 In this example, we're going to demonstrate physiologic nystagmus. These are oscillations that don't represent pathology, but are usually seen when the patient's eyes are directed too far in extreme lateral gaze. You can get fooled if you don't pay attention to how far you're bringing the patient's eyes over laterally. Most pathologic nystagmus are either seen in primary gaze or when gaze is directed laterally, usually not more than say 20 or 30 degrees. What we're doing here is sequentially moving the patient's eyes farther and farther laterally. Note how fixation is steady even at this position of gaze. Now the patient's eyes are brought into extreme gaze and what you can see are oscillations of the eyes. Note how the patient's having trouble maintaining fixation. Occasional horizontal jerk nystagmus can be seen more obvious than the AB ducting eyes. These are not gaze evoked nystagmus.