Overview

The shape of our eyes is directly dependent on eyelid tone, position, and contour. Eyelid anatomy is not only significant from a cosmetic standpoint, giving vitality to our eyes and lending them their shape; its function is also essential for guaranteeing a normal blink and protecting the eyes’ surface.

The lateral canthus, located where the upper eyelid meets the lower eyelid, is arguably the most distinctive feature of our eyelids. This anatomical region is highly complex, composed of intricate structures such as skin, muscle, fat, and tendon harmoniously providing eyelid support and tone. The canthus should meet at a perfect angle, called the commissure, to give the eyes their much-desired almond shape.

Restoring eyelid shape and contour: cosmetic canthal procedures

Because eyelid function depends so much on the integrity of this area, eyelid surgeons are regularly required to manipulate the lateral canthus in cosmetic and functional operations. The lateral canthus is essential in determining upper and lower eyelid position. Oculoplastic surgeons have the difficult task of operating on intricate structures that may affect eyelid function if done incorrectly; it is, therefore, understandable that most surgeons would prefer to stay clear of this area. However, canthal surgery is an essential part of cosmetic lower eyelid surgical procedures. Deciding to avoid canthal surgery may result in poor results in the best of cases and postoperative complications in the worst-case scenario.

What is the purpose of a canthal suspension?

The lateral canthus is such a complex structure that any manipulation of its architecture could affect the appearance of the eyes and the function of the eyelids. Therefore, the key is to do the least manipulation necessary to achieve the suspension required.

The main reason for surgery on the canthus is to prevent lower eyelid retraction after blepharoplasty. A relatively high percentage of patients who desire lower eyelid cosmetic surgery require skin removal from the lower eyelids. In these cases, if the lateral canthus is not tightened, the lower eyelid will easily pull down, causing eyelid retraction, the characteristic sign of bad lower eyelid surgery. Surgeons became aware that surgically tightening the lower lid at the canthus significantly lowered the probability of this complication. This tightening is known as canthal suspension. Canthal suspension has helped cosmetic eyelid surgeons decrease the risk of complications and achieve consistently excellent results.

Canthal suspension procedures: Canthoplasty vs. Canthopexy

Canthal suspension can be approached in two ways: canthoplasty and canthopexy. The goal of both is to tighten the tendon that attaches the eyelid to the bone to restore eyelid tone and prevent postoperative eyelid retraction. The degree of tightening and amount of surgical manipulation of the canthal structures determines the strength of the procedure, its effectiveness, and the potential for altering normal eyelid anatomy and function. 

Canthopexy: subtle but less powerful.

In a canthopexy, the terminal part of the eyelid is secured but not modified. This operation requires a tuck of the tendon without any cutting or alteration. The lateral canthal tendon is folded on itself and the lid tightened. A significant advantage of the canthopexy is that it respects the architecture of the lateral commissure and does not disrupt anatomy as much as a canthoplasty. Nevertheless, it does so at the expense of a less powerful tightening effect. This may be advantageous in some cases because if you overtighten the lower lid and the lower lid captures part of the upper lid tendon, the upper lid can come down.

Canthal suspension is not for everyone. Some patients do not require canthal suspension, and when this is the case, it is best to steer clear of the eyelid commissure altogether. It is especially true for patients who do not require skin removal or have little or no laxity of the eyelid. Younger patients with small bags underneath the eyes and good skin tone are classic examples of this type of patient.

When a canthal procedure is necessary, it must be performed with meticulous care and great expertise. It is the only way to achieve an elegant eyelid contour while preserving normal eyelid function.

Canthoplasty: a powerful but complex canthal suspension.

Canthoplasty is the procedure that tightens the lower eyelid by cutting the canthus and shortening the canthal tendon. This process draws the lid at the canthus and restores the eyelid tone. The incision will leave a potentially visible scar in this area; however, because it is made in a wrinkle, the scar will barely be noticeable. By definition, a canthoplasty involves modifying the tendon on the terminal part of the lid. This surgical manipulation allows for a powerful tightening of the tendon but may also affect the anatomy of the commissure and blink function. Therefore, canthoplasty is the more effective way to tighten the eyelid but carries a higher risk of affecting the delicate design of the commissure.