Eyelid surgery, or a blepharoplasty, is a specific procedure that corrects oversized, sagging or disproportional eyelids, and can be performed on the upper or lower eyelids, or both. A blepharoplasty involves removing the excess skin and fatty deposits around the eye, and can involve tightening certain muscles in the area. The foremost function of eyelid surgery is for enhancing the appearance of the eyes, creating a more youthful look. However, sagging and excess skin surrounding the eyes can be so extensive in some cases that it may limit their vision, often making the surgery medically necessary.