In-Fold, Out-Fold or Semi-Out: How Eyelid Lines Are Designed
The same double eyelid operation produces very different faces depending on where the line starts and how high it runs — and that design is anatomy first, taste second.
Before any double eyelid operation begins, the decisive work happens with a thin probe and a mirror: choosing the line. Korean practice sorts crease designs into three broad families — in-fold, out-fold and semi-out — named for how the line relates to the small skin web at the inner corner of the eye.
None of the three is inherently superior. Each interacts differently with the epicanthal fold, lid thickness and the distance between brow and eye, so a line that flatters one face can look artificial on another. Understanding the vocabulary helps patients participate in the design conversation instead of merely receiving it.
Three line families, three different eyes
An in-fold line begins inside or beneath the epicanthal fold, so the crease tapers and disappears toward the inner corner. It preserves the fold, reads as subtle and is the design most likely to pass as a natural-born crease, particularly on eyes where the fold is mild and the lid is thin.
An out-fold line runs parallel to the lid margin from a starting point outside the fold, producing a wider, more defined crease across the whole eye. Because a prominent epicanthal fold blocks that inner starting point, out-fold designs are often paired with epicanthoplasty, and the look is bolder — a change acquaintances will notice. Semi-out sits between the two, starting near the fold’s edge and opening gradually, which is why it has become a frequently requested compromise.
What the eye itself gets to decide
The epicanthal fold is the first gatekeeper: a strong fold resists an out-fold line unless the inner corner is released, while a weak fold leaves all three designs on the table. Lid thickness comes next — thick, full lids can swallow a low in-fold line, and very high creases on a thin lid can hollow with time — so surgeons adjust height in fractions of a millimeter against the tissue in front of them.
Beyond the lid, designers weigh horizontal eye length, the brow-to-lash distance, whether the eyes are deep-set or prominent, and the overall balance of the face. Two people can bring the same reference photo and correctly receive two different plans — individual variation in anatomy, not the surgeon’s preference, is what forces the divergence.
The design consult, and what happens after
A proper design session simulates the candidate lines on the patient’s own lids with a probe, in both a mirror and photographs, sitting upright since gravity changes the lid. It should end with the patient able to say not just which look they prefer but why that line suits their fold, thickness and face — the standard a board-certified specialist consultation is expected to meet.
After surgery the line looks higher than planned while swelling lasts, settling toward its final height over a recovery period of weeks to months. As with any eyelid operation there is a possibility of side effects — asymmetry, a line that loosens or deepens unevenly, and dissatisfaction with a design chosen in haste — which is one more argument for spending as long on the drawing as on the operation.
Before your consultation
- Collect reference photos of lines you like and dislike — both teach the designer.
- Ask which of the three families your fold and lid thickness realistically allow.
- Request a probe simulation while sitting upright, checked in both mirror and photos.
- Ask whether your plan requires epicanthoplasty and what that adds to recovery.
- Confirm when the line will settle and how asymmetry would be handled if it remains.
MediIndex articles are for general information only and are not medical advice, diagnosis, or advertising. Outcomes vary by individual — consult a board-certified specialist for personal decisions.
