Possible Clues:

• Excessively narrow view of things
• Sight defect
• Single-minded concentration that Tube driver needs?
• Connects Britain and France to ghost with narrow focus
• Sounds like something footballers see at start of match? It's an ability to look obsessively for a single goal!
• Limited outlook shown by new king entering marriage after a little time
• Narrow-mindedness
• Single-mindedness of worried vet on insulin
• Passage on apparition is far from the full view
• Passage from 20 down is far from the full view