The timing of surgical alignment for congenital (infantile) esotropia

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

PURPOSE

To determine the anticipated reduction of baseline angle of esotropia and identify predictors of change following botulinum neurotoxin (BNT) injections in large-angle infantile esotropia.

METHODS

This was a prospective, longitudinal study of children <10 years of age diagnosed with infantile esotropia of >30^Δ and given either 1, 2, or 3 BNT injections. Post-injection change from baseline deviation was recorded, and predictors of reduction were analyzed. For this study, children were further divided into subgroups based on initial deviation of ≤60^Δ (group 1) and >60^Δ (group 2). The outcomes of subsequent surgeries in failed cases were analyzed.

RESULTS

A total of 117 children were included, 55 in group 1 and 62 in group 2. Mean age was 30.3 ± 18.8 months. Mean baseline deviation was 62.5^Δ ± 13.1^Δ: 51.4^Δ ± 8.4^Δ in group 1 and 73^Δ ± 7.5^Δ in group 2. The mean number of injections was 2.2 ± 0.7. Success was achieved in 25.6% of patients (33.4% in group 1; 16.2% in group 2). The mean percentage reduction of deviation after BNT injection was 55.2% ± 26%, larger in group 1 than in group 2 (61.3% vs 51.1% [P = 0.001]). Five children reverted to baseline deviation. In multivariate analysis, adjusting for number of injections, younger age and larger baseline deviation were significant independent predictors of a larger absolute amount of reduction (P = 0.02, and 0.002, resp.). Thirty-two children had subsequent surgery; 22 were followed for a minimum of 6 months, and 20 were aligned within 10^Δ of orthotropia.

CONCLUSIONS

In large-angle esotropia there was a reduction of approximately 50% of baseline deviation, with greater relative reduction for smaller baseline deviations; the absolute change in angle was greater in younger children. Alignment after subsequent surgery appeared to remain stable and surgery required less recession than would have been needed for the original angle of esotropia.

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.

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.

[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).

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.

Comitant strabismus

A review of the literature on comitant strabismus of the period from April 1999 until April 2000 is presented. A rather new and increasingly important issue is the psychosocial aspect of strabismus. Two studies have demonstrated that strabismus creates a significant negative social prejudice on the patients and that it can significantly reduce an applicant's ability to obtain employment. Subsequently, strabismus surgery can no longer be called "cosmetic". Concerning the timing of surgery in congenital esotropia, it was reported that early surgery does not ensure continued alignment, but frequently requires additional operations. The increased risk of early-onset strabismus in prematurely born children was confirmed by several studies, and the importance of regular ophthalmologic controls of all preterm infants screened for retinopathy of prematurity was stressed. It was reported that risk factors are cicatricial retinopathy of prematurity, refractive error, family history of strabismus, and poor neurodevelopmental outcome, rather than low gestational age and regressed acute retinopathy of prematurity. A number of other aspects of interest concerning exotropia, esotropia, and dissociated vertical deviation are presented in this review.

Development of refraction and strabismus

Research on the etiology and causes of refractive errors has become a very active field of study during the past few years. Most of this research has focused on myopia. But hyperopia and astigmatism are also being examined both in comparison to myopia and in their own right. Animal models have also been developed for the study of experimentally induced myopia and hyperopia. These studies demonstrate the chain of neural and molecular events that occurs in induced myopia and hyperopia with increasing precision. In the future, these results may elucidate the mechanisms that underlie the refractive errors seen in human populations. Research into the development of strabismus has not progressed with the same vigor. The links among hyperopia, accommodative convergence, and strabismus are well established. Numerous neural, oculomotor, and subjective correlates of strabismus are now well established, but there has been a failure to develop the experimental paradigms needed to demonstrate the causal relations among these different factors.

Development of refraction and strabismus

In the past year, as in recent years, most of the research on the development of refraction has focused on the following: 1) mechanisms whereby the eye can maintain coordinated growth to achieve emmetropia and 2) disruptions of emmetropization resulting in myopia or hyperopia. Preterm children and those with Down syndrome have higher refractive errors than other children, suggesting a failure of emmetropization. One of the most intriguing studies of the past year and one certain to lead to follow-up studies reported that ambient room illumination at night in a child's first two years is associated with a higher prevalence of myopia than sleeping in darkness. Reports on the development of hyperopia showed that it is axial in nature, similar to myopia. The effects of spectacle interventions to correct refractive errors are still being debated, with recent evidence from children suggesting that lenses do not exacerbate myopia. Analyses of risk factors and numerous new screening procedures detect patients with strabismus for referral at a variety of sensitivity and specificity levels. Hyperopia and high AC/A ratios are most clearly associated as causal agents for esotropia and intermittent exotropia. However, the action of even these simple mechanisms is confounded by abnormal binocular fusion mechanisms and the inability of optical correction to align the eyes of many patients. Asymmetric optokinetic nystagmus, latent nystagmus, and dissociated vertical deviation appear to be linked to infantile esotropia from before its onset. But the way the mechanisms underlying these oculomotor anomalies are causally related to the onset of infantile esotropia remains a mystery.