Inferior Rectus Muscle Thermal Injury Following Transconjunctival Blepharoplasty Using Carbon Dioxide Laser

A 56-year-old woman was referred to the authors' hospital after the removal of the lower eyelid fat through a transconjunctival approach using a carbon dioxide laser. The patient was noted to have vertical diplopia in the primary position, with worsening diplopia on downgaze. Detachment of the right inferior rectus (IR) muscle from its insertion point was observed during exploratory surgery. The thermally damaged IR muscle fibers were attached to a location posterior to the original insertion point. At 6 months postoperatively, 8 prism diopters of right hypertropia in the primary position and a -3 degrees limitation on downgaze were still present. The patient underwent the vertical transposition of the lateral and medial rectus muscles to the IR muscle. After strabismus surgery, orthotropia was observed with no vertical diplopia in the primary gaze, but ocular motility limitation on the downgaze has permanently remained.