Silicone Oil Migration to the Lateral Rectus Muscle: An Unusual Finding

We report a case of silicone oil migration to the lateral rectus muscle discovered during otherwise uncomplicated strabismus surgery in a patient with multiple previous vitreoretinal surgical interventions. A 58-year-old female underwent strabismus surgery to correct a long-standing sensory exotropia. This patient underwent numerous previous vitreoretinal surgical interventions due to a complex history of retinal detachments with subsequent repairs, including inserting and removing intraocular silicone as an endotamponade. During this procedure, silicone oil cysts were discovered firmly adhered within the substance of the lateral rectus muscle. These cysts were subsequently removed either by rupture or whole excision, and specimens were sent for pathological examination. Microscopy confirmed sections of fat necrosis of the lateral rectus muscle with areas incorporating silicone oil. Following this, a lateral rectus recession and medial rectus resection were performed, and the exotropia was satisfactorily corrected. This report highlights an unusual complication of otherwise unchallenging strabismus surgery. Intraocular silicone oil introduced during vitreoretinal surgical procedures may present as cysts embedded on extraocular muscle, thus presenting a unique finding of strabismus surgery.