Strabismus (eye turn), commonly referred to as crossed eyes, wandering eyes, or squint, is a visual condition where the two eyes point in different directions. Eye turns are present in about 4% of the population.
An eye can turn in (esotropia), out (exotropia), up (hypertropia), or down (hypotropia). The eye turn may be constant or occasional. The eye turn may occur in only one eye or switch between the eyes. It is also very common to notice an eye turn with fatigue, illness, day-dreaming, or visually-demanding tasks.
Strabismus is a Brain Problem, Not an Eye Problem
Strabismus is a type of binocular (two-eyed) vision problem. Our visual systems are designed to take a separate picture with each eye and have the pictures married in our brains (binocular fusion). Without fusion, we are at risk of double vision. The combination of the two pictures creates a three dimensional image, also known as “depth perception” or 3-D vision. Depth perception is critical to intelligently guiding our bodies to make sophisticated, coordinated movements.
During normal development, a child learns to use the two eyes together around 3 to 6 months of age and binocular vision continues to develop thereafter. However, if somewhere along the child’s development there was interruption in learning to use information coming from both eyes simultaneously, then the child’s brain may choose strabismus. Children do not “grow out of” strabismus. Adults can also develop strabismus suddenly after a traumatic brain injury or stroke.
A common misconception is held that eye turns are caused by a “weak” eye muscle. In fact, true eye muscle problems make up a small minority of cases.
A clear majority of eye turns are a developmental delay of binocular fusion. Quite simply, the brain controls where the eyes point, and the child’s brain did not learn to efficiently use the information from both eyes together. To prevent double vision, the brain will look through one eye and turn the other, making it easier to ignore the input coming from the turned eye. Over time, our highly adaptable brains create strategies for coping with information coming from two eyes which point in different directions. However, the solution (strabismus) does create problems of its own.
The Cosmetic Problem
Strabismus causes a problem with appearance. Children may tease, taunt, or shun a child whose eyes look different. Adults with eye turns are often self-conscious because others don’t know which eye to look at during conversations.
The Seeing Problem
Eye turns affect not just the way we look, but the way we see. When an eye first crosses, the pictures from the two eyes are so different the brain cannot marry the pictures. and the world doubles and runs together. At this point, the person with an eye turn may exhibit problems with coordination or balance because seeing double is visually confusing. Over time, if the eye is allowed to continue crossing, the child’s brain actively chooses to ignore the turned eye (i.e. suppression). Although the child’s brain has learned to eliminate the double vision, the depth perception is sacrificed. If the brain chooses to constantly turn one eye in, then amblyopia (lazy eye), a separate condition, occurs along with strabismus.
The Social Problem
The psychological impact of strabismus is well recognized. Research shows that teens and adults with strabismus have difficulties with self-image and interpersonal relationships. They report high levels of anxiety and depression. People with eye turns also generally avoid activities that brings attention to their defect.
“I have found that most of the Indian and US squint [strabismus] surgeons (including me) have been giving occlusion therapy and the surgical correction for treatment of squint. Adding the newer binocular and orthoptic therapies can be a major game changer in the treatment of squint and the quality of life of patients with squint. Mr. Robert F Hess (Canada) and Ms. Eileen Birch (USA) have done some commendable work and we have been finding the new Dichoptic therapies (Home based and office based eye exercises) to be of great help in improving the functional outcome of strabismus treatment.” ~ Dr. Mihir Kothari, Strabismus Surgeon
A longstanding, “Old School” treatment of strabismus is to patch the straight eye so that the turned eye works. This practice only teaches a patient to be a “one eyed person.” Patching does not address loss of 3-D vision (a two-eyed phenomenon) or may cause further breakdown of eye teamwork in the brain, resulting in an eye that turns more often!
Eye Muscle Surgery
“What we are currently doing with surgery is an orthopedic solution to a neurologic problem.” ~ Dr. Sean Donahue, Strabismus Surgeon
Surgeons are beginning to admit that strabismus is not a problem with the eyes or eye muscles – it is a brain problem. But eye muscle surgery is not brain surgery! It neither provides improvement in the communication and teamwork of the eyes nor teaches the brain to manage the protective coping strategies to prevent seeing double. Without an improvement in binocular vision and depth perception, the brain is unprepared to control and keep the eyes straight. As a result, the eyes will turn again after the surgery!
While we do a surgical referral as a tool in our optometric toolbox, we are very cautious to select the right patients. If the eye turn is not present all the time, do not be rushed into surgery. If the child can use the eyes together even part of the day, then that skill should be encouraged and nurtured through non-invasive optometric vision therapy. During the parent-doctor conference, we properly educate our patients and parents about the success rates and potential risks. For a second opinion regarding eye muscle surgery, please call 239-682-0945 or click on the Request an Appointment tab above to schedule an appointment.
Prescribing the right pair of lenses is the first step of treatment. In some cases, lenses alone will straighten the eyes at least temporarily. However, in the absence of further optometric vision therapy, half of these cases will show an eye turn.
Optometric Vision Therapy
Our treatments may include lenses and non-invasive optometric vision therapy: a kind of biofeedback that teaches the brain to increase simultaneous processing of both eyes. Improved eye alignment is the reward of better fusion. Our goal is to keep the number of surgeries to a minimum and to improve two-eyed coordination and depth perception for easier learning, sports, and self-esteem.
In instances where eye muscle surgeries have already been performed, whether the eyes are straight or not, there may very well still be problems with coordination, depth perception, reading, writing, learning, and athletics. We work with patients post-surgery to teach them how to use their vision more efficiently.
The Center for Vision & Learning is a vision care practice specializing in developmental optometry and optometric vision therapy. We proudly serve Naples, Fort Myers, Cape Coral, and all of Southwest Florida – and beyond. If you would like to schedule a Developmental Vision Evaluation for you or someone you know, please call 239-682-0945 or click on the Request an Appointment tab above.