Agree with the comment that the focus seems sharper on the front hair (or nose) than the eyes--although it is very slight. In addition to the incredibly narrow depth-of-field with an f/1.4 lens, you may have a very slight backfocus/frontfocus issue. While there are precise ways to test for it (e.g., Lens Align, which I've used on all my lenses and my a77), try playing a bit with your AF Micro Adj. for the lens in your menu. This lens might need a small adjustment (try +/- 2 for a start). Again, this is very minor, given the narrow depth of field and the fact that virtually no lens is as sharp wide open as it is stopped down a bit.