An image enters the eye, passing through first the cornea, then enters through the iris and gets focused through the lens, which is situated behind the iris. This focused light goes through a process called chromatic aberration which separates the light into the colors it is made up. This is focused to the point in the retina that contains 90% of the cones called the fovea. The green coded cones are focused more towards the center whereas the red and blue are more centered around the edges. This is because through the process of chromatic aberration the green hits the center and the blue red waves hit the edges.
Chromosteriposis happens when the frequency of the blue and red hits the same point in the fovea. This causes a binocular effect within the eye which the brain doesn’t know how to interoperate and so it falls back on the only binocular effect that its had used in the past, which is depth perception.