In the human brain, the left side actually controls the movement of the right side of the body, and the right side of the brain controls the movements of the left side of the body, such as a left handed person using the right side of the brain.
Although in many ways both sides of the human brain are equal in the way they work, each side however does appear to have a more leading role in certain areas of function. The left side of the brain appears to have a more dominant role when it comes to languages, and the right side of the brain being more in control of things such as Spatial Temporal Reasoning (the mental visualization of something and putting it into an ordered sequence in your mind.) Following so far? Good!
Now here is where things get a little more complicated; it is the brain after all. Even though the eyes have two sets of nerves, one functioning for each eye, the two sets of nerves come together called the Optic Chiasm, and then each set of nerves splits in half, one half for the left side of the eye and one half for the right side of the eye. This happens for both the left and the right eye. Now, the left halves of the nerves from both eyes go to the left side of the brain and the right halves of the nerves go to the right side of the brain.
A little more complicated than it needed to be don’t you think? But that’s just the way things work up there.