Eye analysis: canthal tilt, spacing, and shape

Eye analysis measures the geometry of the periocular region: canthal tilt (the angle of the line from the inner to the outer eye corner relative to horizontal), eye spacing (intercanthal and interpupillary distance), and the proportions that give an eye its apparent shape. All of these are continuous measurements with wide normal ranges.

Canthal tilt: what it is

Every eye has two corners: the medial canthus at the inner corner near the nose, and the lateral canthus at the outer corner. Canthal tilt is the angle between the line connecting those two points and the true horizontal.

• Positive tilt — the outer corner sits higher than the inner corner. The line slopes upward and outward. Slightly positive tilts are the population norm; typical values are commonly cited as around 2–6 degrees.
• Neutral tilt — both corners sit at approximately the same height, an angle near 0 degrees.
• Negative tilt — the outer corner sits lower than the inner corner. This is also normal variation, and average tilt tends to drift downward with age as the lateral canthal tendon relaxes.

Tilt varies with ancestry, sex, and age, and the two eyes of one face frequently differ by a degree or two — a form of the ordinary asymmetry covered in our face symmetry guide.

Why canthal tilt trends on social media

Canthal tilt became a fixation of "looksmaxxing" communities, where positive tilt is presented as attractive and negative tilt as a flaw to fix. What the measurement actually shows is much less dramatic:

• It is one small angle among dozens of measurements that describe an eye region — lid exposure, brow position, eye spacing, and orbital depth all shape the same impression.
• The differences being argued over are typically a few degrees, near the limit of what an observer can perceive in a moving, expressive face.
• Apparent tilt changes with head pitch, smiling, and camera height. A camera held slightly below eye level can make a neutral tilt look positive; one held above can do the opposite. Many before/after images circulating online differ only in pose.
• No peer-reviewed evidence supports a threshold at which tilt becomes "bad." Both positive and negative tilts appear across widely admired faces.

Eye spacing: intercanthal and interpupillary distance

Two different measurements describe how far apart the eyes are, and they are often confused:

• Intercanthal distance (ICD) — the gap between the two medial canthi, i.e. the width of the space between the eyes. Adult values are commonly cited around 30–35 mm.
• Interpupillary distance (IPD) — the distance between the centers of the two pupils, the number opticians use to fit glasses. Adult values are commonly cited around 54–74 mm, with roughly 60–66 mm typical.

The classical rule of thumb says the face divides into fifths, with the eyes "one eye width apart": intercanthal distance approximately equal to the width of one eye (palpebral fissure length). When ICD is noticeably larger than one eye width, the eyes read as wide-set; noticeably smaller, close-set. Like all neoclassical canons, this is a compositional convention — anthropometric surveys show most faces deviate from it without anyone noticing.

Eye shape categories

Eye "shape" labels describe how the lids, crease, and canthi combine. Common descriptive categories include:

• Almond — visible lid crease, tapered corners, iris slightly covered by the upper and lower lids.
• Round — more visible white above and below the iris, greater vertical opening relative to width.
• Monolid — no visible crease in the upper eyelid; common and entirely normal, particularly in East Asian populations.
• Hooded — the skin fold below the brow covers part or all of the lid crease. Can be present from youth or develop with age.
• Downturned / upturned — shape labels that restate canthal tilt: outer corners below or above the inner corners.
• Deep-set / prominent — describes how far the eyeball sits within the orbit relative to the brow and cheek.

These categories overlap freely — an eye can be almond, hooded, and slightly downturned at once — which is why measurement-based description is more precise than a single label.

How AI measures the eye region

Refrakt maps dense landmarks around each eye — canthi, lid margins, iris outline, brow — and derives measurements in four steps:

1. Pose correction. The head is rotated to a level reference using stable midline landmarks, so head tilt doesn't masquerade as canthal tilt.
2. Canthus location. The medial and lateral canthus of each eye are located, and tilt is computed as the angle of the canthal line against the corrected horizontal — separately for each eye, because they usually differ slightly.
3. Distance normalization. Intercanthal distance, palpebral fissure length, and fissure height are measured and expressed relative to face width, since absolute pixel distances mean nothing without scale.
4. Shape description. Lid crease visibility, iris exposure, and height-to-width ratio are combined into a descriptive profile rather than a single shape verdict.

Typical eye measurements

All ranges are approximations drawn from anthropometric literature and vary by population, sex, and study methodology. They describe where most people fall — not where anyone should fall.

A note on normal variation

None of the features on this page are flaws. Negative canthal tilt, wide-set or close-set eyes, monolids, hooded lids, and left–right differences are all ordinary points on continuous distributions that every human face samples from. Measurement is useful for understanding what you're seeing in photos — and for catching when a camera angle, not your anatomy, is doing the talking. It is not a diagnosis, and it is not a verdict.

Frequently asked questions