Healy hobbled off during Saturday's scrappy 17-13 warm-up win over Samoa. The loosehead prop, who became Ireland's most capped forward with his 125th appearance, has played an key role off the bench in closing some of Ireland's biggest recent wins.
The Leinster's prop's absence from what would have been his fourth World Cup opens the door for Munster's Jeremy Loughman (28), who was a late addition to the wider squad due to concerns over fellow backup frontrow Dave Kilcoyne's (34) fitness.
Ireland travel to France as the world's top ranked side, Six Nations Grand Slam champions and winners of their last 13 games. That meant Farrell only had a couple of tight calls on the edges of an extremely settled 33-man squad.
All bar two of the 31 players who featured in the Grand Slam campaign made the cut.
The other absentee Kieran Treadwell (27), who played just seven Six Nations minutes, was released from the wider squad earlier this month following the emergence of young Leinster lock Joe McCarthy (22).
Farrell opted to bring 18 forwards and 15 backs, making room for Stuart McCloskey (31) to travel as a fourth out-and-out centre and one of the few backs not expected to cover multiple positions in an ultra-versatile squad.
That squeezed Cian Prendergast (23) out of contention for a spot among the forwards. As expected, Keith Earls (35) got the nod over Jacob Stockdale (27) elsewhere in the backs.
Ireland, who have never gone beyond the quarter-finals at a World Cup, open their Pool B fixtures against Romania on September 9th.
Ireland squad
Forwards: Ryan Baird, Finlay Bealham, Tadhg Beirne, Jack Conan, Caelan Doris, Tadhg Furlong, Iain Henderson, Rob Herring, Ronan Kelleher, Dave Kilcoyne, Jeremy Loughman, Joe McCarthy, Peter O'Mahony, Tom O'Toole, Andrew Porter, James Ryan, Dan Sheehan, Josh van der Flier
Backs: Bundee Aki, Ross Byrne, Craig Casey, Jack Crowley, Keith Earls, Jamison Gibson-Park, Mack Hansen, Robbie Henshaw, Hugo Keenan, James Lowe, Stuart McCloskey, Conor Murray, Jimmy O'Brien, Garry Ringrose, Jonathan Sexton (captain)