Botulinum toxin for the treatment of early-onset esotropia in children with cerebral palsy.

To the Editors: It is well established that children with cerebral palsy have an increased incidence of ocular misalignment with unpredictable surgical outcomes.1 We describe three children with periventricular leukomalacia who were treated in our unit with botulinum toxin for correction of their early-onset esotropia. The three children in our case series all presented between 4 and 10 months of age with a moderateto large-angle non-accomodative esotropia. Both surgical and non-surgical options were discussed with the childrens’ parents, and botulinum toxin was the preferred treatment option. All children underwent general anesthesia and had 0.1 mL of 2.5 units Botox (Allergan, Irvine, CA) injected into their medial recti, with a 90-second pause between the injection and withdrawal of the needle. The results appear in the table. All children achieved an improvement in their ocular alignment following the injections. One child remained stable after just one injection at 10 diopters (D) base out. One child required two injections before stabilizing at 2 D base out with gross stereopsis and the final child required three injections before stabilizing at 20 D base out with intermittent stereopsis. None of the children in our series developed ptosis or amblyopia as a result of the injection. The psychosocial effects of strabismus surgery are well recognized and children with strabismus often encounter significant negative social bias.2,3 However, there is a high incidence of unpredictable outcomes following strabismus surgery in this group. Previous studies have indicated overcorrection after using the standard surgical dosage of bimedial medial rectus recessions as a primary treatment for their esotropia or undercorrection with altered normograms.1 It is therefore difficult to adequately counsel parents with regard to how many operations may be needed and the degree of correction achieved. Multiple surgeries also cause scarring, discomfort, redness, and a mechanical restriction of eye movements. There have been several recent studies showing a good response to botulinum toxin in normal children with mild to moderate early-onset esotropia.4,5 Our results match these findings and we believe that botulinum toxin is an excellent alternative to surgery in children with cerebral palsy that should be considered as a viable option in the management of early-onset esotropia in children with periventricular leukomalacia.