Yahweh continues describing what his servant will do.
Causing blind people to see is spoken of as if it were opening their eyes. Also, Yahweh speaks of his servant delivering those who have been wrongly imprisoned as if his servant were restoring sight to blind people. AT: “to enable the blind to see” (See: rc://en/ta/man/translate/figs-metaphor)
These two phrases mean basically the same thing. The verb may be supplied in the second phrase. AT: “to release the prisoners from the dungeon, and to release those who sit in darkness from the house in which they are confined” (See: rc://en/ta/man/translate/figs-parallelism and rc://en/ta/man/translate/figs-ellipsis)