Botulinum toxin management of essential infantile esotropia in children.

BACKGROUND: Infantile esotropia has an onset during early infancy when visual cortical connections are established for binocular fusion and stereopsis. The goal of early treatment is to achieve normal binocular alignment and a favorable sensory outcome.

OBJECTIVE: To determine the long-term effects of the use of botulinum toxin for the management of infantile esotropia in children.

PATIENTS: Seventy-six neurologically normal children ranging from 4 to 48 months of age were entered consecutively into the study after being given the initial diagnosis of infantile esotropia with a mean strabismic angle of 33 prism diopters.

INTERVENTIONS: Simultaneous bilateral injections of 2.5 U of botulinum toxin type A were made into the medial rectus muscles under nitrous oxide and ethrane anesthesia. Patients were followed up for 12 to 95 months after the last injection. Forty patients required 1 bilateral injection and 36 patients required multiple bilateral injections to achieve a favorable motor outcome.

RESULTS: Bilateral medial rectus muscle injections of botulinum toxin were effective in reducing the mean preinjection deviation of 33 PD to an average esotropic angle of 2 PD. Binocular alignment (+/- 10 PD) was achieved in 68 patients (89%). Boys required significantly fewer injections than did girls. The secondary incidence of overacting inferior oblique muscles was significantly greater in boys, while girls had a significantly greater incidence of late-onset refractive errors.

CONCLUSION: Botulinum toxin is an effective treatment modality for the management of infantile esotropia in infants and children, producing binocular alignment of the visual axes.