Eye-to-mouth angle

The pupils form the upper corners of the triangle and the mouth centre forms its lower corner. With pupil spacing unchanged, bringing the mouth closer to the eye line opens the angle. Moving it farther down makes the triangle deeper and the angle smaller.

Widening pupil spacing also opens the angle, although the mouth stays at the same height. A large angle can therefore describe either widely spanning eyes or a mouth placed relatively close beneath them.

A small angle with ordinary pupil spacing can reflect a long eye-to-mouth distance. More of the central face lies between the eye line and mouth, which may make the region look elongated. The nose and the interval below it determine where that height is distributed.

A small angle with closer pupils creates a narrower triangle without requiring extra height. Inside broad cheeks, it can make the central features look concentrated; inside a narrow face, it may continue the shape of the surrounding outline.

At a larger angle, wide pupil spacing spreads the upper part of the triangle, while a higher mouth makes it shallower. These changes affect different features. Their overall scale can also vary: a large and a small triangle may share an angle while occupying different amounts of the face.

Danel and Pawlowski examined an eye-mouth-eye angle with its vertex at the mouth and lines through the pupils. Among the young male faces rated by young women, smaller angles and lower angular asymmetry were associated with higher attractiveness ratings.

The study compared photographed faces rather than independently moving the eyes and mouth. It therefore leaves open whether narrower pupil spacing, greater eye-to-mouth height or other accompanying features contributed to the association.

Midface ratio uses a similar arrangement, but the lower endpoints are not identical. It ends at the top of the upper lip, while this angle ends at the mouth seam. A taller upper lip increases the distance between those points, so the angle may describe a deeper triangle than the midface ratio suggests.

Mouth width adds information that a single point at the mouth centre leaves out. A deep triangle above a wide mouth has a substantial horizontal span at its bottom. The same triangle above a narrow mouth continues the concentration of the central features. Mouth-to-pupil width helps distinguish those arrangements.

The outer face changes the impression again. A deep triangle within a long, narrow face repeats the overall elongation. In a broad, short face, it places more of the visible length at the centre. A shallow triangle can sit between a tall forehead and a long lower chin region without making the entire face compact.

Pallett and colleagues found that changing eye and mouth placement altered attractiveness ratings even when the features themselves stayed the same. Their experiment used different spacing measurements from this angle.

A mouth shifted to one side or pupils at different heights can produce an uneven triangle with the same total angle as a centred one. Inspect the lines on each side before interpreting the number. The asymmetry finding in Danel and Pawlowski's study makes that arrangement particularly relevant.

As the central face grows, the mouth may move farther below the eyes even while pupil spacing increases. If vertical growth is greater in proportion, the angle becomes smaller. If both distances increase proportionately, the angle can remain stable while the measured region grows.

Later changes in lip shape can affect the mouth seam and the appearance around it. Sforza and colleagues documented changes in mouth dimensions and visible lip height with age. A relaxed, closed mouth and direct gaze give more consistent endpoints when comparing photographs.

The 45–50° interval provides a comparison for the illustrated triangle. The observational angle study does not validate those limits as a universal preferred range.