I was asked recently by some Jewish friends of mine why Jesus misquotes the OT in the Gospels. One example they provide is Luke 4:18.
because he has anointed me
to proclaim good news to the poor.
He has sent me to proclaim liberty to the captives
and recovering of sight to the blind,
to set at liberty those who are oppressed,
and they compare that to Isaiah 61
because the Lord has anointed me
to bring good news to the poor;
he has sent me to bind up the brokenhearted,
to proclaim liberty to the captives,
and the opening of the prison to those who are bound;
to proclaim the year of the Lord's favor,
and the day of vengeance of our God;
to comfort all who mourn;
Their particular concern is the phrase Jesus uses, "and recovering of sight to the blind." This phrase is not used in Is 61, yet Jesus puts it in as he reads from Isaiah. They claim this is either Luke misquoting Jesus or Jesus misquoting Isaiah, or both.
I found a web site that articulates the same argument:
http://www.messiahtruth.com/luke.html
How would you respond to this question and position?

The LXX does contain the phrase in question in Isaiah 61. However, what does that prove? The LXX translation is in error?