The goals of eyelid reconstruction are 3-fold: (1) to provide adequate eyelid function, (2) to afford globe protection, and (3) to achieve acceptable aesthetic results. The functioning upper eyelid serves a more important role in globe protection than the lower eyelid because the upper eyelid covers a greater area of the cornea. The normal vertical excursion of the upper eyelid is approximately 12 mm, compared with 5 mm for the lower eyelid. Globe protection requires appropriate coverage by the eyelids and adequate tear lubrication. In upper eyelid reconstruction, an in-depth knowledge of the anatomy is an absolute prerequisite for success.
The most common indication for upper eyelid reconstruction is defects due to resection of malignancies. The majority of tumor excisions in the periorbital region are performed via Mohs micrographic surgery. This method of resection provides a high certainty of negative histologic margins prior to reconstruction. Less often, eyelid reconstruction is indicated for traumatic injuries. In evaluating reconstructive demands for the upper eyelid, the anatomic defects must be carefully appraised. The vertical, horizontal, and depth dimensions of the eyelid injury or defect must be determined, and availability of regional and distant tissue for reconstruction must be evaluated.
Eyelid reconstruction is indicated in all but a few instances when defects are present. Healing by secondary intention is a viable option when the defect is confined to the medial canthus region. Small defects (< 1 cm) in this concave area heal well by secondary intention. However, involvement of the lacrimal apparatus requires primary reconstruction. Small defects of the upper eyelid (< 5 mm) that do not involve the lid margin or the canthus can be similarly allowed to heal without reconstruction. All other defects of the eyelid should be repaired.
The upper eyelid can be divided into 3 subunits: (1) the medial canthus, (2) the lateral canthus, and (3) the upper eyelid proper. The eyebrow is better categorized as a subunit of the forehead because its skin thickness, elasticity, and contour better match those of the forehead.
The medial canthus contains the lacrimal drainage system and the medial canthal tendon. The medial canthal tendon is comprised of a fibrous extension of the tarsus, which inserts into the lacrimal crest of the lacrimal bone. At its most medial extension, the medial canthal tendon divides to surround the lacrimal sac located in the lacrimal crest. The 2 heads of the tendon insert into the anterior and posterior lacrimal crest. By surrounding the lacrimal sac, the medial canthal tendon heads impart a significant functional impact on the lacrimal pump. The lacrimal tendon is further supported at its insertion by a vertical component, which inserts above the lacrimal crest.
Tears drain into the lacrimal sac through the superior and inferior puncta, which open 5-7 mm lateral to the canthal angle. The upper punctum extends superiorly 2 mm as an ampulla prior to assuming a horizontal direction towards the lacrimal sac.
The lateral canthus is located slightly superior to the medial canthus along the orbital rim. Deep to the eyelid skin and orbicularis muscle, a fibrous extension of the upper tarsal plate joins that of the lower tarsus to become the lateral canthal tendon. This inserts into the lateral orbital tubercle (Whitnall tubercle), located on the inner aspect of the lateral orbital rim. In the area of the lateral orbital tubercle, several other structures join the lateral canthal tendon to form the lateral retinaculum. These other structures include the lateral horn of the levator aponeurosis, the inferior suspensory ligament (Lockwood ligament), and the check ligament of the lateral rectus muscle.
The eyelid can be divided into the anterior and posterior lamellae. The anterior lamella is composed of skin and the orbicularis oculi muscle. The marginal arterial arcade is located 3 mm superior to the lid margin within the orbicularis fibers. The posterior lamella consists of the conjunctiva, the tarsus, the levator aponeurosis, and the Müller muscle. The peripheral arterial arcade is situated at the upper edge of the tarsus, anterior to the levator aponeurosis.
The anatomy of the upper eyelid becomes more complicated as one moves from the lid margin superiorly. Along the lid margin, the eyelid is composed of skin, pretarsal orbicularis, tarsus, and conjunctiva. The orbital septum and levator aponeurosis insert into the lower two thirds of the anterior tarsus. In the eyelids of whites, some of the levator aponeurosis fibers also insert into the upper eyelid skin below the level of the tarsal fold, to create the supratarsal fold.
Stability of the upper eyelid is imparted by the tarsus, which is composed of thick fibrous tissue. The tarsus is 10-12 mm thick centrally, and tapers at its edges.
The upper eyelid above the tarsus is composed of skin, preseptal orbicularis, orbital septum, orbital fat, levator aponeurosis, Müller muscle, and conjunctiva. Below the orbital equator, the levator muscle assumes a more fibrous appearance and becomes the levator aponeurosis. The Müller muscle, which is a nonstriated, sympathetically innervated elevator of the upper lid, finds its origin on the posterior aspect of the levator muscle and inserts into the superior tarsal edge. The superior ligament of Whitnall is a fascial condensation along the upper aspect of the levator muscle. This ligament attaches to the trochlear fascia medially and to the fascia of the lacrimal gland laterally.
Upper eyelid reconstruction has few contraindications. In a patient with only one seeing eye, procedures that obstruct vision, such as the Cutler-Beard flap, should be abandoned in favor of those that maintain the ability to see. In patients with significant comorbidities, complex and time-consuming reconstructive procedures may be contraindicated because of the risks associated with perioperative cardiopulmonary complications.