Neutral Canthal Tilt

What near-level means

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 “no tilt” in the sense of 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]

What happens around 0°

Zero is the horizontal reference after roll is removed, not a target. Two photos can fall on opposite sides of zero when the head leans slightly, the expression changes, or one corner is marked a few pixels higher. That crossing is a reason to look at quality and to retake, not a reason to treat the face as two types.

Positive, near level, and negative

Retake checklist

• Camera at eye level, face toward the lens
• Both eyes open, corners uncovered
• Enough light to see the corners without a hard shadow
• If a marker misses, use Adjust eye corners before you keep the number

Measure on the homepage scanner, or compare the drawings on the positive versus negative page. The full reference choice is on the methodology page.