Which form of nystagmus is characterized by an elevation and intorsion of one eye with depression and extorsion of the fellow eye?

• A. Vertical nystagmus
• B. Pendular nystagmus
• C. Jerk nystagmus
• D. See-Saw nystagmus

Answer: (D)

See-saw nystagmus is a dissociated vertical-torsional eye movement where the two eyes move in opposite directions: one eye rises and intorts while the other depresses and extorts, then the pattern reverses. This creates a rocking “see-saw” effect. It stands apart from vertical nystagmus, where both eyes move together in the vertical plane; from pendular nystagmus, which is a symmetric, rhythmic back-and-forth movement without disjunctive torsion; and from jerk nystagmus, which has a slow phase and a fast corrective phase in the same eye. The key feature is the opposite vertical positions paired with opposite torsional movements of the eyes.