templeait:

– Bucky Barnes Is Blind –

“Hydra has this brand new device they want to test, the one that allows a blind person to see (features include: thermal imaging, infrared, x-ray, etc.), can zoom in, focus, record and transmit whatever the person wearing it sees. So, why not test it on the Asset? It’s not like it’s difficult to blind someone; he’ll become deadlier, and watching his actions and controlling him will become even easier.
What if he breaks out, though? Simple as well: plant an explosive in the device. Something tiny and unnoticeable. If compromised, the explosive will destroy the device and half of the Asset’s head. Foolproof.”

When Steve breaks Bucky’s programming in the helicarrier and it triggers the countdown, Bucky manages to hear it and tear the device off just in time before it blows up.
He can’t escape blind, though. So he’s brought into the Tower.