We are not eye doctors. Determining the acuity and clarity of your vision, and the health of the eye itself — the retina, the optic nerve — is the work of an ophthalmologist or optometrist, and we don't do that. In fact, we recommend a visit to an eye doctor before we initiate any behavioral retraining of the brain networks that control the aiming of the eyes. This is especially important with a history of traumatic brain injury, where we need to be certain that the eye, the retina, and the optic nerves are structurally intact before we begin. Vision therapy addresses the coordination and aiming of the eyes — the neurology of binocular control. It presupposes healthy eyes.
Vision therapy
Turns out, good readers and great athletes have really good binocular coordination, precise "3-D" vision, and eyes that don't tire from hours of close work. Not everyone comes that way — but this skill is very trainable. Pro athletes get "Sports Vision Training." Kids (and adults) with reading and/or depth perception problems get "Vision Therapy." Same thing. Really key.
How well can you see up close? How precisely can you judge distance?
If your eyes don't converge powerfully, after you read for a while you'll start slowing down, skipping words, and get tired eyes. If your eyes don't diverge quickly and precisely when you look far away, your brain can't calculate precise depth. In some people these visual functions develop optimally. They become naturally good readers and "natural athletes".
Precise, quick and optimal convergent and divergent fusion (the bringing together of the slightly offset images from the two eyes) doesn't always develop fully. That's why the eye doctors who treat the problem are called "developmental" optometrists. Without optimal convergent fusion there will be slower reading, the necessity of re-reading, not quite knowing what you just read. Kids with this problem start thinking they're stupid when they see other kids reading quickly and enjoying it. And without good divergence you won't be as good as you could be at catching a ball. You might have trouble driving because of limited perception of space at distance, while moving. You might think you're "just clumsy". Wrong answer. You might need vision therapy.
The results of vision therapy in people with mild to moderate brain injury
When you hit your head, or even sustain a strong whiplash injury, you may disrupt the precision timing of the very complex brain network that controls the 8 muscles (4 for each eye) that aim the eyes. This eye "teaming" depends on no less than eighteen separate clusters of brain cells working together really fast. Some of those are in the front, some in the back, some in the middle and some in the bottom of the brain. So when you shake that brain up, it is easy to cause slight damage to this network, which causes problems with eye teaming.
Data from a presentation by Dr. Nash at the International Society for Neuronal Regulation (iSNR) annual conference in 1997 documented pre-post results from 40 consecutive patients with mild to moderate traumatic brain injury, some with injuries from 10 years prior, some recent. The typical patient had very poor binocular convergence (median 8 prism diopters) and very poor binocular divergence (median 6 prism diopters). "Prism diopter" is the measure of how strong the convergence or divergence is and is measured objectively with simple "3-D" images, the Bernell tranaglyphs.
Optimal convergence is 30 prism diopters and optimal divergence is 18 diopters — these patients were at about one-third of proper binocular visual control.
This results in poor reading, poor depth perception, headaches doing close work, and a general sense of confusion. You don't locate yourself quickly and automatically in your space, so there is a general anxious feeling — you don't know where it comes from, which makes it all the more strange.
Our data also shows that virtually all patients can be re-trained to have optimal binocular control. When this is done, problems with reading, depth perception, eye-strain headaches, as well as the anxiety are greatly reduced or eliminated.
A surprise encounter with an eye doctor
Clayton Odell Johnson, O.D. introduced himself as a behavioral/developmental optometrist after a talk on ADHD and neurofeedback. He explained that he'd been eliminating "ADHD" by doing vision therapy. Some of his patients had been diagnosed with ADHD, but after VT the children were taken off medications and did absolutely great in school and at home. What that means is that the "ADHD" was a misdiagnosis.
If a child — or an adult — has a bad problem converging their eyes, they won't want to stick to desk work, homework, or the book. They won't be able to read fast and they'll make mistakes, skip words, do poorly on evaluations and lose interest in academics. If the eyes don't diverge well, looking at the teacher, the board, and doing sports is not going to be much fun. So you'll tune out. ADHD? Nope.
Real-deal ADHD involves many executive control networks in the brain and doesn't go away when you fix the convergence/divergence problems. But when you fix the visual issues AND train the brain to be able to be alert, focused, and relaxed — then you've got a nice situation.
Dr. Johnson trained me, hands-on, for three years. We discovered that coupling neurofeedback with vision therapy increased the speed of training for both technologies. Sadly, these years turned out to be his last, but he made a lasting contribution to many children and adults. I've continued to do vision therapy, coupled with neurofeedback, and we refer the more difficult cases to excellent developmental/behavioral optometrists in the Minneapolis/St. Paul area.