/ˌtʌnl ˈvɪʒn/
tunnel vision
BrE /ˌtʌnl ˈvɪʒn/
NAmE /ˌtʌnl ˈvɪʒn/
[U]
(medical)
a condition in which sb cannot see things that are not straight ahead of them
(disapproving)
an inability to see or understand all the aspects of a situation, an argument, etc. instead of just one part of it