Eyelid Lacerations

Kyle J. Godfrey

Sirivalli Chamarti

THE CLINICAL CHALLENGE

Eyelid trauma is a common presentation to the emergency department (ED). Eyelid lacerations account for 7.7% of all complaints of eye trauma presenting to the ED.¹^,² The eyelids contain complicated and sensitive anatomy that is easily damaged in trauma. Care must be taken to ensure that the anatomic structures and functional relationships are preserved and repaired in a timely manner. The eyelids must maintain proper position relative to the ocular surface and visual axis, have adequate functional excursion with dynamic blink, and facilitate tear drainage through the nasolachrymal system. The lacrimal outflow system must remain patent, and the punctum must maintain proper apposition to the ocular surface and tear lake. Inadequate eyelid reconstruction can cause eyelid malposition, resulting in ptosis, secondary ocular surface problems, and chronic tearing (epiphora).

PATHOPHYSIOLOGY

As a concise review of the relevant anatomy, the upper and lower eyelids should rest in close apposition to the globe and tear film. At the eyelid margin, the eyelid can be conceptualized as containing four layers organized into two lamellae: the anterior lamella, composed of eyelid skin and the circumferential orbicularis oculi muscle, and the posterior lamella, composed of the tarsus and palpebral (eyelid) conjunctiva. In the upper eyelid, the tarsus is approximately 10 mm in height and in the lower eyelid, approximately 4 mm in height.³^,⁴

Beyond the tarsus, the eyelid anatomy becomes somewhat more complex. In both the upper and the lower eyelids, beneath the eyelid skin is the orbicularis oculi muscle, the circumferential protractor muscle, innervated by the temporal and zygomatic branches of the facial nerve, which enables both voluntary and involuntary blinking. Deep to the orbicularis oculi muscle is the orbital septum. The orbital septum defines the anterior boundaries of the orbit, and fuses with the periosteum of the orbital bones at the arcus marginalis, which circles the anterior margin of the bony orbital rim.

Beneath the orbital septum is orbital fat, which is generally superficial to the eyelid retractors. The eyelid retractors in the upper eyelid include the more superficial levator palpebrae superioris, which inserts on the anterior aspect of the tarsus and the deeper, sympathetically innervated Mullers muscle, which inserts at the superior border of the tarsus. In the lower eyelids, the rudimentary lower eyelid retractors insert near to the inferior tarsal border.⁵ Deep to the retractors is the conjunctival epithelium, which contacts the tear film and ocular surface.

The canalicular anatomy is highly relevant in eyelid trauma. In the upper and lower eyelids, the puncta are medial and lateral to the plica semilunaris, respectively, and have a diameter of approximately 0.3 mm at the mucocutaneous junction directed posteriorly into the tear lake. The puncta overlie the canaliculi, which travel approximately 2 mm vertically, turn medially at 90° angles, and travel 8 to 10 mm within the orbicularis oculi muscle before entering the lacrimal sac. In most individuals, the upper and lower canaliculi converge to form a common canaliculus
before entering the posterolateral nasolachrymal sac deep and slightly superior to the anterior crus of the medial canthal tendon. Without support from the tarsus, which terminates near the punctum, the medial eyelid has only soft tissue support and is vulnerable to injury.⁶

Owing to their relative proximity, concurrent injury to both the canaliculi and the medial canthal tendon complex is common. A high index of suspicion for canalicular laceration or medial canthal tendon avulsion should be maintained in all cases of eyelid trauma, particularly when there is evidence of trauma medial to the punctum. Canthal avulsions and canalicular lacerations most commonly occur secondary to blunt trauma, animal bites, motor vehicle collisions, falls, and assault with lateral traction to the eyelid. They are often associated with avulsion of the medial canthal tendon. Lacerations of the inferior system are more common than the superior.⁷

APPROACH/THE FOCUSED EXAM

After life-threatening injuries are addressed and the patient is stabilized, the priority in assessing any ocular adnexal injury should be to evaluate the status of the globe. Once any globe injuries have been evaluated and appropriately addressed, a careful examination of the eyelids and lacrimal system should be performed. Collecting a focused history regarding the circumstances of the injury is critical in guiding the examination. In assessing the eyelids, several clinical features are important to recognize, including (1) laceration extent and depth, (2) status of the eyelid margins, (3) involvement of the canthal tendons, (4) involvement of the canalicular system. Additionally, in any ocular adnexal trauma, care should be taken to evaluate for an orbital compartment syndrome caused by a retrobulbar hemorrhage. In the presence of significantly elevated orbital compartment pressure, consideration may be given to lateral canthotomy and cantholysis to relieve orbital tension and/or delayed repair of eyelid lacerations to prevent containing an expanding hemorrhage.

Regarding depth, abrasions and superficial lacerations will involve the skin and possibly muscle layer only. Knowing that deep to the orbicularis oculi muscle and orbital septum is orbital fat, the presence of orbital fat in any eyelid wound signifies violation of the orbital septum and should raise suspicion for deeper injury to the globe, orbital structures, and the possibility of a retained orbital foreign body (Figure 31.1). Depending on the mechanism of injury, and when safe to do so, orbital imaging (typically computed tomography) should be performed in this context.

Figure 31.1: Orbital fat protruding through the site of a left upper eyelid penetrating injury, suggesting violation of the orbital septum and deeper orbital involvement.

After excluding orbital extension of the laceration, it is critical to evaluate the status of the eyelid margin. Any laceration involving the eyelid margin requires specialized repair to prevent notching, eyelid malposition, and ocular surface injury.

Next, the eyelid should be evaluated for any possible injury to the lacrimal canaliculi. Canalicular injury should be suspected with any laceration medial to the lacrimal puncta on the eyelid margin. In cases of suspected canalicular injury, punctal exploration should be performed (Figure 31.2). In most cases, canalicular exploration should be performed by an ophthalmologist to minimize risk of iatrogenic injury to the delicate canalicular system.

Finally, the eyelid should be evaluated for any injury to the medial or lateral tendon complexes. Medial canthal avulsion is suggested by laxity of the medial canthal complex with increased distractibility of the lower eyelid laterally and anteriorly (Figure 31.3). Similarly, lateral canthal
tendon injury should be suspected with increased distractibility of the lower eyelid laterally and anteriorly. Comparison with the contralateral, unaffected eyelid may be useful for practitioners unfamiliar with normal horizontal eyelid tone (Figure 31.4). Additionally, a “snapback” test can be performed, where the lower eyelid is distracted inferiorly toward the cheek with a single finger. On release, a normal eyelid will “snap back” into its normal position touching the globe. A positive test is marked by slow or incomplete return of the lower eyelid to its normal position. Although age-related laxity may also produce a positive snapback test, any significant delay in return, particularly with asymmetry in comparison with the contralateral, unaffected side should raise suspicion for tendon injury.

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