The article deals with some aspects of the theory of vision, the theory of circular motion by Leonardo da Vinci. He believed that visible objects emit infnitely many rays, each ray carries information to all points in the atmosphere. The perceiving eye, moving, not only sees the world, but feels it, and is a part of it. He compared the spherical rotation of the eye with similar rotational functions of the body. The possibilities of rotations as universal forms of movement of the body and eyes, and as the basis of the eternal mechanics of the universe, were studied in detail by Leonardo, using the example of anatomical experiments, kinetics and optics. He used observations in the feld of anatomy and biomechanics for his engineering inventions and pictorial compositions. The article also considers little-studied drawings from the Huygens Code, on the topic of circular motion and changes in the proportions of the human body, which researchers associate with unknown drawings by Leonardo.