Discovering Vision Therapy Blog

Strabismus in adults and children (Part 1 - Definition)

Strabismus in Adults and Children

When I was but a wee lad, I remember my older brother crossing his eyes, and shook my head as he ignored the conventional wisdom on strabismus in adults and children and – gasp – crossed his eyes. 

Didn’t he know that if you cross your eyes, they can remain permanently crossed?  How could he so blithely ignore this well-known, if not medically proven, fact? 

I obviously didn’t know much as all about strabismus in adults and children when I was a kid. 

As an adult, however, I’ve learned that the old wives’ tale about crossed eyes is definitely fiction, although you will experience eye strain if you keep your eyes in one position. 

I’ve also learned quite a bit more about strabismus.  I'm going to share the insights gleaned from Drs. Kellye Knueppel and Dr. Brandon Begotka over a series of posts on strabismus.

What is strabismus?

The more common term used is “cross-eyed,” and surgeries and thick-lens glasses are usually considered the only way to treat it.

They’re not.  Fortunately, there is a less invasive treatment that gets at the root of the problem and can improve visual function in a person with strabismus.  We were lucky to have one of the more famous cases of strabismus visit us two years ago:  Dr. Susan Barry, commonly known as Stereo Sue.

Dr. Barry is an amazing person, and she’s chronicled her story and her condition to an amazing degree. 

She’s had strabismus since she was a child, and despite a number of surgeries, she had never enjoyed stereoscopic vision.  Then, as an adult, she received optometric vision therapy and suddenly a world in 3D opened up to her.

Her story is well-chronicled in her book “Fixing My Gaze,” and it’s a story that is replayed often at The Vision Therapy Center.  Before we delve into how vision therapy can be used to treat strabismus, let’s define the condition. 

Defining Strabismus

According to the American Optometric Association, “Crossed eyes, or strabismus as it is medically termed, is a condition in which both eyes do not look at the same place at the same time.  It occurs when an eye turns in, out, up or down.”

Why does strabismus occur?  According to Dr. Brandon Begotka of The Vision Therapy Center, there is a delicate muscle and nerve system that controls the position of the eyes.  We actually have six muscles attached to a vast network of nerves that control their movements.  Any disruption to those muscles and/or nerves that control them can result in strabismus.   

But there’s another way that strabismus can occur: when the brain develops drastically different  perceptions of visual space in each eye. A person’s perception of visual space is developed beginning at birth. Each eye should perceive visual space the same in order to work together as a ‘team’. When the two eyes develop very different perceptions of visual space, strabismus can occur. 

Depending on when strabismus develops, it can be classified as:

1. Infantile- Strabismus developed in the first year of life.

2. Acquired Strabismus – Strabismus that develops after the first year of life. Acquired strabismus can be the result of an injury in the brain:  blunt force trauma the head, an aneurysm, a brain tumor and strokes are all examples of brain injuries that can cause strabismus. 

Here is a list of the different types of strabismus:

  • Esotropia:  When one or both eyes turn in.
  • Exotropia:  When one or both eyes turn out.
  • Hypertropia:  When one eye turns up.
  • Hypotropia:  When one eye turns down.

Strabismus can also:

  • Occur constantly or intermittently.
  • Involve only one, both or alternate between both eyes.

Strabismus doesn’t always mean crossed eyes

Strabismus doesn’t always mean “crossed eyes” either, which was what surprised me the most.  Any disruption to those six muscles and the nerves that control them can cause the eye to turn in a number of different ways.  The eye may move in, out, up or down – not just toward center, like my brother used to do. 

Strabismus may also occur only some of the time, a condition which is referred to as intermittent strabismus.  For example, the eyes may be lined up most of the time and only turn when fatigued, such as after extended periods of near work or when a person is tired, sick or stressed. 

In our next post, we’ll discuss the symptoms of strabismus, and the effects it can have on a person’s visual function.

 The Vision and Learning Guide from The Vision Therapy Center.Learn how undetected vision problems can impact a child's ability to learn.  Download your free Vision and Learning Guide.

Posted by   Greg Mischio