title: A computer analysis of reflex eyelid motion in normal subjects and in facial neuropathy.
abstract: OBJECTIVE
  To demonstrate how computerized eyelid motion analysis can quantify the human reflex blink.
  
  
  METHODS
  Seventeen normal subjects and 10 patients with unilateral facial nerve paralysis were analyzed.
  
  
  BACKGROUND
  Eyelid closure is currently evaluated by systems primarily designed to assess lower/midfacial movements. The methods are subjective, difficult to reproduce, and measure only volitional closure. Reflex closure is responsible for eye hydration, and its evaluation demands dynamic analysis.
  
  
  METHODS
  A 60Hz video camera incorporated into a helmet was used to analyze blinking. Reflective markers on the forehead and eyelids allowed for the dynamic measurement of the reflex blink. Eyelid displacement, velocity and acceleration were calculated. The degree of synchrony between bilateral blinks was also determined.
  
  
  RESULTS
  This study demonstrates that video motion analysis can describe normal and altered eyelid motions in a quantifiable manner.
  
  
  CONCLUSIONS
  To our knowledge, this is the first study to measure dynamic reflex blinks. Eyelid closure may now be evaluated in kinematic terms. This technique could increase understanding of eyelid motion and permit more accurate evaluation of eyelid function. Dynamic eyelid evaluation has immediate applications in the treatment of facial palsy affecting the reflex blink. Relevance No method has been developed that objectively quantifies dynamic eyelid closure. Methods currently in use evaluate only volitional eyelid closure, and are based on direct and indirect observer assessments. These methods are subjective and are incapable of analyzing dynamic eyelid movements, which are critical to maintenance of corneal hydration and comfort. A system that quantifies eyelid kinematics can provide a functional analysis of blink disorders and an objective evaluation of their treatment(s).
authors.affiliation: Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Louisville, 320 MDR Building, Louisville, KY 40292, USA.
authors.forename: N N
authors.initials: NN
authors.lastname: Somia
authors.forename: G S
authors.initials: GS
authors.lastname: Rash
authors.forename: E E
authors.initials: EE
authors.lastname: Epstein
authors.forename: M
authors.initials: M
authors.lastname: Wachowiak
authors.forename: M J
authors.initials: MJ
authors.lastname: Sundine
authors.forename: R W
authors.initials: RW
authors.lastname: Stremel
authors.forename: J H
authors.initials: JH
authors.lastname: Barker
authors.forename: D
authors.initials: D
authors.lastname: Gossman
mesh_terms: D000054:Acceleration; D000328:Adult; D000368:Aged; D001767:Blinking / Q000502:physiology*; D003315:Cornea / Q000502:physiology; D005143:Eyelids / Q000502:physiology*; D005158:Facial Paralysis / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D009068:Movement; D013223:Statistics as Topic; D013997:Time Factors; D014743:Videotape Recording