Eye Sphincter Reanimation in Facial Paralysis: Evaluation, Indications, Techniques, and Outcomes.

ABSTRACT: Facial nerve paralysis (FNP) sequela includes dysregulation of the ocular surface protective mechanism, nasolacrimal system pump failure and punctal eversion causing chronic epiphora, foreign body sensation, corneal injury, and, in the most severe cases, visual loss, particularly in the presence of comorbid corneal hypesthesia. Concerns over the ocular surface protection in FNP patients have led to the development of numerous static and dynamic procedures. While initial assessment of the FNP patients is complex and requires a comprehensive understanding of the blink reflex physiology, clinical evaluation and the use of additional work should be directed toward potential eye sphincter reanimation using a multidisciplinary approach. As with any treatment algorithm, numerous factors must be considered to provide an individualized treatment plan. In the case of FNP, it is important to consider denervation time, patient age, cause of paralysis, and neurologic severity of the paralysis. The aim of this article is to provide a thorough review of the physiology of the blink reflex, evaluation of the eye sphincter mechanism in FNP, and a comprehensive treatment algorithm incorporating static and dynamic procedures, along with a historical perspective.