Stereo vision (depth perception) in preschool children - what if my child can't see 3D?

One of the easiest ways to diagnose a vision disorder in a very young child is to test his or her stereo acuity or depth perception.  Poor 3D vision is often caused by a vision disorder, some of which may be serious disorders that are best treated in early childhood.  Poor 3D vision may even be the sing of life threatening diseases such as tumours, as in this famous story from Ontario.

A new study published in the journal Optometry & Vision Science examined the a large population of pre-school children and tested their depth perception using the Stereo Smile II test.  The researchers then looked at the association of poor 3D vision with vision disorders.

The study found that children with vision disorders had significantly worse median stereoacuity than that of children without vision disorders. Children with the most severe vision disorders had worse stereoacuity than that of children with milder disorders.

The researchers also found that testability was excellent at all ages of the children included in the study. The results support the validity of the Stereo Smile II for assessing random-dot stereoacuity in preschool children.  The results also point to the need to take children who have poor stereo vision to a developmental optometrist to be evaluated and treated for developmental vision disorders that may be the cause of the poor stereo vision.

For more information visit our 3D vision web page at http://www.visiontherapy.ca/3dmediaandvision.html

Stereo vision, vision therapy and the TED talks

Stereo vision and treatment of depth perception problems with optometric vision therapy has been the subject of TED talk featuring neuroscientist Dr. Susan Barry:

Related articles on children and depth perception

What is 3D Vision Syndrome? 

Don't like 3D movies? You may have 3D Vision Syndrome

Take your kids to see "Thor": doctor's orders!

Life threatening disease found in girls eye - lack of 3D vision was the clue

Fixing My Gaze - Can you imagine not having 3D vision?

TED - ideas worth spreading - Susan Barry on how vision therapy gave her 3D vision

Source

Stereoacuity and Vision Disorders in Preschool Children
Optom Vis Sci 2014 Jan 23;[EPub Ahead of Print], EB Ciner, G-S Ying, MT Kulp, MG Maguire, GE Quinn, E Graham, D Orel-Bixler, LA Cyert, B Moore, J Huang

3D movies, depth perception, stereopsis and binocular vision disorders

At the end of this post is an excellent movie about 3D Vision Syndrome, an eye movement disorder that prevents people from seeing in three dimensions normally.  3D vision is called "stereopsis" and people who can't see in 3D are called "stereoblind".

If you or your child don't experience 3D movies they way other people do, you may have a binocular vision disorder that needs to be treated with vision therapy.

Here are some previous articles we have written on 3D vision and depth perception:

What is 3D Vision Syndrome? 

Don't like 3D movies? You may have 3D Vision Syndrome

Take your kids to see "Thor": doctor's orders!

Life threatening disease found in girls eye - lack of 3D vision was the clue

Fixing My Gaze - Can you imagine not having 3D vision?

TED - ideas worth spreading - Susan Barry on how vision therapy gave her 3D vision

When seniors loose depth perception and need to see a developmental optometrist

Dr. Susan Barry writes the blog "Eyes on the Brain" at psychologytoday.com about the eye-brain connection.  She is the author of the popular book Fixing My Gaze about how optometric vision therapy cured her stereo-blindness allowing her to see in three dimensions for the first time in her life.

One of her recent blog posts deals with the issue of seniors with eye movement disorders.  The post is compelling because such disorders are usually diagnosed and treated in children - at least we hope that they are (because if allowed to persist into adulthood they are associated with lots of undesirable social problems like unemployment and behavioral problems.)

Susan Barry

She wrote about her father who decided to quit driving in his early eighties. Dr. Barry noticed that over the next couple of years her father's life dramatically changed by contracting to the point where her father barely left the house. He was also becoming withdrawn and upset. Dr. Barry noticed that her father kept squinting his left eye shut. She wondered, "Could my father be squinting his left eye because it was turning in? If so, the left eye would be aimed at a different place in space than his right, providing his brain with confusing and conflicting visual input."

Dr. Barry knew to ask that question because she suffered from strabismus (crossed eyes) as a child and was successfully treated by an optometrist with with vision therapy.  She then did enough investigating that she realized that she should take her father to the optometrist:

I thought back to a story my father had told me about his days in the Air Force during World War II. Since he was an artist, he had been assigned to interpret aerial photographs. Sometimes, he’d be given stereo pairs of photographs which he viewed through a stereoscope. While he could see the 3D in the images, he told me that his sense of the 3D was not as good as others. Perhaps, he had always had subnormal binocular vision. When he stopped driving, he no longer needed to look in the distance. Indeed, he rarely looked further than the walls of his tiny house. Without driving, he had lost the ability to keep his eyes aligned, especially for distance viewing. Eye alignment, I concluded, was not a strong suit in our family.

So, one afternoon, during a typical visit, I sat about five feet from my dad and asked him, quite casually, how many heads did I appear to have. My father studied me for a while and then responded with great surprise: “You have two!” He could still read without the letters doubling, but when we gazed out the window, all the objects outside appeared double. He hadn’t noticed this previously, but, then again, he had avoided looking out. No wonder, my father was reluctant to take a walk with me. His perceptual world was thrown into confusion.

Dr. Barry then took her father to a developmental optometrist who diagnosed him with esotropia - a condition in which one eye turns in toward the nose.  Since her father's two eyes were not pointing at the same object, double vision and poor depth perception resulted.  The optometrist fit Dr. Barry's father with specially designed prism glasses that bent light in a way that compensated for her father's turned eye.

As Dr. Barry  notes in her post, falls are a leading cause of serious injury in seniors and people with poor depth perception are much more prone to falls than the general population.  When you combine old age and poor depth perception, you may have a recipe for disaster.  It's a good idea for seniors to get comprehensive binocular vision eye exams.  Not all optometrists test binocular vision and patients and their care-givers need to ask the right questions of their doctors to ensure that the right tests are being done.  To find a developmental optometrist visit the website of the College of Optometrists in Vision Development.

Don't like 3D movies? You may have 3D Vision Syndrome.

Some people are watching Titanic 3D without 3D glasses.  Why would they do that?  They may have an emerging vision disorder.  To go with it, a new medical term is emerging: "3D vision syndrome".

3D vision syndrome applies to a collection of symptoms that some people (some estimates peg the number at millions of people) suffer when exposed to 3D media content.  3D vision syndrome is coming to attention now because 3D movies, television, and video-games and other 3D media devices and applications have recently proliferated and many people are discovering that they cannot comfortably experience 3D.

3D media has significantly affected how we interact with our world. New mechanisms for delivering 3D content appear frequently from movies to television to video games.  Can the 3D internet be far behind? 3D has come into our theaters, hour homes and now even our schools.  Many schools are now using 3D content to improve their ability to teach a subject and studies show that 3D is very effective in the classroom.  One study found that the use of 3D in school increased test results by 17%.

Unfortunately, many people have a hard time seeing simulated 3D.  Chances are you know someone like this.  When viewing 3D content many people suffer from a number of symptoms during viewing such as blurred vision, headache, double vision, dizziness and vision induced motion sickness.

Binocular vision dysfunctions are the usual culprit when someone has problems with 3D.  And the impact of binocular vision dysfunction is not just restricted to 3D.  Studies have show that people with binocular vision dysfunctions have lower academic performance. Fortunately, binocular vision problems are effectively treated with vision therapy.

A famous case of vision therapy treatment for inability to see in 3D is the that of "Stereo Sue", or Dr. Susan Barry, a neuroscientist who wrote the book Fixing my Gaze about how vision therapy cured her stereoblindness and enable to see in 3D for the first time in her life at the age of 48.  Her story was also the subject of an article in the New Yorker written by Oliver Sacks.  She also gave a TED talk on vision therapy:

Vision Source Vancouver optometrists have successfully treated a number of patients who have had little or no depth perception. For some of these patients, their stereoblindness was caused by strabismus (eye turn) and persisted despite 2-3 surgeries that attempted to fix the problem. First vision therapy was used to straighten the eyes (vision therapy has a 87% success rate in treating strabismus) and then a completely different course of therapy is prescribed to establish 3D vision and depth perception.

For more information on 3D vision, click here.

The best online resource for 3D vision and health is the American Optometric Association's 3D vision website at   http://www.3deyehealth.org/ .

TED: Ideas Worth Spreading: Dr. Susan Barry on how vision therapy cured stereoblindess

Neuroscientist, Dr. Susan Barry, gave a TED talk on how optometric vision therapy allowed her to see in three dimensions for the first time at the age of 48.  Until then, she was stereo-blind, meaning that she could not see the world in 3D like people with normal vision.  Stereo-blindness is also called stereopsis.


TED stands for Technology, Entertainment and Design and is a global set of conferences owned by the private non-profit Sapling Foundation, formed to disseminate "ideas worth spreading".

Dr. Barry's story is now fairly well known.  Her 2009 book, Fixing My Gaze was Amazon.com's number 4 most popular science book of the year.  Her story was also the subject of an article in the New Yorker by famous scientist Oliver Sacks (who was played by Robin Williams in the film Awakenings).  


In this talk, Dr. Barry discusses the notion of the "critical period", a long-held belief among neuro-scientists which is being dis-proven by Sue Barry's story as well as current research.  Until very recently, it was thought that there was a critical period in human brain development beyond which the brain was "set in stone" and could not change.  The implication of this belief was that people with disorders like stereo-blindness or amblyopia that originate in the brain could not be cured beyond the age of 5 or 6.


Scientists now accept that the brain displays considerable neuroplasticity and that even the brains of adults can be trained to see normally.  In addition to conditions such as stereo-blindness, this has important implications for other brain-eye disorders such as strabismus, amblyopia and visual information processing disorders.  


Neuroplasticity is actually a prime reason for the success of vision therapy in treating these disorders.  As developmental optometrists will often say, vision therapy is like physical therapy for the eyes and brain.


More people that ever before are discovering that they are stereo-blind.  With the explosion of 3D entertainment, some parents are noticing that their children do not experience 3D media the way that normal-seeing people experience it.  This is often a red flag that prompts the parents to take their child to the optometrist for an eye examination.  Fortunately, as Susan Barry's story demonstrates, we can successfully treat people who are stereo-blind.


Click here to learn more about 3D vision and stereo-blindness.

Fixing My Gaze - Can you imagine not having 3D vision?

I just read an inspirational book called Fixing My Gaze about neuroscientist, Susan Barry, who was born with strabismus (an eye turn) and had lived all her life without stereo vision, meaning that she could not see in three dimensions.

She had three surgeries to "correct" the eye turn cosmetically but she still could not see properly and the eye was still turned, although less than before. She had lived this way for over 40 years until she met optometrist Dr. Theresa Ruggiero.

Dr. Ruggiero treated Susan with vision therapy and corrected the eye turn and allowed her see in three dimensions for the first time in her life. Can you imaging how her world was transformed? I've heard rumors of a "Fixing My Gaze" movie but have not been able to confirm them.

Here is what Susan Barry said in an interview with Scientific American about how the world looked different after vision therapy:

"For the first time, I could see the volumes of space between different tree branches, and I liked immersing myself in those inviting pockets of space. As I walk about, leaves, pine needles, and flowers, - even light fixtures and ceiling pipes - seem to float on a medium more substantial than air. Snow no longer appears to fall in one plane slightly in front of me. Now, the snowflakes envelope me, floating by in layers and layers of depth. It's been seven years since I gained stereovision, but ordinary views like these still fill me with a deep sense of wonder and joy."

Our vision therapy practice includes many patients with strabismus but all of them are very young (obviously it is better to fix the problem when a patient is young to save her from living years with the condition).

Susan Barry's story is remarkable in that she was in midlife when she received vision therapy. The conventional wisdom, now being disproved by new studies, was that after the age of 7 or 8 , the brain could not be trained (or "rewired") to see in new ways. The old scientific thinking was that after early childhood, the brain became fixed. In fact, Susan Barry herself and other scientists thought that it was impossible for her to ever see in 3D.

Now, we know that the brain exhibits neuroplacticity and that given the proper behavioural therapy, even adults can rewire their brains. This has given hope to many people who did not receive treatment for visual processing disorders at a young age. Now it seems possible that even older patients with amblyopia or strabismus and other binocular vision disorders can benefit from treatments like vision therapy.

You can hear interviews with Susan Barry and read more about her story at her website: http://www.fixingmygaze.com/.