Correct! This is infantile nystagmus syndrome, an oscillatory disorder that begins within the first six months of life. Its distinguishing feature is that the oscillation has an atypical horizontal waveform that remains horizontal in upgaze and downgaze, unlike all forms of acquired nystagmus, which convert to upbeat on upgaze. This form of nystagmus usually converts to jerk nystagmus on side gaze. On the way toward side gaze to one side, the eyes pass through a “null zone” where the nystagmus amplitude is least. Although this nystagmus often remains idiopathic, some patients have an underlying retinal or optic nerve disorder that must be discovered. Hence the need for a thorough ophthalmological examination!