title: Spontaneous blinking in patients with Graves' upper eyelid retraction.
abstract: OBJECTIVE
  To describe spontaneous blink kinematics in Graves' upper eyelid retraction (UER).
  
  
  METHODS
  The magnetic search coil technique was used to record spontaneous blinks of 15 healthy subjects (aged 23-56 years, 15 eyelids) and 15 patients with Graves' UER (aged 22-62 years, 15 eyelids) during a 5-min period of video observation, and the signals were digitized at 200 Hz (12 bits). Overall, a total of 2,798 blinks were recorded for the controls and 1,860 for the patients. The distance between pupil center and upper eyelid margin in the primary position of gaze (MRD) was measured with the Image J software.
  
  
  RESULTS
  The blinking rate of patients was lower than that of control subjects, with a mean (+/- SEM) blinking rate (blinks/min) of 13.0 +/- 1.7 for patients and of 20.0 +/- 2.1 for the controls (t = 2.58, P = 0.016). There were no statistically significant differences in blink amplitude between controls (22.7 +/- 3.1 degrees) and Graves' patients (24.7 +/- 3.3 degrees). However, while only 22% of the blinks performed by controls were smaller than MRD, this rate was 78% for patients. In addition, in blinks larger than 25 degrees, patients showed lower down-phase velocity than controls.
  
  
  CONCLUSIONS
  Patients with Graves' UER show reduced blinks rates and abnormal blink kinematics, which might be related to the development of exposure keratitis in this disease.
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology, and Head and Neck Surgery, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
authors.forename: Denny Marcos
authors.initials: DM
authors.lastname: Garcia
authors.forename: Andre
authors.initials: A
authors.lastname: Messias
authors.forename: Luciana Oliveira
authors.initials: LO
authors.lastname: Costa
authors.forename: Carolina Trindade
authors.initials: CT
authors.lastname: Pinto
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Barbosa
authors.forename: Antonio Augusto Velasco
authors.initials: AA
authors.lastname: Cruz
mesh_terms: D000328:Adult; D001767:Blinking; D005143:Eyelids / Q000503:physiopathology*; D005260:Female; D006111:Graves Disease / Q000503:physiopathology*; D006801:Humans; D008280:Magnetics / Q000379:methods; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors; D055815:Young Adult