The research on bed bug vision has been very poor thus far. We do know that bed bugs prefer dark to light so there is a photo sensitive component to the bed bug. We also know that bed bugs prefer certain colors over other colors (ie they like red better than yellow). But the exact vision capabilities of the bed bug has not been determined.
I have been attempting to modify glue boards to reduce their repellency for the last year. During this time I have noted that when I place a new batch of bugs into a glue board experiment arena (in a full light environment) that many bugs will approach the glue board suspiciously and stop a few millimeters away from the glue board and walk away without touching it. On the other hand the bugs were more than willing to walk right into the edge of the teflon pan at full speed and attempt to climb the vertical wall. Given the glue board is not much thicker than an unfed bed bug it is interesting that caution is displayed for such a small item but no caution is displayed when approaching a vertical wall. Hmmm.
I have also noted other occasions where bugs would appear to look at me. I have attempted to avoid anthropomorphizing a vision component to the bugs in these situations but I am slowly being persuaded that bed bugs do have at least some form of vision. I really do look forward to some research being conducted in this area.