What about we stop saying 'eyes' and start saying 'vision' ideas. Because in real life, we have multiple ways to see, we could sense vibrations, see reflections of light, or hear things move, or actually use echolocation (I know the bots are single celled, and some of these aren't single celled functions, but eyes aren't single celled are they?)
We then can use one of these methods, or more...each with their ups and downsides. For example, vibrations are very long range, and can even be sensed through shapes...But dissapointingly can't tell what type of bot it is, it can only return the size...and rough location. Then, seeing reflections of light, good allrounder, your classic eye, but it fades with light intensity, close up it can tell lots of infomation, very far away with good light intensity can tell some infomation. Then hearing things move, this is affected by shapes quite majorly, and if its a crowded enviroment for example your an MB then you might get some interference from your pals. Then echolocation, who knows?
Then light be shown up on DB...Bioluminesence is a really nice one
Now when a creature is seen, its 2 widest points then are traced directly back to the hunter, the further apart these points the greater chance that it is visible, or more infomation can be told about it, of course if its far away when these points hit the hunter theyre much closer together. Now if we add smell, thats an idea i've wanted for a while, a trail of particles emitted behind and around a bot (Can be shifted by currents or wind, which may also push the bot a bit?) and these particles can be sensed.
In responce to wanting to know distance, multiple sight mechanisms combined could give you that, OR binocular vision of some form.
Final little point, mildly less related to sight, is MB structuring. It needs to be slightly more developed, can each tie have a POSITIVE and a NEGATIVE end. the person who fires it has the positive end. this would help structuring in a species a lot, but if a foreigner fires a tie at you, you generally know. Also finally, these ties to slowly harden over 20 cycles (maybe even 30) being effected by the tie control commands even from the start....but it slowly incrementing