Eyelid retraction is diagnosed be present if, with the eyes in primary position, the sclera is visible above the superior corneal limbus. It is usually acquired but may be present at birth. The most common cause of eyelid retraction in adults is thyroid eye disease. Eyelid retraction is more frequently associated with Graves' ophthalmopathy. Preterm infants occasionally have a benign transient conjugate down gaze associated with upper eyelid retraction. This finding is thought to be caused by immature myelination of the vertical eye movement system and immaturity or dysfunction of the extrageniculocalcarine visual pathways.