I know that vision system is already in rework. But maybe one or the other idea of my proposal could be useful:

Both eyes have amount of receptor cells ( 1/2, 1, 2, 4, 8, 16, 32,.... regulated via gen for retina) evenly distributed on individual angle for right and left eye.  
A one dimensional retina represents these by a row of pixels. If angles overlap, the resolution is dubbled and output a value for closeness in this section. Therefore it is good sight but narrow angle OR less sight but better all-round view.  
  
The Bibite has a focus defined by target color. It can have mutilple foci.   
If rgb fits,   
**angle** is center of cells with target color,   
**size** is sum of (cell size \* brightness of target color),   
**closeness** is existing mechanics and **moves** indicates, if colored area is moving relatively different from apparent motion.   
  
Cell/ Size of cell / Angle / Closeness   
  
L4 / 1 / -0,83 / 0   
L3 / 1 / -0,5 / 0   
L2 / 0,5 / -0,25 / value   
L1 / 0,5 / -0,083 / value   
R1 / 0,5 / 0,083 / value   
R2 / 0,5 / 0,25 / value   
R3 / 1 / 0,5 / 0   
R4 / 1 / 0,83 / 0   
  
Every object in FOV is reduced to   
color, diameter and closeness   
for retina rendering.   
So this is no ray tracing.  
.

Proposal for Vision System