Rabbits are extremely farsighted and they have monocular vision, a biological indication that the rabbit is prey, not predator. Animals of prey have vision that is designed to detect motion in as much of their environment as possible. Their eyes operate independently, with a field of vision that can reach 180 degrees each, but their vision doesn't meet in front to see straight ahead; that is their blind spot and the reason they seem unable to locate a favorite piece of food that is put directly in front of them.
Predators, on the other hand, have binocular vision, as do humans, where the brain assembles signals from both eyes to create acute, 3-D vision. They need this to locate prey and keep it in focus as they approach straight on.
To compensate for non-binocular vision, your rabbit may cock her head and look at you sideways; she's actually looking as straight at you as a bunny can.
"Scanning" or "tracking" is a vision-related rabbit behavior that can cause concern in those unfamiliar with it. Some rabbits will sit and weave or sway slowly back and forth. They appear to be causing motion in order to see an object that is within a short distance of themselves. This behavior is also observed when carrying a rabbit facing forward. Head motion is thought to be a means of enhancing distance measurement. When the eye is moving, close objects move faster than distant ones.
If your rabbit is a scanner--most common in pink-eyed rabbits--she will regularly scan; it won't be a sudden-onset behavior. As with so many other aspects of rabbit behavior and health, sudden changes indicate health problems.
Is it a stroke?
If your rabbit, especially an older rabbit, suddenly appears unstable, disoriented with eyes that "twitch," it's very important to note whether the eyes are moving up and down or back and forth.
This eye twitching is called nystagmus. Up and down eye movement signifies a brain problem, whereas back and forth signifies an inner ear infection or other problem. In either case, the rabbit needs to get to her veterinarian as soon as possible.