Stereo-blindness, stereopsis, 3D video games, movies and vision

Testing for 3D vision

Optometrists routinely check a patient's stereo vision in the office using a test called the Randot Stereo Fly test.  The test consists of a three dimensional image of a fly and the patient is asked to pinch the wings of the fly.  A patient who sees the wings in the plane of the page likely cannot see in three dimensions and has a condition known as stereopsis.

Why lack of 3D vision is a concern

Stereopsis is of concern because it can limit a person's ability to play sports, to drive, to read and process information efficiently and it limits a person's job prospects.  For example, you cannot be an eye surgeon unless you can can see in three dimensions. Humans evolved the ability to see in three dimensions and it is an important part of our experience of the world around us.

What causes stereopsis?

Stereopsis is often caused by underlying conditions like amblyopia (lazy eye) and strabismus (cross eyes, eye turn).  Correction of the underlying condition using vision therapy is often a cure for stereopsis.  These conditions, especially amblyopia, are most effectively treated at an early age.  That is why it is critical to take your child to the optometrist for a comprehensive eye health examination every year.  It is also important to observe your child when they are interacting with 3D media; any worries you have should be taken to your doctor of optometry immediately. 

How 3D video games and movies can help you and your child

The exciting thing about the popularity of 3D games and movies is that it enables parents to essentially administer the Randot Stereo Fly Test at home or at the movie theater. If a child does not think that there is anything remarkable about a 3D movie or video game and experiences it the same way that they experience an ordinary movie or game, there may be reason to worry about the child's three dimensional vision. 

A famous case of stereopsis

A famous case of stereopsis is that of neuroscientist Susan Barry, who wrote about her experience in her book, Fixing my Gaze.  Susan Barry had strabismus and stereopsis and had a number of surgeries to try to correct the problem.  Surgery had a cosmetic effect in that her eyes looked normal but they did not function normally.  Eventually in her 40's Dr. Barry found an optometrist who practiced vision therapy.  Vision therapy very quickly enabled Dr. Barry to see in three dimensions for the first time.

Image: Salvatore Vuono / FreeDigitalPhotos.net

See the TED talk on vision therapy by Dr. Susan Barry.