Crow's feet:
causes, signs and the order of treatment

What causes crow's feet?

Crow's feet are caused by the orbicularis oculi, the circular muscle around the eye, contracting against skin that is thin and loosely attached. Its outer fibres pull the skin toward the eye each time you smile, laugh, squint or close the eyes firmly, and the skin folds in the same radiating pattern every time. Young dermis springs back; dermis that has lost collagen and elastin keeps a trace of the fold, and the trace deepens with repetition.

Several things speed that process up. Ultraviolet light degrades collagen and elastin, and the outer eye is exposed in every outdoor hour in Singapore, which is why sun protection is the first item on any plan. Squinting in bright light or at a small screen recruits the same muscle for hours a day. Smoking, poor sleep and a dehydrated skin barrier all show first in this thin skin. Genetics sets the baseline: some faces fold here from their twenties, others barely at all.

The same mechanism that writes crow's feet also writes the lines on the forehead and between the brows, and the botulinum toxin page sets out how muscle-driven lines are approached across the upper face. The condition guide for forehead lines and frown lines covers the other two upper-face groups in the same way as this page.

What do crow's feet look like, and how are they graded?

Crow's feet begin as a fan of fine lines that appears at the outer corner of the eye on smiling and disappears when the face relaxes. These are dynamic lines, and they are the earliest and most reversible stage. Over time some of the lines remain faintly visible with the face at rest, then more clearly, and the skin between them can take on a crepey texture. These are static lines, and they signal that the dermis itself has changed.

At assessment the lines are examined in three states: at rest, in a gentle smile and in a full squint. The pattern matters as much as the depth. Lines that fan upward and outward from the eye belong to the orbicularis. Lines that run down onto the cheek and deepen with a broad smile are often made by the cheek-lifting muscles pushing skin upward, and they do not respond to toxin placed in the orbicularis. Under-eye crepe below the lashes is a skin-quality problem rather than a muscle problem. Each of these looks like crow's feet in a photograph and is treated differently.

The distinction that matters most is simple and is checked at the first visit: do the lines vanish when the face is still? If they do, movement is the whole problem. If they do not, the skin has learned the crease and softening the muscle alone will not remove it.

“If the line is there at rest, reducing muscle movement will not remove it.”

Dr Sin YongOn dynamic versus static lines

In what order is treatment planned?

Treatment is planned in order of cause. The first step is protection: daily broad-spectrum sunscreen, sunglasses in glare and a retinoid or barrier-repair routine where the skin tolerates it, because nothing done in clinic holds well on skin that is still being degraded every lunchtime. This step is not a substitute for treatment, but it is the floor everything else stands on.

The second step is the muscle. Botulinum toxin is a prescription medicine that blocks the signal from nerve to muscle, so the outer fibres of the orbicularis contract less and the skin is folded less often. Dr Sin Yong places small doses at mapped points at the outer eye after examining the smile, keeping the dose conservative so that the eyes still crease naturally when you laugh. The effect is temporary and wears off as the nerve endings recover, so any repeat is timed at review rather than on a fixed calendar.

The third step is the skin, and it is needed only where lines remain at rest. Skin boosters and polynucleotides hydrate and thicken thin periorbital skin; fractional laser and radiofrequency microneedling remodel collagen in the creased dermis. These are chosen by how thin and how etched the skin is. For crepey, finely wrinkled skin around the eyes, Dr Sin Yong’s preferred laser is the FSX laser. Filler is used sparingly here, if at all, because the skin is thin and the area swells readily. Where the real problem is loose excess skin of the lower lid, an oculoplastic or plastic surgery specialist is the right referral rather than more injections.

Who it suits and who should wait?

Botulinum toxin for crow's feet suits people whose lines appear mainly in expression, who want a lighter fan rather than an immobile eye, and who are comfortable with a temporary effect reviewed over time. It also suits people with early static lines as the first half of a two-part plan, with skin treatment following once movement is softened.

Treatment is deferred in pregnancy and breastfeeding, with an active infection, stye or cold sore near the eye, and when there is a neuromuscular condition such as myasthenia gravis, a known allergy to a botulinum toxin product, or medicines that affect nerve-to-muscle transmission that have not been reviewed. People hoping to erase lines that are deeply etched at rest, or to tighten loose lower-lid skin, tend to be disappointed by toxin alone and are offered a skin-directed or surgical route instead.

What are the risks, and when should you call?

The common effects are small bruises at the injection points, mild swelling and tenderness, which settle. Less commonly, toxin spreads to a neighbouring muscle: into the cheek elevators, giving a flatter or uneven smile, or toward the lower eyelid, giving a weaker blink, a watery or dry eye, or a small bulge of the lower lid on smiling. Because the medicine acts for as long as it acts, these effects cannot be reversed on demand; they fade as it wears off. Accurate placement, conservative doses and an examination of the smile beforehand reduce the chance of them, and no technique removes it.

Call the clinic for a drooping lid or brow, a change in the smile, double vision, or an eye that will not close fully. Difficulty swallowing, speaking or breathing after any botulinum toxin injection needs urgent care at a hospital emergency department. The complication care page explains what to do if something feels wrong after a treatment, wherever it was done.

What determines the fee for crow's feet treatment?

Singapore's advertising rules prevent clinics from publishing prices, so this page gives factors rather than figures. The fee depends on whether the outer eye is treated alone or together with the forehead and frown, on the dose each side needs, which varies with muscle strength and the pattern of the smile, and on the formulation chosen. Where etched lines call for a skin-directed treatment as well, that is quoted separately. A written quote follows the consultation, and how quotes are prepared is explained on the fee page.

When should you see a doctor about crow's feet?

See a doctor when lines at the outer eye are deepening at rest despite daily sun protection, when the two sides have become noticeably different, or when the lines sit alongside a heavy or drooping upper lid, which changes the plan. A new one-sided change in how the eye closes or how the face moves needs medical review rather than a cosmetic appointment. Eye irritation, redness or watering that has started with the lines should be checked, since squinting against discomfort writes lines faster.

At the consultation the lines are examined at rest, in a smile and in a squint, the brow and lids are checked, and the options are explained with their risks, including the option of no treatment. The consultation process page describes what to expect and what to bring.