visual fatigue
  • Words moving or floating on the page

Not all children voice complaints about their visual performance (many think how they see is 'normal'). Parents and teachers should look for the signs of an underlying vision problem:

  • Abnormal posture during near tasks (tilting or turning the head, leaning very close to the page, constant moving and re-positioning while working)
  • Avoidance of visual tasks, such as reading (would rather be 'read to' or refuses to read)
  • Covering or closing one eye (especially while reading)
  • Difficulties completing visual tasks (reading, taking notes, etc) in the time allowed
  • Drastic improvement with verbal tasks as compared to visual tasks
  • Frequent blinking
  • Skipping or re-reading words or lines of text
  • Squinting
  • Use of a finger (or line guide) to keep place while reading



Children do not grow out of the types of vision conditions identified during a Binocular Vision Assessment. As adults, they continue to experience the same symptoms as they did as children (blurred or fluctuating vision, double vision, eye strain or headaches). Many have found ways to compensate for their visual conditions; often by avoiding or limiting visual tasks. Others have accepted their visual limitations as 'normal for them'.

A Binocular Vision Assessment should be performed for adults with symptoms such as:

  • Blurred or fluctuating vision despite correction with glasses or contacts
  • Difficulties with 3D movies or TV (poor depth perception, discomfort, nausea)
  • Double vision (even intermittent)
  • Eye strain or discomfort with visual tasks (such as reading or computer work)
  • Headaches following reading, computer work or time on electronic devices
  • Visual fatigue

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Why Have a Binocular Vision Assessment?

A Binocular Vision Assessment allows our team to identify several vision conditions often missed during a typical eye exam or vision screening. A Binocular Vision Assessment with Advanced Vision Therapy Center is specifically designed to assess several visual skills that are typically overlooked during a routine eye exam.

These vision conditions include: accommodative dysfunction (eye focusing deficits), binocular vision dysfunction (difficulties with eye teaming - including strabismus), oculomotor dysfunction (eye tracking deficits), visual perceptual deficits (difficulties interpreting visual information) and prolonged visual processing speed (slow to extract visual information).

Vision is a critical component to learning and most tasks of daily life. Undiagnosed vision conditions can impede academic success or one's ability to use their eyes comfortably and efficiently during work and hobbies. Identifying a vision problem allows a treatment plan to be put in place to effectively remove visual barriers to success.

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What is Tested During a Binocular Vision Assessment?

Our team evaluates several aspects of visual function during a Binocular Vision Assessment using age-normed, standardized testing. Based on the results, our doctors will prescribe an individualized treatment plan. Skills tested include:

Accommodation (Eye Focusing)
While seeing clearly is important, it is equally important to keep things clear. Accommodation, or eye focusing, allows an athlete to keep the game in focus. The strength, speed and accuracy of accommodation are especially important when viewing objects moving at high speeds (such as a ball or puck) or when scanning the field of play.
Depth Perception (3D)
Often called “3D vision”, depth perception is dependent on the ability to use both eyes together in a very precise manner. Depth perception is important in every sport. Precise depth perception allows you to identify the exact location of an object (for example a ball) so that you can hit, kick or catch it. Depth perception also tells that athlete where they are in space, which is especially important when in motion.
Fusion is the ability to use both eyes together - is the foundation of depth perception and binocular vision (utilizing both eyes in a coordinated manner). Stable fusion allows the athlete to take in visual information in a reliable and consistent way. Instability of fusion disrupts athletic performance and can lead to inconsistent performance or difficulties with specific aspects of your game.
Presence of Conditions That Affect Binocular Vision Function
There are several conditions that affect binocular vision function. Some of these conditions are ocular (such as amblyopia, strabismus, cataracts, glaucoma, and several other ocular diseases) while others are systemic (such as diabetes, stroke, thyroid dysfunction, autism, and cerebral palsy to name a few). Our doctors work with your other health care providers to ensure a multi-disciplinary team approach to your overall care.
Ocular Motility (Eye Movements)
Eye movements must be fast, accurate, and coordinated while participating in sports. Eye movements are used to quickly scan the field of play or to track a moving object. The saying 'keep your eye on the ball' stresses the importance of efficient eye movements during competition.
Ocular Posture (Resting Position)
Ocular posture, or the resting position of the two eyes, is evaluated to determine the presence or absence of strabismus (eye turn). Eye position is also related to how hard you must work to coordinate your eyes. Depth perception, fusion, ocular motility, vergence, and visual acuity are all affected by ocular posture.
Vergence (Eye Teaming)
The strength and flexibility of the eye teaming system should be evaluated. Deficits in eye teaming will result in double vision, eyestrain, fatigue, headaches, or dizziness. Deficiencies of the vergence system will affect sports performance either globally or during specific aspects of your game (such as putting in golf).
Visual Acuity (Clarity)
Clear vision is the foundation of both visual performance and overall performance. Simply put, if you cannot see well you cannot expect to play well. While 20/20 vision is adequate for daily life, most competitive athletes benefit from seeing better than 20/20. Athletes rely on clear vision to perform at their best.
Processing Speed
Once visual information is taken in, it must be processed by the brain. Visual processing speed refers to how quickly and efficiently an athlete is able to make sense of visual information. In other words, how much information can an athlete process in a given amount of time. Processing speed allows for split second decisions and reactions to a changing visual environment.
Spatial Awareness/Visual Attention
People often comment that an athlete has 'vision' or 'sees the game'.They are referring to the player's spatial awareness and visual attention. Sports often require an athlete to divide their visual attention between central objects (such as the ball) and peripheral objects (such as incoming defenders). Seeing the game allows an athlete to play at a high level.
Visual Integration
The integration of visual information with the other senses is critical. Making sense of your world relies on all of the senses working harmoniously. The integration of visual and motor skills is important during athletic competition. People often refer to this skill as 'hand-eye coordination'.
Visual Perception
This group of skills includes visual discrimination (determining likeness), spatial relations (determining differences), form constancy (determining sameness even when changed in size or orientation), visual memory, visual sequential memory, figure-ground (extracting valuable information from the background), and visual closure (ability to put the pieces together to form the whole). These perceptual skills are essential for athletic success.
Working Memory
This perceptual skill is critical for the acquisition of new material and concepts. Deficits in working memory can result in challenges learning new concepts; such as spelling. Those who struggle with working memory often find that no matter how hard (or how long) they try, the desired results are not achieved.

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When Should a Binocular Vision Assessment be Performed?

A Binocular Vision Assessment should be performed as soon as concern arises from the eye doctor, the teacher, therapists who work with the child, the parents of the child or the individual themselves. While binocular vision conditions can be successfully treated in both children and adults, it is ideal to treat these vision conditions as early as possible. Early diagnosis and intervention allows a child to reach their full potential.

Unfortunately, vision conditions often go undiagnosed or are misdiagnosed (vision conditions are commonly mistaken for ADHD and dyslexia). Children with undiagnosed vision conditions often struggle in school. 80% or more of classroom learning occurs through the visual system. Visual deficits put a child at a huge disadvantage and prevent them from performing to their potential. When a child struggles in school, it is important to schedule a Binocular Vision Assessment to rule out a visual component to their struggles. Classroom tasks, such as reading or taking notes, rely on an efficient visual system. One of the early stages of intervention should be to treat any vision conditions that are present. Extra help with reading, tutors and fluency programs will not solve underlying vision conditions. You must first ensure that the child sees the book with clear, comfortable, single vision before asking them to read with greater fluency and comprehension. Image how difficult it would be to read if the text became blurry, split into two or moved on the page. 


If you suspect binocular vision deficits with yourself or someone you know, call Advanced Vision Therapy Center (208)377-1310 to schedule an appointment.

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Frequently Asked Questions About Binocular Vision Assessments

Are vision problems and behavioral problems related?

According to a recent survey, 39% of parents don't realize that behavioral problems can be an indication that a child has a vision problem. A child with undetected vision problems may get frustrated or bored in school because he or she can't see the board, the teacher or read a book easily. Therefore, students with problems seeing sometimes act out. Studies indicate that 60% of children identified as having a learning problem actually suffer from undetected vision problems.

My child dislikes reading, could this be a vision problem?

Children with convergence insufficiency will start out satisfactorily, but after a short period of working up close will find it difficult to continue reading due to the amount of difficulty with their vision. Their tendency to look away will make them appear to be disinterested, or have a poor attention span. These same children will appear more interested when they are being read to, or listening. They will then be labeled “attention deficit” or “lazy” when they are simply limited based on their visual abilities.

Why do I see double?

There are several causes of double vision and it is very important to determine the underlying cause. Double vision can present in may different ways and the pattern of double vision (where the two images are relative to one another, how often the double vision is present, where the double vision is present, etc) will help our doctors determine the underlying cause.

Causes of double vision include:

  • Convergence insufficiency
  • Cranial nerve palsy (due to trauma, ischemia, aneurysm, brain tumor, or other neurological event)
  • Damage to the cornea (infection, scarring, etc)
  • Dry eye
  • Extraocular muscle entrapment (occurring after trauma)
  • Lens problems (such as cataracts)
  • Loss of fusion due to ocular disease process (such as glaucoma, macular degeneration, etc)
  • Strabismus (eye turn)
  • Stroke
  • Systemic conditions (Myasthenia gravis, Grave's disease, multiple sclerosis, Lyme disease, diabetes, etc)

Please note, if you see double at any time you should be evaluated by a doctor with advanced training (such as a residency) in binocular vision and neuro-optometry.

Will I know if I have binocular vision dysfunction?

Unfortunately not all individuals with binocular vision dysfunction are symptomatic. When symptoms do occur they include:

  • Blurry vision
  • Dizziness
  • Double vision
  • Eyestrain
  • Fatigue (especially with near work)
  • Headaches
  • Impaired sports performance
  • Lack of depth perception
  • Light sensitivity
  • Motion sickness (car sick)
  • Nystagmus (jumping eyes)
  • Reading difficulties

When someone with binocular vision dysfunction becomes symptomatic, adaptations usually begin to occur.

  • If a child struggles with reading due to binocular vision dysfunction they may begin to use their finger or line guide for support, turn their head while reading, cover one eye while reading, prefer enlarged print (or e-reader), or avoid reading all together.
  • If someone sees double they will often close or cover one eye, tilt or turn the head, or avoid the task or position that makes them see double.
  • If the brain perceives double, it is capable of “shutting off” or suppressing the input from one of the eyes to eliminate the double vision. Suppression will eliminate the double vision, but prevents binocular vision functioning and stereopsis (3D vision).
  • Lastly, some people just assume that the binocular vision dysfunction is “normal” and get used to eyestrain at the computer, headaches at 3D movies, and even double vision. If you suspect that you or your child has an undiagnosed vision problem, the next step is to schedule a binocular vision assessment with Advanced Vision Therapy Center.

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Before vision therapy, Sarah struggled with reading, experienced frequent headaches, and overall had difficulties focusing during school.  Despite tutoring and summer literacy programs, she continued to struggle with reading; she skipped lines and never volunteered to read aloud.  Following vision therapy, Sarah no longer loses her place while reading and even volunteers to read aloud. "Until Dr. Johnson tested for Sarah's vision issues we all were unaware they existed.  This experience help… 
- Sarah's Story
In the few weeks Erin has been attending vision therapy, we are already beginning to notice changes. Homework doesn't take as long as it did two months ago, there are no more tears when she has a lot to write, she is becoming more and more independent as time goes on. She still needs a lot of guidance, but seems to "catch on" to what is expected of her a lot faster. The greatest improvement, however, has been in her report card. Last year, Erin's third grade teacher wanted to fail her because s… 
- Erin's Story
"Bella loves reading now, whereas before she hated it. I have already recommended that two of my friends bring their children here because they are struggling with similar issues. Bella had so much fun with therapy and I have enjoyed seeing her improve in her reading and the rest of school."  
- J.G.
"Before I started vision therapy, I hated doing homework or reading.  I would give my mom a hard time and homework would take forever.  Now, I love school, schoolwork, homework, and reading.  My glasses helped out a lot.  I have seen a difference in my handwriting, reading and just seeing things in a new way.  Vision therapy has helped me open up and accept changes, it has helped me be more aware of what is going on.  Vision therapy kept me out of the Special Ed. class at my old school and help… 
- K.A.
"Before vision therapy Aidan hated school and homework.  He would jump from line to line while reading, he rubbed his eyes a lot while doing homework, and he turned words completely around when reading (saw became was).  After vision therapy with Advanced Vision Therapy Center, his reading scores have improved drastically, he is less disruptive in class, and his overall view of school is much better.  He is looking forward to starting second grade and reads like a champ!"  
- F.L.
"About two years ago I went to the eye doctor and he discovered I had a problem with my vision.  We tried glasses, but it made it worse.  My doctor recommended vision therapy.  From the start of vision therapy I loved the sessions.  I got to play games while fixing my eyes.  I went to vision therapy for a few months and my eyes made huge improvements, my regular eye doctor was amazed.  It is remarkable how exercises and games can improve somone's eyesight dramatically.  If anyone has eye proble… 
- L.B.
"Thank you so much for introducing me to vision therapy.  This was brand new to me and it surprised me with it's effectiveness.  I can definitely tell a difference in my eyes while reading.  This has particularly improved at times when my eyes are tired, when I used to get most uncomfortable.  As a student, I can tell a difference in my study habits, and vision therapy has also helped me enjoy reading more than I used to. I would recommend vision therapy to anyone with a similar problem with… 
- C.W.
My son's eyes were consistently red after school and while attempting to sit down and do homework, he complained that he was seeing two of everything. He just fought me when it came time to read. This started in kindergarten and followed into first grade, so I had patience with his struggles, basing it on the fact that maybe he still needs some time to learn how to read. It was not until the school started to reach out to me that he was not at reading level and also acting out in class that I d… 
- Rachelle T.

Call 208.377.1310 to Schedule Your Assessment

Advanced Vision Therapy Center is Idaho’s premier clinic for Vision Therapy, Neuro-Optometric Vision Rehabilitation and Sports Vision Training. We offer vision assessments and customized treatment for both children and adults that are tailored to the specific vision condition of each individual.

Not sure which type of vision assessment is right for you? Call us today and we'll help you determine the best assessment to achieve your visual goals.

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