Strabismus surgery and binocular outcomes

Boy with strabismus.

Strabismus, commonly known as ”crossed eyes”, is a condition in which both eyes do not align and point in the same direction. It can lead to double vision and affects the development of stereopsis. Binocular stereopsis or stereo vision refers to the capacity to estimate an item’s distance purely based on the relative positions of the object in the two eyes. In other words, it refers to the ability to perceive depth and spatial relationships.

For complex skills, normal binocular vision with strong stereopsis is required. As a result, it is crucial to restore stereopsis in patients who have lost their binocularity. We have talked more about the importance of stereopsis and why does it matter in this blog.

Strabismus surgery is a procedure performed to correct misaligned eyes and restore binocular vision. The surgery involves repositioning the eye muscles. Consequently, the alignment of the eyes improves. After the strabismus surgery, there are several factors which can affect the binocular outcomes.

In cases of acquired strabismus, treating the double vision may help the patient regain their previous level of stereopsis. Additionally, in kids with congenital strabismus, the binocular function may be improved with the right intervention in the first few years of life. Recently, it has been claimed that stereopsis can get better even in people who have had strabismus since childhood.

Effects of ocular realignment on stereopsis

What are the effects of surgical ocular realignment on the improvement of stereopsis? Eshaghi et al (2021) did a study with 194 patients observing the stereopsis after strabismus surgery. Patients with exotropia had much higher initial stereopsis than those with esotropia. The first finding, confirming previous studies, is that surgery substantially improved the stereopsis in patients, whether it was in the form of exotropia or esotropia. Eshaghi et al (2021) demonstrated that early surgical intervention can enhance stereopsis in patients with acquired exotropia and esotropia. What is more, the presence of vertical deviation had a negative impact on the final stereopsis in patients with horizontal strabismus.

Factors affecting binocular outcomes

Several factors can affect the binocular outcomes after strabismus surgery. These include:

  • Age: Children have a better chance of developing stereopsis after strabismus surgery than adults, as their brains are more plastic and better able to adapt to changes in vision.
  • Severity and duration of strabismus: Long-standing and severe strabismus can result in the suppression of vision in one eye, making it more difficult to develop stereopsis after surgery.
  • Amblyopia (lazy eye): Strabismus surgery is often performed in conjunction with amblyopia treatment, as the two conditions often occur together. Amblyopia can affect the binocular outcomes of strabismus surgery, as it can result in a reduction in visual acuity in one eye.
  • Other vision problems: Patients with other vision problems, such as significant refractive errors, can have a more difficult time developing stereopsis after strabismus surgery.

In conclusion, strabismus surgery can be a highly effective way to restore binocular vision and stereopsis. With proper care and rehabilitation, patients can experience a significant improvement in their visual function, allowing them to enjoy a more normal and fulfilling life. However, the outcomes are dependent on various factors described above. If you are experiencing symptoms of strabismus, it is important to seek the advice of a specialist to determine if surgery is the right option.

Eshaghi, M., Arabi, A., Banaie, S., Shahraki, T., Eshaghi, S., & Esfandiari, H. (2021). Predictive factors of stereopsis outcomes following strabismus surgery. Therapeutic Advances in Ophthalmology, 13, 251584142110030.