Double eyelids, in ophthalmic terminology, are called upper eyelid folds. The presence or absence of an eyelid depends on the anatomical basis of the orbital septum and the levator aponeurosis, which must be located at the upper edge of the lid. In Caucasians, the septum and levator aponeurosis are located at the upper edge of the lid plate, so most of the septum is located at the front edge of the lid plate, and in some people, the orbital fat is also removed, so most oriental people have single eyelids, and some people have “swollen” eyelids. In addition, if the septum is high, the eyelids will be larger, and vice versa, they will be smaller, or form an “inner double”, which is a small double eyelid where the lower lip of the eyelid is smaller and covered by the upper lip. Double eyelids can add dimension to the eyes, and single eyelids can make the eyes look big and shiny. However, not all people are suitable for double eyelid surgery. The following cases are not suitable for double eyelid surgery: people with small eyes and eyelid fissures smaller than normal (28 mm), the double eyelid will make the middle of the lid fissure wider and give people a round and frothy feeling; people with “flesh bubble eyes” are not suitable for double eyelid surgery. If you have too much fat under the eyelid, it will still sag when you open your eyes, making the top of the surgical suture thicker and more bulging, and narrowing the width of the eyelid accordingly, which is not good. This is a condition in which the skin is bruised or operated on, and the wound or incision produces a proliferative scar with an uneven surface. In this case, not only is there no blepharoplasty effect, but the eyelid is also deformed; in people over 40 years old, the eyelid is loose and there are more deep wrinkles after opening the eyes. Therefore, it is important to be cautious about whether or not to have blepharoplasty. People with multiple eye diseases. If you want to have double eyelids, you must be examined by a doctor before you can be sure. How to choose double eyelid surgery.