The article makes clear that the reference is about patients who tilt their heads to balance chin point to midline which leads to false impression as to the extent of the eye asymmetry they have. For example, people who look in the mirror, see they have asymmetry to areas of face below the eyes and then tilt their heads so an imaginary vertical line cuts straight through the centers of their nose, lips and chin point. So, when they get a surgery where they don't have to tilt their head anymore, the eye asymmetry, (which I guess they don't focus on when looking in the mirror), gets less. So, if you want to know IF bimax surgery will make your eyes even, you would have to know IF you tilt your head for parts other than the eyes looking asymmetrical.
Gadwins,
To look at symmetry changes, one has to construct reference lines. Asymmetry is best seen by constructing mirror symmetry from each side of a photo. Example included.
QUIZ (for anybody): Tell me which side she's tilting her head towards and your reasoning as to why.