Pendular nystagmus Seesaw nystagmus 2012-08-01T12:06:36Z HP:0012044 UMLS:C0344243 Seesaw nystagmus can be a manifestation of lesions of the optic chiasma. SNOMEDCT_US:95782001 Seesaw nystagmus is a type of pendular nystagmus where a half cycle consists of the elevation and intorsion of one eye, concurrently with the depression and extortion of the fellow eye. In the other half cycle, there is an inversion of the ocular movements.