Crow's feet
Crow’s feet are the lines that fan outward from the outer corners of the eyes. U.S. prescribing information calls them lateral canthal lines. They become more visible during smiling or squinting as the lateral orbicularis oculi contracts, although lines visible at rest may also reflect skin and soft-tissue changes that muscle relaxation does not fully address.
The condition is a clear example of why a broad phrase such as “aesthetic botulinum toxin” is insufficient. Several products have a U.S. glabellar-line indication, but only some name lateral canthal lines in their current U.S. labels.
Current U.S. lateral canthal line scope
Section titled “Current U.S. lateral canthal line scope”| Product | Lateral canthal lines in the current U.S. label | Interpretation |
|---|---|---|
| BOTOX Cosmetic (onabotulinumtoxinA) | Yes | Adult lateral canthal lines are a named aesthetic indication. |
| XEOMIN (incobotulinumtoxinA) | Yes | Adult lateral canthal lines are included individually and within upper-facial-line treatment. |
| DYSPORT (abobotulinumtoxinA) | No | Its current U.S. aesthetic indication is glabellar lines. |
| JEUVEAU (prabotulinumtoxinA-xvfs) | No | Its current U.S. label is specific to glabellar lines. |
| DAXXIFY (daxibotulinumtoxinA-lanm) | No | Its aesthetic indication is glabellar lines; cervical dystonia is a separate therapeutic indication. |
| LETYBO (letibotulinumtoxinA-wlbg) | No | Its current U.S. label is specific to glabellar lines. |
“No” means lateral canthal lines are not named in the current U.S. prescribing information. It does not describe another country’s approval, published research, or clinical use outside the U.S. label. The U.S. aesthetic facial-area matrix places this distinction beside glabellar, forehead, and platysma-band labels.
Smile anatomy changes the treatment question
Section titled “Smile anatomy changes the treatment question”The orbicularis oculi helps close the eyelids and contributes to both blinking and facial expression. Lateral canthal lines also interact visually with cheek elevation, eyebrow position, eye shape, skin elasticity, and the individual’s smile pattern. Reducing one muscle-driven line pattern does not reproduce the same expression or result in every face.
This anatomy is close to, but clinically distinct from, blepharospasm. Crow’s-feet treatment seeks temporary aesthetic improvement of lines during facial animation. Blepharospasm treatment seeks to reduce involuntary eyelid closure and preserve visual function.
Outcomes and comparison limits
Section titled “Outcomes and comparison limits”| Outcome | What it can answer |
|---|---|
| Line severity during maximum smile | Whether the dynamic lateral canthal pattern became less prominent at a defined assessment point |
| Subject-reported appearance | Whether the person perceived a meaningful aesthetic change |
| Resting-line appearance | Whether a static component changed; this may differ from the response during smiling |
| Facial animation and symmetry | Whether the result remains balanced during blinking, smiling, and other expressions |
| Duration and adverse effects | How long useful benefit and unwanted effects persist for the studied product and protocol |
Product trials may use different severity scales, assessment times, treatment patterns, and responder definitions. Cross-trial percentages therefore should not be treated as a direct brand ranking, and a glabellar-line study cannot by itself establish efficacy for lateral canthal lines.
Periocular safety interpretation
Section titled “Periocular safety interpretation”Unwanted local weakness around the eye may alter smile symmetry, eyelid function, or brow position. Dry eye, reduced blinking, eyelid droop, visual symptoms, bruising, and local discomfort are relevant considerations across product-specific labels and periocular anatomy. Pre-existing dry eye, eyelid laxity or malposition, facial nerve dysfunction, asymmetry, and prior periocular procedures can change risk.
Class-wide prescribing information also warns about symptoms consistent with distant spread of toxin effect. New persistent eye irritation, eye pain, marked redness, visual change, or difficulty closing the eye warrants clinical assessment.
See How anatomy changes botulinum toxin interpretation, Unit interpretation, and Safety and adverse-effect interpretation.
Related topics
Section titled “Related topics”References
Section titled “References”- U.S. National Library of Medicine. BOTOX Cosmetic prescribing information 🔗.
- U.S. National Library of Medicine. DYSPORT prescribing information 🔗.
- U.S. National Library of Medicine. XEOMIN prescribing information 🔗.
- U.S. National Library of Medicine. JEUVEAU prescribing information 🔗.
- U.S. National Library of Medicine. DAXXIFY prescribing information 🔗.
- U.S. National Library of Medicine. LETYBO prescribing information 🔗.
- Cochrane. Botulinum toxin type A for facial wrinkles 🔗.