In the West, if Mass cannot be said in such a way that the priest physically faces East, it is
supposed to be said facing ‘Liturgical East,’ with the priest facing the same way as the people, acting as head of the assembly. Cardinal Ratzinger explains:
Where priest and people together face the same way, what we have is a cosmic orientation and also in interpretation of the Eucharist in terms of resurrection and trinitarian theology. Hence it is also an interpretation in terms of
parousia, a theology of hope, in which every Mass is an approach to the return of Christ. (San Francisco:
Ignatius Press, 1986, pp. 140-41.)
I think it’s very interesting to note that the IGMR and Sacramentary are written in such a way that it is assumed that the priest is celebrating Mass ad orientem. Oh, well. Who reads those things anyway?

I don’t really know why the Vatican has permitted such a fundamental blunder to take place in the liturgies of the Latin church. My reaction to the practice of offering Mass ‘facing the people’ is pretty similar to that of my Byzantine pastor’s: “Who in the world THOUGHT of that?!”
“…a common turning to the East during the Eucharistic Prayer remains essential. This is not a case of accidentals, but of essentials. Looking at the priest has no importance. What matters is looking together at the Lord. It is not now a question of dialogue, but of common worship, of setting off towards the One who is to come. What corresponds with the reality of what is happening is not the closed circle, but the common movement forward expressed in a common direction for prayer…” (
adoremus.org/0500-Ratzinger.html)