This is an introduction to a multi-post series on vision therapy. With each new post, we will discuss a different binocular vision disorder, the anatomy and pathology behind it, diagnosis, treatment strategies, and what to expect from vision therapy sessions!
Why Do We Need Vision Therapy?
The eyes are very complex organs. For an image to be seen correctly by the brain, light must properly pass through the eye, land on the retina (the very back structure of the eye), be turned into chemical signals, be sent along a course from the front of the face to the back of the brain, and then be processed by the brain as sight!
To make everything more complicated, we have two eyes. This means this process must not only be extremely precise for one eye—but both of them!
Monocular vision occurs when only one eye is being used to see an image (like when you cover one eye).
Binocular vision is what we typically use in our day-to-day activities and involves image processing from both eyes in the brain. For binocular vision to occur, we have to have both of our eyes open and focusing on the same target.
Binocular vision is what allows us to see in depth, perceive distance, and establish relationships between two objects.
The two eyes must move together, focus together, and be processed by the brain together in order for a binocular image to be created appropriately.
Any slight misalignment of the eyes causing them to not work together can result in binocular vision problems—double vision, eye strain and fatigue, distorted images, etc.
What Problems Can Be Treated with Vision Therapy?
Binocular vision disorders can be broken down into three major categories—problems with accommodation, vergence, and oculomotor function.
Accommodation is the eye’s natural ability to focus a near target (reading, computer work, writing, etc.). Issues with accommodation can be monocular (one eye) or binocular (both eyes).
Vergence is the ability of the two eyes to move in opposite directions to look at a far target or a near target.
Convergence is when the two eyes come together (i.e. both move in towards the nose). Convergence is used when trying to focus on a near target.
Divergence is when the two eyes move apart (i.e. both move away from the nose, or toward the ears). Divergence is used when trying to focus on a target in the distance.
Oculomotor function is the ability of the eyes to move as they should.
Oculomotor function problems can stem from issues with the eye muscles themselves, or they can be caused by a visual processing deficit.
In any of these major categories, problems can arise when we have too much or too little of a given thing. Some examples include accommodative insufficiency, accommodative excess, divergence insufficiency, divergence excess, etc.
To further complicate things, an individual can have problems in multiple categories!
It is important to undergo a through binocular vision evaluation or visual efficiency evaluation (VEE) to narrow down exactly what the problem is before initiating vision therapy to fix it.
How Do I Know if I Have a Binocular Vision Disorder?
Many individuals think the only issue with the eyes that can be corrected is clear vision. This is not the case!
Binocular vision disorders can cause a plethora of problems that can be improved upon including:
- Headaches (especially behind the eyes)
- Eye Strain
- Eye Fatigue
- The inability to focus on near tasks
- The feeling that words are “swimming around” the page
- Lack of Depth Perception
- Double Vision (Diplopia)
- Feeling as though the two eyes are not working together
- Blurry vision (yes this can be due to things that cannot be corrected with glasses!)
- These problems can cause secondary symptoms of:
- Attention Deficits
- Poor hand-eye-coordination
- Skipping lines/losing place easily when reading
- Decreased reading speed and comprehension
- Inability to copy information (ex. writing down notes from a chalkboard)
If any of these signs or symptoms sound familiar to you, be sure to bring it up at your next appointment. While these findings do not necessarily mean you have a binocular vision problem, they certainly could, and vision therapy may be an excellent solution for you!
What Is Vision Therapy?
Now that you have a basic idea of problems that can arise with the binocular vision system, we can finally answer this question.
Vision therapy is a physical therapy regimen for the eyes to help improve the eyes’ accuracy and alignment to minimize symptoms caused by a binocular vision disorder.
Think about physical therapy for the leg or arm—but specialized to the eyes! The eyes have complex series of muscles too, sometimes all it takes is a little extra work to get them up and functioning to their full potential.
However, it is important to understand that vision therapy is not a “cure all”. It is a therapy, meaning it can strengthen your eyes’ abilities to focus and work together–thus alleviating symptoms.
Vision therapy cannot guarantee symptoms will go away completely, but the success rate of improving symptoms has been high in most patients.
During vision therapy, your vision therapist will work with you to complete exercises based on your complaints and disorder. They will coach you to help train your eyes to do tasks you might not have thought possible.
Vision therapy takes place over the time span of several weeks and includes in-office visits and at home exercises and practices. If you choose to go through a vision therapy program, it is crucial that you commit to all exercises and practices to get the most out of your therapy.
It may not always be fun, but if you put in the hard work you will see the benefits!
Interested in learning more? Check back for our next post to learn about the visual pathway (and where things can go wrong!)—Part 2 of the Visual Therapy Series!