Structural defect from the superficial lateral canthal tendon in two adolescent female patients: a case series

The lateral canthal tendon (LCT) is essential in maintaining eyelid tension and position. It comprises both deep and superficial limbs, the latter anchoring to the periosteum and lateral orbital thickening through the orbital retaining ligament and raphe of orbicular oculi muscle. Disruption of this structure can lead to functional eyelid instability in older patients and is often overlooked in younger patients. The authors present two adolescent female patients with chronic ocular discomfort-including dry eye sensation and eyelid fatigue-despite having no prior facial trauma or surgery. In the first case, a 15-year-old exhibited mild ptosis (marginal reflex distance [MRD] 1, 2 mm), reduced levator function (6 mm), and moderate bilateral fish-mouthing with marked lid laxity and eversion. Intraoperatively, both superficial LCTs were found completely ruptured with orbital fat herniation. In the second case, a 16-year-old girl with a long-standing history of allergic conjunctivitis, habitual eye rubbing, and over five years of colored contact lens use, showed preserved eyelid position (MRD1, 5 mm; levator function test, 12 mm) and a positive canthal tilt. However, mild bilateral fish-mouthing was noted clinically. Surgical findings confirmed bilateral attenuation and partial detachment of the superficial LCT, more pronounced on the left side.