Canthal tilt (eye corner angle): what it is
- Nerve
- Highlighted area
Quick facts
- Definition
- The angle between the line joining the inner and outer corners of the eye and a horizontal line.
- Reading
- Positive when the outer corner sits higher than the inner one; negative when it sits lower.
- Anatomical basis
- The medial and lateral canthal tendons, which anchor the eyelids to the rim of the orbit.
- What changes with age
- Laxity of the lateral canthal tendon and lower eyelid, and loss of support around the eye.
- Relevance in HOF
- Contributes to the impression of a tired or drooping look, along with the brow, eyelids and midface.
Canthal tilt, the angle of the eye corner, is the angle formed between the line joining the inner corner (medial canthus) and the outer corner (lateral canthus) of the eye and a horizontal line. When the outer corner sits higher than the inner one, the tilt is positive; when they are level, neutral; when the outer corner sits lower, negative. It is one of the components of the impression of a rested, tired or "droopy" look.
What defines the position of the corners?
The corners are the points where the upper and lower eyelids meet. Each one is anchored to the rim of the orbit by a tendon:
| Structure | Where it attaches | Role |
|---|---|---|
| Medial canthal tendon | Medial region of the orbit, near the lacrimal sac | Anchors the inner corner, which is relatively stable |
| Lateral canthal tendon | Inner face of the lateral rim of the orbit | Anchors the outer corner; its laxity changes the tilt |
| Lower eyelid | Between the two tendons, supported by the tarsus | Tone and support influence the shape of the outer corner |
In general, the outer corner sits slightly higher than the inner one, but the range considered harmonious varies with ethnicity, sex and age. There is no single "ideal" angle.
Why does the tilt change over time?
With aging, the lateral canthal tendon and the lower eyelid lose tone, and the outer corner may drop and become rounded. A drooping tail of the brow, loss of volume in the temples and midface, and excess upper eyelid skin increase the impression of a drooping look, even when the angle changes little. Previous eyelid surgery can also alter the corner.
Why does it matter in HOF?
Canthal tilt helps explain a common concern: "I look tired." The assessment separates what comes from the corner, what comes from the brow, what comes from the eyelid and what comes from support. Some injectable approaches are discussed to change how the lateral look is perceived, such as adjusting the strength of the orbicularis oculi at the tail of the brow, the subject of botulinum toxin in the brow, or restoring support in the temples and cheekbone. They do not change the point where the tendon attaches.
How does it appear in the assessment?
- Standardized frontal photo: head in a neutral position, no lateral tilt, because any rotation changes the angle. See standardized clinical photography and the Frankfurt plane.
- Comparison between sides: a difference between the eyes is common and is part of reading facial asymmetry.
- Lower eyelid traction test: assesses the tone and laxity of the corner.
- Upper eyelid: separate the tilt of the corner from eyelid ptosis, which depends on the levator of the upper eyelid.
- Brow and temples: position and volume change how the upper third reads. The anatomy of the area is in periorbital.
Also known as: canthal tilt, canthal inclination, intercanthal axis, intercanthal angle.
Frequently asked questions
What is canthal tilt?
It is the angle between the line joining the inner and outer corners of the eye and the horizontal. When the outer corner sits higher, the tilt is positive; when it sits lower, it is negative.
Does facial harmonization change canthal tilt?
Injectables do not change where the canthal tendon attaches to the bone. They can change how the eyes are perceived, for example by shifting the position of the tail of the brow or the support around the eye. Actually changing the position of the corner is surgical.