Pseudoretraction of the eyelid in thyroid-associated orbitopathy

Two patients with previously stable thyroid-associated orbitopathy presented with the fairly sudden onset of apparent upper eyelid retraction in their nondominant eye, accompanied by asymmetry of the eyebrows, with elevation on the side without the eyelid retraction. No other signs of worsening of the orbitopathy were present, and instillation of 2.5% phenylephrine hydrochloride in the contralateral, dominant eye relieved the eyelid retraction and normalized the eyebrow position. At surgery, both patients were found to have levator aponeurogenic ptosis in the eyelid that appeared to be "normal." This occurrence is explained by Hering's law and should be considered in planning surgery to reestablish palpebral fissure symmetry in such patients.