Binocular vision, for many people, conjures up the idea of being able to see great distances. It almost sounds like something out of a Marvel movie. Nevertheless, what binocular vision truly means is that your eyes can focus together in the same direction. When your binocular vision is working as it’s supposed to, it sets you up to experience stereoscopic vision. More plainly, the brain can create a single image from two eyes that are communicating slightly different information. It’s this combined image that allows you to experience depth perception and accurately judge the speed of an object. Quite simply, it’s how you’re able to catch a ball and of course some much more!
When it works properly, your binocular vision should seem completely effortless. However, when there is even the slightest interruption in how the eyes work together or how the brain receives signals, it can cause incredible discomfort and severely affect your ability to navigate the world around you.
While it’s essential that everyone has routine eye examinations, many of the conditions that interrupt regular binocular vision begin to occur quite early in life, so it’s crucial that parents and teachers are observing their children for anything out of the ordinary.
Some general symptoms to be aware of that may indicate a binocular vision disorder:
- Unable to maintain eye contact
- Double Vision
- Dizziness, Nausea, or Headaches
- A sudden lack of interest in playing familiar sports
- General Anxiety
- Trouble concentrating while reading
- Poor reading comprehension
- Acting out in class
We are going to look at a few common disorders that can interfere with proper binocular vision and a variety of treatment options. Although, you may have noticed that many of the symptoms of binocular vision disorders can present very similar to those of Attention Deficit Disorder (ADD) or Attention Deficit Hyperactivity Disorder (ADHD). For this reason, it’s essential to have children’s vision tested regularly and keep your eye doctor informed more generally about their overall development. If your child is struggling to focus, be sure to include a trip to the eye doctor as part of the search for a solution.
A thorough eye examination will include the testing of the essential binocular visual skills listed below as well as a general discussion of your child’s behaviour at school to determine if any problems might be vision related.
- Tracking (the ability to move your eyes across a sheet of paper)
- Fusion (the ability to use both your eyes together at the same time)
- Stereopsis (the ability to perceive depth)
- Convergence (the ability of your eyes to move and work as a team)
- Visual Motor Integration (the ability to use our eyes and our hands in a coordinated and efficient way)
This condition refers to the brain preferring one eye over the other, and it is often referred to merely as “lazy-eye.” What is happening is that one eye is producing a significantly weaker signal. As such, the brain starts ignoring input from the weaker eye altogether and relying predominantly on the stronger eye. If left too long without treatment, Amblyopia can cause long-term impairment of the weaker eye and put considerable strain on the “good eye.” Not to mention, with the overall loss of depth perception, it becomes much harder to navigate the world.
Amblyopia is a condition that usually presents during infancy and as such, can be challenging to detect. A simple method to check for any disparity between the eyes is to cover your child’s eyes one at a time and watch to see how they respond. If they are experiencing Amblyopia, most infants will react by fussing or crying when the stronger eye is covered.
Sometimes Amblyopia can be effectively treated by fully correcting the refractive errors in both eyes with glasses or contact lenses. However, usually, the patient will have to wear a patch over the “good eye” for at least some time to force the brain to process the visual input from the amblyopic eye and enable healthy vision development to occur in that eye.
This condition is a failure of the two eyes to maintain proper alignment and work together as a team.
Your eyes each have six extraocular muscles that control eye position and movement. To allow for normal binocular vision, these muscles for both eyes must be coordinated perfectly and able to respond in unison to external stimuli.
When someone has strabismus, one eye will look directly at the object they are viewing, while the other eye will be misaligned in one of four directions. Esotropia is when the misalignment is inward, often referred to as “cross-eyed.” Exotropia is a misalignment outwards, sometimes called “wall-eyed.” Hypertropia and hypotropia are misalignments up or down, respectively.
The condition occurs when either neurological or anatomical problems interfere with the control and function of these extraocular muscles. The problem may originate in the muscles themselves, in the nerves, or the vision centers in the brain where binocular vision is controlled.
Treatment of strabismus often involves strabismus-surgery to straighten the eyes, followed by eye patching and often some vision therapy to assist both eyes in working together equally as a team.
Probably the most challenging condition to notice, Convergence Insufficiency is a type binocular vision problem that occurs when the pictures from both eyes don’t merge smoothly at close distances. The eyes fail to team together, causing them to cross or slide apart during reading and other near tasks, making it impossible for the brain to create one image.
A standard eyesight examination will not always detect convergence insufficiency, and therefore, many children remain undiagnosed. When this goes on too long, their brain learns to adapt and disregard information from one eye to prevent double vision. However, this vision suppression results in the loss of depth perception, which in turn causes the decline of proper coordination and the ability to judge distance.
In the case of Convergence Insufficiency, we’ve seen significant positive results with the use of Vision Therapy. This non-surgical treatment is like physical therapy for the entire visual system, including the eyes and the parts of the brain that control vision. We essentially teach the optical system to correct itself. The process can include the use of prism lenses, colour filtered glasses, computerized visual activities and non-computerized viewing instruments. Successful vision therapy outcomes are achieved through active collaborative work of the administering doctor, the patient and, in the case of children, their parents.
Vision Therapy as a Treatment Option
Due to the personalized non-invasive process of Vision Therapy, we’ve found it to be compatible with treating the entire range of Binocular Vision disorders. With Vision Therapy, we are determining where the breakdown in communication is between the eyes and the brain, and then using a corrective program to retrain the entire visual system. While some cases of Amblyopia may require eye patching and many occurrences of strabismus require surgery, Vision Therapy has proven to be complementary to these methods as part of the overall treatment plan. Please have a look at our past article on Vision Therapy to learn a little more about the process, or call us today to learn more.
Binocular vision is so fundamental to how we experience our world that it’s vital that we do everything we can to make sure it’s functioning correctly and keep a close watch on our children’s ocular development. With a little vigilance and regular check-ups, we can make sure our children get to experience the world, the way it was intended, in all its splendour.