A medial canthus is an extra fold of skin at the inner corner of the eye that connects the upper and lower eyelids, making the corner of the eye at an acute angle and giving the impression that the eye is narrowed. It is a characteristic of the Mongolian race, which means that most people in China have different degrees of medial canthus. Clinically, it is usually categorized into simple medial canthus and complex medial canthus. In the former case, there is only inner canthus, the eye crack is slightly narrowed, single lid or inner double, without other deformities; in the latter case, it is accompanied by a significant narrowing of the eye crack, thickening of the skin and subcutaneous tissue of the eyelid, orbicularis oculi muscle dysplasia, the lid plate is short and narrow, and there is often a drooping eyelid (the eyes don’t open much). Blepharoplasty, or medial canthoplasty, eliminates this redundant upper eyelid tissue through fine cosmetic surgical incisions without leaving visible surgical scars, and is designed to reveal the tear trough as completely as possible. In addition to actually widening the shape of the eye, this procedure also prevents the curve of the double eyelid from hiding in the inner corner of the eye. Generally, the length of the eyes can be increased by 1 to 3 millimeters by correcting the inner canthus, and the results are even better if blepharoplasty is added.