Long-Term Effects of Botulinum Toxin A Versus Incisional Surgery for Management of Partially Accommodative Esotropia in Children: Comparison of Three Approaches.

PURPOSE: To compare the effect of bilateral medial rectus injection of botulinum toxin A (BTX-A), bilateral medial rectus muscle recession surgery (BMR rc), or unilateral medial rectus muscle recession combined with lateral rectus muscle resection surgery (R&R), in the management of partially accommodative esotropia (PAET) in children. DESIGN: Retrospective comparative clinical study. METHODS: The study cohort included 98 patients diagnosed with PAET who had BTX-A injection or incisional surgery between December 2014 and January 2023. The main outcome measures included motor and sensory results as well as complications. Follow-up was at least 12 months for all patients. RESULTS: There were 28 patients in the BTX-A group, 45 in the R&R group, and 25 in the BMR rc group. The motor success rates at distance and near fixation respectively were 50% (14/28) and 54% (15/28) in the BTX-A group, which were lower than that of the R&R group (78% [35/45], 84% [38/45]) and the BMR rc group (72% [18/25], 84% [21/25]) (P = .042 for near and P = .006 for distance). For patients with onset age <2.5 years old, there was no statistical difference amongst the 3 surgical approaches (P = .656). For patients with onset age ≥2.5 years, the motor success rate of the R&R group (81% [26/32]) and the BMR rc group (88% [14/16]) was higher than that in the BTX-A group (38% [5/13]; P = .004). There was no statistical difference in sensory outcomes for patients regardless of onset age or treatment methods (P > .05 for all). During follow-up, 4% (2/45) of patients in the R&R group and 20% (5/25) in the BMR rc group developed consecutive exotropia; no patient in the BTX-A group was overcorrected (P = .017). CONCLUSIONS: Bilateral medial rectus muscle injection with BTX-A in patients with PAET is a safe, accessible, and low-cost alternative. Although motor success rates were higher, overall, in patients treated with incisional surgery, for patients with earlier age of onset (≤ 2.5 years old), BTX-A injection may be preferred to incisional surgery. In older children treated with unilateral recession-resection surgery, fewer developed consecutive exotropia.

A Comparative Analysis of Surgical Outcomes for Infantile Esotropia With and Without Prior Botulinum Toxin A Injection.

PURPOSE: To compare the surgical outcomes in patients who had a failed botulinum toxin A injection before surgery versus those who had surgery as primary treatment (primary surgery) for infantile esotropia. METHODS: The files of patients who had strabismus surgery in the Strabismus Unit of Beyoglu Eye Training and Research Hospital between January 2012 and March 2022 were reviewed. This study included 104 eyes of 52 patients with infantile esotropia. The angle of deviation before and 1, 3, and 6 months after botulinum toxin A injection or surgery, complications, pattern deviations, family history, abnormal head position, history of prematurity, intensive care unit admission, and consanguineous marriage were noted. A successful outcome was defined as ocular alignment of 10 prism diopters (PD) or less. RESULTS: The study population consisted of 52 patients: 27 (52%) boys and 25 (48%) girls. In the botulinum toxin A group (n = 26), the mean age at admission was 14.0 ± 6.8 months, whereas the mean preoperative near and far angle of deviation were 41.92 ± 12.2 and 41.3 ± 13.0 PD, respectively. The mean age at the time of surgery was 40.6 ± 18.1 months. In the primary surgery group (n = 26), the mean age at admission was 34.0 ± 15.9 months. The mean preoperative near and far angle of deviation were 37.3 ± 8.0 and 35.3 ± 10.5 PD, respectively. The mean age at the time of surgery was 48.1 ± 18.5 months. The success rates 6 months after treatment in the botulinum toxin A group and the primary surgery group were 76.9% and 88.5% in near (P > .05) and 80.8% and 88.5% in far (P > .05), respectively. Three patients had transient ptosis and one had consecutive exotropia after botulinum toxin A injection. CONCLUSIONS: In infantile esotropia treatment, strabismus surgery after failed botulinum toxin A injection compared to primary surgery has statistically comparable surgical success rates. [J Pediatr Ophthalmol Strabismus. 2024;61(4):245-251.].

Effect of refractive errors on the results of botulinum neurotoxin administration in patients with infantile esotropia.

PURPOSE: To investigate the effect of refractive errors on the results of patients followed up with infantile esotropia (IE) and treated with botulinum neurotoxin (BNT) injection. METHODS: The files of patients with IE who presented to the ophthalmology pediatric ophthalmology unit and underwent BNT injection into both medial rectus muscles between 2019 and 2021 were reviewed retrospectively. Sixty eyes of 30 patients were included in the study. Patients with additional systemic or ocular diseases and those with a history of ocular surgery were excluded. Distance and near deviations were measured (with the prism cover test or Krimsky method) before and at the first, third, and sixth months after BNT injection. RESULTS: In Group 1 (n = 20) with a spherical equivalent of + 2.0 diopters (D) or less, the mean near and distance deviation value was both 36.8 ± 12.7 prism diopter (PD) before injection. In Group 2 (n = 10) with a spherical equivalent of above + 2.0 D, the near deviation was measured as 35.0 ± 7.1 PD and distance deviation as 31.8 ± 7.9. At six months after BNT injection, the near and distance deviation values were 20.6 ± 12.3 and 20.6 ± 11.6 PD, respectively in Group 1 and 10.1 ± 10.3 and 8.8 ± 10.8 PD, respectively in Group 2. The change in deviation did not statistically significantly differ between the groups (p > 0.05), but the distance and near deviation values were lower in Group 2 at sixth months after BNT injection. CONCLUSIONS: BNT injection is a preferred method in IE. Higher hypermetropic values seem to increase the success of BNT injection.

[Clinical observation of botulinum toxin A injection in the treatment of acute comitant esotropia: a retrospective cohort study].

Objective: To observe the efficacy and safety of botulinum toxin A (BTA) injection in the treatment of acute comitant esotropia (ACE) with different doses. Methods: This retrospective cohort study included data from patients with ACE who received BTA injection treatment at the First Affiliated Hospital of Zhengzhou University from June 2019 to June 2022. All patients underwent routine ophthalmic examinations, including best-corrected visual acuity (BCVA), spherical equivalent (SE), as well as specialized examinations for strabismus, including the degree of esotropia, eye movement status, and binocular visual function. Patients were categorized into small esotropia [≤60 prism diopters (PD)] and large esotropia (>60 PD) groups based on the pre-treatment degree of esotropia. Each group was further divided into 2.5 U and 5.0 U dose subgroups. Monocular injections were administered to the non-dominant eye. The esotropia degree was recorded and compared at 1, 2, 3, and 6 months of follow-up. The proportion of effectively treated patients in each group was documented. The number of cases with various levels of visual functions (including simultaneous vision, near stereopsis, and distance stereopsis) at 6 months post-treatment was compared, and complications during the follow-up period were observed. Statistical analyses were conducted using t-tests, Mann-Whitney U tests, and χ2 tests. Results: A total of 70 patients were included in the study, comprising 46 males and 24 females, with a median age of 5.0 (4.0, 8.3) years. Among them, 37 patients had small esotropia, with 25 in the 2.5 U group and 12 in the 5.0 U group. Thirty-three patients had large esotropia, with 18 in the 2.5 U group and 15 in the 5.0 U group. There were no statistically significant differences in baseline data, including age, duration of the condition, pre-treatment esotropia degree, BCVA and SE, between the two dose groups in both small and large esotropia patients (all P>0.05). In small esotropia patients, at 1 and 2 months post-treatment, the esotropia degree in the 5.0 U group was -20.00 (-37.50, -7.00) and 0.00 (0.00, 0.00) PD, respectively, which was significantly lower than the 0.00 (-10.00, 4.50) and 5.00 (0.00, 6.50) PD in the 2.5 U group (all P<0.05). At 3 and 6 months post-treatment, the esotropia degree in the 2.5 U group was 5.00 (0.00, 15.00) and 2.00 (0.00, 6.00) PD, respectively, while in the 5.0 U group, it was 0.00 (0.00, 4.50) and 0.00 (0.00, 3.75) PD, with no statistically significant differences between the two groups (all P>0.05). In the 2.5 U group, 20 cases were effectively treated, accounting for 80.0%, while in the 5.0 U group, 10 cases were effective, accounting for 10/12, with no significant difference between the two groups (P>0.05). In the 2.5 U group and the 5.0 U group, the proportions of cases with various levels of visual functions were as follows: simultaneous vision, 76.0% (19/25) and 10/12; near stereopsis, 48.0% (12/25) and 7/12; distance stereopsis, 44.0% (11/25) and 7/12, respectively. No statistically significant differences were observed in these proportions (all P>0.05). In patients with large esotropia, the esotropia degrees in the 5.0 U group at various follow-up times were -5.00 (-25.00, 5.00), 0.00 (0.00, 7.00), 2.00 (0.00, 10.00), and 5.00 (0.00, 7.00) PD, respectively. For the 2.5 U group, the corresponding values were 5.00 (2.75, 27.75), 10.00 (3.75, 24.75), 12.00 (3.75, 38.75), and 14.00 (3.50, 54.00) PD, respectively. The esotropia degrees in the 5.0 U group were consistently lower than those in the 2.5 U group (all P<0.05). The proportion of effective treatment in the 5.0 U group (13/15) was higher than that in the 2.5 U group (9/18), and the proportion of cases with distance stereopsis in the 5.0 U group (9/15) was higher than that in the 2.5 U group (4/18), both showing statistically significant differences (all P<0.05). The number of cases with simultaneous vision and near stereopsis showed no significant differences between the two groups (all P>0.05). The proportion of complications in the 2.5 U and 5.0 U groups in both large and small esotropia patients was 9/18, 13/15, 80.0% (20/25), and 10/12, respectively, with no statistically significant differences (all P>0.05). All complications spontaneously resolved within 3 months post-treatment. Conclusions: BTA injection is effective in the treatment of ACE, and for ACE patients with esotropia degrees greater than 60 PD, increasing the injection dose to 5.0 U can achieve better therapeutic outcomes.

Botulinum toxin for the treatment of strabismus.

BACKGROUND: The use of botulinum toxin as an investigative and treatment modality for strabismus is well reported in the medical literature. However, it is unclear how effective it is in comparison with other treatment options for strabismus. OBJECTIVES: The primary objective was to examine the efficacy of botulinum toxin therapy in the treatment of strabismus compared with alternative conservative or surgical treatment options. This review sought to ascertain those types of strabismus that particularly benefit from the use of botulinum toxin as a treatment option (such as small angle strabismus or strabismus with binocular potential, i.e. the potential to use both eyes together as a pair). The secondary objectives were to investigate the dose effect and complication rates associated with botulinum toxin. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS and three trials registers on 6 July 2022, together with reference checking to identify additional studies. We did not use any date or language restrictions in the electronic searches for trials. SELECTION CRITERIA: We planned to include randomized controlled trials (RCTs) comparing botulinum toxin with strabismus surgery, botulinum toxin alternatives (i.e. bupivacaine) and conservative therapy such as orthoptic exercises, prisms, or lens therapy for people of any age with strabismus. All relevant RCTs identified in this update compared botulinum toxin with strabismus surgery. DATA COLLECTION AND ANALYSIS: We used standard methods expected by Cochrane and assessed the certainty of the body of evidence using GRADE. MAIN RESULTS: We included four RCTs with 242 participants that enrolled adults with esotropia or exotropia, children with acquired esotropia, and children with infantile esotropia. The follow-up period ranged from six to 36 months. Two studies were conducted in Spain, and one each in Canada and South Africa. We judged the included studies to have a mixture of low, unclear and high risk of bias. We did not consider any of the included studies to be at low risk of bias for all domains. All four studies reported the proportion of participants who improved or corrected strabismus, defined as ≤ 10 prism diopters (PD) at six months (two studies) or ≤ 8 PD at one year (two studies). Low-certainty evidence suggested that participants treated with the surgery may be more likely to improve or correct strabismus compared with those who treated with botulinum toxin (risk ratio (RR) 0.72, 95% confidence interval (CI) 0.53 to 0.99; I² = 50%; 4 studies, 242 participants; low-certainty evidence). One study, which enrolled 110 children with infantile esotropia, suggested that surgery may reduce the incidence of additional surgical intervention required, but the evidence was very uncertain (RR 3.05, 95% CI 1.34 to 6.91; 1 study, 101 participants; very low-certainty evidence). Two studies conducted in Spain compared botulinum toxin with surgery in children who required retreatment for acquired or infantile esotropia. These two studies provided low-certainty evidence that botulinum toxin may have little to no effect on achieving sensory fusion (RR 0.88, 95% CI 0.63 to 1.23; I² = 0%; 2 studies, 102 participants) and stereopsis (RR 0.86, 95% CI 0.59 to 1.25; I² = 0%; 2 studies, 102 participants) compared with surgery. Three studies reported non-serious adverse events. Partial transient ptosis (range 16.7% to 37.0%) and transient vertical deviation (range 5.6% to 18.5%) were observed among participants treated with botulinum toxin in three studies. In one study, 44.7% participants in the surgery group experienced discomfort. No studies reported serious adverse events or postintervention quality of life. AUTHORS' CONCLUSIONS: It remains unclear whether botulinum toxin may be an alternative to strabismus surgery as an independent treatment modality among certain types of strabismus because we found only low and very low-certainty evidence in this review update. Low-certainty evidence suggests that strabismus surgery may be preferable to botulinum toxin injection to improve or correct strabismus when types of strabismus and different age groups are combined. We found low-certainty evidence suggesting botulinum toxin may have little to no effect on achievement of binocular single vision compared with surgery in children with acquired or infantile esotropia. We did not find sufficient evidence to draw any meaningful conclusions with respect to need for additional surgery, quality of life, and serious adverse events. We identified three ongoing trials comparing botulinum toxin with conventional surgeries in the varying types of strabismus, whose results will provide relevant evidence for our stated objectives. Future trials should be rigorously designed, and investigators should analyze outcome data appropriately and report adequate information to provide evidence of high certainty. Quality of life and cost-effectiveness should be examined in addition to clinical and safety outcomes.

Long-Term Effects of Botulinum Toxin A for Horizontal Concomitant Strabismus in Chinese Children.

INTRODUCTION: For childhood strabismus, early surgical intervention improves both motor and sensory outcomes. Botulinum toxin type A (BTX-A) injection is an alternative to incisional surgery that is fast, less invasive, and preserves a more normal biomechanical construct. This study was undertaken to assess the safety and effectiveness of BTX-A for horizontal concomitant strabismus in children in our institution. PATIENTS AND METHODS: Records of all children less than age 18 years with follow-up at least 12 months who were treated with BTX-A for horizontal concomitant strabismus at Beijing Children's Hospital between December 2014 and February 2021 were reviewed retrospectively. Bilateral injections of BTX-A (Henli, 1.25 IU to 5 IU/0.1 ml) were made into the medial or lateral rectus muscles according to the angle of deviation. Reinjection was permitted if the initial alignment was not satisfactory within 1 to 6 months post-injection. Motor success was defined as a final misalignment ≤10 PD. Sensory success was defined as the presence of any evidence of sensory fusion, distance stereopsis, or near stereopsis at the last visit. RESULTS: Seventy-one patients were included. Fifty-two had esotropia, and 19 had exotropia. There was a significant decrease in the angle of deviation in all treated patients. The overall motor success rate was 60.6%. The motor success rate was highest in children with esotropia <50 PD (81.5%). Motor success was better for children with partially accommodative esotropia and acquired non-accommodative esotropia (80%, 83.3%, respectively) than for children with infantile esotropia (47.4%). Compared with the esotropia group, the fusion was significantly higher in the exotropia group (p = .007), and the proportion of patients with stereoacuity of better than 100 sec arc was higher also in the exotropia group (71.4%, p = .007), evidence of sensory outcomes were significantly better in the exotropia group. Complications were few. Twenty patients (28.2%) developed transient ptosis after injections; transient vertical deviations were seen in 3 patients (4.2%); and subconjunctival hemorrhage was seen in 5 patients (7%). CONCLUSIONS: BTX-A appears to be an effective treatment for the management of horizontal strabismus with motor outcomes best in children with acquired smaller-angle esodeviations. Children with exodeviations had better sensory outcomes in this cohort. A randomized controlled study comparing incisional surgery to BTX-A will be important for guiding future treatment decisions.

Interventions for infantile esotropia.

BACKGROUND: Infantile esotropia (IE) is the inward deviation of the eye. Various aspects of the clinical management of IE are unclear; mainly, the most effective type of intervention and the age at intervention. OBJECTIVES: To examine the effectiveness and optimal timing of surgical and non-surgical treatment options for IE to improve ocular alignment and achieve or allow the development of binocular single vision. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, one other database, and three trials registers (November 2021). We did not use any date or language restrictions in the electronic searches for trials.  SELECTION CRITERIA: We included randomized trials and quasi-randomized trials comparing any surgical or non-surgical intervention for IE. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodology and graded the certainty of the body of evidence for six outcomes using the GRADE classification. MAIN RESULTS: We included two studies with 234 children with IE. The first study enrolled 110 children (mean age 26.9 ± 14.5 months) with an onset of esotropia before six months of age, and large-angle IE defined as esotropia of ≥ 40 prism diopters. It was conducted between 2015 and 2018 in a tertiary care hospital in South Africa. It compared a maximum of three botulinum toxin injections with surgical intervention of bimedial rectus muscle recession, and children were followed for six months. There were limitations in study design and implementation; the risk of bias was high, or we had some concerns for most domains.  Surgery may increase the incidence of treatment success, defined as orthophoria or residual esotropia of ≤ 10 prism diopters, compared with botulinum toxin injections, but the evidence was very uncertain (risk ratio (RR) of treatment success 1.88, 95% confidence interval (CI) 1.27 to 2.77; 1 study, 101 participants; very low-certainty evidence). The results should be read with caution because 23 children with > 60 prism diopters at baseline in the surgery arm also received botulinum toxin at the time of surgery to augment the recessions. There was no evidence of an important difference between surgery and botulinum toxin injections for over-correction (> 10 prism diopters) of deviation (RR 0.29, 95% CI 0.06 to 1.37; 1 study, 101 participants; very low-certainty evidence), or additional interventions required (RR 0.66, 95% CI 0.36 to 1.19; 1 study, 101 participants; very low-certainty evidence). No major complications of surgery were observed in the surgery arm, while children experienced various complications in the botulinum toxin arm, including partial transient ptosis in 9 (16.7%) children, transient vertical deviation in 3 (5.6%) children, and consecutive exotropia in 13 (24.1%) children. No other outcome data for our prespecified outcomes were reported.  The second study enrolled 124 children with onset of esotropia before one year of age in 12 university hospitals in Germany and the Netherlands. It compared bilateral recession with unilateral recession surgeries, and followed children for three months postoperatively. Very low-certainty evidence suggested that there was no evidence of an important difference between bilateral and unilateral surgeries in the presence of binocular vision (numbers with event unclear, P = 0.35), and over-correction (RR of having exotropia 1.09, 95% CI 0.45 to 2.63; 1 study, 118 participants). Dissociated vertical deviation, latent nystagmus, or both were observed in 8% to 21% of participants. AUTHORS' CONCLUSIONS: Medial rectus recessions may increase the incidence of treatment success compared with botulinum toxin injections alone, but the evidence was very uncertain. No evidence of important difference was found between bilateral surgery and unilateral surgery.  Due to insufficient evidence, it was not possible to resolve the controversies regarding type of surgery, non-surgical intervention, or age of intervention in this review. There is clearly a need to conduct good quality trials in these areas to improve the evidence base for the management of IE.

Success rates of botulinum toxin in different types of strabismus and dose effect.

OBJECTIVE: To determine the effect of botulinum toxin in different types of strabismus and analyze its dose effect. DESIGN: This was an interventional clinical study performed in a tertiary care university hospital. METHODS: Eighty six patients treated with botulinum toxin for strabismus were included. Main outcome measures involved success of botulinum toxin, alignment change per unit of toxin, and dose effect on complications and outcomes. RESULTS: Success rates were 31% for infantile esotropia, 25% for partially accommodative esotropia, 61.5% for residual esotropia, 25% for third cranial nerve paralysis, 13.3% for sixth cranial nerve paralysis, 75% for Duane retraction syndrome, and 38.5% for nonaccomodative esotropia. Improvement in deviation size after botulinum toxin treatment was significant in patients with infantile esotropia (p = 0.001), residual esotropia (p = 0.001), and nonaccomodative esotropia (p = 0.03). Mean deviation change per 1 unit of toxin was 2.7 ± 2.4 prism diopters (PD) with a single injection and 2.1 ± 1.9 PD with multiple injections. A 3.32 PD of early deviation change with botulinum toxin corrected 1 PD of final deviation. Success rate was not correlated with age (r = 0.040, p = 0.8), sex (r = -0.083, p = 0.6), mean dose (r = -0.149, p = 0.35), or total dose (r = 0.165, p = 0.29) but was significantly correlated with deviation size (ß = -0.077, p = 0.0001). Complications were not associated with the dose of botulinum toxin (p > 0.05). CONCLUSIONS: Botulinum toxin has variable outcomes in different types of strabismus. Still, it reduces the deviation size in most patients, thus allowing for a smaller amount of subsequent muscle surgery. Early overcorrection is a more powerful indicator of better outcome than postinjection duction deficit.

Efficacy of botulinum toxin injection versus bilateral medial rectus recession for comitant esotropia: a meta-analysis.

OBJECTIVE: To compare the effectiveness of botulinum toxin injection (BTX) and bilateral medial rectus recession (BMR) in the treatment of comitant esotropia. METHODS: An exhaustive search of the literature from Pubmed, EMBASE, Web of Science, and Cochrane Library databases was carried out until April 2022. No language restrictions were applied. The literature was rigorously screened against eligibility criteria. Odds ratios (ORs) and 95% confidence interval (CI) were calculated. RESULTS: A total of 9 articles with 1100 participants were included in this meta-analysis. Three studies compared the effects of BTX to BMR on infantile esotropia, five studies compared the effects of BTX to BMR on acute acquired comitant esotropia, and one study compared the therapeutic effects between BTX and BMR for partially accommodative esotropia. Our pooled results showed that BMR achieved higher overall success rate compared with BTX (OR, 0.49; 95%CI, 0.37-0.64; P < 0.001) and patients subjected to the BTX procedure had higher overall rate of undercorrection (OR, 2.27; 95%CI,1.71-3.02; P < 0.001). No statistical difference in the overall overcorrection rate was observed between the two groups (OR = 0.42, 95% CI: 0.17 ~ 1.03, P = 0.06). Further analysis found that BMR was more effective for infantile esotropia compared to botulinum toxin injections (OR, 0.40; 95%CI, 0.27-0.57; P < 0.001). Nevertheless, the same effect was observed for BMR and BTX in the treatment of acute acquired comitant esotropia (OR, 0.97; 95%CI, 0.50-1.87; P = 0.93). CONCLUSION: The present meta-analysis indicated that the BMR procedure achieved a higher success rate and a lower undercorrection rate in patients with comitant esotropia. However, BTX demonstrated similar treatment effects to BMR surgery in the treatment of acute acquired comitant esotropia.

Botulinum toxin treatment for bielschowsky acquired commitant esotropia in adults.

BACKGROUND: Many researchers have noticed that there is an increasing trend of Bielschowsky acquired comitant esotropia (ACE) in recent years related to excessive near work, but the exact pathogenesis and treatment methods have not been reported yet. Therefore, we aimed to characterize the clinical features of this ACE in adults and to evaluate the efficacy of botulinum toxin (BTX) injections in these patients. METHODS: This was a prospective consecutive case series of 47 patients with Bielschowsky ACE. BTX was injected bilaterally into the medial rectus muscle of 45 patients, and twenty-seven of them (27/45) completed 10 months of follow-up after their last injection. Angle of deviation, fusion, stereopsis, subjective assessment of diplopia were documented before and after BTX treatment, and repeated measures data were compared by the Wilcoxon signed-rank test or Analysis of variance. The relationship between BTX dosage and corrected esotropia was explored by the Regression analysis. Meanwhile, possible risk factors for ACE including time spent on near work, refraction error, patients' personality, glasses wearing habits and duration of symptoms were recorded and analyzed with General Linear Models. RESULTS: The patients aged 32.32 ± 10.96 (range 15-53) years spent 8.34 ± 2.38 h on near work each day, and most myope habitually removed their glasses at near. Their chief complaint was distance diplopia, with more significant esotropia at distance (around 20 PD) than at near. This series of patients also exhibited perfectionist tendencies. However, most patients achieved orthophoria after BTX treatment, only with a mild residual esotropia (+ 3.96 ± 5.79 PD), which left them asymptomatic most of the time. CONCLUSION: This group of ACE patients was characterized by diplopia with more significant esotropia at distance. Besides excessive near-work, habitually removing myopic glasses and perfectionist tendencies may also contribute to this type of ACE. Fortunately, bilateral BTX injection safely and effectively reduced the esotropia with complete resolution of symptoms, especially for those treated at an early stage.

Conventional surgery versus botulinum toxin injection for the management of esotropia in children with Down syndrome.

PURPOSE: To compare the success rates of strabismus surgery and botulinum toxin injection (BTX) in treating esotropia in patients with Down syndrome (DS). METHODS: This multicenter retrospective cohort study included all consecutive patients having DS with esotropia between 2014 and 2021 at King Abdullah Specialist Children Hospital, King Abdullah International Medical Research Center, and King Khaled Eye Specialist Hospital, Saudi Arabia. We divided the patients into two groups according to interventions. Success was defined as angle of deviation of <10Δ at final visit. RESULTS: A total of 53 patients were included: 23 in the surgery group and 30 in the BTX group. There were no significant differences between groups with regard to age, sex, diagnosis, spherical equivalent, and preoperative deviation angle. Before the intervention, the median angle of deviation was 30.0Δ (IQR, 30Δ-45Δ) in the surgery group and 37.5Δ (IQR, 28.8Δ-50.0Δ) in the BTX group (P = 0.802). Postoperatively, the median (IQR) deviation angle was 0.0Δ (0.0Δ-16.0Δ) in the surgery group and 22.5Δ (6.75Δ-30.0Δ) in the BTX group (P = 0.006). The success rate in the surgery and BTX groups was 65% and 30%, respectively (P = 0.011). Two patients developed dissociated vertical deviation in the surgery group. One patient presented consecutive exotropia and one inferior oblique overaction in the BTX group. CONCLUSIONS: In this study, conventional surgery showed a higher success rate than BTX in the management of esotropia.

[Efficacy of botulinum toxin in infantile esotropia]. / Efficacité de la toxine botulique dans l'estropie de l'enfant.

INTRODUCTION AND OBJECTIVE: Botulinum toxin (BT) is used in a variety of therapeutic applications, including the treatment of strabismus. Two injection techniques coexist - transconjunctival injection and open sky injection. The goal of this study was to evaluate the results of BT injections in esotropia in children under 10 years of age and to compare the two techniques. PATIENTS AND METHOD: This is a retrospective, monocentric study, including children who received BT injections to treat their strabismus by the aforementioned techniques between 2014 and 2017. The results of these injections were recorded, and subgroup analyses (injection technique, age, degree of deviation, type of strabismus) were performed. The primary endpoint was the optimal success rate defined as residual strabismus less than or equal to 10 Δ. RESULTS: The study included 68 children with a mean age of 28.9 months and a mean deviation angle of 34.7 Δ. Patients received 1.2 BT injections. The success rate was 38% at 6 months, 35% at 12 months, and 35% at 24 months. There was 33% transient ptosis and 5% consecutive exotropia. There was no evidence of significant difference in success rate between the transconjunctival and open sky injection methods, baseline angles, age of injection, or type of strabismus. CONCLUSION: BT injection is effective and safe in pediatric esotropia, regardless of the injection method.

The Effect of Different Treatment Methods on Acute Acquired Concomitant Esotropia.

Objective: The application of botulinum toxin type A (BTXA) in the treatment of paralytic strabismus has been recognized, but there are few studies on the treatment of acute acquired comitant esotropia (AACE). This study was aimed to investigate the clinical characteristics of AACE and compare the therapeutic effects of BTXA and traditional surgery. Methods: 78 patients with AACE in Renmin Hospital of Wuhan University between March 2019 and March 2021 were reviewed. The relevant medical records of the patients were collected, and they were divided into surgical group (n = 46) and botulinum toxin type A (BTXA) group (n = 32) according to different treatment approaches. The surgical group was treated with squint correction, whereas the BTXA group was treated with microinjection of BTXA in MR. Eye alignment, esotropia, stereopsis, and complications were examined before and after treatment in both groups. Results: The refractive status of 78 patients with AACE was mostly myopic refractive error. In general, the angle of esotropia at distance was larger than which at near, with a statistically significant difference. At follow-up assessments of 1 week, 1 month, 3 months, and 6 months after treatment, the total effective rates of the surgical group and the BTXA group were 100% and 90.48%, respectively. The residual angle of esotropia of both groups was lower after treatment. Additionally, the incidence rate of complications in the BTXA group was significantly lower than that in the surgical group. Conclusion: AACE occurs mostly in people with myopic refractive errors and is associated with prolonged near work. Besides surgical treatment, micro-injection of BTXA is also an effective and safe treatment for AACE.

[Botulinum therapy for acute esotropia]. / Botulinoterapiya v lechenii ostro voznikshei ezotropii.

PURPOSE: To determine the effectiveness of the use of botulinum toxin type A in the treatment of acute esotropia in children. MATERIAL AND METHODS: A retrospective analysis of the results of using botulinum toxin type A in the treatment of acute convergent strabismus in 16 children was performed. Children's ages ranged from 3 to 15 years. Botulinum toxin was injected into the medial rectus muscles. In 6 patients with acute esotropia, botulinum toxin was injected into the internal rectus muscle of both eyes, in the rest of patients the toxin was injected into one eye. Two patients underwent chemodenervation of extraocular muscles twice. The injected dose of botulinum toxin (from 1 to 5 U) was chosen depending on the strabismus angle, the patient's age, and the duration of the disease. In order to form binocular vision, all patients underwent orthopto-diploptic treatment. The observation period lasted 12 to 18 months. RESULTS: One month after chemodenervation, the orthoposition of the eyes was persistently restored in 7 children (43.75%). Esodeviation angle decreased steadily to 2 degrees in 4 patients (25%). A second injection of botulinum toxin was required to achieve orthotropy in 2 patients (12.5%) 4-6 months after chemodenervation. An increase of esodeviation angle was recorded in 3 patients (18.75%), which required classical surgical treatment of strabismus. One month after the injection, unstable binocular vision developed in 11 children (68.75%). After 1 year, binocular vision was successfully formed 13 patients (81.25%). CONCLUSION: Chemodenervation in the majority of children with acute esotropia led to persistent orthoposition of the eyes. This created favorable conditions for the restoration of binocular vision during subsequent orthopto-diploptic treatment.

Response to botulinum neurotoxin injections in large-angle infantile esotropia: a post hoc analysis.

PURPOSE: To determine the anticipated reduction of baseline angle of esotropia and identify predictors of change following botulinum neurotoxin (BNT) injections in large-angle infantile esotropia. METHODS: This was a prospective, longitudinal study of children <10 years of age diagnosed with infantile esotropia of >30Δ and given either 1, 2, or 3 BNT injections. Post-injection change from baseline deviation was recorded, and predictors of reduction were analyzed. For this study, children were further divided into subgroups based on initial deviation of ≤60Δ (group 1) and >60Δ (group 2). The outcomes of subsequent surgeries in failed cases were analyzed. RESULTS: A total of 117 children were included, 55 in group 1 and 62 in group 2. Mean age was 30.3 ± 18.8 months. Mean baseline deviation was 62.5Δ ± 13.1Δ: 51.4Δ ± 8.4Δ in group 1 and 73Δ ± 7.5Δ in group 2. The mean number of injections was 2.2 ± 0.7. Success was achieved in 25.6% of patients (33.4% in group 1; 16.2% in group 2). The mean percentage reduction of deviation after BNT injection was 55.2% ± 26%, larger in group 1 than in group 2 (61.3% vs 51.1% [P = 0.001]). Five children reverted to baseline deviation. In multivariate analysis, adjusting for number of injections, younger age and larger baseline deviation were significant independent predictors of a larger absolute amount of reduction (P = 0.02, and 0.002, resp.). Thirty-two children had subsequent surgery; 22 were followed for a minimum of 6 months, and 20 were aligned within 10Δ of orthotropia. CONCLUSIONS: In large-angle esotropia there was a reduction of approximately 50% of baseline deviation, with greater relative reduction for smaller baseline deviations; the absolute change in angle was greater in younger children. Alignment after subsequent surgery appeared to remain stable and surgery required less recession than would have been needed for the original angle of esotropia.

Treatment of partially accommodative esotropia in children using a medial rectus muscle fenestration technique.

PURPOSE: To report the results of bilateral fenestration of the medial rectus muscle in cases of partially accommodative esotropia in pediatric patients. METHODS: In this fenestration technique, two splitting incisions are made by blunt dissection parallel to the muscle fibers on the superior and inferior borders of the medial rectus muscle, leaving a thin strip of muscle fibers on each edge. The wide, central part of the muscle is excised from its insertion to a point 5-8 mm from the insertion, depending on the angle of the esotropia. Sutures are not used in this procedure. Children with partially accommodative esotropia and no high ratio of accommodative convergence to accommodation who underwent surgery from February 2018 to August 2019 were prospectively enrolled. The success rate was defined as alignment within 8 prism diopters of orthotropia at the last follow up. RESULTS: A total of 61 children were included. The procedure was well tolerated by patients and reduced the angle of esotropia for distance from 22.20Δ ± 4.22Δ to 2.72Δ ± 4.71Δ (P < 0.001) and caused no incomitance or distance-near disparity. Satisfactory horizontal alignment defined as alignment within 8Δ of orthotropia at distance was achieved in 88% of the cases at 3-6 months' follow-up. There were no overcorrections. CONCLUSIONS: In our study cohort, the fenestration technique reduced the angle of deviation in cases of partially accommodative esotropia.

Conventional surgery versus botulinum toxin injections for partially accommodative esotropia.

PURPOSE: To compare the effect of botulinum toxin injection (BTX) to bilateral medial rectus recession (BMR) in partially accommodative esotropia (PAET). METHODS: The medical records of children 1-14 years of age treated for PAET with BMR or BTX between 2010 and 2020 at a single institution were reviewed retrospectively. PAET was defined as residual esotropia of at least 14Δ after 6 weeks of continuous wear of full cycloplegic refraction (> +2.5 D). Success was defined as esotropia of 0Δ-10Δ after a single surgery or ≥1 BTX injections. RESULTS: Of 224 patients, 121 received BTX and 103 underwent BMR. BMR showed a higher success rate than BTX (70.9% vs 53.7% [P = 0.006]). BMR was more successful in males, in patients >5 years of age, and when spherical equivalent was ≤ +5.00 D (79.2%, 74.3%, and 67.5%, resp. [P < 0.05]). Mean follow-up was shorter in the BMR group than in the BTX group (16.7 ± 14.7 vs 31.4 ± 29.5 months [P = 0.0001]). Mean duration of surgery was significantly shorter in the BTX group (5.2 ± 4.3 vs 70.5 ± 31.4 min [P = 0.0001]). Postoperative inferior oblique overaction was more common in the BTX group (7.4%; P = 0.02 [Fisher exact test]), and persistent ptosis was only seen in the BTX group (0.8%); consecutive exotropia was only seen in the BMR group (2%). CONCLUSIONS: In our study cohort, BMR had a higher success rate than BTX. Conventional surgery allowed for shorter follow-up and fewer complications than BTX in the treatment of PAET.

Factors Affecting the Efficacy of Botulinum Toxin Injection in the Treatment of Infantile and Partially Accommodative Esotropia.

PURPOSE: We aimed to investigate the effect of botulinum toxin (BT) injection on the treatment of infantile and partially accommodative esotropia (PAET). METHODS: This retrospective cohort study included patients who received BT injections for infantile and PAET between January 2015 and December 2018. Treatment was considered successful if orthotropia, consecutive exotropia, or esotropia within 10 prism diopters (PD) was achieved. RESULTS: The overall success rate was 47.4%, with a mean follow-up period of 27.8 months in 403 children. BT treatment was considered successful in 37.1% of cases of infantile esotropia and 53.1% of cases of partially accommodative esotropia. The average deviation angle before starting treatment was 35.5 ± 13.9 PD. Side effects 1 week after BT injections included transient overcorrection (63.8%) and transient ptosis (41.7%). There were no significant differences in the success rates between the different doses of BT (P = 0.69). The angle of deviation at presentation was significantly associated with the success rate of BT injection (failed group, mean: 38.1 ± 15.3 PD vs. success group, mean: 32.6 ± 11.6 PD; P < 0.001). Other factors associated with higher success rates were overcorrection at 1 week and PAET, while multivariate logistic regression analysis showed that a smaller angle of deviation and overcorrection (1 week after injection) were associated with a higher success rate. CONCLUSION: A smaller angle of deviation and transient overcorrection were associated with a higher success rate, and no significant difference was observed in the success rates of different BT doses.