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

Critical age of botulinum toxin treatment in essential infantile esotropia

PURPOSE

To assess the results of botulinum toxin treatment in 60 consecutive children with essential infantile esotropia.

METHODS

Bilateral simultaneous injection of botulinum toxin into the medial rectus muscle was performed in 60 patients under direct visualization with an "open sky" technique. Fluothane/sevoflurane insufflation anesthesia was used. Each patient underwent a single bilateral botulinum toxin injection. Patient age at the time of injection ranged from 5-8 months.

RESULTS

Mean patient age at the time of treatment for the 88% of patients who gained a good alignment (within +10 prism diopters [delta] of residual esotropia) was 6.5 months, while mean patient age at time of injection for the 12% of patients who were undercorrected or the deviation relapsed was 7.8 months. Follow-up averaged 5.2 years (range: 2-9 years, SD 2). No variation of the angle of strabismus was observed after 6 months from injection. In some patients with hyperopic refraction, plus lens corrections were prescribed during follow-up to stabilize the alignment.

CONCLUSION

Botulinum toxin can be effective in essential infantile esotropia when children are treated by age 7 months.

Botulinum treatment of infantile esotropia with abduction nystagmus

PURPOSE

To examine the effect of botulinum toxin type A (BTA) on the final correction of esotropia, A and V patterns, overaction of the oblique muscles, and dissociated vertical deviation (DVD) in infantile esotropia with nystagmus in abduction.

METHODS

This retrospective study examined 54 patients treated with simultaneous bilateral medial injection of BTA. Subjects were divided into two groups: group 1 (first injection <18 months of age) and group 2 (first injection >18 months of age).

RESULTS

Pre-BTA, group 1 patients had an angle of esotropia noticeably higher and fewer A patterns than group 2 patients. Post-BTA, group 2 received significantly fewer injections of BTA than group 1. The magnitude of the A patterns improved. Prior frequency of DVD increased significantly in group 1 (100%): 79% of DVD was decompensated compared with 47% in group 2. Overall success was obtained in 14% and 58% of groups 1 and 2, respectively.

CONCLUSION

We do not support BTA treatment in infantile esotropia with nystagmus in abduction prior to age 18 months. After 18 months, the horizontal results are excellent and neither the incidence nor the degree of previous DVD are decompensated, resulting in high success rates for overall deviation and improving anisotropy in A.

Why does early surgical alignment improve stereoacuity outcomes in infantile esotropia?

PURPOSE

Recent studies of infantile esotropia suggest that early surgical alignment may enhance stereopsis and that alignment during the first 6 months of life may be optimal. Early surgery both establishes alignment during an early critical period for the development of stereopsis and minimizes the duration of misalignment. Here we examine the role of these 2 factors in promoting improved stereopsis outcomes.

METHODS

Participants were 129 consecutive patients enrolled in a prospective study of infantile esotropia who were followed up for a minimum of 5 years. At ages 5 to 9 years, Randot stereopsis was evaluated.

RESULTS

Multiple linear regression indicated that duration of misalignment, but not age at alignment or age at onset, was a significant factor in determining random dot stereopsis outcomes. Moreover, patients with stereopsis were less likely to have a loss of horizontal eye alignment requiring surgery than patients without stereopsis (14% versus 32%; z = 1.96, P =.05). Patients with stereopsis were also less likely to have dissociated vertical deviation than patients without stereopsis (25% versus 63%; z = 3.36, P <.001).

CONCLUSIONS

The results suggest that early surgical alignment is associated with better stereopsis in those patients with infantile esotropia who were treated during the first 24 months of life, because early surgery minimizes the duration of misalignment, not because alignment is achieved during an early critical period of visual maturation. Random dot stereopsis can also be achieved in patients with alignment provided that the duration of misalignment is not prolonged. Improved outcomes of random dot stereopsis are associated with more stable long-term alignment outcomes.

Results of early alignment of congenital esotropia

OBJECTIVE

To determine the long-term motor and sensory results after early surgical correction of patients with congenital esotropia.

DESIGN

Noncomparative interventional case series.

PARTICIPANTS

Ten infants with congenital esotropia.

INTERVENTION

Patients had bimedial rectus recession between 83 and 159 days of age; were re-examined in a regular follow-up program; and were retreated when required for strabismus, amblyopia, and refractive errors.

MAIN OUTCOME MEASURES

Final alignment, stereo acuity, variations in vision, alignment, refraction, and number and types of retreatments required during the period of observation.

RESULTS

All patients were aligned initially with bimedial rectus recession of 8.0 to 10.0 mm measured from the limbus. A total of 11 additional surgical procedures were performed on 7 patients to maintain alignment. Four patients required hyperopic spectacle correction to maintain alignment, and two patients required short periods of patching. Visual acuity was 20/40 or better in 19 eyes at the most recent examination, which was between 8.3 and 11.8 years after initial surgery. All patients had final alignment to within 10 prism diopters (PD) of orthotropia at either distance or near. Nine of ten patients had dissociated vertical deviation (DVD), and four of ten patients had latent nystagmus. Four patients had measurable stereo acuity at their last visit, with two achieving a stereo acuity of 3000 seconds (the Titmus fly), one 400 seconds, and one 140 seconds.

CONCLUSION

Surgical alignment of congenital esotropia can be achieved in the 4-month-old with bimedial rectus recession, but this does not ensure continued alignment. At least one additional surgical procedure is required on average to maintain alignment in the first 10 years after initial successful surgery. These patients can also be expected to have one or more of the following: DVD, latent nystagmus, refractive component, or latent strabismus. Regardless of outcome, patients with congenital esotropia have optokinetic asymmetry. Attainment of stereo acuity, including high-grade stereo acuity, may be enhanced by attainment of orthotropia or small-angle esotropia but is likely to be ultimately dependent on constitutional factors rather than age of alignment.