title: The relationship between two types of upper eyelid movements: saccades and pursuit.
abstract: OBJECTIVE
  To establish the relationship between upper eyelid saccades and upper eyelid pursuit movements.
  
  
  METHODS
  Upper eyelid saccades and periodic sinusoidal upper eyelid pursuit movements were recorded in a sample of controls and patients with Graves upper eyelid retraction. A video-computerized system was used to register both types of movements that accompanied 60 degrees of eye rotation across the upper and lower hemifields. The forced harmonic oscillator model was used to fit saccadic and pursuit movements.
  
  
  RESULTS
  Mean mid-pupil eyelid distance for the Graves patients (6.6 +/- 1.1 mm) was significantly higher than for the controls (4.6 +/- 0.8 mm; t = 7.18; P < 0.00001). Despite the difference in the upper eyelid resting position, saccades and pursuit eyelid movements of both groups were extremely well fitted by underdamped solutions and steady forced solutions of the harmonic oscillator model, respectively. For the controls, the amplitude of the pursuit movements was well correlated with the upward and downward saccades. The amplitude of the eyelid movements of the Graves patients (saccades and pursuit) was significantly reduced compared with that of the controls.
  
  
  CONCLUSIONS
  Saccadic and pursuit movements of the upper eyelid can be described by the harmonic oscillator model. In healthy subjects and Graves patients, the amplitude of pursuit lid movements is correlated to the saccade amplitude. Pursuit eyelid movements are more difficult to register than saccades, and their measurements do not allow clear separation of the relaxation and contraction properties of the upper eyelid retractors.
authors: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
authors: Marcele F
authors: MF
authors: Falcão
authors: Jorge Mario C
authors: JM
authors: Malbouisson
authors: Antonio Augusto V
authors: AA
authors: Cruz
authors: André
authors: A
authors: Messias
mesh_terms: D000328:Adult; D000368:Aged; D005143:Eyelids / Q000503:physiopathology*; D005260:Female; D049970:Graves Ophthalmopathy / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011698:Pursuit, Smooth / Q000502:physiology*; D011930:Reaction Time; D012438:Saccades / Q000502:physiology*; D014741:Video Recording