Positive vs negative canthal tilt: what the angle means

Canthal tilt is the angle of the line from the inner corner of the eye to the outer corner. Outer corner higher than inner: positive. Lower: negative. Roughly level: neutral. It is one angle per eye, a few degrees either way on most faces. The canthal tilt test measures it from a short camera scan, in your browser, and reports each eye with its spread across 8 frames.

The anatomy

The canthi are the corners of the eye, where the upper and lower lids meet. The medial canthus sits beside the nose; the lateral canthus toward the temple. Each is anchored to the bone of the eye socket by a canthal tendon. The lateral tendon attaches to a small bump on the inside of the orbital rim, usually a little higher than the medial one, which is why most adult eyes measure level to slightly positive.

Draw a line between the two corners, compare it with level, and the angle is your canthal tilt. In MediaPipe’s landmark model the corners are points 133 and 33 for the right eye and 362 and 263 for the left.

Positive, neutral and negative

• Positive (above about +2°): the outer corner sits higher and the line rises toward the temple.
• Neutral (within about ±2°): the corners sit at nearly the same height.
• Negative (below about −2°): the outer corner sits lower and the line falls toward the temple.

The boundaries are conventions, not anatomy. A reading of +1.8° and one of +2.3° describe nearly the same eye; only the label differs. Look at the angle and its spread before the label.

How much it matters for attractiveness

Less than its reputation online suggests. A slight upward tilt tends to read as alert and youthful, and clinical aesthetics treats a few degrees positive as the reference. The attractiveness score reflects that: across the range real eyes show, a more positive tilt scores a little better. The formula’s peak sits at 14°, beyond almost every real eye, so read it as a direction, not a target. Tilt is one measurement inside a component that also covers how open the eyes are and their size against the face, and that component carries 15% of the score. A neutral tilt costs very little; a strongly positive one gains little more. Symmetry, averageness and proportions each move the score further.

Tilt also varies between families and across ancestries, and a face reads as a whole. The score measures the angle and weighs it lightly; it does not treat one direction as a verdict.

How the measurement works

The hard part is deciding what level means. A head is rarely perfectly straight, and a roll of a few degrees toward one shoulder lifts one eye and drops the other. So the test does not use the edge of the camera frame. It measures each eye against the line through both inner corners, which cancels roll.

Pitch is the bigger problem. The outer corners sit further back in the head than the inner ones, so tipping the chin down raises them in the image and tipping it up lowers them. A camera held below eye level does the same. The scan deals with this by only capturing the front view when your head is within ±6° of straight in both yaw and pitch, then taking the median of 8 frames. The spread it reports is the range across those frames.

What changes canthal tilt

In the reading

• Head pitch and camera height: chin down or camera low raises the outer corners; chin up or camera high lowers them.
• Expression: a smile lifts the lower lids and cheeks; raised brows pull the upper lids; squinting changes both.
• Eye makeup: winged liner changes how the eye looks without moving where the lids meet, though heavy liner can pull the detected corner.
• Light: a shadow at the outer corner makes it harder to place.

In the eye itself

Bone and the canthal tendons set the angle. Over decades the lateral tendon loosens and the outer corner drifts down, which is the main reason tilt becomes less positive with age. Puffiness and tiredness move it slightly from day to day. Eyelid surgery and some cosmetic procedures change it permanently; makeup and brow grooming change how it reads without changing the angle.

How to measure it fairly

1. Prop the phone at eye level, straight in front of you, an arm’s length away or further.
2. Keep a relaxed, neutral face: no smile, brows at rest, eyes open normally.
3. Take off glasses and move hair away from your eyes and temples.
4. Face soft, even light, such as a window.
5. Scan twice. If the two readings agree within their spread, the angle is yours, not the setup’s.

Reading two different eyes

A difference of a degree or two between your eyes is ordinary; no face is perfectly symmetric. Because the measurement cancels head roll, a larger difference that repeats across scans is a real asymmetry in where the corners sit. The symmetry guide explains how the score treats asymmetry in general.

When you are ready, measure yours with the canthal tilt test. The free result is the angle of each eye; the report adds eye openness, size and spacing, and where tilt sits in your score.