What this site is for
This is patient education about the lines at the outer eye corner, published by Chongqing West District Hospital, a tertiary general hospital in Jiulongpo District, Chongqing. It is a concern guide rather than a procedure page: it answers why this is happening, whether it needs treatment, and which of several paths applies. The techniques themselves, and the anatomy they work on, are explained on the pages that cover those treatments, and repeating them here would help nobody.
The distinction the site is built on
Two different things are called crow's feet. One is a crease produced by the orbicularis oculi, the ring of muscle that squints and closes the lid, folding the same skin along the same line thousands of times a day. The other is a change in the skin itself: it is the thinnest skin on the face, it has almost no fat beneath it, and it takes a lifetime of sun. The two look like one line in a mirror and they answer to different things, which is why a treatment chosen before they are separated is a guess, and why most disappointment in this area comes from having addressed one while the other is what shows.
What it deliberately does not do
It does not name products or brands, quote prices or dosages, or promise a result. It does not present a cream as an alternative to treating the muscle where the muscle is what makes the line, or describe an injectable as a treatment for skin that has lost its elasticity. It does not describe technique, because that belongs to the pages that cover those treatments. And it does not treat a one-sided change, a drooping lid, a new lump or a change in vision as an appearance problem at any point.
The limits of a website
Nothing here can tell you how much of your own line is muscle and how much is skin, and that proportion is what decides which rung is worth reaching for. It requires someone to watch the eye corner at rest and in movement, to feel the thickness of the skin, and to look at the lid edge and the brow while doing it. Use this site to arrive at an assessment with better questions, and treat any answer you receive here as general information rather than as advice about you.