Crow's Feet: Why the Outer Eye Creases First, and What Helps

Crow's feet are the lines that fan out from the outer corner of your eye. They form where the orbicularis oculi, the ring of muscle that closes your eye, folds thin skin each time you smile or squint. Sun damage decides how soon they stay after the smile has gone. Below: why this skin creases early, what squinting and sun add, what the evidence supports, and where a clinic comes in.

What are crow's feet?

MedlinePlus puts it simply. As skin ages, the skin around the eyes wrinkles, creating crow's feet at the side of the eyes. Clinicians call them lateral canthal lines, after the lateral canthus, the outer corner where your lids meet.

The muscle underneath explains their shape. The orbicularis oculi is a sphincter-like muscle arranged in rings around the upper and lower lids, and its main job is closing them. Facial muscles insert directly into the skin, so repeated contraction forms lines perpendicular to the direction of pull. A ring that tightens toward the eye pleats the skin at its outer edge into lines that point away from it, like spokes.

They start as movement lines. The same 2022 review describes crow's feet as lines that radiate from the outer corner and appear first on smiling. With aging, sun damage and skin remodeling, they may become static. The lines below the lower lid are a separate problem with separate causes, covered in under-eye wrinkles.

You can check which stage yours are at. Smile hard in a mirror, then let your face go completely slack and look again under even light. Lines that vanish at rest are still movement lines. Lines that stay have started to set.

Why the skin at the outer eye creases early

The skin here is thin. In a study of 10 cadaver heads sampled at 39 sites, eyelid skin was the thinnest on the face. An earlier study used the upper eyelid as its baseline and found brow and forehead skin about 2.8 times thicker. Crow's feet begin at the edge of that thin eyelid skin, where smiles and squints fold it.

The lines also arrive early. The 2022 review calls lateral canthal wrinkling possibly one of the earliest signs of aging. A 2014 study of 200 adults aged 20 to 70 found that in women, lines around the eyes were the first visible wrinkles. In men, forehead lines came first, and men's wrinkles appeared earlier overall.

Smiling and squinting: the muscle side

Two everyday movements do most of the folding. The review traces crow's feet to repeated contraction of the muscles used in smiling and squinting, notably the orbicularis oculi.

The smile part is not a flaw. A smile that engages the eye muscle is called a Duchenne smile, and research links it with enjoyment. A 2021 study used photos of people taken before and after wrinkle-relaxing treatment of the outer eye muscle. Smiles with the muscle active were rated as more felt, spontaneous, intense and happier. After treatment, the faces looked younger but not more attractive. The study was funded by Allergan.

Squinting is the part you can reduce. Bright light makes you narrow your eyes, and narrowing uses the same ring of muscle. Sunglasses take away one reason to squint. We found no trial testing whether they prevent crow's feet, so treat that as reasoning, not evidence.

Your pillow can add lines too. A 2016 review separates sleep wrinkles from expression wrinkles by cause, location and pattern. If the lines on one side run deeper, the side you sleep on is worth a thought.

The sun side: skin that sunscreen misses

Sun damage is one reason moving lines become fixed. In 186 pairs of identical twins, the twin with more sun exposure looked older, and so did the twin who smoked longer. Same genes, different habits.

The eye area is also where sunscreen goes missing. In a Liverpool study, 57 people were photographed with a UV camera before and after applying sunscreen. They missed a median 14 percent of the eyelid region, against 7 percent of the rest of the face. A follow-up in 84 people found SPF moisturizer did worse. It missed 20.9 percent of the eyelid region, against 14.0 percent for sunscreen, and the participants did not realize it.

The Liverpool team notes that these missed areas are prone to skin cancer, and it recommends UV-blocking sunglasses as extra protection. So apply sunscreen to the outer eye on purpose, not in passing. The randomized evidence for daily sunscreen comes from a 4.5-year trial in 903 adults. The daily group showed 24 percent less skin aging than the group that used it at their own discretion.

What the evidence supports for crow's feet

Few topical trials measure crow's feet on their own. Here is what we found, with the limits attached.

Approach	Best evidence we found	Limits
Daily sunscreen	4.5-year randomized trial, 903 adults	Graded skin surface texture, not crow's feet
Retinol	52-week trial of 0.1 percent retinol, 62 people, crow's feet measured	One industry-funded trial, and retinoids can irritate
Centella	Two 12-week placebo-controlled trials around the eyes	Small, and extracts are not standardized
Argireline	4-week randomized trial, 60 people, around the eyes	Short, and its reach to the muscle is uncertain
Moisturizer	Smooths the surface for about 4 hours	Temporary

Retinol. The year-long trial applied 0.1 percent stabilized retinol or a plain vehicle to the full face. After 52 weeks, crow's feet fine lines had improved by 44 percent, and gains continued with longer use. That is one trial. A 2021 review of nine vehicle-controlled retinol trials found major methodological flaws in every positive one, this one included, and noted it was funded by a skincare company. Irritation is the usual cost: in a Japanese retinol trial, 3 of 57 women withdrew because of it. Our retinol guide covers how to start slowly.

Centella. A 2020 network meta-analysis found five small trials in 172 Asian women. Two of them applied centella to the skin around the eyes for 12 weeks against placebo. The authors concluded it improved eye-area wrinkles, and flagged weak reporting and unstandardized extracts. More in our centella explainer.

Argireline. This peptide, listed on labels as acetyl hexapeptide-8, was tested in 60 Chinese adults for 4 weeks around the eyes. In the subjective assessment, 48.9 percent of the peptide group were rated as improved, against none on placebo, and skin replicas showed less roughness. Four weeks is short. A 2025 review calls the peptide's ability to reach the junction between nerve and muscle uncertain when applied to skin. Our peptides explainer has the wider picture.

Moisturizer. Hydration flattens the valleys between skin ridges, and the effect usually lasts about 4 hours. That is worth having. It is also why a cream can seem to work at breakfast and not by dinner.

When a clinic is the more honest answer

If your crow's feet are mostly movement, the clinic tool aimed at them relaxes the muscle, and whether it suits you is a question for a dermatologist. A 2021 Cochrane review pooled 65 randomized trials of botulinum toxin type A, with 14,919 participants. Treatment reduced wrinkles within four weeks, but probably raised the risk of a drooping eyelid. Only seven of those trials treated crow's feet. Most treated the frown lines between the brows, and the reviewers judged none of the 65 to be at low risk of bias in every domain.

The eye muscles make placement matter. The 2022 review warns that product spreading toward one of the muscles that move the eye can cause double vision. It sets distance limits from the eye for that reason. The AAD warns against any botulinum toxin treatment at a non-medical spa, a party, a salon or someone's home.

For etched lines and texture, the AAD lists chemical peels, microdermabrasion and laser resurfacing among its wrinkle treatments. Fillers are a poor fit here: the FDA recommends against using dermal fillers around the eyes.

If you own a home microneedling device, keep it off the eyelid, the lash line and anything inside the orbital rim. Our entry on microneedling under the eyes explains what the thin skin changes.

There is one more reason to see a dermatologist. The Liverpool researchers describe the eyelid region as prone to skin cancer. A new or changing spot near your eye is not a wrinkle question.

Frequently asked questions

At what age do crow's feet start?

Often earlier than other lines. In a study of 200 adults aged 20 to 70, lines around the eyes were the first visible wrinkles in women, while men showed forehead lines first. Crow's feet usually begin as movement lines that show only when you smile. Sun damage and age are what make them stay.

Are crow's feet caused by smiling?

Partly. Smiling and squinting both contract the ring of muscle around the eye, and the lines form at its outer edge. A genuine smile engages that muscle, which is part of why people read it as felt. The lines stay at rest once sun damage and age have changed the skin they sit in.

Does eye cream help crow's feet?

It depends on what is in it. Moisturizing smooths fine lines for a few hours. Retinol has one year-long, industry-funded trial that measured crow's feet, while centella and argireline have small, short trials. The word "eye" on the jar does not change the evidence.

Can you use retinol for crow's feet?

Many people do. One 52-week trial of 0.1 percent retinol measured crow's feet directly and reported improvement, though a 2021 review judged the positive retinol trials methodologically weak. Irritation is the usual side effect, so start with a low strength a few nights a week. See a dermatologist first if your skin is reactive or you have eczema near the eyes.

Do sunglasses prevent crow's feet?

We could not find a trial that tested it. Sunglasses shade the skin that sunscreen application most often misses, and the researchers who measured that gap recommend UV-blocking sunglasses. They also take away one reason to squint.

What are the risks of wrinkle-relaxing treatment for crow's feet?

A Cochrane review found it probably raises the risk of a drooping eyelid. Product spreading toward the muscles that move the eye can cause double vision, which is why clinicians keep a set distance from the eye. Most side effects are mild and temporary. If you are considering it, talk to a board-certified dermatologist, never a spa or a party.