Relationship Between Eyelid Pressure and Lacrimal Status in Mild Facial Nerve Palsy

Purpose: Facial nerve palsy is frequently associated with both epiphora and dry eye, and orbicularis oculi muscle weakness or paralysis is the main cause of these symptoms. Eyelid pressure is a quantitatively measurable parameter for evaluating the tone and function of the orbicularis oculi muscle. The aim of this study was to examine the relationship between eyelid pressure and lacrimal status in patients with mild facial nerve palsy. Methods: This prospective, interventional study included 10 patients with unilateral facial nerve palsy. The severity of facial nerve palsy was determined using the CADS scale (cornea, static asymmetry, dynamic function, and synkinesis). Eyelid pressure was measured using a blepharo-tensiometer. Lacrimal status was quantified through tear meniscus height (TMH), clinical assessment of meibomian gland dysfunction (MGD) (eyelid margin abnormalities, Marx line, meibum expression, and loss of meibomian glands), corneal fluorescein staining, tear break-up time, and Schirmer test I results. Results: All 10 patients suffered from mild facial nerve palsy without eyelid ectropion or entropion, or gustatory epiphora. Lower eyelid pressure during forceful eye closure was significantly decreased in affected eyes (P = 0.007), but upper eyelid pressure during forceful eye closure and static upper and lower eyelid pressure were not significantly different between the affected and unaffected sides (P > 0.050). The TMH, MGD, and dry eye measurements showed no significant difference between the affected and unaffected eyes (P > 0.050). Conclusions: Mild facial nerve palsy is associated with decreased lower eyelid pressure during forceful eye closure. However, no other differences in upper eyelid pressure during forceful eye closure, static eyelid pressure, TMH, MGD, or dry eye disease symptoms were noted. These results imply that eyelid pressure slightly decreases due to mild facial nerve palsy, but this change may be clinically negligible.