Outcome study of surgical alignment before six months of age for congenital esotropia

Surgical Outcomes and Factors Related to Their Success of Infantile Esotropia in a Tertiary Hospital: A Retrospective Study

Purpose

This study aims to evaluate the outcomes of surgical intervention for infantile esotropia at a tertiary care hospital.

Patients and Methods

Medical records of patients with esotropia who underwent surgical correction at our tertiary hospital between January 2013 and June 2023 were retrospectively analyzed. Patient demographics, preoperative and postoperative ocular alignment, surgical techniques employed, complications or reoperations, and factors related to successful surgery were analyzed.

Results

The study included 77 participants with an average age of 9.54 ± 10.87 years at the time of surgery. Postoperatively, 71.4% (55/77) patients achieved successful alignment, which was defined as an ocular deviation of ≤10 prism diopters (PD), at the final follow-up. The average follow-up period was 12 months, during which no complications were noted. Reoperation was required in 15.6% (12/77) patients. Multivariate logistic regression revealed that having a smaller preoperative deviation of <50 PD positively influenced the success of strabismus surgery (adjusted odds ratio, 7.13; 95% CI, 2.04-24.86).

Conclusion

The surgical correction of infantile esotropia in a tertiary care setting yielded favorable alignment outcomes in most cases, with no complications and a low reoperation rate. A preoperative angle of <50 PD emerged as a prognostic factor for successful surgical outcomes in this population. Further studies with longer follow-up periods are recommended to evaluate the long-term stability of these outcomes and identify additional influencing factors.

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.

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

Introduction: The purpose of the present study was to determine the factors that affect the outcome of strabismus surgery in terms of improvement in stereopsis and binocularity.

Methods: Data were collected prospectively from patients with childhood-onset, concomitant, constant strabismus greater than 30 prism diopters (PD) with postoperative alignment within 10 PD. Pre- and postoperative stereopsis and binocularity testing were performed using the Titmus fly test, random dot test, Bagolini striated glass test, and Worth four dot test at one, four, and 12 weeks postoperatively.

Results: A total of 73 patients (55% males and 45% females) who underwent surgery at our center were studied. The mean age at the time of surgery was 16 ± 7.7 years (range: 5-35 years). We found that factors such as age of strabismus onset, type of deviation, and amblyopia had a statistically significant influence on the postoperative surgical outcome. A statistically insignificant relationship was noted with gender, refractive error, and duration of strabismus. Patients who had strabismus after six months of age noticed a significant improvement in stereopsis (p-value = 0.000) than those who had strabismus before six months of age (p-value = 0.660). Further, there was a statistically significant improvement in patients having exotropia (p-value = 0.018) or combined horizontal and vertical deviations (p-value = 0.000), but there was no significant improvement in patients with esotropia (p-value = 0.180). Moreover, non-amblyopes had a significantly better postoperative stereopsis than amblyopes (p-value = 0.006). Although there was no association between preoperative deviation and improvement in stereopsis (p-value = 0.081), patients having preoperative deviation in the range of 31-45 PD had a statistically significant improvement in stereopsis (p-value = 0.000). There was no significant difference between postoperative residual deviation and final stereopsis (p-value > 0.05). All the results were the same for both the Titmus test and the random dot test. Binocular fusion was observed in 34 subjects, and uniocular suppression was noted in 38 subjects preoperatively. It was observed that only one patient gained binocular single vision postoperatively.

Conclusion: The presence of amblyopia, esotropia, early onset of strabismus (within six months of age), and a larger preoperative deviation (>45 PD) were associated with poorer stereopsis. In patients with horizontal strabismus, the coexistence of vertical deviation had a positive impact on the postoperative stereopsis. Gender, refractive error, and duration of strabismus did not influence the final stereopsis in our study.

Timing of surgery in essential infantile esotropia - What more do we know since the turn of the century?

This review summarizes the results and interpretations of studies pertaining to the long-standing debate regarding the timing of surgery in infantile esotropia, more recently referred to as essential infantile esotropia. A systematic search of studies from the year 2000 onward pertaining to the timing of surgery in infantile esotropia as listed in PubMed, Google Scholar, and the Cochrane database was performed. Appropriate cross-references from the articles were also included. Data collected included demographics, presentation, time of surgery, complications, and outcomes. Very early surgery, that is, within 6 months of the onset of infantile esotropia, offers significant advantages in terms of the quality of stereopsis and binocular vision as well as promoting the development of cortical visual processing, thereby benefiting cortical development in human infants. However, the postoperative alignment was not found to be significantly different in the very early, early, or late surgery groups. The reduction in the incidence of manifest dissociated vertical deviation postoperatively in the very early surgery group also showed measurable benefits. The results of this recent literature review demonstrated that very early surgery, within 6 months of misalignment, showed demonstrable benefits in essential infantile esotropia.

Relationship between stereopsis outcome and timing of surgical alignment in infantile esotropia

PURPOSE

To clarify the relationship between stereopsis outcome and timing of surgical alignment in infantile esotropia.

METHODS

The medical records of otherwise healthy patients with infantile esotropia who underwent surgery by 8 years of age were divided into the following groups according to age at time of surgery: very early surgery (≤8 months), early surgery (>8 to ≤24 months) and late surgery (>24 months). Binocular response and stereopsis were compared between groups.

RESULTS

A total of 76 patients were included: 22 in the very early group, 30 in the early group, and 24 in the late group. Binocular response at near was found in 96% of the very early group and in 80% of the early group, significantly higher than the 50% of the late group (P < 0.001 and P < 0.05 [Dunn test], resp.). Stereopsis was present in 77% of the very early group, significantly higher than the 20% of the early group and 13% of the late group (P < 0.001 [Dunn test]). A significant correlation was also found between age (months) at surgery and stereopsis (seconds) outcome (logarithmic fit: y = 2539.4ln(x) + 147.2; R² = 0.2691; P < 0.001).

CONCLUSIONS

In this study cohort, earlier surgery was associated with better binocularity in patients with infantile esotropia. Our results suggest that very early surgery, at ≤8 months, can improve the chance for postoperative stereopsis, with the caveat that some infants might have had spontaneous esotropia resolution.

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.

Critical periods of brain development

Brain plasticity is maximal at specific time windows during early development known as critical periods (CPs), during which sensory experience is necessary to establish optimal cortical representations of the surrounding environment. After CP closure, a range of functional and structural elements prevent passive experience from eliciting significant plastic changes in the brain. The transition from a plastic to a more fixed state is advantageous as it allows for the sequential consolidation and retention of new and more complex perceptual, motor, and cognitive functions. However, the formation of stable neural representations may pose limitations on future revisions to the circuitry. If sensory experience is abnormal or absent during this time, it can have profound effects on sensory representations in adulthood, resulting in quasi-permanent adaptations that can make it nearly impossible to learn certain skills or process certain stimulus properties later on in life. This chapter begins with a brief introduction to experience-dependent plasticity throughout the lifespan (Section Introduction). Next, we define what constitutes a CP (Section What Are Critical Periods?) and review some of the key CPs in the visual and auditory systems (Section Key Critical Periods of Sensory Systems). We then discuss the mechanisms whereby cortical plasticity is regulated both locally and through neuromodulatory systems (Section How Are Critical Periods Regulated?). Finally, we highlight studies showing that CPs can be extended beyond their normal epochs, closed prematurely, or reopened during adult life by merely altering sensory inputs (Section Timing of Critical Periods: Can CP Plasticity Be Extended, Limited, or Reactivated?).

Comparison of contrast sensitivity based on the surgical results for intermittent exotropia

AIM

To compare contrast sensitivity (CS) based on the surgical results for intermittent exotropia (IXT) and to examine the relationship between CS and photophobia.

METHODS

Medical records of the patients who underwent bilateral lateral rectus muscle recession for IXT between 4 and 12 years old were reviewed retrospectively. They were categorized based on the surgical results; successful correction group (n=36) and overcorrection group (esotropia ≥10 PD at 3mo postoperatively, n=18). Using CGT-2000 test for CS was performed binocularly, and subjective reports of photophobia was investigated preoperatively and at 3mo postoperatively. Objective photophobia was defined as a significant decrease in CS in the presence of glare.

RESULTS

Preoperatively, there was no difference in CS between the groups. Postoperatively, under mesopic conditions, significant improvement of CS was observed at 6.3°, 4°, and 2.5° in the successful correction group and at 6.3° and 4° in the overcorrection group, regardless of glare. Under photopic conditions, at all visual angles except 0.64°, improvement in CS was noted in both groups while CS worsened significantly at 0.64° in the overcorrection group postoperatively. At all visual angles under photopic conditions postoperatively, regardless of glare, CS in the overcorrected group was significantly worse than that in the successful correction group, and CS was significantly decreased by addition of glare in both groups. All patients except one (96.4%) in the successful correction group and 8 patients (61.5%) in overcorrection group showed improvement of photophobia postoperatively, which correlated with CS under photopic conditions (P=0.001, 0.03).

CONCLUSION

After surgery for IXT, CS under photopic conditions improve at all visual angles except 0.64°, while CS is significantly worse in the overcorrection group postoperatively at 0.64°. Subjective photophobia have significant correlation with CS under photopic conditions, and may be used as an objective indicator of photophobia.

Relation between preoperative hyperopia and surgical outcome in infantile esotropia

AIM

To evaluate the relation between preoperative hyperopia and surgical outcomes of infantile esotropia in patients younger than 24 months of age.

METHODS

Medical records of patients who underwent bilateral medial rectus muscle recession for infantile esotropia between November 1, 2002 and December 1, 2011 were retrospectively reviewed. Patients were divided into two groups according to the degree of preoperative hyperopia. Group I had less than +3.0 diopter (D) of hyperopia and group II had between +3.0 and +5.0 D of hyperopia. Postoperative alignments were evaluated 1wk, 3, 6mo, and 1y after surgery. Following the 1-year postoperative visit, patients were monitored yearly. Relationships between preoperative factors including hyperopia and postoperative outcomes were evaluated.

RESULTS

Forty-six patients were included, with 33 patients in group I and 13 patients in group II. The preoperative mean refractive error was +0.88 D in group I and +3.45 D in group II. Surgical outcomes were not significantly different between groups at any postoperative time point examined. Cumulative probability of surgical success, prevalence of inferior oblique overaction, dissociated vertical deviation, and re-operation rate were not significantly different between groups.

CONCLUSION

Preoperative moderate hyperopia (less than +5.0 D) did not affect the surgical outcome of infantile esotropia. Therefore, the surgical correction of esotropia should be considered when the angle of esodeviation is unchanged following hyperopia correction, even in children with moderate hyperopia.

The Functional Benefits of Strabismus Surgery

When performed prior to visual maturity, strabismus surgery can result in the development or recovery of binocularity. When strabismus surgery is performed after visual maturity, the functional benefits of the surgery should be dichotomized according to whether the onset of the strabismus was before or after visual maturity. If the onset was after visual maturity, patients typically are diplopic. Specific success rates for eliminating diplopia vary according to the nature of the strabismus; however, overall the success rate is quite high. There is a common misperception that surgery in adults for strabismus that began prior to visual maturity is merely cosmetic. Numerous studies contradict this misconception. Even if the strabismus has been longstanding, most adults will experience some improvement in binocular function after strabismus surgery. In esotropic patients, this improvement typically takes the form of an expansion of binocular visual fields; however, some patients may also regain stereopsis. There are many psychosocial benefits to adult strabismus surgery. This is reflected in the finding that the majority of adults surveyed with strabismus would trade a portion of their life expectancy to be rid of their strabismus.

Outcome of early surgery in infantile esotropia: Our experience in tertiary care hospital

BACKGROUND

Infantile esotropia is a convergent strabismus presenting before 6 months of age and is the most common strabismus disorder presenting in the ophthalmology OPD. The dilemma of whether to go for early surgery and how early has been a matter of research for the last 50 years. We describe our results of surgery in infantile esotropia at variable age groups, as well as with different reoperation rates and compare with the results in western literature.

METHODS

A prospective study was carried out through a review of 113 cases operated for infantile esotropia between February 2013 and August 2014. The variables studied were: age at surgery, type of fixation, refractive error, associated nystagmus, inferior oblique overaction or dissociated vertical deviation (DVD), type of surgery performed and pre- and postoperative deviation angles.

RESULTS

There were 67 male and 46 female cases of infantile esotropia. The age group of patients varied from 6 months to 12 years. Latent nystagmus was seen in 22 cases, inferior oblique overaction in 49 cases and DVD (mild) in 14 cases. Bimedial rectus recession was done in 78 cases and recession-resection in non-dominant eye in remaining 35 cases. The postoperative residual deviation was <10 PD in 102 cases, between 10 and 16 PD in 5 cases and more than 16 PD in 6 cases. Only 6 cases (5.3%) required reoperation for correction of residual deviation.

CONCLUSION

The authors recommend surgery before 12 months in all cases of infantile esotropia. The reoperation rates in the current study were considerably low.

Long-Term Changes in Refractive Error and Clinical Evaluation in Partially Accommodative Esotropia after Surgery

We investigate the changes in refractive error and clinical evaluation in partially accommodative esotropia(PAET) after surgery. A total of 68 patients PAET who received at least 2 years of follow-up after surgery were enrolled in this study. We performed a retrospective study in patients who underwent unilateral or bilateral medial rectus recession for a non-accommodative component of PAET between January 2005 and March 2013. Patients were divided into groups according to the presence of dominancy (dominant, non-dominant, alternative eye), and presence of amblyopia (amblyopic, fellow, normal eye). Changes and changing pattern in SE refractive error were analyzed in all patients and compared between groups. Patients were divided into two groups, those weaned off of hyperopic glasses and those who continued using them, then factors that significantly influenced the continued use of glasses were analyzed. The changes and changing pattern in SE refractive error according to time after operation and presence of amblyopia or dominancy. The mean length of follow-up was 4.89±1.74 years after surgery and the mean change in SE refractive error rate per year was -0.284±0.411 diopters (D). The pattern of changes in the mean SE refractive error for those with dominant, non-dominant, and alternative eyes was not significantly different (p = 0.292). The pattern of changes in the mean SE refractive error for those with amblyopic, fellow, and normal eyes was significantly different (p = 0.0002). Patients were successfully weaned off of hyperopic glasses at an average age of 9.41±2.74 years. The average SE refractive error in the group weaned off of hyperopic glasses was significantly lower than that in the group maintained on hyperopic glasses (p = 0.0002). The change of SE refractive error in amblyopic eyes decreased less than that in fellow or normal eyes, which may be correlated with the presence of amblyopia. Patients with a smaller esodeviated angle without hyperopic correction, a lower degree of hyperopia, and who were older at the time of disease onset were discontinued from hyperopic glasses sooner after surgery.

Essential Infantile Esotropia: Postoperative Sensory Outcomes of Strabismus Surgery

BACKGROUND

The optimum age for Essential Infantile Esotropia surgery is a controversial subject. Sensory status was evaluated in patients who underwent surgery at different ages in a retrospective study. The setting of the study is the ophthalmology department of a teaching hospital.

METHODS

Different clinical characters were analyzed pre- and postoperatively; nine different surgeries were performed. A total of 188 patients presented valid postoperative sensorial data, divided in two groups: surgery at ≤2 years (n=69) or >2 years (n=119). Sensory status was dichotomized in binocular single vision (BSV) and exclusion. Univariate differences were assessed with the chi-square test (or Fisher exact test). To identify the independent role of factors associated with the sensory status, all variables showing in univariate analyses a significant association (p<0.05) with the outcome variable were entered into a multivariate logistic regression model. All statistical tests were two-sided.

RESULTS

Multivariate analysis confirmed that children operated >2 years were 0.4 times less likely to obtain BSV compared with children operated at ≤2 years (AOR. 0.38, 95% C.I. 0.17-0.89, p=0.025). Patients operated on by OO MR rec.+ OO LR res. + OO IO rec.-ap. (intervention type 6) were about 11 times more likely to have BSV than those by OO rec.MR + unilateral res. LR (operation type 2); AOR.: 10.67, 95% C.I.: 1.34 - 85.29, p=0.026). Twenty-nine patients (12.1%) operated at ≤2 years of age underwent a reoperation, compared to 33 (8.6%) who underwent surgery after two years (p>0.05).

CONCLUSIONS

Our findings suggest to perform EIE surgery between age 1 and 2 and, when indicated, to prefer a six-muscle approach in order to achieve a better sensory function.

Management of infantile esotropia

PURPOSE OF REVIEW

Surgical treatment has been the accepted mode of treatment for infantile esotropia for decades. The present review of recent literature evaluates the current standing of: type of surgery performed and best timing of surgery to achieve optimal results.

RECENT FINDINGS

Recent studies suggest that early surgical intervention is of benefit by improving the probability of developing stereopsis. A significant advantage of the type of surgical intervention has yet to be demonstrated by the current studies. Botulinum toxin continues to be used for treatment of infantile esotropia, although it has not been shown to be a superior treatment.

SUMMARY

Although many theories exist, the true cause of infantile esotropia remains unknown. The literature suggests that treatment before age 2 and perhaps even earlier improves the potential for binocular vision. After significant review of literature, it is clear that surgery is the treatment of choice for infantile esotropia but no method has a clear advantage. Efforts to define the best surgical procedure and timing of surgery through prospective, randomized multicenter trials are warranted.

Strabismus surgery for children with developmental delay

PURPOSE OF REVIEW

To describe recent evidence regarding the surgical approach of strabismus in children with various forms of developmental delay.

RECENT FINDINGS

There remains variability in surgical outcomes with or without dose adjustment in strabismus surgery for children with developmental delay. However, this should not deter one from performing surgery - even early surgery, as fusional potential remains possible, which can especially impact the quality of vision and quality of life in developmentally delayed children.Future prospective, comparative, long-term studies with larger sample sizes for strabismus surgery in children with developmental delay are still needed.

SUMMARY

Strabismus is one of the most common ophthalmologic findings in children with developmental delay. Surgical correction of strabismus in children with developmental delay is well tolerated and effective, although it remains slightly less predictable, which can depend on the specific type of delay or underlying neurological deficit. Careful consideration of types and severity of developmental delay and attempts to measure binocular potential can help guide the timing, dosage, and type of treatment.Reoperations tend to be more frequently encountered in this population, and this higher degree of variability should be addressed in the consent process.Considering adjusting the surgical dosage in this population, taking careful preoperative measurements, and checking for fusional potential should be taken into account when managing children with developmental delay.

The relationship of age when motor alignment is achieved and the subsequent development of stereopsis in infantile esotropia

PURPOSE

To determine the oldest age beyond which the chance of developing stereopsis is not possible even with excellent motor alignment in patients with infantile esotropia.

METHODS

The medical records of children with infantile esotropia who underwent a single operation and had alignment within 10(Δ) of orthotropia at all follow-up examinations were retrospectively reviewed. Patients were assessed for stereopsis after the age of 48 months.

RESULTS

A total of 38 children were included. There was a statistically significant inverse correlation between age at surgery and final stereopsis (r = 0.494, P = 0.002). There was a significant difference at mean age at surgery between patients having stereopsis better than 1000 arcsec and those having no stereopsis (P = 0.002). Post hoc power analysis revealed a value of 85%. Receiver operating characteristic curve analysis revealed that the optimum cut-off value of the age at surgery for predicting stereopsis was 16 months (Youden index = 0.474; area under ROC curve, 0.784; 95% CI: 0.62-0.90; P = 0.0002).

CONCLUSIONS

Surgery for infantile esotropia is most likely to result in measureable stereopsis if patient age at alignment is not more than 16 months.

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

The objective of this review was to assess the effectiveness of various surgical and non-surgical interventions for IE and to determine the significance of age at treatment with respect to outcome.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to June 2013), EMBASE (January 1980 to June 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to June 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 June 2013. We manually searched the conference proceedings of the European Strabismological Association (ESA) (1975 to 1997, 1999 to 2002), International Strabismological Association (ISA) (1994) and American Academy of Paediatric Ophthalmology and Strabismus meeting (AAPOS) (1995 to 2003). Efforts were made to contact researchers who are active in the field for information about further published or unpublished studies.

SELECTION CRITERIA

We included randomised trials comparing any surgical or non-surgical intervention for infantile esotropia.

DATA COLLECTION AND ANALYSIS

Each review author independently assessed study abstracts identified from the electronic and manual searches.

MAIN RESULTS

No studies were found that met our selection criteria and therefore none were included for analysis.

AUTHORS' CONCLUSIONS

The main body of literature on interventions for IE are either retrospective studies or prospective cohort studies. It has not been possible through this review to resolve the controversies regarding type of surgery, non-surgical intervention and age of intervention. There is clearly a need for good quality trials to be conducted in these areas to improve the evidence base for the management of IE.

Decorrelation of cerebral visual inputs as the sufficient cause of infantile esotropia

BACKGROUND AND PURPOSE

Human infants at greatest risk for esotropia are those who suffer cerebral insults that could decorrelate signals from the two eyes during an early critical period of binocular, visuomotor development. The authors reared normal infant monkeys under conditions of binocular decorrelation to determine if this alone was sufficient to cause esotropia, and associated behavioral as well as neuroanatomic deficits.

METHODS

Binocular decorrelation was imposed using prism-goggles for durations of 3-24 weeks (control monkeys wore plano goggles), emulating unrepaired strabismus of durations 3 months to 2 years in human infants. Behavioral recordings were obtained, followed by neuroanatomic analysis of ocular dominance columns and binocular, horizontal connections in the striate visual cortex (area V1).

RESULTS

Concomitant, constant esotropia developed in each monkey exposed to decorrelation for a duration of 6-24 weeks. The severity of ocular motor signs (esotropia angle; dissociated vertical deviation; latent nystagmus; pursuit / optokinetic tracking asymmetry; fusional vergence deficits), and the loss of V1 binocular connections increased as a function of decorrelation duration. Stereopsis was deficient and motion visually evoked potentials were asymmetric. Monkeys exposed to decorrelation for 3 weeks showed transient esotropia, but regained normal alignment, visuomotor behaviors, and binocular V1 connections.

CONCLUSIONS

Binocular decorrelation is a sufficient cause of infantile esotropia when imposed during a critical period of visuomotor development. The systematic relationship between severity of visuomotor signs and severity of V1 connectivity deficits provides a neuroanatomic mechanism for these signs. Restoration of binocular fusion and V1 connections after short durations of decorrelation helps explain the benefits of early strabismus repair in humans.

Outcome of surgery in long-standing infantile esotropia with cross fixation

BACKGROUND

This is a retrospective study to determine the outcomes of the surgical correction in long-standing infantile esotropia with cross fixation.

METHODS

Medical charts of a group of patients with esotropia who had cross fixation and underwent surgery for strabismus between January 1991 and December 2004 were reviewed. The mean follow-up time was 4.7 years. Binocularity was measured by the Worth 4-dot test and Titmus stereo test. Twenty-six patients underwent surgery for strabismus. Twenty-one patients aged 8 to 26 years with a minimum 3-year postoperative follow-up were included. Five patients were excluded because they were lost to follow-up after surgery.

RESULTS

Bimedial recession and resection of one lateral rectus muscle were performed in all patients. Recession of the inferior oblique muscle with anteriorization was performed in patients who had inferior oblique overaction. Orthotropia was attained in 14 patients, whereas residual esotropia was diagnosed in 5 patients. Two patients were diagnosed as having exotropia. Two patients required a second surgery for dissociated vertical deviation. Overall, 9 of the 21 patients had indications of binocular function and 12 remained the same in their stereoacuity.

CONCLUSION

Surgical correction of long-standing infantile esotropia with cross fixation in young adults may improve binocular function and allow long-term alignment stability.

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.

Instability of ocular alignment in childhood esotropia

OBJECTIVE

Instability of ocular alignment may cause surgeons to delay surgical correction of childhood esotropia. The authors investigated the stability of ocular alignment over 18 weeks in children with infantile esotropia (IET), acquired nonaccommodative esotropia (ANAET), or acquired partially accommodative esotropia (APAET).

DESIGN

Prospective, observational study.

PARTICIPANTS

Two hundred thirty-three children aged 2 months to less than 5 years with IET, ANAET, or APAET of less than 6 months' duration.

METHODS

Ocular alignment was measured at baseline and at 6-week intervals for 18 weeks.

MAIN OUTCOME MEASURES

Using definitions derived from a nested test-retest study and computer simulation modeling, ocular alignment was classified as unstable if there was a change of 15 prism diopters (PD) or more between any 2 of the 4 measurements, as stable if all 4 measurements were within 5 PD or less of one another, or as uncertain if neither criteria was met.

RESULTS

Of those who completed all 3 follow-up visits within time windows for analysis, 27 (46%) of 59 subjects with IET had ocular alignment classified as unstable (95% confidence interval [CI], 33%-59%), 20% as stable (95% CI, 11%-33%), and 34% as uncertain (95% CI, 22%-47%). Thirteen (22%) of 60 subjects with ANAET had ocular alignment classified as unstable (95% CI, 12%-34%), 37% as stable (95% CI, 25%-50%), and 42% as uncertain (95% CI, 29%-55%). Six (15%) of 41 subjects with APAET had ocular alignment classified as unstable (95% CI, 6%-29%), 39% as stable (95% CI, 24%-56%), and 46% as uncertain (95% CI, 31%-63%). For IET, subjects who were older at presentation were less likely to have unstable angles than subjects who were younger at presentation (risk ratio for unstable vs stable per additional month of age, 0.85; 99% CI, 0.74-0.99).

CONCLUSIONS

Ocular alignment instability is common in children with IET, ANAET, and APAET. The impact of this finding on the optimal timing for strabismus surgery in childhood esotropia awaits further study.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Duration of binocular decorrelation in infancy predicts the severity of nasotemporal pursuit asymmetries in strabismic macaque monkeys

PURPOSE

Strabismus in human infants is linked strongly to nasotemporal asymmetries of smooth pursuit, but many features of this co-morbidity are unknown. The purpose of this study was to determine how the duration of early-onset strabismus (or timeliness of repair) affects the severity of pursuit asymmetries in a primate model.

METHODS

Binocular image decorrelation was imposed on infant macaques by fitting them with prism goggles on day 1 of life. The goggles were removed after 3 weeks (n=2), 12 weeks (n=2) or 24 weeks (n=3), emulating surgical repair of strabismus in humans at 3, 12, and 24 months of age, respectively. Two control monkeys wore plano lenses. Several months after the goggles were removed, horizontal smooth pursuit was recorded using binocular search coils and a nasal-bias index (NBI) was calculated.

RESULTS

Each animal in the 12- and 24-week groups developed a constant, alternating esotropic strabismus and a nasotemporal asymmetry of pursuit when viewing with either eye. Spatial vision was normal (no amblyopia). The 3-week duration monkeys were indistinguishable from control animals; they had normal eye alignment and symmetric pursuit. In the 12- and 24-week monkeys, the longer the duration of binocular decorrelation, the greater the pursuit asymmetry: for 15 degrees /s target motion, the NBI in the 12-week and 24-week animals was 16x and 22x greater respectively, than that in the 3-week animals (ANOVA, P=0.03).

CONCLUSIONS

Binocular decorrelation in primates during an early period of fusion development causes permanent smooth pursuit asymmetries when the duration exceeds the equivalent of 3 months in human. These findings support the conclusion that early correction of infantile strabismus promotes normal development of cerebral gaze pathways.

Improvement in motor development following surgery for infantile esotropia

PURPOSE

Infantile esotropia is associated with abnormal visual development and thus may delay the achievement of developmental milestones. Although early surgery can improve visual function, less is known about its effect on motor development. Here we address whether early surgery can improve motor development.

METHODS

Recently, our lab devised the Infant Developmental Skills Survey, a 25-item questionnaire designed to assess sensorimotor and gross motor development. The questionnaire was completed by the parents of 3- to 10-month-old patients with infantile esotropia prior to surgery (n = 143) and the parents of 6- to 11-month-old patients following surgery (n = 58). A subset of parents (n = 40) completed the questionnaire both before and after surgery. For comparison, the questionnaire was completed by the parents of infants with normal ocular alignment (n = 194).

RESULTS

Before surgery 4-, 5-, 6-, 7-, 9-, and 10-month-old patients showed delayed achievement of sensorimotor milestones (p < 0.01), and 5-, 9-, and 10-month-old patients demonstrated delayed attainment of gross motor milestones (p < 0.05) compared with normal children. However, following surgery, patients demonstrated a greater rate of sensorimotor development than age-matched controls (p < 0.0001) and caught up with normal children on both sensorimotor and gross motor skills.

CONCLUSIONS

Prior to surgery, patients with infantile esotropia were delayed in their achievement of developmental milestones. However, following surgery, a comparison group of patients showed rapid development and possessed motor skills comparable to those of normal children, suggesting that early surgery is beneficial to both visual and motor development.

Effect of preoperative stability of alignment on outcome of strabismus surgery for infantile esotropia

INTRODUCTION

Some strabismus surgeons wait until the angle of deviation stabilizes prior to operating on patients with infantile esotropia. This study evaluated whether a preoperative increase in the angle of deviation affected surgical outcomes.

METHODS

This was a retrospective comparative case series in which records of patients with infantile esotropia, who had surgery performed before age 2 years and who were followed for at least 2 years postoperatively, were reviewed to identify two groups for comparison: the first had </=5(Delta) change in the angle of deviation between the first office visit and time of surgery; the second had a >/=10(Delta) increase in the angle of deviation prior to surgery. In the latter group, surgery was performed for the angle present at the time of surgery. Outcomes were considered successful if the patients had microtropias.

RESULTS

Fifteen patients were identified in each group. The interval between the first office visit and time of surgery was the same in both groups (mean, 2 months). Outcomes were successful in 11 of 15 (73%) in each group (no significant difference, p = 0.659).

CONCLUSIONS

There was no difference in outcome between children whose angles of deviation were stable and those whose angles increased prior to surgery. This indicates that strabismus surgery does not need to be delayed while waiting for the angle of deviation to stabilize. Surgical correction may therefore be achieved at an earlier age, which may have a beneficial effect on outcome.

Long-term motor and sensory outcomes after early surgery for infantile esotropia

PURPOSE

The proper timing of surgery for infantile esotropia remains controversial. Early surgery may yield better sensory outcomes whereas later surgery may result in better alignment. Several recent studies reported promising sensory outcomes in small groups of children that underwent surgery by 6 months of age. Here, we present motor and sensory outcomes of a cohort of 50 consecutive children enrolled in a prospective study who had surgery by 6 months of age and were followed for 4-17 years.

METHODS

Angle of deviation, subsequent surgeries, treatment with spectacles, amblyopia, fusion, and stereopsis were evaluated during follow-up. Outcomes from the early surgery group were compared with a concurrently recruited cohort who had surgery at 7-12 months (n=78).

RESULTS

On the initial visit, both cohorts had the same median angle of deviation (45(Delta)) and similar refractive error; the median angle of deviation increased by the final preop visit (55(Delta)). Postoperatively, both cohorts had alignment within 6(Delta) in 83-94% of cases on all visits. Both cohorts had similar rates of additional surgery, and 44-48% wore hyperopic correction postoperatively. Compared with the 7- to 12-month cohort, more children in the early-surgery cohort had peripheral fusion (78% vs 61%; p < 0.02), central fusion (15% vs 2%; p < 0.01), Randot stereopsis (38% vs 16%; p < 0.003), and Randot stereoacuity of 200 seconds or better (20% vs 9%; p < 0.05).

CONCLUSIONS

Early surgery was associated with a higher prevalence of fusion and stereopsis, without adverse motor outcomes.

Final report of the early vs. late infantile strabismus surgery study (ELISSS), a controlled, prospective, multicenter study

BACKGROUND

The optimal age for surgery for infantile esotropia is controversial. Proponents of early surgery believe that further loss of binocular vision can be prevented by early surgery, a minority believes that binocular vision can even be restored by early surgery. The ELISSS compared early with late surgery in a prospective, controlled, non-randomized, multicenter trial.

METHODS

Fifty-eight clinics recruited children aged 6-18 months for the study. Each clinic operated all eligible children either 'early', i.e. at age 6-24 months, or 'late', i.e. at age 32-60 months. At baseline the angle of strabismus, refraction, degree of amblyopia and limitation of abduction were assessed. Intermediate examinations took place every six months. Children were evaluated at age six in the presence of independent observers. Primary endpoints were (i) level of binocular vision, (ii) manifest angle of strabismus at distance and (iii) remaining amblyopia. Secondary endpoints were number of operations, vertical strabismus, angle at near and the influence of surgical technique.

RESULTS

A total of 231 children were recruited for early and 301 for late surgery. Age at entry examination was 11.1 months (SD 3.7 months) in the early group and 10.9 (SD 3.7) months in the late group. Refraction, amblyopia and limitation of abduction were distributed equally in the early and late groups, but the angle of strabismus was slightly larger in the early group. Dropout-rates were 26.0% in the early and 22.3% in the late group. At age six, 13.5% of the early vs. 3.9% of the late group recognized the Titmus Housefly; 3.0% of the early and 3.9% of the late group had stereopsis beyond Titmus Housefly. No significant difference was found for angle of strabismus. 35.1% of the early group and 34.8% of the late group did not have an angle between 0 degrees and 10 degrees , the thresholds set for re-operation. For ratio of the visual acuities (remaining amblyopia) there was a small but significant advantage for the early group. There was hardly any correlation between the baseline parameters and the primary endpoints. Children scheduled for early surgery had first been operated at 20 (SD 8.4) months, but 8.2% had not been operated at age six. Children scheduled for late surgery had been operated at 49.1 (SD 12.7) months, but 20.1% had not been operated at age six. The number of operations per child was 1.18 (SD 0.67) in the early and 0.99 (SD 0.64) in the late group. Age at recruitment, age that strabismus reportedly had started and refraction at entry examination were similar among operated and non-operated children. Only the angle of strabismus at entry predicted, to some extent, whether a child had been operated at age six.

DISCUSSION

Children operated early had better gross stereopsis at age six as compared to children operated late. They had been operated more frequently, however, and a substantial number of children in both groups had not been operated at all.

Twenty years after childhood strabismus surgery

INTRODUCTION

Children with infantile or acquired esotropia often have surgery in the first few years of life. Many of these children have additional surgeries and may also be treated for amblyopia. As pediatric ophthalmologists, we do not often have the opportunity to learn the affect of this strabismus on their life as they have become adults, completed their education and chosen a career and during this time, what has happened to their eye alignment.

METHODS

The charts for all children having had surgery for esotropia by the author from 1977 to 1984 were obtained and attempts were made to contact the patients. Five hundred thirty-one charts were identified, 131 contacts were successfully made, and 37 patients were examined.

RESULTS

Seventy-eight percent of the infantile esotropia patients did not change their alignment from the last regular office visit and 90% of the acquired esotropia patients continued their good alignment an average of twenty-four years following surgery. Patients treated for amblyopia maintained their treated best corrected vision. Most patients did not feel their "corrected" childhood strabismus affected their school or social accomplishments, and most felt they were good readers.

CONCLUSION

Children with "corrected" childhood strabismus tend to maintain this into adult life and it does not affect school performance or their career choice.

Decision analysis with Markov processes supports early surgery for large-angle infantile esotropia

PURPOSE

To assess tradeoffs in time spent with aligned visual axes or stereopsis and risked reoperations between three strategies for the treatment of large-angle infantile esotropia: first surgery at 6, 24, or 48 months of age.

DESIGN

Decision analysis.

METHODS

We simulated three hypothetic cohorts of children with this condition until their eighth year. Potential achievement of stereopsis, the diagnosis of dissociated vertical divergence or inferior oblique overaction, and various complications were modeled. Probability estimates were obtained from a comprehensive literature review. Analyses aimed to determine the strategy that was associated with longer time spent with aligned eyes and/or stereopsis and fewer reoperations.

RESULTS

Eight-year-old children are expected to spend 72.6 vs 58.0 vs 37.8 months with aligned eyes and 26.8 vs 9.0 vs 1.5 months with stereopsis and to receive on average 1.76 vs 1.67 vs 1.46 surgeries, if they first underwent operation at 6 vs 24 vs 48 months, respectively. Children at 8 years are expected to have stereopsis at the rate of 36.1% vs 17.2% vs 5.1%, respectively. Operation at 6 months instead of 48 months is expected to yield an additional 9% of total follow-up time in health states with eye alignment and 11% in health states with stereopsis, per 5% increase in risk for extra operations (5% and 7%, respectively, per 5% increase in risk for operation at 6 vs 24 months). Wide-range sensitivity analyses and long-term projections point to the same direction.

CONCLUSION

Given the benefit/risk tradeoffs, it is probably warranted to attempt to correct large-angle infantile esotropia as early as possible.

[Infantile esotropia: comparison of surgery results when the intervention takes place before or after 30 months of age]

OBJECTIVE

Present and compare surgery results of children with congenital or infantile esotropia, who had surgery before or after 30 months of age, in the Rouen Department of Ophthalmology between 1996 and 2000.

PATIENTS AND METHODS

A retrospective study included 37 patients, 23 females and 14 males, 19 in the first group who had surgery before 30 months at an average age of 24 months (15-30) and 18 in the second group who had surgery after 30 months at an average age of 56 months (38-81). Hypermetropia was found up to 2 diopters for 14 of 19 patients in the first group and 13 of 18 in the second. We noted the surgical procedure. We compared pre- and postoperative amblyopia as well as pre- and postoperative objective deviations at near and distance ranges. The exclusion criteria were follow-up for less than 3 months, esotropia emergence after 12 months of age, children aged more than 7 years at the first surgery, and children with central nervous system disorders. Finally, esthetic aspect, postoperative distance and near sensory results were evaluated. Success was defined by orthotropic position, esotropia less than 15 prism diopters, or consecutive exotropia less than 10 prism diopters.

RESULTS

The mean follow-up after surgery was 30 months (3-56) for the first group and 28 months (3-67) for the second. Motor results were similar between the two groups: we found 10 out of 19 successes (esotropia (E(T)) less than 15 diopters (D) or exotropia (X(T)) less than 10 D) in the first group, and 15 out of 18 successes in the second group. There were 3 out of 19 failures (E(T) more than 20 D or X(T) more than 15 D) in the first group and 3 out of 18 in the second. Hypermetropia and preoperative deviation were not significantly different for good or bad motor results (p<0.05). A second-step surgery was performed for two children in the first group and three in the second group, and one of the three children of the second group had a third step. Sensory results were very similar with 6 of 19 cases achieving binocular union in the first group and 7 of 18 in the second one. Finally, one patient from each group presented amblyopia after surgery.

CONCLUSION

In our study, as in the literature, infantile esotropia surgery can result in excellent motor alignment, while sensory results are not as good. It appears in our study that there is no significant advantage in performing surgery before 30 months for infantile esotropia. The follow-up of our patients may have been insufficient, and our definition of the semi-early surgery (before 30 months) was already too late in comparison with other studies (less than 24 months).

Interventions for infantile esotropia

BACKGROUND

Various aspects of the clinical management of infantile esotropia (IE) are unclear - mainly, the most effective type of intervention and the age at intervention.

OBJECTIVES

The objective of this review was to assess the effectiveness of various surgical and non-surgical interventions for IE and to determine the significance of age at treatment with respect to outcome.

SEARCH STRATEGY

Trials were identified from the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) in The Cochrane Library (Issue 3 2004), MEDLINE (1966 to July 2004), EMBASE (1980 to August 2004) and LILACS (July 2004). We manually searched the conference proceedings of the European Strabismological Association (ESA) (1975-1997, 1999-2002), International Strabismological Association (ISA) (1994) and American Academy of Paediatric Ophthalmology and Strabismus meeting (AAPOS) (1995-2003). Efforts were made to contact researchers who are active in the field for information about further published or unpublished studies.

SELECTION CRITERIA

Randomised trials comparing any surgical or non-surgical intervention for infantile esotropia.

DATA COLLECTION AND ANALYSIS

Each reviewer independently assessed study abstracts identified from the electronic and manual searches.

MAIN RESULTS

No studies were found that met our selection criteria and therefore none were included for analysis.

AUTHORS' CONCLUSIONS

The main body of literature on interventions for IE are either retrospective studies or prospective cohort studies. It has not been possible through this review to resolve the controversies regarding type of surgery, non-surgical intervention and age of intervention. There is clearly a need for good quality trials to be conducted in these areas to improve the evidence base for the management of IE.

Pre-operative stability of infantile esotropia and post-operative outcome

PURPOSE

To define the prevalence and time course of significant changes in angle of deviation during the first months after the diagnosis of infantile esotropia and to determine whether long-term alignment and sensory outcomes differ when surgical alignment is performed on infants with stable vs unstable angles of deviation.

DESIGN

Prospective cohort study.

METHODS

setting: Institutional and clinical practice. patient population: Newly diagnosed patients with infantile esotropia (N = 208). observation procedure: Preoperative measurements of the angle of deviation on the initial visit and at approximate six-week intervals until surgery was performed. main outcome measures: Ocular alignment at six weeks, one year, and four years postoperative and stereoacuity at age five to nine years.

RESULTS

Overall, 57% of infants had an esodeviation on the second visit that was within 10 prism diopters (p.d.) of the deviation measured on the initial visit (stable group), 33% had an increase of 10 p.d. or more (unstable group), and 11% had a decrease of 10 p.d. or more. Among the 127 patients with additional preoperative visits, many switched between the stable and unstable categories during follow-up. Long-term, stable and unstable preoperative alignment groups had similar postoperative motor alignment, re-operation rates, rates of prescription of hyperopic, or bifocal spectacle correction and stereoacuity.

CONCLUSIONS

It may not be necessary to wait for a "stable" angle of esodeviation before surgery since both alignment and sensory outcomes were similar for stable and unstable groups.

Long-term results of bilateral medial rectus recession for congenital esotropia

PURPOSE

This study assessed the long-term results of orthophoria obtained with bilateral medial rectus recession for congenital esotropia.

PATIENTS AND METHODS

The medical records of 214 patients who underwent bilateral medial rectus muscle recession between January 1995 and January 2000 were reviewed. Patients were excluded if neurological abnormalities or developmental delays were documented and if structural eye abnormalities were present. Mean follow up was 54.2 months (range, 36 to 96 months). Rates of reoperation for residual esotropia, consecutive exotropia, oblique muscle overaction, or dissociated vertical deviation were determined.

RESULTS

Forty-five (21%) patients underwent surgery for residual esotropia, 32 (15%) underwent surgery for consecutive exotropia or dissociated horizontal deviation, and 39 (18%) underwent surgery for oblique muscle overaction and dissociated vertical deviation.

CONCLUSION

To maintain long-term alignment of congenital esotropia, additional surgical procedures may be required. The success rate of bilateral medial rectus recession for ocular realignment with one operation is approximately 50%. This method is quicker, simpler, and less traumatic than three or four muscle operations. In addition, the lateral rectus and oblique muscle are left unoperated for future surgeries if necessary.

Surgery and botulinum toxin in congenital esotropia

BACKGROUND

In a previous study we investigated the advantages and drawbacks of early and delayed injection of botulinum toxin as primary treatment of infantile esotropia with nystagmus in abduction (IENA). We carried out a further study to investigate the role and efficacy of surgery in this condition and to determine the possible effect of previous injection of both medial recti with botulinum toxin in patients requiring a final horizontal surgical correction.

METHODS

Review of the records of 44 patients (24 girls and 20 boys) with IENA seen between 1979 and 1998 who had undergone at least one horizontal surgical procedure. The outcomes in the 16 patients who had previously received botulinum toxin were compared with those in the 28 patients for whom surgery was the primary treatment.

RESULTS

There was a negative correlation between the pretreatment esotropic angle and age (Pearson's r = -0.45, p < 0.05). The first visit to a surgical specialist took place very late (mean age 43 months [standard deviation (SD) 39 months]). Of the 35 children seen during the period in which botulinum toxin was available, 20 (57%) had additional factors inducing unsteadiness of binocular vision (e.g., moderate to severe initial relative amblyopia, initial ametropia). Administration of 5 units of botulinum toxin before 18 months of age destabilized dissociated vertical deviation. Overall, 39 patients (89%) had a final residual deviation of less than 10 prism dioptres. The first surgical correction was horizontal and vertical-torsional in 30 patients (68%). A total of 23 patients (52%) required some retreatment (botulinum toxin or surgery or both). Children treated initially with botulinum toxin had less surgery than those with initial surgery (mean recession or resection 8.9 mm [SD 4.5 mm] vs. 14.2 mm [SD 4.0 mm]) as well as fewer horizontal muscles operated (mean 1.6 [SD 0.6] vs. 2.3 [SD 0.6]).

INTERPRETATION

Surgery with or without further interventions is a reasonable approach for IENA with delayed diagnosis and in cases associated with unsteadiness of binocular vision or with nonhorizontal deviations. Initial treatment with botulinum toxin, injected into both medial recti, is effective, reducing the amount of further horizontal surgery and favouring postoperative stability, except in children under 18 months, in whom injection of 5 units induces unbalanced dissociated vertical deviation.

La toxine botulique dans les ésotropies précoces

PURPOSE

To evaluate long term results of botulinum toxin in infantile esotropia.

METHODS

Nineteen infants between 6 and 13 Months of age were treated with botulinum toxin injected into the medial recti. The amount of deviation, the different symptoms of infantile esotropia, and the need for surgery were studied.

RESULTS

Esotropia reappears frequently with time. Dissociated vertical deviation and manifest/latent nystagmus are only partially improved. Surgery is usually mandatory over the long term.

CONCLUSION

Despite some good results, a single botulinum toxin injection is less effective than incisional surgery in treating the different symptoms of infantile esotropia.

Stereopsis and long-term stability of alignment in esotropia

PURPOSE

Recent studies of infantile and accommodative esotropia (ET) have focused on stereoacuity as a final outcome measurement for judging the success or failure of treatment. The purpose of the present study was to extend this approach by evaluating whether the presence of stereopsis developing immediately after surgical alignment or optical correction plays a role in maintenance of long-term alignment.

METHODS

Random-dot stereoacuity was assessed within 3 months of initial surgical alignment in 70 children with infantile ET and within 3 months of initial optical correction in 66 children with accommodative ET. At > or = 5 years of age, adverse outcomes were assessed including loss of alignment, amblyopia, and nil stereopsis. Risk-factor analysis was used to evaluate whether early nil stereopsis increased the risk for subsequent adverse outcomes.

RESULTS

In the infantile ET cohort, early nil stereopsis was associated with a 3.6 times (95% confidence interval [CI] 2.4 to 4.1) greater risk of surgery for recurrent ET or consecutive exotropia and a 4.2 times (95% CI 3.3 to 4.4) greater risk for nil stereopsis at > or = 5 years of age. In the accommodative ET cohort, early nil stereopsis was associated with a 17.4 times (95% CI 3.3 to 32.2) greater risk of surgery for ET and a 32.2 times (95% CI 15.8 to 35.6) greater risk for nil stereopsis at > or = 5 years of age.

CONCLUSION

Treatment protocols designed to optimize stereoacuity outcomes promote long-term stability of alignment.

Binocular visual function in congenital esotropia after bilateral medial rectus recession with loop suture

PURPOSE

Our aim was to evaluate the binocular visual function in congenital esotropia after bimedial rectus recession with loop suture and to address the factors that could take part in the attainment of binocular function.

SUBJECTS AND METHODS

Forty children with congenital esotropia who were operated on between 12 and 48 months of age were included in the study group. Postoperative follow-up ranged from 2 to 10 years. In order to determine the factors affecting the sensory results in congenital esotropia, we classified our patients into two groups according to their fusion status. We compared the preoperative and postoperative characteristics of patients in these two groups.

RESULTS

Twenty-one of 40 patients (52.5%) fused the Worth four-dot at near (Group 1), 19 patients (47.5%) did not (Group 2) at the final examination. No patient showed evidence of stereopsis. We found significant differences between these two groups in respect to the final angle of vertical deviation, the age at surgery, the presence of postoperative inferior oblique overaction, dissociated vertical deviation and abnormal head position. Correlation analysis revealed that early alignment of the eyes and the absence of postoperative vertical deviation were associated with increased incidence of achieving some degree of binocular vision.

CONCLUSION

In congenital esotropia, not all infants may have the potential for normal binocular function owing to yet unknown constitutional factors. We determined that achieving some degree of binocular function may be related to early alignment of the eyes. Additionally, close follow-up and precise treatment of the accompanying vertical deviation, especially inferior oblique overaction and dissociated vertical deviation, in a timely manner may enhance the attainment of binocular sensory function.

Outcome study of stereopsis in relation to duration of misalignment in congenital esotropia

PURPOSE

A recent outcome study of Randot stereopsis in congenital esotropia reported early surgical alignment is associated with a higher percentage of patients with stereopsis and a higher quality of stereopsis because early surgery minimized the duration of misalignment. We compared the Titmus stereopsis with the duration of misalignment and the age of alignment for a group of patients who were surgically aligned by 24 months of age.

METHODS

The data previously obtained in a study of 90 patients aligned by 2 years of age, examined in a masked, independent evaluation for binocularity was analyzed. The age of alignment and duration of misalignment was correlated with the percentage of patients with stereopsis and quality of the stereopsis result as determined by the Titmus vectograph overlay.

RESULTS

Patients aligned by 6 or 12 months of age or within 6 or 12 months of duration of misalignment did not differ in percentage with stereopsis. However, patients aligned after 12 months of age did show a decrease percentage with stereopsis (P <.05, power 0.8). The quality of the stereopsis that was established was similar for those aligned by 6 or 12 months (P >.05, power 0.8). The quality of stereopsis, however, was decreased for patients with duration of misalignment greater than 12 months (P <.001, power 0.8).

CONCLUSION

Alignment within 1 year of age or within 12 months of misalignment favorably affects the percentage of patients who develop stereopsis in the treatment of congenital esotropia. The quality of the stereopsis result is affected by the duration of the misalignment, rather, than the age of alignment per se.

Factors associated with horizontal reoperation in infantile esotropia

PURPOSE

Risk factors for requiring multiple surgeries in infantile esotropia remain unclear. We identified clinical and demographic factors associated with horizontal reoperation in this disease.

METHODS

A retrospective chart review of patients who underwent surgery from 1994-1997 was performed. Subjects were divided into 2 groups: those requiring only one operation and those requiring 2 or more operations to achieve orthotropia +/-10 PD.

RESULTS

In 149 patients, the overall horizontal reoperation rate was 34%. There were no statistically significant differences between the 2 groups with respect to mean age at first surgery, mean preoperative deviation, gender, prematurity, Medicaid coverage, parental age, family history of strabismus, or refractive error. The presence of nystagmus, oblique muscle dysfunction, dissociated vertical deviation (DVD), or a variable angle of esotropia was not associated with increased horizontal reoperation rate. There was a greater frequency of horizontal reoperation in patients with amblyopia, although not significant. Premature infants and infants with neurologic dysfunction had a lower incidence of horizontal reoperation, but also not significant. Deviations of less than 30 PD were associated with fewer horizontal reoperations (16% vs 31%, P =.047). Significantly more patients underwent horizontal reoperation when initial surgery was performed at less than or equal to 15 months of age (67% vs. 47%, P =.022).

CONCLUSIONS

Several factors thought to predispose to poor sensorimotor outcome (dissociated vertical deviation, oblique muscle dysfunction, and nystagmus) were not associated with an increased incidence of horizontal reoperation. Horizontal reoperation was less frequent in patients with angles less than 30 PD. Although some studies suggest that early surgical intervention in patients with infantile esotropia affords better sensory outcome, it may be associated with a higher horizontal reoperation rate.

The clinical spectrum of early-onset esotropia: experience of the Congenital Esotropia Observational Study

PURPOSE

To describe historical and presenting features of infants with the onset of esotropia in early infancy to provide a better understanding of the clinical spectrum of the disorder.

DESIGN

Prospective multicenter cohort study.

METHODS

Eligibility criteria included age at enrollment 4 to < 20 weeks and an esotropia at near measuring at least 20 prism diopters (pd). Historical information was elicited from the parent or guardian. The esotropia was measured at near and characterized as constant, variable, or intermittent.

RESULTS

175 infants were enrolled. Their average age at enrollment was 97 +/- 26 days. The esotropia was characterized as constant in 56% of the patients, variable in 25%, and intermittent in 19%. Forty-nine percent of the deviations were > or = 40 pd. Most of the larger angle deviations were constant whereas the majority of the smaller angle deviations were intermittent or variable. The majority of patients first seen after 12 weeks of age had constant deviations (65%), whereas the majority seen before 12 weeks of age had intermittent or variable deviations (57%). At enrollment, amblyopia was diagnosed in 19% of patients.

CONCLUSION

The clinical presentation of esotropia in early infancy shows more variation in the esotropia's size and character than has been previously appreciated. Only a minority of the infants who are diagnosed to have esotropia before 20 weeks of age have the commonly accepted profile for congenital esotropia of a large-angle constant deviation. Amblyopia frequently develops, so an evaluation for amblyopia should be an integral part of the examination of an infant with esotropia.

Spontaneous resolution of early-onset esotropia: experience of the Congenital Esotropia Observational Study

PURPOSE

To determine the probability of spontaneous resolution of esotropia with onset in early infancy.

DESIGN

Prospective multicenter cohort study.

METHODS

Eligibility criteria included age at enrollment 4 to < 20 weeks and an esotropia measuring at least 20 prism diopters (pd). The primary outcome measure was ocular alignment at 28 to 32 weeks of age. The esotropia was classified as resolved when there was a misalignment of 0 to 8 pd at the outcome examination either with or without spectacle correction.

RESULTS

Outcome data were available for 170 of the 175 enrolled patients. The esotropia was classified as resolved in 46 of the 170 patients (27%, 95% confidence interval = 21% to 34%). Most of the resolved cases had an intermittent or variable deviation at enrollment. Resolution occurred in only one of 42 cases that had a constant esotropia > or = 40 pd on both the baseline and first follow-up examination and had a refractive error < or = + 3.00 diopters. In another patient, who had an esotropia of 35 pd at baseline and 40 pd at the outcome examination, the esotropia resolved subsequent to the outcome examination.

CONCLUSIONS

Esotropia with onset in early infancy frequently resolves in patients first examined at less than 20 weeks of age when the deviation is < 40 pd in size and is intermittent or variable. Cases with a constant deviation > or = 40 pd presenting after 10 weeks of age have a low likelihood of spontaneous resolution. Our results can be used to define a clinical profile for which persistence of the esotropia is sufficiently likely that surgical correction at 3 to 4 months of age could reasonably be considered.