The null point is the direction of gaze where nystagmus has the lowest amplitude.

• A. Null point
• B. Neutral point
• C. Fast phase
• D. Slow phase

Answer: (A)

The key idea is that nystagmus intensity varies with where you gaze, not just when it happens. In many forms, there’s a specific direction of gaze where the eye’s drift and the corrective fast movements align so that the overall movement is smallest. This direction is called the null point (or null zone). When you look toward the null point, the nystagmus amplitude drops, giving longer moments of stable foveation and better visual clarity. If you shift gaze away from that point, the movement tends to increase, worsening acuity.

The fast phase and slow phase describe the two components of the nystagmus cycle, not a particular gaze direction with minimal movement, so they don’t denote the position of lowest amplitude. The neutral point is a different concept used in other diagnostic contexts, and it doesn’t specify the gaze direction with the least nystagmus amplitude.