Characteristics of Facial Asymmetry in Congenital Superior Oblique Palsy according to Trochlear Nerve Absence

Figure 2

Seven indices of facial asymmetry automatically measured by the software. (1) Face tilt (°) is the angle between the vertical line (white dotted line) and the line that passes between the landmark points of the facial midline (black line). (2) Slope of eyebrows (°) is the angle between the line connecting both eyebrows (white line) and the perpendicular line to the facial midline (black dotted line). (3) Difference in slopes of eyes (°) is calculated by the difference in slopes of the lines passing through the eye corner points of each eye (white arrows). (4) Difference in hemifacial area (%) was calculated by the proportion of “absolute difference of left and right hemifacial area” to “total face area.” (5) Nose deviation (°) is the angle between the line connecting the corners of the nasal base (white double headed arrow) and the perpendicular line to the facial midline (black dotted line). (6) Slope of lips (°) is the angle between the line that passes through the corners of both lips (black arrow) and the perpendicular line to the facial midline (black dotted line). (7) Difference in slopes of eye and mouth (°) was calculated by the angle between the line connecting the center of each eye (black double-headed arrow) and the line that passes through the corners of both lips (black arrow). The center of each eye was calculated as the average coordinate of six landmark points on the upper and lower eyelids.