Factors associated with horizontal reoperation in infantile esotropia

Postoperative outcome and influencing factors of strabismus surgery in infants aged 1-6 years

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.

Long-term Motor and Sensory Outcomes After Unilateral Medial Rectus Recession-Lateral Rectus Resection for Infantile Esotropia

PURPOSE

To report long-term motor and sensory outcomes after unilateral medial rectus recession-lateral rectus resection for infantile esotropia.

METHODS

The medical records of patients who had undergone unilateral medial rectus recession-lateral rectus resection for infantile esotropia and were followed up postoperatively for a minimum of 10 years were reviewed retrospectively.

RESULTS

A total of 100 patients were included. The mean age at surgery was 2.9 ± 2.2 years (range: 2.5 months to 9.0 years). The mean postoperative follow-up was 15.7 ± 4.4 years (range:10.0 to 27.5 years). Overall, 54 patients (54%) had surgical success at their last follow-up visit. Age at first surgery, strabismus duration, degree of hyperopia, preoperative size of deviation, presence of dissociated vertical deviation, inferior oblique overaction, or both dissociated vertical deviation and inferior oblique overaction, and the number of esotropia surgeries did not predict motor outcome after surgery. Consecutive exotropia developed in 43% of patients (constant in 18% and intermittent in 25%). Residual and recurrent esotropia occurred in 20% and 21% of patients, respectively. Refractive accommodative esotropia developed in 17% of patients and there was a high accommodation convergence/accommodation ratio esotropia in 2%. Peripheral binocular single vision was achieved in 54% of patients and stereopsis in 1%. Patients with 1.5 years or less of strabismus duration had better chances of achieving peripheral binocular single vision.

CONCLUSIONS

Nearly half of the patients with infantile esotropia achieved a successful long-term motor outcome and peripheral binocular single vision. Consecutive exotropia occurred frequently. Recurrent esotropia and refractive accommodative esotropia developed in some patients, and a high accommodation convergence/accommodation ratio esotropia in a few. Stereopsis outcome was extremely poor. [J Pediatr Ophthalmol Strabismus. 2024;61(2):106-113.].

Comparison between bupivacaine injection and mini-tenotomy in the management of horizontal small angle strabismus in children

PURPOSE

To compare the outcome of bupivacaine (BUP) injection vs mini-tenotomy of extra-ocular muscles in treating small angle horizontal strabismus in children.

METHODS

A prospective comparative study that included a total of 40 patients. Twenty patients received 3 ml of 0.75% Bupivacaine (BUP) injection in both medial recti in case of exotropia and in both lateral recti in case of esotropia. MRI orbit was performed before and 30-60 days' post injection of bupivacaine to estimate changes in muscle size. Mini-tenotomy was done in the other 20 patients, performed on both lateral recti in case of exotropia and on both medial recti in case of esotropia.

RESULTS

Mean change of alignment at the end of 6 months in exotropic patients in bupivacaine group was 5.50 ± 4.10 PD and in esotropia patients 4.00 ± 3.38 PD with an average increase in muscle thickness of 0.12 mm ± 0.08 and 0.13 mm ± 0.09 in exotropia and esotropia, respectively. There was an average increase in volume 23 mm3 ± 17.3 and 17.00 mm3 ± 9.50 in exotropia and esotropia, respectively, as measured with MRI. The mean change of alignment in mini-tenotomy was 5.33 ± 4.12 PD, 5.75 ± 4.95 PD in exotropia and esotropia, respectively.

CONCLUSION

Bupivacaine and mini-tenotomy are safe and effective alternative treatment, that improved eye alignment in 65% of patients with small angle horizontal deviation.

Outcomes of Bilateral Lateral Rectus Resection in Residual Esotropia following Bilateral Medial Rectus Recession

Purpose:

To evaluate the success rate, dose-response ratio, and predictive factors of success in patients with residual esotropia (≥25 prism diopter [pd]) following bilateral medial rectus (BMR) recession who underwent bilateral lateral rectus (BLR) resection.

Methods:

In a retrospective study, medical records were reviewed for 47 patients with equal or more than 25 pd residual esotropia following 6 mm BMR recession. Sex, age at second surgery, the interval between first and second surgery in months, visual acuity, refraction, presence of amblyopia, presence of dissociated vertical deviation or inferior oblique overaction/superior oblique overaction, preoperative and postoperative angle of deviation, amount of BLR resection, and months of follow-up were evaluated. Surgical success was defined as postoperative deviation within 8 pd of orthophoria.

Results:

The mean age of patients at reoperation was 48.59 ± 21.46 months. The mean near and far residual esotropia before BLR resection was 34.57 ± 11.02 and 33.83 ± 10.99 pd, respectively, reduced to 8.12 ± 1.43 pd in near and 6.32 ± 2.1 pd in far postoperatively. The mean BLR resection dosage was 5.53 ± 1.22 mm and each millimeter of BLR resection (1 mm for each eye) corrected an average of 7.95 pd of deviation in near and 7.40 pd in far. The success rate was 74.5%. After analysis using multivariate logistic regression, there were no factors associated with success.

Conclusions:

Bilateral rectus resection in patients with a previous BMR recession has acceptable outcomes. The recommended surgical table can be used as a guide by strabismus surgeons in patients with residual esotropia.

Infantile Esoropia: Management results and prognostic factors

BACKGROUND

Infantile esotropia is characterized by a significant deviation angle and a marked sensory perversion. Although the motor surgical results are satisfactory, the sensory results remain disappointing.

AIM

Our work aims to describe the methods of surgical management, its motor and sensory results as well as its prognostic factors.

METHODS

Retrospective study of 68 cases of infantile esotropia. All patients underwent a complete ophthalmologic examination and sensorimotor assessment. They were operated on, under general anesthesia, by the same surgeon. We assessed the motor and sensory results. The prognostic factors studied were age of onset, treatment delay, amblyopia severity, strabismus deviation angle, and presence of a vertical element.

RESULTS

The mean minimum angle of deflection was 38.6 ± 13.2D. Inferior oblique muscle hyper action was noted in 73.5% and a dissociated vertical deviation in 5.8%. Bilateral medial rectus muscle recession was the most performed surgery (60.2% of cases). The overall success rate was 94.11%. No patient acquired stereoscopic vision. Multivariate logistic regression analysis showed that preoperative nail (p = 0.007), immediate postoperative outcome (p <0.001) and surgical dosage (p = 0.009) were associated with long-term motor success.

CONCLUSION

The motor results of early esotropia surgery are generally satisfactory; the sensory results are often disappointing. Detecting poor prognostic factors improves operative results.

Extraocular muscle resection, recession length and surgery outcome modelling in strabismus treatment: a pilot study

Background

Many surgical formulas have been developed and proposed based on the experience of surgeons to improve the predictability of strabismus surgery. However, the consent among strabismus surgeons regarding the dose effect of the extraocular muscle (EOM) recession or resection was not achieved yet and the disagreement about the appropriate amount of strabismus surgery still exists.

Objective

Our study aimed to propose an instrument for EOM resection (RsL) and recession length (RcL) estimation before the surgery and second to elaborate an postoperative angle of deviation (PAD) predictive model using simple potential predictors.

Methods and Analysis

The analytical prospective clinical study was conducted from April 2016 to July 2019, on a sample of 216 patients (aged between 2–58) with concomitant strabismus who underwent strabismus surgery in Clinical Republican Hospital ‘Timofei Mosneaga’and Children Hospital ‘Em Cotaga’ from Republic of Moldova. The correlations of patients’ age, strabismus type, amblyopia degree, RsL, RcL, preoperative angle of deviation (PreAD) with PAD were estimated using Pearson’s correlation analysis. Multiple linear regression analysis, multicollinearity analysis and residual analysis were performed.

Results

The EOM RsL was predicted using strabismus type, patient’s age, PreAD and EOM RcL. EOM RcL, in turn, was estimated by the similar covariates set, instead of RcL being RsL. PAD modelling showed the PreAD, EOM RsL and EOM RcL predictive ability for strabismus surgery outcome prediction.

Conclusion

In our study, we propose four mathematical models as potential instruments for EOM RsL, EOM RcL and PAD modelling in esotropia and exotropia surgery.

Surgical outcomes and occurrence of associated vertical strabismus during a 10-year follow-up in patients with infantile esotropia

Purpose:

Authors analyzed long-term surgical outcomes of infantile esotropia and the occurrence of associated strabismus, inferior oblique overaction (IOOA), and dissociated vertical deviation (DVD). Clinical factors related to the occurrence of IOOA and DVD in patients with infantile esotropia were also evaluated.

Methods:

Medical records of patients with infantile esotropia, who underwent surgery between 1995 and 2008, were reviewed retrospectively. Included patients were followed for at least 10 years. The incidence and age at development of IOOA and DVD were analyzed. To evaluate predisposing factors for developing IOOA or DVD, patients were divided into two groups: those with infantile esotropia only (group A) and those who developed IOOA or DVD (group B).

Results:

A total of 122 patients were enrolled and mean follow-up period was 16.0 years (range: 10–32 years). The mean number of surgeries was 1.7 (range: 1–5), and 64 (52.5%) patients achieved optimal horizontal alignment (esotropia <10 prism diopters [PD] and orthotropia). Fifty (41.0%) patients developed IOOA at a median age of 3 years (range: 1–21 years); 54 (44.3%) developed DVD at a median age of 5 years (range: 1–25 years). Patients in group B underwent more horizontal surgeries than those in group A (P = 0.028), and favorable surgical outcomes between the two groups were not different at final visit. There were no other significant differences in clinical factors between the two groups.

Conclusion:

Approximately, 52.5% of patients achieved favorable surgical outcomes through 1.7 surgeries during the 10-year follow-up period. DVD tended to develop at a later age than IOOA, and in some cases, up to 20 years after diagnosis of infantile esotropia. To achieve favorable horizontal alignment at final visit, patients with associated vertical strabismus underwent more horizontal muscle surgeries than patients with infantile esotropia only. The presence of IOOA/DVD may affect horizontal alignment outcomes.

Morphological Differences in the Inferior Oblique Muscles from Subjects with Over-elevation in Adduction

Purpose

We examined inferior oblique muscles from subjects with over-elevation in adduction for characteristics that might shed light on the potential mechanisms for their abnormal eye position.

Methods

The inferior oblique muscles were obtained at the time of surgery in subjects diagnosed with either primary inferior oblique overaction or Apert syndrome. The muscles were frozen and processed for morphometric analysis of myofiber size, central nucleation, myosin heavy chain (MyHC) isoform expression, nerve density, and numbers of neuromuscular junctions per muscle section.

Results

The inferior oblique muscles from subjects with Apert Syndrome were smaller, and had a much more heterogeneous profile relative to myofiber cross-sectional area compared to controls. Increased central nucleation in the Apert syndrome muscles suggested on-going myofiber regeneration or reinnervation over time. Complex changes were seen in the MyHC isoform patterns that would predict slower and more sustained contractions than in the control muscles. Nerve fiber densities were significantly increased compared to controls for the muscles with primary inferior oblique overaction and Apert syndrome that had no prior surgery. The muscles from Apert syndrome subjects as well as those with primary inferior oblique overaction with no prior surgery had significantly elevated numbers of neuromuscular junctions relative to the whole muscle area.

Conclusions

The muscles from both sets of subjects were significantly different from control muscles in a number of properties examined. These data support the view that despite similar manifestations of eye misalignment, the potential mechanism behind the strabismus in these subjects is significantly different.

Essential Infantile Esotropia: A Course of Treatment From Our Experience

Background: Essential infantile esotropia (EIE) is the most common type of childhood esotropia. Although its classical approach is surgical, less invasive techniques have been proposed as an adjunct or alternative to traditional surgery. Among them, chemodenervation with botulinum toxin (BT) has been investigated, showing variable and sometimes conflicting results. Objectives: To compare the outcomes of bilateral BT injection and traditional surgery in a pediatric population with EIE in order to optimize and standardize the therapeutic approach. Other purposes are to evaluate whether early intervention may prevent the onset of vertical ocular deviation (which is part of the clinical picture of EIE) and/or influence the development of fine stereopsis, and also to assess changes in refractive status over time among the enrolled population. Methods: A retrospective consecutive cohort study was conducted in 86 children aged 0-48 months who underwent correction of EIE. The primary intervention in naïve subjects was either bilateral BT injection (36 subjects, "BT group") or strabismus surgery (50 subjects, "surgery group"). Results: Overall, BT chemodenervation (one or two injections) was effective in 13 (36.1%) subjects. With regard to residual deviation angle, the outcomes at least 5 years after the last intervention were overlapping in children receiving initial treatment with either injection or surgery; however, the success rate of primary intervention in the surgery group was higher, and the average number of interventions necessary to achieve orthotropia was smaller. Both early treatment with chemodenervation and surgery at a later age were not found to prevent the onset of vertical ocular deviation, whereas, surprisingly, the percentage of subjects developing fine stereopsis was higher in the surgery group. Finally, with regard to the change in refractive status over time, most of the subjects increased their initial hyperopia, whereas 10% became myopic. Conclusions: Our data suggest that a single bilateral BT injection by age 2 years should be considered as the first-line treatment of EIE without vertical component; whereas, traditional surgery should be considered as the first-line treatment for all other cases and in subjects unresponsive to primary single BT injection.

Effects of Surgical Timing on Surgical Success and Long-term Motor and Sensory Outcomes of Infantile Esotropia

PURPOSE

To investigate the effect of surgical timing on long-term motor and sensory outcomes in patients with infantile esotropia.

METHODS

The medical records of patients who underwent strabismus surgery for infantile esotropia were reviewed retrospectively. The patients were divided into three groups according to age at the time of surgery: early group (6 to 11 months), late group (12 to 17 months), and very late group (18 to 27 months). The main outcome measures were final alignment, surgical success rate (the angle of deviation at final follow-up of ≤ 10 prism diopters [PD] of esotropia, no exotropia and no need for reoperation), stereoacuity, visual acuity, and the number of reoperations required during the follow-up.

RESULTS

A total of 79 patients (44 female, 35 male) met the inclusion criteria. The surgical success rate was 25.9%, 23.1%, and 53.8% in the three groups, respectively (P = .035). After a mean follow-up of 96 months, the average number of operations per child was 1.7 ± 0.9, 1.6 ± 0.6, and 1.4 ± 0.6 in the three groups, respectively (P = .020). The measurable stereopsis rate was higher in the early group (37% vs 3.8% and 3.8%, respectively) (P = .001). The amblyopia rate was similar between groups.

CONCLUSIONS

The results show that performing surgery later in life in patients with infantile esotropia increases the motor success rate of surgery. In addition, orthophoria is achieved with fewer surgical operations. However, earlier surgery may improve stereopsis. [J Pediatr Ophthalmol Strabismus. 2020;57(5):319-325.].

Consecutive strabismus after infantile nystagmus syndrome surgery and potential risk factors

PURPOSE

The aim of this study is to evaluate the incidence of consecutive strabismus after infantile nystagmus surgery and its potential risk factors.

METHODS

A retrospective study including 89 patients was conducted. Patients presented infantile nystagmus (idiopathic or ocular disease-associated nystagmus) without previous or coincidental strabismus. Sex, age at surgery, amblyopia, botulinum toxin (BT) injection before surgery, spherical equivalent, anisometropia, surgery procedure (Anderson's or retroequatorial recessions of four horizontal recti), and follow-up were analyzed. Kaplan-Meier and univariate Cox regression were performed.

RESULTS

The median age at surgery was 5 years. The median follow-up was 36 months. The incidence of consecutive strabismus was 11.2%. There were eight patients with exotropia and two patients with esotropia. Consecutive strabismus was associated with severe bilateral amblyopia (p = 0.036), previous treatment with BT injection (p = 0.025), and large recessions of the four horizontal muscles (p = 0.001). The hazard ratio for patients with severe bilateral amblyopia was 5.4 (95% CI 1.1-25.8), and for patients previously treated with BT was 6.1 (1.3-29.3). The survival rate was 95.4% at 6 months and 88.5% at 3 years.

CONCLUSION

Severe bilateral amblyopia, previous BT treatment, and type of surgery seem to be associated with consecutive strabismus after infantile nystagmus surgery. Most cases appear within the first months after surgery.

Outcome of Esotropia Surgery in 2 Tertiary Hospitals in Cameroon

Purpose

To evaluate the ocular alignment following esotropia surgery in our setting.

Patients and Methods

We conducted a cross sectional descriptive study which spanned 19 years, from October 1999 to September 2018 at the Douala General Hospital and the Yaoundé Central Hospital. Complete medical records of patients who underwent surgery for esotropia during the study period were included. Data collected included age at diagnosis, sex, age of onset of esotropia, age at surgery, refractive error, type of surgery performed, pre and post-operative angle of deviation. The outcome was considered good when the postoperative angle was ≤10 prism diopters (PD).

Results

Four hundred and ninety patients with primary esotropia were seen during the study period. Only 155 returned for follow-up after wearing the full cycloplegic correction for a minimum period of 3 months. Accommodative esotropia was found in 32 cases (20.6%). Among the 123 cases requiring surgery, 63 cases underwent surgery (51.2%). Fifty-nine complete records were included (59.3% females and 40.7% males). The mean age at the time of diagnosis was 6.5 ± 6.1 years and the mean age at the time of surgery was 8.7 ± 6.1 years. The mean preoperative angle at distance was 42.8 ±10.8 PD. The outcome was good in 91.5% of cases. No factor influenced the outcome of surgery.

Conclusion

The outcome of esotropia surgery was good in this study. This could serve to increase patient motivation to accept surgery in our setting.

Long term motor and sensory outcome after surgery for infantile esotropia and risk factors for residual and consecutive deviations

Purpose: To present long-term motor and sensory outcomes after surgery for infantile esotropia and assess risk factors for residual and consecutive deviations.Methods: Data of infantile esotropia patients operated between 2002 and 2016 with minimum follow-up of 2 years were retrospectively reviewed.Results: Among a total of 62 patients, 35 had a successful motor outcome (alignment within 10 PD from orthotropia) after one surgery (Group A), while 27 required horizontal reoperation (Group B). Patients with residual esotropia had larger preoperative angle of deviation (P = .005) and younger age at first surgery (P = .01), while consecutive exotropia was associated with longer follow-up (P = .03) and higher rate of DVD (P = .003) compared to patients in Group A. Stereopsis was present in 30.3% of patients in Group A and associated with younger age at first surgery (P = .03).Conclusions: Successful motor alignment may be obtained with single surgery in infantile esotropia; however, reoperations are common. Younger age at first surgery may be associated with both higher rate of stereopsis and risk of reoperation. Careful preoperative assessment and surgical timing, with long-term postoperative follow-up is required to achieve satisfactory outcome.

Accuracy of the Ultrasound Biomicroscopy Bag/Balloon Technique in Locating Horizontal Extraocular Muscle Insertions Before and After Strabismus Surgery

PURPOSE

To investigate the accuracy of high frequency ultrasound biomicroscopy using the bag/balloon technique to locate recti muscle insertions before and after strabismus surgery.

METHODS

This was a prospective masked study. The distance from the limbus to horizontal recti muscle insertions was measured by caliper intraoperatively and ultrasound biomicroscopy preoperatively and during follow-up. Accuracy was defined as the difference between ultrasound biomicroscopy and caliper measurements.

RESULTS

Thirty-nine muscles (19 medial rectus and 20 lateral rectus) of 22 patients were included. The mean age of the patients was 34.7 ± 15.5 years (range: 18 to 78 years). Follow-up measurements were available for 25 muscles: 12 muscles were recessed and 13 were resected/advanced. Twelve of the included muscles underwent prior surgery. There was a strong correlation between preoperative mean ultrasound biomicroscopy and caliper measurements (P < .001, r_p = 0.872) without significant difference between the accuracy of identification of medial rectus and lateral rectus muscles (P = .116 and .377, respectively). On average, postoperative ultrasound biomicroscopy measurements of recessed muscles were 1.15 mm greater than caliper measurements at the end of surgery (P = .003), whereas the mean difference in the resected muscles was not statistically significant (-0.07 mm, P > .999). Overall, in 16 of 25 muscles (64%), the differences between the postoperative measurements and the end of surgery measurements were less than 1 mm. There was no correlation between the accuracy and the time of ultrasound biomicroscopy after surgery (P = .516).

CONCLUSIONS

The ultrasound biomicroscopy bag/balloon technique is an accurate and reliable method of locating recti muscle insertions before and after strabismus surgery. Ultrasound biomicroscopy may assist strabismologists in planning repeated operations. [J Pediatr Ophthalmol Strabismus. 2020;57(1):12-20.].

Gene expression profile of extraocular muscles following resection strabismus surgery

This paper aims to identify key biological processes triggered by resection surgery in the extraocular muscles (EOMs) of a rabbit model of strabismus surgery by studying changes in gene expression. Resection surgery was performed in the superior rectus of 16 rabbits and a group of non-operated rabbits served as control. Muscle samples were collected from groups of four animals 1, 2, 4 and 6 weeks after surgery and processed for RNA-sequencing and immunohistochemistry. We identified a total of 164; 136; 64 and 12 differentially expressed genes 1, 2, 4 and 6 weeks after surgery. Gene Ontology enrichment analysis revealed that differentially expressed genes were involved in biological pathways related to metabolism, response to stimulus mainly related with regulation of immune response, cell cycle and extracellular matrix. A complementary pathway analysis and network analysis performed with Ingenuity Pathway Analysis tool corroborated and completed these findings. Collagen I, fibronectin and versican, evaluated by immunofluorescence, showed that changes at the gene expression level resulted in variation at the protein level. Tenascin-C staining in resected muscles demonstrated the formation of new tendon and myotendinous junctions. These data provide new insights about the biological response of the EOMs to resection surgery and may form the basis for future strategies to improve the outcome of strabismus surgery.

Lateral rectus sag and recurrent esotropia in children

PURPOSE

To describe the clinical and intraoperative findings of an anatomic abnormality in children that resembles sagging eye syndrome documented in older adults and that led to recurrent esotropia after surgery.

METHODS

We reviewed records of 4 patients with substantial recurrent esotropia after bilateral medial rectus recession who required subsequent surgery combining lateral rectus resection with correction of the anatomic abnormality affecting the lateral rectus path. Binocular alignment was sequentially analyzed.

RESULTS

Three young patients (2-3 years of age) presented with acquired esotropia but minimal cycloplegic refractive error. The fourth patient (14 years of age) initially had moderate hyperopia and partially accommodative esotropia, but subsequently developed marked bilateral overelevation in adduction. In all patients, esotropia recurred within 5^Δ of preoperative deviation after bilateral medial rectus recession. Surgical exposure demonstrated that bilateral lateral rectus paths were inferiorly displaced more than one-half tendon width from their normal paths near the globe's equator, despite normal scleral insertions. Equatorial myopexy and lateral rectus resection resulted in stable esotropia correction.

CONCLUSIONS

Lateral rectus sag in children creates a type of acquired esotropia and overelevation in adduction poorly responsive to standard surgery but correctable with lateral rectus resection and equatorial myopexy that normalizes the lateral rectus path through permanent scleral fixation.

The relationship between abduction deficit and reoperation among patients with infantile esotropia

AIM

To determine the relationship between abduction deficit and reoperation among patients with infantile esotropia (IET).

METHODS

The records of 216 patients (432 eyes) with IET who underwent surgery, from 2010 to 2015 were studied. Patients with IET whose deviation appeared before 6mo of age and had stable preoperative deviation in two examinations with at least 2wk apart and a minimum 3mo postoperative follow up were included. Cases with early onset accommodative esotropia, congenital cataract, retinopathy of prematurity (ROP), manifest nystagmus, fundus lesions, neurologic and ophthalmic anomalies, 6^th nerve palsy and Duane's syndrome were excluded. Preoperative abduction deficit was considered from -1 to -3 grading scale. Three months after surgery, children were classified into no-need reoperation [deviation≤15 prism diopters (PD)], and need-reoperation groups (deviation>15 PD).

RESULTS

In this retrospective study, 117 female and 99 male patients with the mean surgical age of 4.7±6.4y were included. Reoperation rate was 33.3% and 16.0% in IET patients with and without abduction deficit, respectively in patients who had a history of late surgery. Abduction deficit increased the odds of reoperation by 82% [OR=1.82, 95% confidence interval (CI) =1.05 to 3.19, P=0.003] in patients who had a history of late surgery (>2 years old, P=0.021). Abduction deficit was improved significantly after operation (P<0.001).

CONCLUSION

Based on our results, abduction deficit can be considered as a risk factor of reoperation in IET patients who are operated at the age of more than 2y.

Prognostic preoperative factors for successful outcome of surgery in horizontal strabismus

CONTEXT

Surgery for horizontal strabismus reportedly has a success rate of 60%-80%. However, which preoperative factors are predictive of this success is not clear.

AIMS

To identify prognostic factors those are predictive of successful outcome in horizontal strabismus surgery.

SETTINGS AND DESIGN

Observational analytical study using multiple logistic regression (MLR).

SUBJECTS AND METHODS

We assessed the medical records of patients who had undergone first-time horizontal muscle strabismus surgery between 2002 and 2013, where complete follow-up data were available for ≥6 weeks, and also, we collected data prospectively on patients operated between January 2014 and September 2015. Successful outcome was defined as a postoperative angle of deviation within 10 prism diopter of orthophoria at ≥6 weeks postoperatively. Independent variables considered were age at onset, age at surgery, duration, gender, deviation - type and amount, logMAR visual acuity (VA) - mean and of the poorer eye, mean refractive error, amount of anisometropia, and presence of dense amblyopia. Only those with P < 0.2 on univariate analyses (UAs) were included in the MLR, with significance set at P ≤ 0.05.

STATISTICAL ANALYSES

UA (Chi-square for categorical variables and t-tests for continuous variables), followed by logistic regression analysis.

RESULTS

Of 113 patients, on UA, type of deviation (P = 0.01), age at surgery (P = 0.16), absence of dense amblyopia (P = 0.002), and logMAR VA of the poorer eye (P = 0.005) qualified for the inclusion in MLR. On MLR, esotropia (ET) (odds ratio [OR]: 4.46) and absence of dense amblyopia (OR: 5.90) were associated with success.

CONCLUSIONS

With an overall success rate of 83%, ET and absence of dense amblyopia were significantly predictive of surgical success.

Infantile esotropia: risk factors associated with reoperation

The aim of this study was to identify clinical and demographic factors associated with misalignment after first surgery performed on children affected by infantile esotropia to evaluate the reoperation rate. A retrospective study was carried out, analyzing data from 525 children who underwent bilateral medial recti recession, bilateral lateral recti resection, and inferior oblique recession and anteroposition by the same surgeon (AM). Postoperative evaluation included assessment of motor alignment at approximately 3 months, 6 months, 1 year, and 5 years. Statistical analysis was performed with a logistical regression model in which the dependent variable was the presence/absence of reoperation. We found that late surgery (after 3 years of age) and a family history of strabismus are associated with a higher risk of reoperation, while some clinical factors, including some classically associated with worst motor outcome as preoperative angle, dissociated vertical deviation, and amblyopia, did not influence the incidence of reoperation in infantile esotropia. Male patients and patients with hyperopia in preoperative examinations have a significantly decreased reoperation rate.

Surgical treatment for residual or recurrent strabismus

Although the surgical treatment is a relatively effective and predictable method for correcting residual or recurrent strabismus, such as posterior fixation sutures, medial rectus marginal myotomy, unilateral or bilateral rectus re-recession and resection, unilateral lateral rectus recession and adjustable suture, no standard protocol is established for the surgical style. Different surgical approaches have been recommended for correcting residual or recurrent strabismus. The choice of the surgical procedure depends on the former operation pattern and the surgical dosages applied on the patients, residual or recurrent angle of deviation and the operator's preference and experience. This review attempts to outline recent publications and current opinion in the management of residual or recurrent esotropia and exotropia.

Factors related to strabismus decompensation after a period of prolonged postoperative stability

PURPOSE

To identify factors associated with late decompensation of horizontal strabismus after a period of prolonged (>12 months) postoperative stability.

METHODS

Charts from all pediatric horizontal strabismus surgical cases from 1999 to 2009 were reviewed. Patients with a distance or near alignment of <10(Δ) at the first visit >12 months following surgery were included. The primary outcome was time from surgery to strabismus decompensation. Multiple variables were analyzed using the Cox proportional hazards model.

RESULTS

A total of 185 cases were included. Mean age at surgery was 5.1 years and mean follow-up was 62.2 months. Late decompensation rate was 31%; of these, 54% underwent reoperation. Using two different models, a higher risk of decompensation was associated with both the presence of preoperative oblique dysfunction (P = 0.023/0.002) and larger distance/near deviations at the first >12 months postoperative visit (P = 0.033/0.012).

CONCLUSIONS

Worsening of alignment >12 months after horizontal strabismus surgery occurs in almost one-third of patients. Preoperative oblique dysfunction is associated with long-term instability, possibly because it is a surrogate for sensory torsion and poor fusion. Additionally, larger distance and near deviations at >12 months after surgery were each associated with late decompensation. The rate of decompensation for patients with deviations of 0(Δ) to <4(Δ) was less than those with deviations of 4(Δ) to <8(Δ) and >8(Δ), suggesting that the biologic behavior of all deviations within the monofixation range (0(Δ) to 8(Δ)) is not uniform.

Evaluation of the utility of hospital databases to provide data in assessing the quality of strabismus surgery

AIMS AND BACKGROUND

Rates of re-operation, which may be related to an unsatisfactory surgical outcome, can provide a long-term index of the quality of strabismus surgery. This study aims to evaluate the utility of the Scottish Morbidity Records (SMR1) in determining nature and rates of re-operation for strabismus at the Royal Hospital for Sick Children (RHSC), Glasgow.

METHODS

SMR1 data on strabismus surgery performed on children aged between 0 and 17 years at the RHSC, Glasgow, between January 2000 and March 2009 were analysed.

RESULTS

In total, 1376 strabismus procedures were carried out on 1274 individuals. The median time between first and subsequent procedures was 19 months; the commonest reasons being under-correction or recurrence. The Kaplan-Meier rate of undergoing re-operation was 7.4% after 9 years with a 95% confidence interval of 5.4-9.9%.

CONCLUSIONS

The SMR1 is a useful source of hospital-based and population data. With supplementation from parallel databases, routine administrative databases like the SMR1 can provide better quality data to inform practice.

The prevalence of reoperation and related risk factors among patients with congenital esotropia

PURPOSE

To determine the prevalence rate and related risk factors of reoperation among patients with congenital esotropia.

METHODS

One hundred fifty-seven children with congenital esotropia were divided into two groups after at least one operation: children with deviation within 10 PD (n = 89; success group) and those with deviation greater than 10 PD or history of reoperation (n = 68; failure group). The relationship of risk factors such as age at first operation and primary congenital esotropia of less than 30 or more than 50 PD and accompanying factors such as inferior oblique muscle overaction (> +1), dissociated vertical deviation, lateral rectus muscle underaction, and A-V pattern with reoperation were studied. Final sensory status of children 5 years and older was evaluated by Worth 4-dot and Titmus tests.

RESULTS

Reoperation was indicated in 32.4% of children who had residual esotropia greater than 15 PD after 3 months following their first operation. Congenital esotropia greater than 30 PD (P = .002) and lateral rectus muscle underaction of −1 to −2 (P < .005), were statistically different between the two groups. Initial operation at younger than 3 years was more likely to achieve gross stereopsis in children 5 years and older (P = .032).

CONCLUSION

Congenital esotropia greater than 30 PD and lateral rectus muscle underaction were found to be risk factors of reoperation.

Predictability of strabismus surgery in children with developmental disorders and/or psychomotor retardation

BACKGROUND

Children with developmental disorders and/or psychomotor delay may respond differently to strabismus surgery than children who develop normally, but the literature is conflicting.

METHODS

We studied 37 patients with spasm, trisomy 21, prematurity, epilepsy, psychomotor retardation, and/or hydrocephalus (study group) and 67 control patients, all between 14 months and 14 years of age. All received a recession of one or both medial rectus muscles (Rc-surgery) or a monocular recession-resection of medial-lateral rectus muscles (RcRs-surgery) for esotropia. Rc-surgery was performed in cases with convergence excess. Spectacles were prescribed prior to surgery for all hyperopia > 2D, all partly accommodative esotropia, and all myopia.

RESULTS

(effect per mm of surgery): For Rc-surgery, after 2 months follow-up, at 2.5 m fixation distance, the effects (change of angle per millimeter of surgery, mean + or - SD) were 2.07 + or - 0.82 degrees /mm (study group) and 1.07 + or - 0.74 degrees /mm (control group) (P < 0.001). At 30 cm fixation distance, the effects were 2.42 + or - 0.79 degrees /mm (study group) and 1.53 + or - 1.00 degrees /mm (control group) (P < 0.001). Effects at infinity were similar to those at 2.5 m. Because of this larger effect on near angles, convergence excess decreased after surgery in both study and control groups. For RcRs-surgery, at 2.5 m fixation distance, the effects were 1.78 + or - 0.43 degrees /mm (study group) and 1.78 + or - 0.42 degrees /mm (control group) (P = 0.741). At 30 cm fixation distance, the effects were 1.82 + or - 0.39 degrees /mm (study group) and 1.84 + or - 0.58 degrees /mm (control group) (P = 0.918). At fixation distance infinity, results were similar to those at 2.5 m. For both Rc-surgery and RcRs-surgery, reported differences were similar after one year follow-up. Success of surgery: After 2 months of follow-up, esotropia between 0-6 degrees was present, for Rc-surgery in 64% in the study group (with adjusted dosages) and 93% in the control group; and for RcRs-surgery in 66% in the study group and 88% in the control group.

CONCLUSIONS

Rc-surgery in children with developmental disorders and/or psychomotor delay has a larger effect per mm of surgery than in normal children. RcRs-surgery has a similar effect in delayed and normal children.

Persistently recurrent infantile esotropia

INTRODUCTION

Children with infantile esotropia often require more than one surgery to align the eyes horizontally, for either recurrent esotropia or consecutive exotropia. We report an unusual subset of patients who had persistently recurrent esotropia despite multiple surgeries.

METHODS

The records of 11 patients who presented before age one year with infantile esotropia and who had three or more surgeries for recurrent esotropia were reviewed. The number of surgeries, outcomes, and associated systemic conditions were recorded.

RESULTS

These 11 patients represented 4% of children who were operated upon for infantile esotropia during the time of the study. The number of surgeries per patient ranged from 3-9 (mean 5). All of the horizontal surgeries in eight patients were for esotropia, while three patients developed exotropia after three or more surgeries for esotropia. Three children were otherwise normal, three had mild nonspecific developmental delay, one was premature, one had Trisomy 21, and one had spina bifida and high myopia. Following their most recent surgery, eight children had deviations of 8delta or less, and three had deviations between 8delta and 16delta. Seven patients demonstrated fusion. Age at last follow-up ranged from 2-13 years (mean 6.7 years).

CONCLUSION

Persistently recurrent esotropia is an unusual occurrence in children with infantile esotropia. Developmental delay is common in these patients, although none were markedly delayed. Satisfactory ocular alignment can be achieved in most patients, but several surgeries may be necessary to achieve this.

Is the incidence of infantile esotropia declining?: a population-based study from Olmsted County, Minnesota, 1965 to 1994

OBJECTIVE

To investigate the incidence of infantile esotropia from a defined population in the United States over a 30-year period. Recent reports from the United Kingdom have suggested that strabismus or strabismus surgery is occurring less frequently today than in previous years.

METHODS

The medical records of all patients diagnosed with infantile esotropia within Olmsted County, Minnesota, from January 1, 1965, through December 31, 1994, were retrospectively reviewed.

RESULTS

The birth prevalence of infantile esotropia during the 30-year period was 25 (95% confidence interval, 21-29) per 10 000, or 1 in 403 live births. Although there were slightly more cases of infantile esotropia in the earlier years (45 from 1965-1974, 51 from 1975-1984, and 34 from 1985-1994), the change in incidence over time was not statistically significant (P = .32). The mean number of surgeries performed on each patient in this cohort was similar during the 30-year study: 1.8 for those diagnosed from 1965 to 1974, 1.9 for 1975 to 1984, and 1.6 for 1985 to 1994.

CONCLUSIONS

The incidence of infantile esotropia in this population has not significantly changed from 1965 through 1994. Moreover, the rate of surgical intervention over these years is similar for this patient population.

Long-term follow-up of congenital esotropia in a population-based cohort

PURPOSE

To report the long-term outcomes of a population-based cohort of children diagnosed with congenital esotropia during a 30-year period.

METHODS

The medical records of all patients diagnosed with congenital esotropia as residents of Olmsted County, MN, from January 1, 1965, through December 31, 1994, were retrospectively reviewed.

RESULTS

A total of 130 children were diagnosed during the 30-year period at a median age of 7.4 months with a mean deviation of 30(Delta). During a median follow-up of 11.9 years, 126 patients underwent a mean of 1.8 strabismus surgeries. The risk for undergoing a second surgery was significantly greater in patients with a larger presenting angle (p = 0.017) and a younger age at first surgery (p = 0.006). The Kaplan-Meier rate of having a second surgery was 51% at 10 years and 66% at 20 years. For those with 6 weeks or more of follow-up from the final surgery, last examined at a mean age of 15.1 years, 42 of 94 (45%) were within 8(Delta) of orthotropia and 30 of 98 had some level of stereopsis (</=3000 arcsec).

CONCLUSIONS

In this population-based study of children with congenital esotropia, a second surgery was necessary in half the patients after 10 years and was more likely in those patients with a larger presenting angle and a younger age at first surgery. Approximately half of the patients were within 8(Delta) of orthotropia and one-third had measurable stereopsis after a mean of 10.9 years of follow-up.

Botulinum toxin pretreatment augments the weakening effect of injection with ricin-mAb35 in rabbit extraocular muscle

PURPOSE

To examine force generation and duration of effect of botulinum toxin pretreatment, followed by injection of ricin-mAb35 in extraocular muscle.

METHODS

In normal adult rabbits, one superior rectus muscle was injected with either 5 units botulinum toxin or 1/50 maximally tolerated dose for rats (rMTD) of ricin-mAb35. Additional rabbits were first injected with 5 units botulinum toxin, and after 1, 2, or 4 weeks the same muscle was injected with either 1/10 or 1/50 rMTD ricin-mAb35. In each treatment group, the contralateral muscle was injected with an equal volume of saline. After 12 weeks (1/50 rMTD) or 6 months (1/10 rMTD), the rabbits were euthanized. Both SR muscles were removed and assayed physiologically, using an in vitro apparatus.

RESULTS

Twelve weeks after treatment with either botulinum toxin or immunotoxin alone, only ricin-mAb35-treated muscles were weaker than control muscles at tetanic stimulation frequencies. Pretreatment with botulinum toxin prior to injection with immunotoxin, especially at shorter intervals between injections, resulted in significant decreases in twitch and tetanic force generation compared with controls and muscles treated with ricin-mAb35 only or botulinum toxin only. At 6 months, force generation was decreased from control only in muscles treated with the higher dose of ricin-mAb35. Botulinum toxin pretreatment did not augment this effect at 6 months.

CONCLUSIONS

Upregulation of postsynaptic nicotinic acetylcholine receptors caused by botulinum toxin pretreatment amplifies the reduction of force generation in extraocular muscle following secondary injection of the immunotoxin ricin-mAb35 within 3 months of treatment.

Myogenic growth factors can decrease extraocular muscle force generation: a potential biological approach to the treatment of strabismus

PURPOSE

Future pharmacologic treatment of strabismus may be optimized if drugs that are less potentially toxic to patients can be developed. Prior studies have shown that direct injection of extraocular muscles (EOMs) with insulin growth factor or fibroblast growth factor results in significant increases in the generation of EOM force. The purpose of this study was to examine the morphometric and physiological effects of direct EOM injection with the growth factors BMP4, TGFbeta1, Shh, and Wnt3A.

METHODS

One superior rectus muscle of normal adult rabbits was injected with BMP4, TGFbeta1, Shh, or Wnt3A. The contralateral muscle was injected with an equal volume of saline to serve as a control. After 1 week, the animals were euthanatized, and both superior rectus muscles were removed and assayed physiologically. The muscles were stimulated at increasing frequencies to determine force generation. A separate group of treated and control superior rectus muscles were examined histologically for alterations in total muscle cross-sectional area and myosin heavy chain isoform (MyHC) composition.

RESULTS

One week after a single injection of BMP4, TGFbeta1, Shh, or Wnt3A, all treated muscles showed significant decreases in generation of force compared with control muscles. BMP4, TGFbeta1, Shh, and Wnt3A significantly decreased the mean myofiber cross-sectional area of fast MyHC-positive myofibers. BMP4 resulted in a conversion of fast-to-slow myofibers and a significant decrease in the percentage of developmental and neonatal MyHC-positive myofibers. Alterations in mean cross-sectional area and proportion of MyHCs were seen after injection with TGFbeta1, Shh, and Wnt3A. TGFbeta1 and BMP4 injections resulted in increased Pax7-positive satellite cells, whereas BMP4, TGFbeta1, and Wnt3A resulted in a decrease in MyoD-positive satellite cells.

CONCLUSIONS

These results suggest that, rather than using toxins or immunotoxins, a more biological approach to decrease muscle strength is possible and demonstrate the potential utility of myogenic signaling factors for decreasing EOM strength. Ongoing drug-delivery studies will elucidate means of extending treatment effect to make such agents clinically useful.

Activated satellite cells in medial rectus muscles of patients with strabismus

PURPOSE

The goal of this study was to determine whether the medial rectus muscles of patients with a history of medial rectus underaction or overaction show alterations in the process of satellite cell activation when compared with normal age-matched control muscles.

METHODS

Medial rectus muscles were obtained with consent from adult patients undergoing surgical resection due to medial rectus underaction or overaction and were prepared for histologic examination by fixation and paraffin embedding. Control muscles were obtained from cornea donor eyes of adults who had no history of strabismus or neuromuscular disease. Cross sections were obtained and stained immunohistochemically for the presence of activated satellite cells, as identified by MyoD immunoreactivity, and the presence of the total satellite cell population, as identified by Pax7 immunoreactivity. The percentages of MyoD- and Pax7-positive satellite cells per 100 myofibers in cross section were calculated.

RESULTS

As predicted from results in the literature, MyoD-positive satellite cells, indicative of activation, were present in both the control and resected muscles. In the underacting medial rectus muscles, the percentages of MyoD- and Pax7-positive satellite cells, based on the number of myofibers, were approximately twofold higher than the percentages in the control muscles. In the overacting medial rectus muscles, the percentage of MyoD-positive satellite cells was twofold less than in the control muscles, whereas the percentage of Pax7-positive satellite cells significantly increased compared with that in the control specimens.

CONCLUSIONS

The presence of an increased number of activated satellite cells in the resected underacting medial rectus muscles and the decreased numbers of activated satellite cells in the overacting muscles was unexpected. The upregulation in the number of MyoD-positive satellite cells in underacting muscles suggests that there is potential for successful upregulation of size in these muscles, as the cellular machinery for muscle repair and regeneration, the satellite cells, is retained and active in patients with medial rectus underaction. The decreased number of activated satellite cells in overacting MR muscle suggests that factors as yet unknown in these overacting muscles are able to affect the number of satellite cells and/or their responsiveness compared with normal age-matched control muscles. These hypotheses are currently being tested.

[Binocular vision and vertical strabismus]

BACKGROUND/AIM

Elevation in adduction is the most common pattern of vertical strabismus, and it is mostly treated with surgery. The results of weaking of inferior oblique muscle are very changeable. The aim of this study was to evaluate binocular vision using sensory tests before and one and six months after the surgery.

METHODS

A total of 79 children were divided in two groups: the first, with inferior oblique muscle of overaction (n = 52), and the second with dissociated vertical deviation (DVD), and primary inferior oblique muscle overaction (n = 27). We tested them by polaroid mirror test (PMT), Worth test at distance and near, fusion amplitudes on sinoptofore, Lang I stereo test and Wirt-Titmus stereo test. We examined our patients before and two times after the surgery for vertical strabismus.

RESULT

Foveal suppression in the group I was found in 60.5% of the patients before, and in 56.4% after the surgery. In group II Foveal suppression was detected in 64.7% of the patients before, but in 55.6% 6 months after the surgery with PMT. Worth test revealed suppression in 23.5% of the patients before, and in 40.7% after the vertical muscle surgery. Parafoveal fussion persisted in about 1/3 of the patients before the surgery, and their amplitudes were a little largen after the surgery in the group I patients. Lang I stereo test was negative in 53.9% before and 51.9% after the surgery in the group I, and in 48.2% of the patients before and after the surgery in the group II patients. Wirt-Titmus stereo test was negative in 74.5% of the patients before and in 72.9% after the surgery in the group I, but in the group II it was negative in 70.8% before and in 68.0% of the patients 6 months after the surgery.

CONCLUSION

Binocular responses were found after surgury in 65.7% of the patients the group I and in 55.6% patients the group II. There was no significant difference between these two groups, but binocular responses were more often in the patients of the group I.

Increasing muscle strength as a treatment for strabismus: sustained release of insulin-like growth factor-1 in rabbit extraocular muscle

PURPOSE

Currently, no drug treatment is available for strengthening underacting extraocular muscles (EOM) in strabismus. We showed previously that single injections of insulin-like growth factor (IGF-1) result in significant but short-term increases in muscle force generation. This study examined the effects of sustained release of IGF-1 on force generation in rabbit superior rectus muscles.

METHODS

In adult rabbits, slow-release pellets containing IGF-1 were implanted on the global side of one superior rectus muscle. After 1 week, or 1, 2, 3, or 6 months, treated and control muscles were examined for force generation using an in vitro physiology apparatus. All muscles were prepared for histology and mean myofiber cross-sectional areas were determined.

RESULTS

One and 3 months after pellet implantation, treated muscles generated significantly greater force than contralateral control muscles, whereas at 2 months, no significant difference was found. Force per cross-sectional area (mN/cm(2)) at 3 months also increased significantly in the treated muscles. Mean muscle cross-sectional area increased significantly after 1, 2, and 3 months of sustained exposure to IGF-1 compared with controls. After an additional 3 months without IGF-1 exposure, mean cross-sectional areas were significantly greater than controls but significantly reduced compared with areas at 1, 2, and 3 months.

CONCLUSIONS

IGF-1 appears to be highly effective in increasing muscle force generation. Because slow release of IGF-1 results in sustained increases in EOM force generation, it may be a potentially useful alternative to surgical resection procedures because it avoids many of the potential long-term biomechanical hazards of resection surgery.

Increased extraocular muscle strength with direct injection of insulin-like growth factor-I

PURPOSE

Previous work has demonstrated the effectiveness of insulin-like growth factor (IGF)-II in increasing force generation in extraocular muscle (EOM). Studies in the literature have suggested that IGF-I would be even more effective than IGF-II. This study was performed to assess the effects on muscle mass and force generation of IGF-I injection in adult rabbit superior rectus muscle.

METHODS

Adult rabbits received a single injection of IGF-I at one of several doses into one superior rectus muscle. One week after treatment, the rabbits were euthanatized, and the superior rectus muscle from each orbit was removed. Force generation was measured using an in vitro apparatus, and injected muscles were compared with the contralateral control. A second group of animals were injected similarly, and the muscles were examined at 1 week for changes in cross-sectional area of individual myofibers.

RESULTS

EOMs demonstrate significant numbers of cells expressing the IGF receptor. After the EOMs were injected with IGF-I, there were significant increases both in muscle force generation and cross-sectional area at all doses tested in this study. Doses of 10 and 25 microg IGF-I were most effective.

CONCLUSIONS

Direct muscular injection of IGF-I effectively increases EOM force generation without the potential biomechanical hazards of surgery such as permanently altered muscle length or insertional position on the globe.