Botulinum toxin management of essential infantile esotropia in children
K. W. McNeer, M. G. Tucker and R. F. Spencer
Smith-Kettlewell Eye Research Institute, San Francisco, Calif., USA. KMCNEER@Gems.VCU.EDU
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.
