The lateral canthus is the point where the outer edge of the upper and lower eyelids meet. These two structures join to form an angle. Rounding or blunting of this angle may occur after previous eyelid surgery or with aging.
How eyelid rounding is treated
A surgical procedure called canthoplasty is performed to repair the lateral canthal angle. Canthoplasty is a rearrangement of the section where the upper and lower eyelids meet.
The outer canthal angle is separated with a partial or complete canthotomy. This incision disconnects the fusion point between the upper and lower eyelids. Other attachments may be severed above and below the lateral canthal fusion line. Dissection exposes the upper and lower eyelid tarsus, a connective tissue support structure. If the eyelid opening is to be made horizontally wider, the tarsus (and the lateral angle) is anchored to the internal aspect of the lateral orbital rim via the bone lining (periosteum).
The angle is reformed with a stitch placed at the outer corner of the eyelids between the upper and lower tarsus at the precise location of the new angle. The skin edges are then approximated with stitches.
Stitches are removed at 7 – 14 days. Swelling and/or bruising are common during the healing period.
Rounding or blunting can return if the anchoring suture separates or if the outer canthus does not maintain its position at the lateral orbital rim. Webbing or scarring can cause the angle to lose its sharp definition.