It might be Night Walk by Bob Shaw (1967).
From the Wikipedia article, emphasis mine:
He is blinded when Cherkassky shoots him in the face with a dart gun, destroying his
eyes. He is taken to a secret prison complex in the southernmost tip
of the most distant continent to convalesce. While he is there, he
enlists the aid of the scientific elite among the other political
prisoners there, and together they design a pair of electronic "sonar"
eyes. The headgear delivers different tones to distinguish various
objects. Later, they make another breakthrough: they make a device
that can sense and interpret the nerve signals of the eyes of nearby
living things. Tallon can now see, but only through others' eyes.
After they develop and test this device, Tallon and his partner
Winfield try to break out, but Winfield is shot during the attempt.
Tallon must flee alone, depending on encountering local animal life in
order to see.