Calibration
Neutral Canthal Tilt
Near level means the corners are close to the face-relative horizontal. The signed angle still comes first.
−2°
Band edge
0°
Reference
+2°
Band edge
Measure a near-level result
A second level photo is the useful check when the number sits near zero.
Use your own photo
Front-facing · Eye-level · Neutral expression · Good lighting
Local processingYour image stays on this device.How privacy worksValues near zero
On this site, an average from −2° through +2° is the near-level display band. −1.5° is a negative direction inside that band. +1.5° is a positive direction inside it. Neither result is a perfectly level line.
Why the band exists
A tenth of a degree can come from where a landmark sits on a lash. Without a band, the label would flip between negative and positive on repeated photos of the same face. The band is a display rule. Published clinical classes use different cutoffs, including a 0° boundary in one surgical series.[1]
Why results near zero can change
Same eye. A photo pose, a landmark a few pixels high, or a second photo can cross 0°. That is uncertainty, not two different faces.
When to retake
- The camera is below the chin or above the forehead
- The head is turned, or one corner is in shadow
- A marker sits on a lash instead of the corner
- Two photos of the same face fall on opposite sides of zero
Hold the camera at eye level, look straight ahead, and keep both corners visible. Then read the quality mark.
Context
Where near level sits
The same eye, drawn at the three display directions.
The reference choice is on the methodology page.
References
- 01
Diagnostic analysis of vertical orbital dystopia and canthal tilt for surgical correction
PubMed ↗