DS9 Odo's perception

Question

I'm still on my DS9 kick, and one thing struck me. Odo is a shape-shifter whose natural state is a liquid. I know there is one episode where he basically outlines that he keeps human form because it makes interacting with others easier. So, much like his face, hair, uniform, etc, his eyes are merely there for appearance.

Also, there are plenty of instances where Odo takes the shape of say, a drink cart, or a painting, and is able to sneak up behind someone while they are not looking. This, I would think, indicates his perceptions are not dependent upon his form.

So my question is ultimately: If Odo doesn't require eyes, Why can't he 'see' behind himself if the eyes are merely an affectation? Or is his vision limited to say.. a 180 degree radius, and how do we know? (Specifically I was just watching an episode where Jake and Nog sneak BEHIND Odo to avoid beeing seen.. )

Answer 1

Out of universe the explanation is simply poor planning. There are a lot of things about the DS9 shape-shifters that don't make sense or are at least inconsistent with how they describe themselves.

In universe, there are 3 possibilities I can think of:

1. Odo does see Jake and Nog, but simply pretends he doesn't. Throughout the series, you get the feeling that Odo knows a lot more about the criminal happenings on DS9 than he lets on. He does this for strategic reasons. If he were to bust every minor offense, it would distract him from more serious crimes as well as tip his hand to the major criminal elements. There are also rare occasions where he deliberately lets people get away with minor offenses because he feels sorry for or indebted to them (e.g. Quark smuggling Denevan Crystals).
2. Odo theoretically has vision across his entire body surface, but his observation abilities are limited by what he's capable of mentally processing. So if he's focusing intently in one direction, he develops a sort of mental tunnel vision and might not notice something happening in the opposite direction. Change blindness in humans can also be caused in a similar fashion.
3. When changelings become solids, they actually become indistinguishable from the genuine article by all known scanners. So perhaps when Odo becomes a hawk, he has the visual acuity of a hawk, but also can't see from his feathers. However, this doesn't explain why Odo can see and hear when he's, say, a drink cup. So this is the weakest explanation.