Acquired esotropia as presenting sign of craniocervical junction anomalies

Basilar impression and Arnold Chiari malformation are two congenital cranio cervical junction anomalies that could remain unrecognized until symptoms start at a certain age. Generally the first symptoms are nystagmus and hyperactive deep tendon reflexes. The authors present two cases of acquired esotropia, one with Arnold Chiari malformation and the other with basilar impression together with Arnold Chiari malformation. Divergence palsy is thought to be the underlying mechanism of esotropia in these patients due to the brainstem dysfunction. The authors would like to emphasize the importance of early diagnosis with MRI and unnecessary ophthalmic surgery.