The distribution of levator palpebrae superioris muscle on the knee is the factor that determines whether the eyes are double eyelids or single eyelids. In patients with double eyelids, a small part of levator palpebrae muscle fibers are attached to the skin, and most of levator palpebrae muscle is distributed on the tarsal plate, and double eyelids appear when muscles contract and lift; The levator palpebrae superioris muscle has no muscle fibers distributed in the upper eyelid skin, but all of them are distributed in the upper eyelid plate. When the muscles contract and lift, only the eyes open to form a single eyelid.
The formation of single eyelid and double eyelid;
Single eyelid refers to the smooth skin between the lower edge of the eyebrow arch of the upper eyelid and the eyelid margin. When you open your eyes, there are no wrinkles, which is called a single eyelid, commonly known as a single eyelid. Double eyelid means that the skin of the upper eyelid has a shallow groove above the eyelid margin. When you open your eyes, the skin under this groove moves upward, while the skin above this groove hangs loosely at the double eyelid groove and folds down into a horizontal fold, which is called double eyelid. In people's minds, the difference between double eyelids and single eyelids is obvious. In fact, there are aesthetic differences, morphological differences and anatomical differences between them.
Human single eyelid and double eyelid are related to heredity and generally remain unchanged for life. But a few people change with age. Some gradually become double eyelids as they grow up to adulthood; Some are aging and drooping eyelid skin, which covers the folds of the original double eyelids and gives people the appearance impression of a single eyelid. People's double eyelids are generally symmetrical in shape, but about 2.85%-8.89% people have different double eyelids, showing that one side is a single eyelid and the other is a double eyelid. For orientals, single eyelid and double eyelid are two different eyelid forms. Physiologically, both of them are normal, and there is basically no difference. But from an aesthetic point of view, single eyelids often give people the feeling that their eyes are small and "not beautiful". Functionally, it is not as good as double eyelids to express emotions and show bright eyes. Therefore, double eyelid plastic surgery can not only add aesthetic feeling, but also have certain functional significance in a sense, which is also the main reason for double eyelid plastic surgery.
Morphologically, the difference between a single eyelid and a double eyelid is that the skin of the entire upper eyelid is thick and bloated, and the skin is slightly drooping, covering the edge of the eyelid, and the root of eyelashes can't be seen when looking up. The upper eyelid skin is thin and delicate, the upper eyelid skin is not drooping, and the eyelid edge is all visible. The palpebral fissure of single eyelid is short and narrow; The palpebral fissure of double eyelids is longer and wider. The eyelashes of a single eyelid are short and sparse. When looking up, they tend to lean down. Sometimes eyelashes will cover the pupils, affecting vision and vision. People with double eyelids have long eyelashes and slightly upturned when they look up. The corner of a single eyelid is rounded because it is often accompanied by epicanthus; The inner canthus of patients with double eyelids is generally sharp, and there is generally no epicanthus.
Because the occurrence of single eyelid and double eyelid is influenced by race, region, heredity, age and other factors, there are obvious differences in morphology, so there are also obvious differences in anatomical structure. The skin of single eyelid is thicker, the subcutaneous tissue is higher, the orbicularis oculi muscle is more developed, and there is more fat behind the orbicularis oculi muscle. The tarsal plate of single eyelid is thin and narrow, and the levator palpebralis muscle with open eyes is underdeveloped; Double eyelids are just the opposite. The orbital septum position of single eyelid is generally low, and the orbital septum fat can prolapse on the upper edge of eyelid plate or in front of meibomian, while the orbital septum position of double eyelid is high, and there is no orbital septum fat prolapse on the upper edge of eyelid plate or in front of meibomian. Based on the anatomical structure, when the eyelid is open, the skin and orbicularis oculi muscle in front of the tarsal plate can't be lifted together with the tarsal plate, so the upper eyelid can't be folded, showing a single eyelid. When the double eyelids are opened, the skin and orbicularis oculi muscle below the double eyelid line in front of the meibomian can be lifted together with the meibomian, so wrinkles appear on the upper eyelids, showing double eyelids.
There are many ways to change a single eyelid into a double eyelid.
Sticking fake double eyelids;
Surgical formation of double eyelid plasty. Double eyelid plasty is divided into incision and suture, and their basic principles are the same, that is, trauma is caused between the skin of the upper eyelid and the tarsal plate or the aponeurosis of the levator palpebrae, forming scar adhesion. If the scar adhesion is not firm, such as the double eyelids formed by non-surgical methods (embedding thread or so-called polymer double eyelid plasty), the double eyelids will disappear.
Not all people with single eyelids are suitable for double eyelids, and not all people who have cut double eyelids will be satisfied with the operation. The influencing factors include: (1) the design of surgical incision. It is directly related to the surgical effect. The design of incision position is closely related to the patient's requirements and the doctor's aesthetics, so patients should have a serious discussion with plastic surgeons before operation to avoid differences due to different understanding of postoperative results. (2) the patient's own conditions. Some patients want to do double eyelid plastic surgery, but their own conditions are not good enough and the effect is poor. For example, patients with exophthalmos (patients with high myopia) may become stupefied and serious because of the appearance changes after double eyelid surgery. Such factors also include: people with smaller eyes; The distance between eyes is close; Patients with excessive fat in eyebrows and upper eyelid margin and loose upper eyelid skin may have some influence on the surgical effect. These factors should be carefully considered at least before operation. (3) Patients with scar constitution should not do this kind of operation, otherwise it will cause scar hyperplasia after operation and destroy the cosmetic effect. (4) If there are facial infections, such as folliculitis and acne, etc. Facial dermatosis should be cured before considering facial plastic surgery. (5) If you have conjunctivitis in both eyes, you should treat the eye disease first, and then do double eyelid surgery. (6) It is best not to have surgery during menstruation. Because there is much bleeding during the operation, the local swelling time after the operation is long and the reaction is heavy, which affects the operation effect, so it is best to arrange the operation 3-4 days after the menstruation is clean.
Because the skin, subcutaneous fat, orbicularis oculi muscle, orbital septum fascia and orbital fat are all involved in the operation, the blood and lymphatic circulation of eyelids are cut off. When the skin heals, the above-mentioned tissues will swell for a while. Generally speaking, three days after operation, the eyes were swollen obviously, and there were obvious blue spots around the orbit. The stitches were removed 5 days after operation. One week after operation, the swelling basically subsided, and slight blue spots or macula could still remain under the skin around the orbit. The shape of double eyelids is unnatural. It usually takes 1-2 months to return to normal after operation. If the appearance of the double eyelids is not satisfactory, it will take 3 months to repair after the operation.