Eye openness
Palpebral fissure height : length
How tall the eye opening is compared with how long it is, measured at the pupil and averaged over both eyes.
Also searched as palpebral fissure height, hooded eyes and how open the eyes are.
How to read it
the eyes are relatively narrow vertically for their length ("almond" or hooded configuration). Note this value depends heavily on gaze, fatigue and expression at the moment of capture.
vertical eye opening is typical for the reference group.
the eyes are relatively round or open for their length. As with the low case, the number depends on state. A brow raise or a look of surprise inflates it.
Reference values by population
| Reference population | Female (mean ± SD) | Male (mean ± SD) | n | Source |
|---|---|---|---|---|
| North American White | 0.349 ± 0.043 | 0.348 ± 0.042 | 2326 | Farkas 1994/2005 (NA White young adults) prov. |
| East Asian | 0.343 ± 0.047 | 0.344 ± 0.046 | 618 | Farkas 2005 (Chinese/Japanese/Vietnamese/Thai pooled); Jayaratne 2012 (Southern Chinese, n=103) prov. |
| South Asian | 0.349 ± 0.044 | 0.35 ± 0.044 | 210 | Farkas 2005 (Indian); Metgudmath 2022 prov. |
| African / African diaspora | 0.348 ± 0.043 | 0.349 ± 0.043 | 300 | Farkas 2005 (African-American, Zulu, Angolan) prov. |
| Middle Eastern | 0.353 ± 0.044 | 0.354 ± 0.044 | 348 | Farkas 2005 (Turkish, Iranian, Egyptian); Al-Sebaei 2015 (Saudi, n=168) prov. |
| Hispanic / Latino | 0.353 ± 0.044 | 0.353 ± 0.044 | 120 | Farkas 2005 (Mexican-American) prov. |
| Not specified — show pooled | 0.349 ± 0.047 | 0.35 ± 0.047 | 3922 | Unweighted pool of the six groups above prov. |
Where these numbers come from
Transcribed from the cited anthropometric literature; SDs of ratios are propagated conservatively (independence assumed). Entries marked prov. await line-by-line audit against the primary tables. See the norm provenance note.
Why every value has an error bar
Every value Canthion reports carries a 1σ uncertainty propagated from MediaPipe Face Mesh's published accuracy (3.96% of inter-ocular distance mean absolute error per landmark, Kartynnik 2019). On a typical photo with 300 px between the pupils, that is about 12 px of wander on every point. Small ratios and angles inherit it, so their intervals are wide. A number without an interval is a number pretending to be more precise than it is.
References
- Farkas, Katic & Forrest (2005). International Anthropometric Study of Facial Morphology in Various Ethnic Groups/Races. J Craniofac Surg 16(4):615–646. doi.org/10.1097/01.SCS.0000171847.58031.9E
- Kartynnik, Ablavatski, Grishchenko & Grundmann (2019). Real-time Facial Surface Geometry from Monocular Video on Mobile GPUs. arXiv:1907.06724. arxiv.org/abs/1907.06724
Common questions
What is eye openness?
How tall the eye opening is compared with how long it is, measured at the pupil and averaged over both eyes. Reported instead of the "Eye Aspect Ratio" (a blink detector that is misappropriated as an aesthetics metric).
How is eye openness measured from a photo?
It is computed from the face-mesh landmarks (up_R, lo_R, up_L, lo_L, en_R, ex_R, en_L, ex_L): mean over eyes of dist(upperLid, lowerLid) / dist(en, ex). Every value carries a 1σ error bar propagated from the landmark detector's published accuracy, with a floor of ± 0.03, so a small difference inside the interval is not a difference.
What is a normal eye openness?
Reference means and standard deviations from the anthropometric literature, by population. North American White: 0.349 ± 0.043 for women, 0.348 ± 0.042 for men; East Asian: 0.343 ± 0.047 for women, 0.344 ± 0.046 for men; South Asian: 0.349 ± 0.044 for women, 0.35 ± 0.044 for men; African / African diaspora: 0.348 ± 0.043 for women, 0.349 ± 0.043 for men. This value is provisional and awaits line-by-line audit against the primary tables. Your own value is placed on the distribution you choose, as a percentile with its error bar.
What does a low or high eye openness mean?
Below the mean: the eyes are relatively narrow vertically for their length ("almond" or hooded configuration). Note this value depends heavily on gaze, fatigue and expression at the moment of capture. Above the mean: the eyes are relatively round or open for their length. As with the low case, the number depends on state. A brow raise or a look of surprise inflates it.
Eye opening is one of the fourteen traits on the masculinity and femininity scale, with its effect size listed.
Related measurements
The rest of the eyes set, then the nearest measurements elsewhere on the face. Every one is computed on the same photograph, in the same run, with its own error bar.
Also: how bone-level measurements are taken from a photo · methodology · glossary · all 35 insight pages