Slow saccades and hypometria in anticonvulsant toxicity

We report a patient with abnormal saccades in association with anticonvulsant toxicity (phenytoin 27.5 micrograms/ml, phenobarbital 18.8 micrograms/ml). The patient looked toward visual targets either with multiple, small, hypometric saccades or with single slow saccades. These abnormalities resolved when anticonvulsant levels returned to therapeutic range. Thus, slow saccades may be clinical evidence of anticonvulsant toxicity.