How eye move on their own?

The human eye is capable of making several different types of movements. These movements are controlled by six muscles that surround the eye. The muscles work together to move the eye in different directions, including up, down, left, right, and diagonally.

Smooth pursuit movements are used to track moving objects. When you follow a moving object with your eyes, your eyes make smooth, continuous movements to keep the object in focus.

Saccadic movements are quick, jerky movements that move the eyes from one point of fixation to another. Saccadic movements are used to scan a scene, and to quickly change the point of fixation.

Vergence movements are used to move the eyes inward (convergence) or outward (divergence) in order to focus on objects at different distances.

Vestibulo-ocular movements are used to stabilize the eyes during head movements. When you move your head, your eyes make compensatory movements in the opposite direction to keep the image of the world on the retina.