noun. 1  a. An old French dance resembling the gavotte, usually in 3/4 or 2/2 time beginning with an upbeat. 2  A movement in ballet in which the dancer transfers body weight quickly from foot to foot, usually on the balls of the feet, in a series of small steps.
Nystagmus is a condition where the eyes make repetitive movements. The eyes can jerk exclusively in one direction, or make back and forth movements. With nystagmus, the eye can look jittery and can affect both eyes or just one eye.
Your eye focuses this light into an image on the layer of the eye called the retina. The eyes receive light from many different directions and distances. To be seen, all this light must focus on the comparatively tiny area of the retina. This means the eyes have to bend light from different angles and directions.