Measurement reference · FaceFluent editorial · September 13, 2026
Canthal tilt
The angle of the line joining the inner and outer corner of one eye, read against the horizontal. Positive means the outer corner sits higher than the inner corner; negative means it sits lower.
Educational method only. Personal numerical values are currently unavailable in the free preview and reports under the current offer. Existing purchases retain their purchased scope.
Also called eye tilt, palpebral fissure inclination, upturned eyes.
Reference range
None.
We have not validated a population reference interval for this photographic method. Published anatomical measurements do not automatically validate mesh-based estimates.
How we calculate it
We take the inner and outer eye-corner landmarks from the face mesh on both sides, correct the whole set for estimated head roll first, then average the left and right angles. Correcting for roll matters: a head tilted five degrees in the photograph would otherwise add five degrees to the result.
What moves the number
Head roll, camera height, a squint or a smile, and landmark placement on soft eyelid edges. Differences of a degree or two between two photographs of the same person are ordinary.
What it cannot tell you
A photograph cannot separate the shape of the bony orbit from eyelid position, and cannot tell whether a tilt is lifelong or recently changed. Typical values also differ between populations, so one band does not describe everyone.
Common questions
What is a negative canthal tilt?
A negative canthal tilt means the outer corner of the eye sits lower than the inner corner, so the angle reads below the horizontal. Positive is the reverse, and a tilt near zero is level. All three are ordinary descriptions of where two landmarks sit, and all three occur in faces everywhere.
Is a negative canthal tilt bad?
No. It is a direction, not a defect. Typical values differ between populations, so there is no single figure that counts as correct, and we do not publish a target band for this measurement because we have not validated one for photographs. Anyone presenting a canthal tilt as a pass or fail is adding a judgement the measurement does not contain.
How is canthal tilt measured from a photo?
By taking the inner and outer eye-corner landmarks on both sides, correcting the whole set for estimated head roll, then averaging the left and right angles. The roll correction is the step that matters most: a head tilted five degrees in the photograph would otherwise add five degrees to the answer.
Why does my canthal tilt change between photos?
Head roll, camera height, a squint or a smile, and where the landmark lands on a soft eyelid edge all move it. A difference of a degree or two between two photographs of the same person on the same day is ordinary and does not mean anything changed.
Does FaceFluent give me a canthal tilt number?
No. Optional on-device analysis draws landmark annotations in your browser without reporting personal numerical values. Haircut preview packs do not include personal measurements or a score. This page explains the method; it does not grade anyone.
References
- Farkas LG. Anthropometry of the Head and Face. 2nd ed. Raven Press, 1994 — the standard reference for how this measurement is defined and taken.
- Hwang K et al. The Latino Eyelid: Anthropometric Analysis of a Spectrum of Findings. Ophthalmic Plast Reconstr Surg, 2017 — one of many papers showing periorbital norms differ by population.
Canthal tilt is an angle between estimated eye-corner landmarks. It does not summarize a face.
Read: What canthal tilt describesTry a haircut on your photo. On-device landmark annotations are optional and stay in this browser.
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