Strabismus

What is strabismus?

Strabismus, sometimes called cross eyed or an eye turn, is a condition that impacts both children and adults where eyes are not aimed at the same place at the same time. One eye may turn in (esotropia), out (exotropia), up (hypertropia) or down (hypotropia), which may only occur sometimes or it can also be constant. The tests required to fully diagnose the type of strabismus are often not included in traditional vision screenings.

What are symptoms of strabismus?

People with strabismus experience one or more of the following symptoms:

  • Apparent eye turn or crossed eyes
  • Eye turn that worsens (gets larger) with fatigue
  • Difficulty reading and concentrating
  • Avoidance of certain visual tasks
  • Reduced sports performance
  • Difficulty with eye hand coordination
  • Poor depth perception
  • Double vision
  • Eye fatigue/tired eyes
  • Reduced vision in one eye
  • Blurred vision in one eye

If you or a loved one experience any of the above symptoms, a Neuro-Vision Evaluation conducted by a Neuro Optometrist is the only means of getting a clear and accurate diagnosis. If you’re interested in better understanding the seriousness and severity of the symptoms you or a loved one are experiencing, we encourage you to take our Vision Symptom Quiz.

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What causes strabismus?

Strabismus can present based on family history or genetics, especially when infantile (present early in life). It can also occur due to a significant lens prescription, particularly if farsightedness is not corrected by the appropriate lens prescription at the time of the onset. In some cases it can be related to an injury, trauma, or a disease process.

How is strabismus treated?

Proper glasses prescription is important in strabismus treatment, particularly esotropia (or an eye turn inward), however, glasses alone do not cure strabismus. Vision therapy offers a successful, non-surgical approach to strabismus treatment. Vision therapy techniques provide feedback to the brain about when the eyes are aimed correctly and when depth perception is achieved. It is through this awareness of correct alignment and depth perception when the brain learns to hold and team the eyes properly. We use advanced technology, such as virtual reality, for these techniques to provide a high-level of visual biofeedback.

Some resources recommend surgery for larger eye turns, which attempt to change eye alignment by cutting and shortening eye muscles that surround the eye.  Surgical outcomes vary drastically for many patients because their brain may not be ready for 3D vision, and the eye turn can return again after surgery. Vision therapy can be a part of a surgical intervention or as a non-surgical option for treating an eye turn, providing lasting results.

Listen to Dr. Susan Barry, a neuroscientist, discuss how she overcame her depth perception issue due to esotropia (eye turn inward) and realigned her eyes through a vision therapy program as an adult.

Click to read more personal stories of success with vision therapy in treating strabismus.

Is strabismus surgery worth it?

Strabismus surgery is an often controversial topic within the eyecare community. Some providers feel that surgery is the only option to correct strabismus (an eye-turn) while other providers tend to take more conservative approaches to treat strabismus and prevent the need for surgery. Surgeries are performed by ophthalmologists who tend to have a different training and background than Developmental Optometrists. Unfortunately, many patients are not fully aware of all of their options when it comes to treating strabismus either for themselves or for their children. 

One of our goals here at NVTI is to discuss surgical intervention as a last resort after all other treatment avenues have been explored. Strabismus surgery involves cutting of the extraocular muscles that surround the eyeball to reposition the eye. Once these muscles are cut, they cannot be uncut. Furthermore, cutting these muscles to reposition the eyeball does not take into consideration the brain’s role in vision. It is important to keep in mind that the eye deviates for a reason. This deviation is often a result of a breakdown of binocular function in the brain’s pathways.

Surgeons tend to be concerned with the cosmetic appearance of an eye turn. Patients may undergo surgery with the idea that binocular vision will be restored when in reality, the eye has simply been repositioned with no concern for how the eyes are working together. Patients may still be left with the same or worse double vision or may still not have any depth perception. Furthermore, surgical intervention often results in an over-correction or an under-correction of the eye turn and many patients end up needing multiple surgeries. This occurs because surgery does not treat the underlying problem of a binocular dysfunction of vision. 

While vision therapy is not a “quick fix” for strabismus, goals tend to revolve around binocular and functional patient improvement. Vision therapy is a neurological rewiring of the brain through a series of specifically designed activities and procedures to restore or improve binocularity, the primary underlying component of strabismus. Every strabismus presentation is unique because every visual system is unique and Dr. Talaber will extensively evaluate you or your child’s visual system to assess your candidacy for vision therapy.

References

A Parent Guide to Strabismus, Eye Muscle Surgery, & Vision Therapy by Steven J. Gallop, OD. 2014. Copyright OEP Foundation.

Summary:  Dr. Gallop’s second book describes, in a clear and straightforward manner, a non invasive and effective approach to the treatment of strabismus and amblyopia using lenses and vision therapy. This book is a must read for anyone who suffers from a crossed or lazy eye and for the parents of a child with these conditions – Susan R. Barry, PhD

This book is a great resource for parents and patients who are considering their options and looking for more information. It is also a valuable reference book for optometrists to loan to their patients who are considering vision therapy as a treatment option for strabismus.

Crossed & Lazy Eyes – Myths, Misconceptions and Truths By Pilar Vergara

Summary: “In her book, Pilar Vergara puts parents behind the eyes of their children with amblyopia and strabismus so they can understand how they see. She discusses, in lay terms, the causes and symptoms of amblyopia and strabismus, the effects of these disorders on a person’s self confidence, and their ability to perform well in school and sports.

Pilar carefully explains different treatment options for these disorders ranging from the traditional medical approaches, such as patching and surgery, to more innovative and more effective treatments, such as the  use of different kinds of lenses, filters, syntonic phototherapy, and optometric vision therapy.

Her statements are backed up with an extensive list of validating scientific research references in the appendix. Pilar uses her 25 years of clinical experience with hundreds of patients, as well as the experiences of other behavioral optometrists worldwide, to illustrate that a child or adult does not have to live with the deficits and disadvantages resulting from amblyopia or strabismus.”

– Susan R. Barry, PhD. Professor of Biology and Neuroscience, Mount Holyoke College, USA

Clinical Management of Strabismus By Elizabeth R. Caloroso, O.D., M.Opt., & Michael W. Rouse, O.D., M.Ed.

Summary: One of the most challenging aspects of vision care is the establishment of clear single binocular vision in patients with strabismus and its associated conditions. This book provides a comprehensive reference for the complete care of these patients and an overview model of visual processing, presenting a practical guide for evaluation of these patients, which leads to accurate diagnosis and development of reasonable prognosis. Presents an overview of general management strategy and treatment options, including lens, prism, occlusion, pharmacological, surgical, and active vision therapies.

Journal Articles:

Vedamurthy I, Knill D, Huang SJ, et al. Recovering stereo vision (3D vision) by squashing virtual bugs in a virtual reality environment. Philos Trans B. 2016;371.

Conclusion: Here we trained adults who were stereo blind or stereo-deficient owing to strabismus and/or amblyopia in a natural visuomotor task—a ‘bug squashing’ game—in a virtual reality environment. We conclude that some adults deprived of normal binocular vision and insensitive to the disparity information can, with appropriate experience, recover access to more reliable stereoscopic information.

Cooper J. Summary of Research on the Efficacy of Vision Therapy for Specific Visual Dysfunctions. Professor of Clinical Optometry at SUNY College of Optometry.

Conclusion: The data suggests that vision therapy is more effective than surgery in patients with smaller angle intermittent exotropia and should be considered part of the treatment regimen for patients who receive surgery.

Garriott R, Heyman C, Rouse M. Role of optometric vision therapy for surgically treated strabismus patients. Optom Vis Sci. 1997;74(4):179-184.

Conclusion: Surgery reduces the magnitude of the deviation, whereas optometric vision therapy provides the unique role of establishing normal sensory processing.