title: Quantitative comparison between upper eyelid retraction induced voluntarily and by Graves orbitopathy.
abstract: OBJECTIVE
  To compare 2-dimensional palpebral fissure measurements of normal subjects with voluntary upper eyelid retraction and patients with Graves upper eyelid retraction.
  
  
  METHODS
  Three groups of monocular palpebral fissure images were measured. Group 1 consisted of 32 images of healthy subjects with the upper eyelid in a normal position of rest. Group 2 included the same subjects with voluntary upper eyelid retraction. Group 3 included 45 images of patients with Graves upper eyelid retraction. Fissure images were acquired with a digital camera and transferred to a Macintosh computer. For all images, three variables were quantified with NIH Image software: the midpupil-to-upper eyelid margin distance and the nasal and temporal upper areas of the palpebral fissure.
  
  
  RESULTS
  Voluntary upper eyelid retraction significantly increases the absolute difference between the temporal and nasal areas of normal subjects. The disproportion between the lateral and medial areas of the palpebral fissure was greater for the patients with Graves than for the control group with voluntary eyelid retraction, even though there was no difference between the midpupil-to-upper eyelid margin distance of these two groups. Overall, there was a positive correlation between the midpupil-to-upper eyelid margin distance and absolute difference between the temporal and nasal areas (r = 0.75, P < 0.0001).
  
  
  CONCLUSIONS
  In normal subjects, voluntary upper eyelid retraction increases the disproportion between the lateral and medial aspects of the fissure. However, even for the same amount of eyelid elevation, the mean disproportion of the control group with voluntary eyelid retraction is smaller than the disproportion displayed by patients with Graves. These findings suggest that an enhanced lateral retraction is a normal finding associated with levator muscle contraction.
authors.affiliation: School of Medicine of Ribeirão Preto, University of São Paulo, Brazil. aavecruz@fmrp.usp.br
authors.forename: Antonio A V
authors.initials: AA
authors.lastname: Cruz
authors.forename: Patricia Mitiko Santello
authors.initials: PM
authors.lastname: Akaishi
authors.forename: Roberto P
authors.initials: RP
authors.lastname: Coelho
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005123:Eye / Q000473:pathology; D005141:Eyelid Diseases / Q000209:etiology* / Q000473:pathology*; D005260:Female; D006111:Graves Disease / Q000150:complications*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D010781:Photography