Intercanthal Distance.

What intercanthal distance is

Intercanthal distance (often abbreviated ICD) is the straight horizontal distance between the inner corners of your eyes — the medial canthi, where the upper and lower eyelids meet near the bridge of the nose. It’s one of the oldest measured facial proportions in art and medicine, going back to da Vinci’s anatomical sketches and to ancient Greek sculpting canons.

The classical rule, attributed to da Vinci’s Vitruvian Man proportions and confirmed by modern anthropometric studies:

The inner-eye-corner-to-inner-eye-corner distance should equal one eye width.

Which means, at eye level, the face should be exactly three eye-widths across:

• Eye 1 (left)
• Gap (between inner canthi) = 1 eye width
• Eye 2 (right)

Total = 3 eye-widths. This is also called the “thirds rule” of eye spacing.

Normal ranges

In adult populations, intercanthal distance averages:

• Adult male: ~30–32 mm
• Adult female: ~28–30 mm

Compared to one eye width (~30 mm in adults), most people are within 2–3 mm of the ideal. Deviations get named:

• Telecanthus — ICD significantly wider than one eye width. Often genetic; common in certain syndromes but also occurs in healthy populations. Reads as childlike or “doll-like.”
• Hypotelorism — ICD significantly narrower than one eye width. Rare. Reads as intense or “predator-like” in mild form; in extreme form is a clinical finding.

Why it matters for face scoring

Intercanthal distance is one of the cleanest applications of the golden ratio and the related rule-of-thirds. It’s reliably measured, it doesn’t move with weight or age, and it correlates with several other things:

1. Apparent eye size — wider ICD makes the eyes look smaller because the same eye is now framed by more “empty” space
2. Apparent face width — wider ICD makes the face read wider at eye level
3. Apparent intelligence and seriousness — narrower ICD correlates with perceived seriousness; wider ICD correlates with perceived approachability and youthfulness
4. Hunter eye look — slightly narrower ICD reinforces the focused, predatory look

In attractiveness research, faces rated most attractive cluster within ±5% of one-eye-width ICD. Beyond that range in either direction, scores drop — even when every other feature is identical.

What “wider than ideal” does

Many otherwise high-scoring faces have slight telecanthus — ICD 5–10% wider than ideal. The visual effect:

• Eyes look slightly small relative to the face
• The midface reads wider, which can be flattering or unflattering depending on jaw width
• The face reads slightly more childlike or “innocent”

For female faces this can actually be a positive — it boosts perceived neoteny. For male faces it tends to soften the look and cost points on the masculinity sub-score.

What “narrower than ideal” does

Less common, more striking:

• Eyes appear larger relative to the face
• The face reads more intense, more focused
• The bridge of the nose appears prominent

Narrower ICD often pairs with hunter eyes and high cheekbones — the combination is the classic “model” face geometry. But pushed too far (true hypotelorism) it becomes a clinical finding and reads as off.

Can you change it?

The bone position of the medial canthi is set in childhood. You cannot change actual ICD without surgery (medial canthopexy or epicanthoplasty, both rare cosmetic procedures).

What you can change is apparent ICD:

• Brow grooming — slightly trimming the inner brow hairs makes the inner canthi look closer together
• Makeup (for female faces) — darker shadow at the inner corner narrows perceived ICD; lighter shadow widens it
• Glasses bridge width — thick, dark bridge widens apparent ICD; thin, light bridge does the opposite
• Beard shape (for male faces) — connecting beard upward toward the eyes pulls visual focus inward, narrowing perceived ICD

How Fazly measures it

Your scan measures ICD in mm and reports the ratio of ICD to single eye width. The app flags whether you’re inside the ±5% ideal band, on the wider side (slight telecanthus), or on the narrower side. It does not recommend surgery — apparent-ICD fixes from grooming and styling almost always close the gap visually.

Eye-area sub-scores combine ICD, canthal tilt, eye size, and brow position. A face can have wider-than-ideal ICD and still score top-tier on the eye sub-score if everything else is in proportion — the system rewards balance, not individual perfection.

Take front-on scans with head perfectly level and camera at eye height for stable ICD readings — small head tilts swing apparent ICD by several mm.