Corneal Protection in Facial Synkinesis

Corneal protection is the first priority in acute facial paralysis. Orbicularis oculi paralysis causes paralytic lagophthalmos, ectropion, impaired blink, and exposure keratopathy. However, many patients progress to synkinesis, in which muscle reactivation may improve corneal coverage. This study aimed to characterize the longitudinal trajectory of corneal status as patients transition from acute facial paralysis to synkinesis.

A retrospective cohort study of synkinetic patients evaluated by ophthalmology between 2009 and 2025 was conducted. Included were patients with at least 2 corneal examinations before surgical intervention. The primary outcome was punctate epithelial erosion (PEE) score. The secondary outcome was scleral show. Examinations were stratified into acute paralysis (0-6 months), synkinesis development (6-16 months), synkinesis plateau (16-63 months), and long-term follow-up (>63 months).

Forty patients contributed 180 corneal examinations. Mean PEE scores were highest during acute paralysis (1.59) and improved during synkinesis development (1.05), synkinesis plateau (0.91), and long-term follow-up (0.81) when compared with acute paralysis (all p<0.05). Twenty-four patients contributed 67 photographic assessments. Scleral show at repose decreased from 10.75 mm to 7.88 mm at long-term follow-up (p<0.001). Scleral show during gentle and forceful eye closure also decreased (all p≤0.002). Complete forceful eye closure increased from 30% during acute paralysis to 100% at long-term follow-up.

Corneal status improves significantly as patients transition from acute paralysis to synkinesis, with greatest improvement during synkinesis development. Synkinesis may provide corneal protection, suggesting surgical intervention may be avoided in many patients.