While there are several things that can cause double vision, in this post, I’m going to just discuss one of the most common causes. In the simplest way of stating it, double vision is most commonly caused when the eyes are not aimed at the same thing. And while knowing that can be good, it doesn’t help us fix the problem, so let’s dive into what can cause the eyes to be misaligned.
Before we get too detailed, it’s important to note that no information presented in this post should be used for diagnosis or treatment. If you are experiencing double vision in any manner, constant, occasional, long-standing, or newly occurring, you should make an appointment with your primary care doctor and an optometrist immediately.
Let’s start with some of the basics of truly understanding our vision before we dive into how it can go wrong and lead to double vision. I often like to refer to our eyes as two individual cameras that are recording our world and sending the information back to our brain to be processed into an image. What is amazing about have two eyes is that, even though the eyes aren’t very far away from each other, they have different viewpoints of our world.
What does this mean for our vision if our brain is trying to process information from two different locations? It means that when our visual processing system and visual skills are properly functioning, we are able to see our world in 3D. This principle of having two offset eyes helps provide us more accurate depth perception as well as increase our peripheral vision.
So now that we know the purpose and benefit of having two individual views of the world, let’s move on to what can go wrong and prevent those two views from coming together in such a way that we see one clear world.
As stated above, the simplest way to explain one of the most common causes of double vision is that the eyes are not lined up at the same thing. If one eye is aimed at a ball and the other is aimed at a cup next to the ball, the brain is going to take the center of both of those images and try to place them on top of each other.
So one image with the ball in the center will have the cup to the side of it and that will be placed on top of an image with the cup in the center and the ball to the other side of it. When the brain attempts to make a clear image out of these two, the image ends up with two of just about everything.
Because each eye is sending information that the ball and the cup are in different places, the brain thinks that there are two of each.
What is causing the two eyes to be misaligned?
If we again start with the simplest answer, we would say that the muscles are not working properly to aim each eye at the exact same spot as the other eye.
Understanding the muscles of the eye takes us to another step in this process of understanding the causes of double vision. Each eye has 6 muscles. Each one moving each eye in a distinct direction.
It is obvious to see, that if there is damage to one of these muscles or the nerve supplying it, then there would be a decreased ability or inability for the eye to move in that direction.
So while trauma to the muscle or nerve supplying it are possible causes for the eye to not align properly, other causes involve problems with the visual processing system in the brain that sends signals to the eye muscles and direct them in their movement.
As vision is more than just 20/20 and requires several visual skills as well as visual information processing skills including visual perceptual skills, it isn’t hard to imagine that something could go wrong in one of the many tasks that the brain has to perform in order for us to have properly functioning vision. One of the most common conditions is convergence insufficiency, which can luckily be treated and often cured with vision therapy.
Disorders that cause the eyes to not line up properly are referred to as binocular vision disorders. They can include issues with the eyes not coming together properly when looking at something up close and causing double vision when reading, not moving apart properly when looking at something far away and causing double vision then, and various other issues.
Remembering that vision is MUCH more than just 20/20, as a developmental eye doctor, I can’t help but always want to educate people on the 17 Visual Skills and all the ones that are specifically needed just to read and that when it comes to learning, 80% of what children learn is take in visually. So it is vital to their academic success and success in everyday activities, as these are not problems children outgrow, that they have well developed visual information processing skills including the visual perception skills here on this page.
Feel like you or your little one are struggling with reading or any of the visual skills needed to live your life comfortably, don’t worry! Vision Therapy has incredibly high success rates for various vision conditions and lazy-eyes (or eye-turns as we like to call them). Call our office today to schedule a complete and comprehensive vision exam