Effects of Chemodenervation on Ocular Synkinesis.

Background: Chemodenervation is widely used for management of synkinesis in patients with facial palsy, but there is limited objective data assessing treatment effect. Objective: To measure the eyelid palpebral fissure height at rest and during movement after chemodenervation of the orbicularis oculi muscle among patients with ocular synkinesis, as measured on photographs with computerized facial analysis application. Methods: A retrospective review of patients who underwent initial chemodenervation to the orbicularis oculi for synkinesis was conducted from January 1, 2015, and July 26, 2023. Changes in palpebral height following injection "at rest" and during "pucker" (activation of ocular synkinesis) were calculated using the Emotrics+ program. Results: Nineteen patients were identified: 78.9% female, 73.7% White, and a mean age of 49.74  ±  13.62yrs. They received a mean of 11.45  ±  3.57 units to the orbicularis oculi. A mean 37.63  ±  11.21 days elapsed between injection and postinjection photograph. Palpebral fissure height increased by a mean of 1.16  ±  1.86 mm while "at rest" (p = 0.014) and 2.31  ±  1.35 mm during "pucker" (p < 0.01). Injected dose was not associated with changes in palpebral fissure height "at rest" (p = 0.141) or during "pucker" (p = 0.125). Conclusions: Our findings suggest that chemodenervation of the orbicularis oculi improves palpebral fissure height in ocular synkinesis, more so during dynamic motion.