From your fave source Wikipedia:
Tunnel vision is a metaphor for narrowmindedness, particularly in describing those who pursue an investigation with their conclusion already decided and proceed by only accepting evidence that supports their conclusion and excluding any evidence that contradicts their assumptions. [See Skywise.]

There is nothing written about "open-minded." Perhaps you can write something up for the online encyclopedia. If so, my dog Simon asked me if you can include his photo.
Callie