Correction of upper eyelid retraction following ptosis surgery using Hering's law: A case report.

[RATIONALE] Blepharoptosis is a common disorder characterized by abnormal eyelid position that affects both visual function and esthetics. Postoperative upper eyelid retraction, which is often due to overcorrection, is a major problem. Under normal circumstances, the operation is usually performed on the overcorrected eye. Here, we present the case of a patient who had previously undergone surgery to correct right upper blepharoplasty, which resulted in asymmetry. Utilizing Hering's law, we decided to correct only the left eye, resulting in remarkable bilateral symmetry after surgery. This proves that for patients with ptosis after upper eyelid surgery, a comprehensive approach should be considered rather than just one treatment method.

[PATIENT CONCERNS] Here, we report a case of overcorrection of ptosis in a male patient who underwent corrective surgery.

[DIAGNOSES] Based on the patient's ocular examination, appearance, medical history, measurement of levator muscle strength, and MRD1 measurement, the diagnosis was postoperative overcorrection of ptosis of the right upper eyelid.

[INTERVENTIONS] In this case, preoperative examination revealed a reduction in the size of the right eye when the left eyelid was lifted, which was in accordance with Hering's law. Consequently, surgical intervention was limited to the left eye, resulting in excellent bilateral symmetry after surgery.

[OUTCOMES] The surgery was successful and resulted in symmetry between both eyes. We followed up with the patient for a year and he was extremely satisfied with the surgical results. The outpatient follow-up revealed no discomfort.

[LESSONS] Postoperative upper eyelid retraction following monocular ptosis correction is a rare condition. The conventional treatment approach typically involves reoperation on the affected eye. However, considering the importance of Hering's law in the management of ptosis, excellent outcomes were achieved in this case through surgery on the contralateral, unaffected eye. When treating a patient, the operation should be tailored to their specific condition.