Three different hollows that get called the same name
Patients say "my under-eye is sunken," but examination usually finds one of three distinct patterns — and they are not treated the same way. The first is hollowing directly under the aegyo-sal, the youthful fullness beneath the lashes: some people are born with a prominent aegyo-sal and little fat below it, and others acquired this hollow after a previous operation removed too much fat. The second is the tear trough itself, which may be congenitally deep, may be exaggerated by visible bluish vessels that read as depth even where there is little true hollowing, or may have been made worse by previous injections. The third is the diagonal extension onto the mid-cheek, typical of lean faces, strong retaining ligaments, and significant weight loss. Identifying which pattern — or which combination — you have is most of the treatment plan.
Why the under-eye punishes casual filling
Fat grafting behaves very differently depending on where on the face it is used. In the forehead or temples, fat can be placed deep and in quantity, and the surface forgives it. The under-eye forgives almost nothing: the skin is the thinnest on the face, it moves with every expression, and there is little tissue between the graft and the surface. Fat placed carelessly here can harden, clump, become visible or palpable, and in some cases calcify. This is not an argument against fat grafting — it is an argument for treating the under-eye as a specialist zone where placement depth, particle size, and quantity all have narrow margins. ST places grafted fat inside the deeper fat compartment, not near the skin or muscle, precisely for this reason.
Where filler fits — and where it backfires
Filler deserves a fair description. It is the simplest option — no harvesting, a short procedure — and in experienced hands it can be genuinely useful for the right indication. Its limits are structural: hyaluronic filler absorbs over roughly six months to a year, so it is a maintenance commitment rather than a correction; non-dissolvable fillers can cause late problems and are far harder to remove. And in exactly the patients who most often ask for it — thin skin, visible vessels — a translucent gel close to the surface can read as a bluish shadow and make dark circles look worse, not better. Filler also cannot address a bulge or a tethered groove; it can only add volume around them.
Where fat grafting fits — and its structural blind spot
Grafted fat has real advantages over filler in this region: it is your own tissue, so rejection is not an issue and infection risk is low; it is opaque, so it does not create the bluish translucency of gel under thin skin, and it can genuinely help the colour of dark circles; and the portion that survives — typically 50 to 80% — is permanent living tissue. But fat grafting has a structural blind spot: it adds volume, and volume is not always the problem. The tear trough is the thinnest, most tethered spot of the under-eye. Graft over an unreleased tear-trough ligament and the material cannot stay in the tethered line — it spreads above and below, the ridges rise, the valley stays anchored, and the groove can look deeper. This is the classic pattern of patients who arrive at ST after grafting elsewhere: irregularity above and below, with the original line still cutting through the middle.
Why repositioned fat behaves differently from injected fat
There is an important distinction between the two kinds of fat used around the under-eye. Free grafted fat is harvested, processed, and re-injected as disconnected tissue; it must regain a blood supply where it lands, which is why a share of it absorbs. Repositioned orbital fat is different: it is moved over the bone edge as a pedicle — still attached to its own blood supply — and fixed in place. Because it never loses circulation, it does not undergo the same absorption, and once fixation holds, the correction is expected to be stable long-term. This is why, when a hollow coexists with a bulge or a tethered groove, repositioning the eye’s own fat is the primary correction, and free grafting is the balancing tool — used to even out a side with genuinely insufficient fat, placed inside the deep compartment.
If your under-eye has already been filled
Many patients arrive not with an untouched hollow but with a history — filler, collagen injections, grafted fat, sometimes several rounds. The practical hierarchy: dissolvable hyaluronic filler is the most manageable, because it can be dissolved with an enzyme injection or removed during surgery. Non-dissolvable filler and collagen are the hardest to clear. Previously grafted fat sits in between — during corrective surgery it can be reduced, but only partially, because fat that has integrated near skin and muscle cannot be stripped out without damaging the normal tissue around it; the goal is judicious reduction, not eradication. If removal leaves one side short, balance is restored by re-grafting — after the structure is corrected, and inside the deep fat compartment. One request matters above all: disclose every previous procedure, including threads and collagen, before surgery. The plan, the operating time, and the honesty of what can be promised all depend on it.