The wrinkles at the outer corners of your eyes are called crow’s feet because they resemble the three-pronged footprint a crow leaves in soft ground. The term dates back to at least 1374, when Geoffrey Chaucer used it in his writing, making it one of the oldest cosmetic terms still in everyday use.
The Visual Connection to a Crow’s Footprint
If you’ve ever seen bird tracks in mud or snow, the resemblance is hard to miss. A crow’s foot has three toes that fan outward from a central point, and the wrinkles at the corner of each eye follow almost exactly the same pattern. Fine lines radiate outward from the outer edge of the eye like spokes on a wheel, branching in slightly different directions. The comparison stuck because it’s genuinely accurate, and more than six centuries later, dermatologists still use the nickname alongside the clinical term “lateral canthal lines.”
The lines are also sometimes called laugh lines, which reflects how they form. Every time you smile, squint, or laugh, a ring-shaped muscle surrounding your eye contracts and bunches the skin at the outer corner. Over years, those temporary creases become permanent grooves.
Why This Spot Wrinkles So Easily
The skin around your eyes is some of the thinnest on your face, and the entire area gets an unusual amount of mechanical stress. The muscle responsible is the orbicularis oculi, a circular muscle that wraps around each eye socket like a sphincter. When its outer fibers contract, they create folds perpendicular to the direction of the muscle, which is why the lines fan outward rather than forming a single crease.
You use this muscle constantly, often without thinking about it. Squinting in bright light, concentrating at a screen, laughing, frowning, even blinking forcefully all engage the outer fibers. Over time, the repeated folding breaks down collagen and elastin in the skin, and the lines stop disappearing when your face relaxes.
Dynamic Lines vs. Permanent Creases
Crow’s feet start as dynamic wrinkles, meaning they only show up when you’re actively making an expression. Everyone has these, regardless of age. The skin buckles under compression from the muscle, and as soon as the muscle relaxes, the skin snaps back smooth.
Static wrinkles are the ones that stay visible even when your face is completely at rest. These typically start appearing in the early 30s and deepen with age. The transition from dynamic to static happens as the skin loses its ability to bounce back. Sun damage plays a major role here. UV exposure breaks down elastic fibers in the skin (a process called solar elastosis), and research on cadaver skin found that wrinkle depth at the outer eye corner continued to increase even after the elastic fiber damage had plateaued. In other words, once the structural damage is done, the wrinkles keep getting worse on their own.
What Makes Crow’s Feet Worse
Sun exposure is the single biggest accelerator. UV radiation denatures the elastic fibers in the upper and middle layers of the skin, which is why people with significant sun exposure develop deeper lines earlier. But it’s not the only factor.
Smoking has a measurable effect on crow’s feet severity. A large multinational study found that current and former smokers had statistically deeper crow’s feet than nonsmokers, even after controlling for age, BMI, and race. The effect was dose-dependent: women who had smoked more than 20 pack-years showed the greatest increase in severity. Cigarette smoke generates free radicals that damage collagen repair mechanisms, reduces collagen and elastin production, and constricts the tiny blood vessels that supply the skin with nutrients. The severity of crow’s feet increased with both how long and how much a person smoked.
Slowing and Treating Crow’s Feet
Prescription retinoid creams are the most studied topical treatment for fine wrinkles. Tretinoin, the strongest form, is available in concentrations from 0.01% to 0.1% and is FDA-approved for treating facial wrinkles. Visible improvement takes time. Clinical trials typically run 24 to 36 weeks before measuring results, so patience matters. Interestingly, a 12-week comparative study found that over-the-counter retinol formulations (0.25% to 1.0%) produced statistically significant improvements in fine lines comparable to prescription tretinoin, which makes retinol a reasonable starting point for most people.
For faster or more dramatic results, botulinum toxin injections temporarily paralyze the outer fibers of the muscle that causes the creasing. The standard treatment involves small injections at three points on each side of the face. Results typically last three to four months before the muscle regains full function and the lines return. Because the treatment targets dynamic lines (the ones caused by muscle movement), it works best on crow’s feet that are still primarily expression-related rather than deeply etched static wrinkles.
Daily sunscreen remains the simplest and most effective preventive measure. Since UV damage to elastic fibers is the primary driver of wrinkle depth at the outer eye corner, consistent sun protection slows the progression more than any single treatment can reverse it. Sunglasses reduce squinting, which cuts down on the repetitive muscle contractions that create the lines in the first place.