PURPOSE: The significance of botulinum toxin to ophthalmologists is twofold. 
Botulism, a medical emergency, frequently presents with ocular findings 
including blurred vision, diplopia, ptosis, and photophobia as a result of the 
neurotoxin produced by Clostridium botulinum. However, botulinum toxins also 
have therapeutic uses for medical conditions including strabismus. The safety 
and efficacy of Botulinum toxin A in patients with a history of botulism has not 
been reported.
OBSERVATIONS: We report a 9-week-old infant, diagnosed with type B toxin 
positive infant botulism treated with human botulism immune globulin, who 
developed a large angle exotropia. The infant was treated with intramuscular 
injections of botulinum toxin A to the extraocular muscles resulting in a 
favorable initial response but ultimately required strabismus surgery. Clinical 
manifestations and management of botulism are reviewed and botulinum toxin in 
the treatment of pediatric strabismus is discussed.
CONCLUSIONS AND IMPORTANCE: This case demonstrates safe administration of 
onabotulinumtoxinA to an infant with a history of antitoxin-treated botulism, 
resulting in a transient improvement in control of infantile exotropia.