Predictive factors of stereopsis outcomes following strabismus surgery

Abstract

Purpose: To determine the predictive factors of post-operative stereopsis in patients with strabismus. Method: In this retrospective study, records of patients who received surgical treatment for strabismus were reviewed. All types of strabismus were included. Pre- and post-treatment stereoacuity were measured using the Titmus Stereo Fly test, and predictive factors of stereopsis were evaluated. Results: A total of 194 patients (132 females and 62 males) with a mean age of 14.8 ± 8.4 years were included. There was a statistically significant improvement in stereopsis following surgery ( p value < 0.001). Patients with a higher amount of deviation at baseline had poorer stereopsis on the final examination ( p value < 0.001). Stereopsis improvement was more prominent in the pure horizontal strabismus group, compared to combined horizontal and vertical deviations. Baseline and the final stereopsis were higher in the “exotropia” group as compared to the “esotropia” group ( p value = 0.003 and 0.0155, respectively); however, the within group change of stereopsis was not significantly different between these two groups ( p value = 0.144). Post surgical residual deviation was associated with a poorer stereopsis ( p value = 0.002, r = 0.251). A longer duration of strabismus before surgery was associated with poorer final stereopsis levels ( p value = 0.026). The presence of amblyopia before surgery was associated with poorer stereopsis on last examination ( p value < 0.001 for both correlations). Conclusion: Based on the result of this study, final stereopsis after strabismus surgery could be affected by the type, duration, and the amount of deviation before surgery, amblyopia, and post operative ocular deviation.

Factors Determining Improvement in Stereopsis and Binocularity After Good Postoperative Alignment in Patients With Childhood-Onset Strabismus

“…We found no association between postoperative residual deviation and final stereopsis (p-value > 0.05), in contrast to the previously published studies [15,21]. There were 14 patients in the study population who achieved postoperative horizontal alignment within 4 PD, and the rest of the 59 patients achieved postoperative horizontal alignment within 10 PD.…”

“…However, on the subgroup analysis, we report that the value of preoperative deviation is significant as patients with preoperative deviation in the range of 31-45 PD had a statistically significant improvement in stereopsis (p-value = 0.000) compared with those having a deviation of more than 45 PD (p-value > 0.05). This finding is partly consistent with a study by Eshaghi et al, who concluded that a higher amount of ocular deviation is associated with immature stereopsis [21].…”

“…We have observed that children who developed strabismus after six months of age had a statistically significant improvement in stereopsis. This finding is consistent with that of a recently published study that concluded that earlier manifestation of ocular misalignment leads to poorer final stereopsis [21]. Strabismus in the first few years of life inhibits the development of binocular sensory neurons in the brain [22].…”

“…Those with esotropia had poorer final stereopsis than those with exotropia or combined horizontal and vertical deviation. This finding is partially consistent with that of previously published studies that concluded that exotropia had a better improvement in stereopsis as opposed to esotropes, but there was no statistically significant association between the type of deviation and final stereopsis [15,21]. In our study, a statistically significant improvement was seen in the combined group in contrast to the previously published studies [21].…”

“…This finding is partially consistent with that of previously published studies that concluded that exotropia had a better improvement in stereopsis as opposed to esotropes, but there was no statistically significant association between the type of deviation and final stereopsis [15,21]. In our study, a statistically significant improvement was seen in the combined group in contrast to the previously published studies [21]. This could be due to the correction of vertical and torsional components of the deviation; however, it requires further validation by future studies.…”