Most people have a dominant eye, and while it uses its non-dominant eye in tandem with the dominant eye most of the time, the brain, being an expert in eliminating redunant information, ignores the images received from the non-dominant eye. However, with special training or practice most individuals can force the brain to temporarily switch to receiving images from their non-dominant eye, even to receive images from both at once, resulting in a blurred chamelion-like or image.
Some individuals however, have a non-dominant eye so weak, that not only does the brain ignore the images it sends, the eye it self no longer moves in tandem with the dominant eye. This is known as strabismus or Lazy eye.
My question is, if the eyes are capable of not moving in tandem in those people, why can't we all train our eyes to move independently, and couldn't we also train our eyes to focus on two different images (on opposite sides) at once?