Abstract
Purpose
To evaluate the postoperative outcome of strabismus surgery performed in children aged 1–6 years by investigating the change of the preoperative angle of deviation (AOD), elevation in adduction, best-corrected visual acuity (BCVA) and refractive error.
Methods
Retrospective chart review of 62 children who received strabismus surgery between January 2018 and December 2021 at the Department of Ophthalmology and Optometry of the Medical University of Vienna. Age, sex, type of strabismus, AOD, BCVA, refractive error and visual acuity were evaluated with respect to the postoperative outcome.
Results
Mean follow-up was 13.55 ± 11.38 months with a mean age of 3.94 ± 1.97 years (range: 1.0–6.0) at time of surgery. 74.19% of patients (n = 46) had isolated or combined esotropia, 12.90% (n = 8) had isolated or combined exotropia and 12.90% (n = 8) had isolated strabismus sursoadductorius. Mean preoperative AOD of 15.69 ± 16.91°/15.02 ± 14.88° (near/distance) decreased to 4.00 ± 9.18°/4.83 ± 7.32° (near/distance) at final follow-up (p < 0.001). BCVA improved from 0.26 ± 0.26/0.25 ± 0.23 (left/right) to 0.21 ± 0.25/0.20 ± 0.23 (left/right) (p = 0.038). There was no significant change regarding refractive error (p = 0.109) or elevation in adduction (p = 0.212). Success rate which was defined as a residual AOD of less than 10° was 74.19% (n = 46). In 3.23% (n = 2) retreatment was necessary.
Conclusion
Strabismus surgery in infants was shown to have a satisfactory outcome with a low retreatment rate. Surgical success rate was not linked to age, sex, type of strabismus or the preoperative parameters AOD, refractive error and visual acuity in this study.
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Introduction
Strabismus is defined as a common ocular misalignment among children with a prevalence of 3–5% [1]. Surgical treatment remains a challenge since the surgical protocols are not standardized and there is still a lack of studies comparing surgical outcomes while considering the various influencing parameters [2].
The age group 1–6 years is particularly important because of the visual development and the impact of intervention on binocular function. Visual impairment during infancy and childhood can result in lifelong social and cognitive complications. The age of 1 to 2 years marks the growth of the optic nerves and the visual cortex. The fovea reaches maturity by the age of 4 and the rest of the visual system is fully developed by the age of 10 [3]. Amblyopia treatment yields the best results when performed before the age of 7, however the visual screening of children can pose problems regarding accuracy and testability [4]. To date, data concerning strabismus treatment in children are limited since the age group 1–6, especially if younger than three years, is often not included in studies [5].
Currently, there is no consensus on the optimal surgical approach for medium-angle strabismus with several different definitions of a successful surgical outcome and a wide age range of children undergoing the strabismus operation. In addition, many trials have focused on small-angle or large-angle strabismus while leaving out the moderate range between 10–20°.
This study was designed to evaluate the outcome of strabismus surgery in the age group 1–6 years and to assess the most important influencing factors in children undergoing a one-, two- or three-muscle surgery.
Material and methods
A search of medical chart records at the Department of Ophthalmology and Optometry of the Medical University of Vienna was conducted to identify patients who underwent strabismus surgery between January 2018 and December 2021. Baseline characteristics as well as pre- and postoperative data were collected to identify which parameter significantly changed after surgery and how they influence the postoperative outcome.
Data consisted of the angle of deviation (AOD) obtained for near and distance, vertical deviation (VD) in proximity and distance, refractive error, best-corrected visual acuity (BCVA), binocular vision and mean duration until surgery or mean follow-up. Two follow-ups are compared with the first follow-up after one month or less and the second follow-up after at least three months after surgery.
Patients aged between 1–6 years that underwent their first strabismus surgery between January 2018 and December 2021 were included in this study. Exclusion criteria included patients outside the age range of 1–6 years, patients with a history of strabismus associated with systemic diseases, patients with history of strabismus because of brain tumors, patients with incomitant strabismus because of neurological diseases, patients with a history of penetrating or perforation eye trauma as well as patients with strabismus caused by severe head injury.
The analyzed demographic characteristics were age at time of surgery and sex, the functional outcome variables consisted of the mean AOD, BCVA and refractive error. The analyzed variables concerning the surgical procedure are the preoperative mean AOD (in degrees) as well as the type of surgery with the postoperative follow-up entailing the postoperative mean AOD, binocular vision function, BCVA and the mean refractive error.
Successful surgery outcome is defined as a postoperative angle of deviation of 10 degrees or less and is the main parameter to measure the success rate. All angles of deviation that were documented in prism diopters were converted in degrees by using the formula of Lachenmayr et al. [6] according to which 1.75 prism diopters correlates to a 1° deviation.
The angle of strabismus was measured in near and distance. Measurements were performed preoperatively, within one month and after at least three months following the surgery. AOD was measured in the primary position by the alternate prism cover test at fixed distances of 33 cm/6 m (near/distance) or by using the modified Krimsky’s test.
Visual acuity was determined through age-appropriate vision tests. The Cardiff-test was used for children under two years in this study. It is based on the Preferential Looking principle according to which a patterned target will rather be perceived than a plain stimulus with the same mean luminance [7]. Child-friendly symbols such as cars, fish or houses are depicted through black lines and used as stimuli. The lines are getting increasingly thinner to determine the child’s visual acuity [7,8,9]. Children over the age of two were examined through the Lea test. The vision sample chart consists of an apple, a pentagon, a square and a circle which the child has to name. The Lea test is known to be suitable for children of preschool age [8,9,10].
Stereopsis was determined using the Lang test, which examines stereoacuity by using the random-dot technique and a cylindrical grid.
All patients underwent complete ophthalmological examination before surgery and at every follow-up visit. Patients received full correction of the refractive error presurgically. Visual acuity was assessed after cycloplegic refraction.
All surgeries were performed under general anesthesia. A limbal approach and no adjustable sutures were used. In patients with esotropia, two-muscle surgery included medial rectus recession and lateral rectus plication and bilateral medial rectus recession and lateral rectus plication in three-muscle surgery. In patients with exotropia, two-muscle surgery included lateral rectus recession and medial rectus plication. Three-muscle surgery included bilateral lateral rectus recession and medial rectus plication. Surgery on the inferior oblique muscle was included in cases of overelevation in adduction. The method and dosage of surgery depended on the angle of strabismus. The surgical dosage is shown in Table 1.
The study was approved by the ethics board of the Medical University of Vienna and adheres to the ethical principles for Medical Research of the Declaration of Helsinki. The statistical analysis was performed with Microsoft Excel and SPSS (IBM Statistics, Version 23). Continuous variables are presented as mean ± standard deviation or median and range, whereas categorical variables are presented as count and percentage. BCVA was transformed to logarithm of minimal angle of resolution (logMar) to create a linear scale for statistical analysis. A p-value ≤ 0.05 was considered as statistically significant. Final BCVA, spherical equivalent and mean AOD were compared pre- and postoperatively using Students t-test or Wilcoxon test. To evaluate the influencing factors of strabismus surgery a multivariate logistic regression was performed.
Results
A total of 62 patients were included in this retrospective cohort study with a total follow-up of 13.55 ± 11.38 months. The mean age of the patients was 3.94 ± 1.97 years. The baseline characteristics are presented in Table 2.
Out of the 46 esotropia patients, 32 underwent surgery on two extraocular muscles and 12 on three muscles. 87.50% of the exotropia patients were operated on two muscles and 12.50% on three muscles. The majority of patients diagnosed with isolated strabismus sursoadductorius had a unilateral surgery on the inferior rectus muscle (MOI) and one patient received bilateral surgery on the MOI.
Success rate, which was defined as a residual AOD of less than 10°, was 74.19% (n = 46). Tables 3, 4 and 5 describe the characteristics of patients with a postoperative AOD of ≤ 10° compared to those with a postoperative AOD of ≥ 10°. There is no general trend visible in the results regarding surgical success. Patients who achieved surgical success with either combined or isolated eso- or exotropia had a smaller preoperative AOD in comparison to those with a postoperative AOD ≥ 10° with a mean preoperative AOD of 19.19 ± 7.64 and 13.01 ± 23.40, respectively.
Angle of deviation
The mean preoperative AOD in patients with esotropia was a mean of 21.46 ± 7.63/17.27 ± 8.26 (near/distance) respectively and improved to 5.50 ± 9.69/4.62 ± 7.71 at first follow up and to 5.62 ± 8.16/6.20 ± 5.30 at longterm follow up (p < 0.001) (Fig. 1).
The mean preoperative AOD in patients with exotropia was 15.36 ± 23.35/14.17 ± 16.95 (near/distance), 17.09 ± 16.17/13.71 ± 12.93 at first follow-up and 5.92 ± 5.12/0.43 ± 13.87 at longterm follow-up (p = 0.004) (Fig. 2).
AOD in patients with isolated strabismus sursoadductorius improved from 12.00 ± 7.02/9.14 ± 11.31 (near/distance) preoperatively to 3.05 ± 3.67/1.14 ± 3.23 at first follow-up and 0.03 ± 10.54/0.71 ± 10.24 at longterm follow-up (p = 0.037) (Fig. 3).
Elevation in adduction
27 patients had combined esotropia with overelevation in adduction. Preoperative vertical deviation in patients with combined esotropia and strabismus sursoadductorius decreased from 9.17 ± 3.72/7.27 ± 4.70 (near/distance) to 3.79 ± 1.86/3.43 ± 1.25 at first follow-up and 4.51 ± 4.64/4.07 ± 3.18 in the longterm follow-up (p = 0.943).
The vertical deviation in patients with combined exotropia and strabismus sursoadductorius changed from 3.81 ± 6.60/1.90 ± 3.30 (near/distance) presurgical to 0.95 ± 1.65/0.95 ± 1.65 at first follow-up and to 1.90 ± 1.65/0.95 ± 1.65 at second follow-up (p = 0.742).
Eight patients had isolated strabismus sursoadductorius and showed improvement in the vertical deviation from 7.51 ± 4.98/7.71 ± 6.88 presurgical (near/distance) to 3.66 ± 3.07/6.86 ± 3.23 at first follow-up and 4.19 ± 3.67/6.86 ± 3.23 longterm in elevation in adduction (p = 0.167).
Visual acuity
The mean age of the patients was 3.72 ± 1.36 years at time of the preoperative BCVA measurement, 3.77 ± 1.38 years at first follow-up and 4.88 ± 1.52 years at longterm follow-up.
BCVA was transformed to logMar for the statistical analysis and showed improvement in patients with esotropia from 0.20 ± 0.21/0.21 ± 0.22 (left/right) to 0.19 ± 0.22/0.18 ± 0.20 after 1 month and 0.20 ± 0.24/0.19 ± 0.25 at longterm follow-up (p = 0.392).
BCVA improved in patients with exotropia from 0.50 ± 0.29/0.42 ± 0.27 (left/right) to 0.31 ± 0.23/0.27 ± 0.21 at longterm follow-up (p = 0.55).
Preoperative BCVA in patients with isolated strabismus changed from 0.28 ± 0.36/0.25 ± 0.21 (left/right) before surgery to 0.08 ± 0.08/0.18 ± 0.18 at longterm follow-up (p = 0.80).
The Cardiff test was used for examining 12.90% of the children in this study while the remaining 87.10% were tested through the Lea test.
Refractive error
The mean age of the patients was 3.72 ± 1.36 years and 4.88 ± 1.52 years at time of the preoperative and postoperative measurements, respectively. Mean refractive error was measured by the spherical equivalent and improved in the operated left eyes from 2.94 ± 2.20 to 2.09 ± 3.82 after surgery and from 2.84 ± 2.11 to 2.26 ± 3.07 in the operated right eyes in patients with esotropia (p = 0.312).
The refractive error in patients with exotropia changed from 0.09 ± 1.51/0.28 ± 1.44 (left/right) to 0.14 ± 1.63/0.25 ± 1.52 (left/right) (p = 0.689).
Patients with isolated strabismus sursoadductorius had a mean preoperative refractive error of 1.08 ± 4.45/0.75 ± 4.45 (left/right) which decreased to 0.17 ± 5.39/0.25 ± 5.19 (left/right) (p = 0.264).
Stereopsis and Re-operations
The test for stereopsis was positive in 16,67% of patients preoperatively and in 38,46% of patients after surgery. The average age was 4.67 ± 0.93 years preoperatively and 5.41 ± 0.92 years after surgery. In 3.23% (n = 2) retreatment was necessary, one patient had combined esotropia with strabismus sursoadductorius and the other had combined exotropia with strabismus sursoadductorius. Both reoperations were conducted on the unilateral MOI after an average time span of 9.27 ± 7.74 months following the initial operation.
Influencing factors
Change in AOD was significant in all three patient groups. Results also show improvement in other subcategories (elevation in adduction, BCVA and refractive error) but were not statistically significant. Multivariate logistic regression was performed to evaluate influencing factors of strabismus surgery. Table 6 shows the individual parameters and the results after the statistical analysis was conducted.
Discussion
The purpose of this paper was to analyze the surgical outcome of strabismus surgery by using a retrospective data set. After running a multivariate logistic regression, there was no significant association between demographic parameters such as age at surgery or sex, preoperative AOD, refractive error, visual acuity or type of strabismus.
Individual parameters and surgical success
The age at which strabismus surgery should be performed has been a subject for debate for many years. Early surgery can minimize harmful habits due to squinting and long lasting sensory changes but later surgery can lead to more accurate measurements and avoid unnecessary surgery [11,12,13] According to Awadein et al. [14] an age greater than 12 years old correlated with a worse surgical outcome. Richard et al. [12] showed that there was no significant difference in strabismus surgery outcome in the age group of 0–6 years. In our study, 50.00% of patients with a successful outcome were between 3 and 4 years old while 31.25% were younger and 1–2 years old. No significant difference was found in relation to age (p = 0.38).
Abbsoglu et al. [15] and Kampanartsanyakorn et al. [16] linked a larger preoperative AOD to a poorer surgical outcome. In this study, however, the preoperative AOD had no statistically significant influence on the surgical outcome (p = 0.38). A study from 2020 by Waheeda-Azwa et al. [17] reported similar findings to ours with a success rate of 81.60% that did not show a significant correlation to the preoperative AOD, with many patients having a large AOD. 13 out of 46 patients with a successful outcome in this study had a preoperative AOD of more than 20°, which could be explained by the young age group with possible congenital strabismus causes [17, 18].
Change in the angle of deviation
Improvement in AOD was statistically significant in all patient groups. Patients with esotropia showed the greatest improvement (p < 0.001) followed by patients with isolated strabismus sursoadductorius (p = 0.037) and patients with exotropia (p = 0.004). Surgical success rate was 74.19% (n = 46) which correlates to findings of other similar studies [16, 19, 20]. Another study conducted by Kumari et al. [21] also reported a poorer success rate for exotropia in comparison with esotropia. A possible reason could be the inclination to postoperative drift in exotropia patients which results in a slightly poorer outcome.
Surgical management of exotropia includes the deliberate esotropic overcorrection as the initial postoperative result since it has been shown to provide good longterm outcomes [22,23,24,25]. But several studies have reported that initial overcorrection does not correlate with a more favorable longterm outcome [26,27,28,29]. Additionally, overcorrection in visually immature individuals, such as children aged 1–6 years, may be associated with consecutive esotropia, loss of stereopsis and amblyopia [24, 30]. It was also linked to a higher reoperation rate [28].
We did not aim for a postoperative overcorrection due to the reasons mentioned above and obtained satisfactory results with a success rate of 87.50% for patients with exotropia. The change between the first and longterm follow-up was not significant (p = 0.181).
Change of the elevation in adduction
Improvement in elevation in adduction was shown in all three patient groups (p = 0.212). As Stager et al. [31] reported, more than 70% of patients with infantile esotropia and more than 30% of patients with intermittent exotropia have primary inferior oblique overaction. Overelevation in adduction has many possible causes that are difficult to correct with one surgical intervention. The study of Stager et al. [31] also reports that residual or recurrent over elevation in adduction is common.
Change in visual acuity
Visual acuity did not show a significance in relation to the surgical success. The results of this study can be explained by the infantile patient group with the strabismus surgery taking place before visual maturity has fully occurred. Kampanartsanyakorn et al. [16] conducted a retrospective study of 304 patients to analyze the outcomes of horizontal strabismus surgery and found that preoperative visual acuity did not significantly influence the surgical success. The results of the study by Ganguly et al. [32] were similar and showed no significant change in visual acuity and binocular vision after strabismus surgery.
Change in refractive error
The refractive error showed general improvement (p = 0.109) and was measured in the preoperative and long-term follow-up without measurements immediately after surgery. Several other studies conclude that strabismus surgery usually leads to short-term improvement regarding the refractive error with a long-term regression due to compensation or other postsurgical factors [33,34,35,36].
Change in binocular vision
Obtaining the information on binocular and stereovision using the Lang test was only partially possible due to the young age of the examined patient group with a mean of four years. The data did not suffice for an in-depth analysis of binocular vision and stereovision. However, there is a trend toward postsurgical improvement with the percentage of a positive Lang test result rising from 16.67% to 38.46%. Children with a positive postsurgical Lang test result had a diagnosis of esotropia or strabismus sursoadductorius. The findings correlate with those of the study conducted by Enz et al. [37] who observed in their study a general improvement without a significant change in binocular vision and stereovision after surgery.
The critical time period for developing stereopsis starts at around 3 months after birth with further maturity until around 18 months of age [38,39,40,41]. Afterwards stereopsis gradually improves until the child is up to 3 years old [42]. Stereopsis was measured with the Lang test which is based on the random-dot technique and shows a cat, a star and a car representing disparities of 1200, 600 and 550 s of arc. The child then has to correctly name the objects [43]. A study by Fawcett et al. [44] investigated the critical period of susceptibility of stereopsis in patients with infantile esotropia and reported an onset at 2.4 months of age and the peak at 4.3 months of age. Other studies also reported the most rapid stereopsis development during the first 12 months after birth [39, 45]. Since we examined children aged 1–6 years in our study and do not have stereovision test results of all patients, we cannot make statements on the influence of strabismus on the development of stereopsis based on our data. We therefore suggest additional studies to further investigate the susceptibility of stereopsis that focus on the period of rapid maturity during the first year of life.
Certain limitations must be discussed as well. As a retrospective study we could only extract the data that were already collected and could not initiate further testing. But with this study we could show the outcome of strabismus surgery and influencing factors in an infantile age group. As a practical takeaway for the prospective surgical treatment of strabismus, the study shows that the overall success rate of strabismus surgery in infants is satisfactory at 74.19%.
5. Conclusion
In conclusion, the analysis showed that strabismus surgery has a good postoperative outcome and can be considered as a safe and effective treatment method for pediatric strabismus. Age, sex, type of strabismus, preoperative refractive error and visual acuity did not significantly influence the postoperative surgical success. Strabismus surgery in the infant showed a highly significant change in AOD with a low rate of retreatments but the best circumstances for surgical intervention are very individual and should be carefully evaluated.
References
Olson JH, Louwagie CR, Diehl NN, Mohney BG (2012) Congenital Esotropia and the Risk of Mental Illness by Early Adulthood. Ophthalmology 119:145–149. https://doi.org/10.1016/j.ophtha.2011.06.035
ElFekih L, Lajmi H, Ben Yakhlef A (2021) Indications and results of exotropia surgical management. Tunis Med 99:569–574
Lam M, Suh D (2022) Screening, Diagnosis, and Treatment of Pediatric Ocular Diseases. Children 9:1939. https://doi.org/10.3390/children9121939
Holmes JM (2011) Effect of Age on Response to Amblyopia Treatment in Children. Arch Ophthalmol 129:1451. https://doi.org/10.1001/archophthalmol.2011.179
Jullien S, Huss G, Weigel R (2021) Supporting recommendations for childhood preventive interventions for primary health care: elaboration of evidence synthesis and lessons learnt. BMC Pediatr 21:356. https://doi.org/10.1186/s12887-021-02638-8
Lachenmayr B, Friedburg D, Buser A (2016) Auge - Brille - Refraktion, 5. Georg Thieme Verlag KG, Stuttgart
Anstice NS, Thompson B (2014) The measurement of visual acuity in children: an evidence-based update. Clin Exp Optom 97:3–11. https://doi.org/10.1111/cxo.12086
Dietze H (2018) Die Bestimmung der Sehschärfe. Klin Monbl Augenheilkd 235:1057–1075. https://doi.org/10.1055/a-0654-2138
Esser J, Friecke J, Friedburg C et al (2012) Strabismus. Georg Thieme Verlag, Stuttgart
Inal A, Ocak OB, Aygit ED et al (2018) Comparison of visual acuity measurements via three different methods in preschool children: Lea symbols, crowded Lea symbols, Snellen E chart. Int Ophthalmol 38:1385–1391. https://doi.org/10.1007/s10792-017-0596-1
Keenan JM, Willshaw HE (1994) The outcome of strabismus surgery in childhood exotropia. Eye 8:632–637. https://doi.org/10.1038/eye.1994.158
Richard JM, Parks MM (1983) Intermittent exotropia. Surgical results in different age groups. Ophthalmology 90:1172–1177
Pratt-Johnson JA, Barow JM, Tillson G (1977) Early Surgery in Intermittent Exotropia. Am J Ophthalmol 84:689–694. https://doi.org/10.1016/0002-9394(77)90385-3
Awadein A, Eltanamly RM, Elshazly M (2014) Intermittent exotropia: relation between age and surgical outcome: a change-point analysis. Eye 28:587–593. https://doi.org/10.1038/eye.2014.29
Abbasoglu OE, Sener EC, Sanac AS (1996) Factors influencing the successful outcome and response in strabismus surgery. Eye (Lond) 10(Pt 3):315–320. https://doi.org/10.1038/eye.1996.66
Kampanartsanyakorn S, Surachatkumtonekul T, Dulayajinda D et al (2005) The outcomes of horizontal strabismus surgery and influencing factors of the surgical success. J Med Assoc Thai 88(Suppl 9):S94-9
Waheeda-Azwa H, Norihan I, Tai EM et al (2020) Visual outcome and factors influencing surgical outcome of horizontal strabismus surgery in a teaching hospital in Malaysia: A 5-year experience. Taiwan J Ophthalmol 10:278. https://doi.org/10.4103/tjo.tjo_71_19
Hoyt CS, Good WV (1994) Infantile strabismus: what is it? Where is it? Br J Ophthalmol 78:325–326. https://doi.org/10.1136/bjo.78.5.325
Trigler L, Siatkowski RM (2002) Factors associated with horizontal reoperation in infantile esotropia. J Am Assoc Pediatric Ophthalmol Strabismus 6:15–20. https://doi.org/10.1067/mpa.2002.120644
Segal ZI, Rehany U, Rumelt S (2000) Measurements for horizontal extraocular muscle surgery from the suture site: Outcome and influencing factors. Eye 14:879–883. https://doi.org/10.1038/eye.2000.241
Kumari N, Amitava AK, Ashraf M et al (2017) Prognostic preoperative factors for successful outcome of surgery in horizontal strabismus. Oman J Ophthalmol 10:76–80. https://doi.org/10.4103/ojo.OJO_133_2016
Scott WE, Keech R, Mash AJ (1981) The Postoperative Results and Stability of Exodeviations. Arch Ophthalmol 99:1814–1818. https://doi.org/10.1001/archopht.1981.03930020688013
Choi J, Kim S-J, Yu YS (2011) Initial postoperative deviation as a predictor of long-term outcome after surgery for intermittent exotropia. J Am Assoc Pediatric Ophthalmol Strabismus 15:224–229. https://doi.org/10.1016/j.jaapos.2010.12.019
Choi J, Choi DG (2021) Initial overcorrection after surgery for intermittent exotropia in children less than 4 years old: Comparison with older children. PLoS ONE 16:e0257465. https://doi.org/10.1371/journal.pone.0257465
Raab EL (1969) Recession of the Lateral Recti. Arch Ophthalmol 82:203. https://doi.org/10.1001/archopht.1969.00990020205010
Leow P-L, Ko STC, Wu PKW, Chan CWN (2010) Exotropic Drift and Ocular Alignment After Surgical Correction for Intermittent Exotropia. J Pediatr Ophthalmol Strabismus 47:12–16. https://doi.org/10.3928/01913913-20100106-04
Schlossman A, Muchnick RS, Stern KS (1983) The Surgical Management of Intermittent Exotropia in Adults. Ophthalmology 90:1166–1171. https://doi.org/10.1016/S0161-6420(83)34411-0
Ruttum MS (1997) Initial versus subsequent postoperative motor alignment in intermittent exotropia. J Am Assoc Pediatric Ophthalmol Strabismus 1:88–91. https://doi.org/10.1016/S1091-8531(97)90004-5
Maruo T, Kubota N, Sakaue T, Usui C (2001) Intermittent exotropia surgery in children: long term outcome regarding changes in binocular alignment. A study of 666 cases. Binocul Vis Strabismus Q 16:265–270
Pineles SL, Deitz LW, Velez FG (2011) Postoperative outcomes of patients initially overcorrected for intermittent exotropia. J Am Assoc Pediatric Ophthalmol Strabismus 15:527–531. https://doi.org/10.1016/j.jaapos.2011.08.007
Stager D, Dao L, Felius J (2015) Uses of the inferior oblique muscle in strabismus surgery. Middle East Afr J Ophthalmol 22:292. https://doi.org/10.4103/0974-9233.159723
Ganguly S, Pradhan R (2011) Effect of monocular surgery for large-angle horizontal deviation in adults. Nepal J Ophthalmol 3:27–30. https://doi.org/10.3126/nepjoph.v3i1.4275
LaMattina KC, DeBenedictis CN (2016) Refractive changes after strabismus surgery. Curr Opin Ophthalmol 27:393–397. https://doi.org/10.1097/ICU.0000000000000290
Preslan MW, Cioffi G, Min Y-I (1992) Refractive Error Changes Following Strabismus Surgery. J Pediatr Ophthalmol Strabismus 29:300–304. https://doi.org/10.3928/0191-3913-19920901-09
Noh JH, Park KH, Lee JY et al (2013) Changes in refractive error and anterior segment parameters after isolated lateral rectus muscle recession. J Am Assoc Pediatric Ophthalmol Strabismus 17:291–295. https://doi.org/10.1016/j.jaapos.2013.03.012
Lee D, Kim MM, Kim WJ (2019) Effect of strabismus surgery on ocular axial length, anterior chamber depth, and intraocular pressure. Medicine 98(22):e15812. https://doi.org/10.1097/MD.0000000000015812
Enz T, Jaggi G, Weber K et al (2014) Inferior Oblique Muscle Anteriorization in Congenital Superior Oblique Palsy. Klin Monbl Augenheilkd 231:386–389. https://doi.org/10.1055/s-0034-1368234
Fox R, Aslin RN, Shea SL (1979) Dumais ST (1980) Stereopsis in Human Infants. Science 207:323–324. https://doi.org/10.1126/science.7350666
Birch EE, Wang J (2009) Stereoacuity Outcomes After Treatment of Infantile and Accommodative Esotropia. Optom Vis Sci 86:647–652. https://doi.org/10.1097/OPX.0b013e3181a6168d
Birch EE, Morale SE, Jeffrey BG et al (2005) Measurement of stereoacuity outcomes at ages 1 to 24 months: Randot® Stereocards. J Am Assoc Pediatric Ophthalmol Strabismus 9:31–36. https://doi.org/10.1016/j.jaapos.2004.11.013
Birch EE, Salomão S (1998) Infant Random Dot Stereoacuity Cards. J Pediatr Ophthalmol Strabismus 35:86–90. https://doi.org/10.3928/0191-3913-19980301-06
Birch E, Williams C, Hunter J, Lapa MC (1997) Random Dot Stereoacuity of Preschool Children. J Pediatr Ophthalmol Strabismus 34:217–222. https://doi.org/10.3928/0191-3913-19970701-08
Ancona C, Stoppani M, Odazio V et al (2014) Stereo tests as a screening tool for strabismus: which is the best choice? Clin Ophthalmol 8:2221–2227. https://doi.org/10.2147/OPTH.S67488
Fawcett SL, Wang Y-Z, Birch EE (2005) The Critical Period for Susceptibility of Human Stereopsis. Invest Opthalmol Vis Sci 46:521. https://doi.org/10.1167/iovs.04-0175
Chinmayee J, Kshama K, Eswaran V (2023) Stereopsis following delayed strabismus surgery in early-onset strabismus. Saudi J Ophthalmol 37:48. https://doi.org/10.4103/sjopt.sjopt_9_22
Funding
Open access funding provided by Medical University of Vienna. No funding was received for conducting this study.
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All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Laetitia Hinterhuber, Sandra Rezar-Dreindl and Eva Stifter. The first draft of the manuscript was written by Laetitia Hinterhuber and all authors commented on previous versions of the manuscript. All the authors have read and approved the final manuscript.
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Hinterhuber, L., Rezar-Dreindl, S., Schmidt-Erfurth, U. et al. Postoperative outcome and influencing factors of strabismus surgery in infants aged 1–6 years. Graefes Arch Clin Exp Ophthalmol 262, 2299–2307 (2024). https://doi.org/10.1007/s00417-024-06404-1
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DOI: https://doi.org/10.1007/s00417-024-06404-1