Stabilized images are images that are fixed on the retina, and are not disrupted by micromovements of the eye. Study on stabilized images finds that they fade from view and become imperceptible, an important adaptation that provides interesting information about visual perception and brain function. The science behind stabilized images appears to be complex, and involves a number of neurological processes that play a role in perception and evaluation of information.
One example of a stabilized image is the blood vessels of the eye, which run between the retina and the pupil of the eye. These vessels should be visible as a tangle of threads in the vision because they interrupt the flow of light into the eye and ought to cast shadows on the retina. This is not, in fact, the case; people don't see their blood vessels unless a very bright light shines into the eye and shifts the cast of the shadows.
The brain has clearly adapted to the vessels in the eye to render them invisible during normal vision, for the purpose of clarifying vision. These stabilized images move with the eye when it moves because the vessels are inside the eye, and thus remain fixed relative to the retina. Studies on stabilized images can use a number of techniques to explore perception and test theories about how this phenomenon works. The mechanics behind it lie in the visual processing centers of the brain, which sift through information sent along the optic nerve to create a meaningful image.
One option is to have subjects stare at an image, holding their eyes still. The involuntary micromovements that occur automatically will not affect the image. Using something like a dark dot projected in the middle of a gray cloud with no clear edge, the researcher can demonstrate that holding the eyes still allows the gray cloud to fade, leaving only the dot behind. Students learning about visual perception may do exercises like this to learn how stabilized images work.
In more extensive experiments, subjects can wear specialized headgear that projects an image and detects eye movements to move the image with the eye. The stabilized images will disappear from view as the eye adapts and adjusts to them. This phenomenon demonstrates that vision is much more complex than simply processing light that hits the retina. The brain learns to dismiss fixed information, assuming it is not relevant, and uses tactics like edge detection to provide meaningful information about an object.
