To report 2 cases of extraocular muscle paresis with ptosis after vincristine treatment in childhood with acute leukemia.

A 4-year-old girl with acute lymphoblastic leukemia experienced diplopia, esotropia and bilateral ptosis after intravenous vincristine treatment. Ptosis improved after two weeks of pyridoxine treatment with vincristine reduction. After 2 months, left abduction defect and ptosis completely disappeared with pyridoxine treatment. A 23-month-old boy with acute lymphoblastic leukemia had bilateral ptosis with worsening pre-existing infantile esotropia after intravenous vincristine treatment. Bilateral ptosis resolved and esotropia improved after vincristine reduction with pyridoxine treatment for 2 months.

We observed extraocular muscle paresis and ptosis after vincristine treatment for acute leukemia in pediatric patients. Physicians should be suspicious of toxic neuropathy related to vincristine treatment when patients have extraocular ophthalmoplegia, and physicians should know that vincristine reduction with pyridoxine supplement may be helpful.