SI Kwon, et al. UPPER EYELID RETRACTION AFTER PERIORBITAL TRAUMA Fig. 4. Case 4: (A) Left upper eyelid retraction was observed one month after canalicular repair. (B) Significant lid lag on downgaze in the left eye. (C) Normal contrast-enhanced CT scan. D iscussio n Ptosis is a common complication of orbital trauma, and is caused by damage of the levator muscle and aponeurosis.8 For that reason, upper eyelid retraction is a paradoxical response. There are few reports on posttraumatic upper eyelid retraction with latency periods ranging from several months to years.4-6 Putterman et al.4 reported upper eyelid retraction after a blow-out fracture, and hypothesized that lid retraction occurs secondary to overaction of Müller’s muscle. This argument was supported by the fact that two patients were successfully treated with excision of Müller’s muscle. In contrast, Conway5 reported upper eyelid retraction following a blow-out fracture of the orbit with enophthalmos and postulated that this was due to traction on the connective tissue sheath of the levator palpebrae muscle through its connective tissue interconnections with other extraocular muscles. Hatt6 also described three cases of posttraumatic upper eyelid retraction without apparent involvement of the superior rectus muscle after latency periods ranging from several months to years; however, he was uncommitted regarding the mechanism of eyelid retraction. In our study, none of the patients had any systemic diseases and they all denied the possibility of preexisting retraction of the upper eyelid prior to trauma. If upper eyelid retraction is caused by overstimulation of the superior rectus and levator, lid lag should improve in downgaze, when innervation to these muscles is minimal.5 In our reported cases, patients had constant lid retraction in all fields of gaze and a significant lid lag in downgaze. These observations suggest a mechanical cause for lid retraction rather than a neuromuscular cause, such as levator overaction. Because thyroid eye disease may occur in the absence of clinical or biochemical evidence of thyroid dysfunction, thyroid orbitopathy cannot be easily excluded.9 However, sudden onset immediately after trauma and only affecting the traumatized eye support the role of adhesion rather than thyroid orbitopathy as the underlying mechanism of eyelid retraction. In the first case, the patient complained of diplopia during downgaze and adduction. Since no limitation was noted at elevation and we relieved all of the incarcerated soft tissue during surgery, this diplopia may have been induced by involvement of the superior oblique muscle, as indicated by the CT scan (Fig. 1D). This hypothesis is similar to that proposed by Conway,5 who suggested that upper eyelid retraction is brought on by adhesion of the levator complex to adjacent connective tissue after a blow-out fracture. In the last two cases of our study, upper eyelid retractions were present without fractures. In case 3, considering the patient’s history of trauma, we believe that an organizing hematoma or granulation tissue caused an adhesion to form around the levator complex, and this adhesion contributed to the upper eyelid retraction. In case 4, CT and laboratory tests showed no abnormalities, and we speculate that a slight adhesion not visualized by CT might have caused the upper eyelid retraction. Cases 2 and 3 complained of eyelid retraction immediately after periorbital contusion without any latency periods. Case 2 especially differs from those previously described as there was no fracture or latency period. Conway5 reported lid retraction 2 months after a blow-out fracture and Hatt6 stated that it took several months to years before lid retraction occurs following periorbital trauma. In our study, it took one to two months to show lid retraction after trauma in the first and fourth cases, but retraction was immediate in cases 2 and 3. We are unable to propose a mechanism underlying this latency, but our cases demonstrate that it can vary greatly. Thus, when taking a history in a patient with upper eyelid retraction, a protracted trauma history should be considered. Eyelid retraction persisted until recent follow–up in all four cases. Case 3 is very concerned about the eyelid retraction, and cosmetic surgery will be undertaken in the absence of improvement over the next 6 months. In summary, eyelid retraction due to superior complex adhesion can occur after orbital trauma, and should be considered one of the complications of trauma. Moreover, adhesions that cause eyelid retraction are likely to be visualized by CT, but they may not be observed in all cases. 257