title: Marx's line of the upper lid is visible in upgaze without lid eversion.
abstract: OBJECTIVE
  To determine whether Marx's line of the upper lid is visible in upgaze without lid eversion, thus raising the possibility that the line may not be the contact area for the upper lid wiping of the ocular surfaces.
  
  
  METHODS
  Consecutive patients in a broad-spectrum practice were enrolled. Exclusion criteria included patients of Asian descent, active anterior segment pathology, obvious lid alterations or deformities, strabismus more than 20Delta. A 20-microL drop of 2% fluorescein was instilled into the lower eyelid conjunctival sac. The complete length of the upper lid margin, in upward fixation (approximately 45 degrees , with the eyes open), was examined for Marx's line.
  
  
  RESULTS
  Sixty-eight males and 131 females were enrolled. The age range was 18 to 80 years; mean age = 51.7 +/- 14.3 years. Before eyelid eversion, Marx's line was visible in 99.0% of eyes and was visibly continuous for the entire eyelid margin length in 93.2% of eyes.
  
  
  CONCLUSIONS
  Marx's line of the upper lid is visible in upgaze, without lid eversion, suggesting that is not the contact area for the upper lid wiping of the ocular surfaces in that position of gaze. Further research is required to determine the position and visibility of the line through all other lid positions during blinking.
authors.affiliation: Korb Associates, Boston, MA 02215, USA.
authors.forename: Donald R
authors.initials: DR
authors.lastname: Korb
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Blackie
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001767:Blinking / Q000502:physiology*; D003228:Conjunctiva / Q000033:anatomy & histology* / Q000502:physiology*; D005143:Eyelids / Q000033:anatomy & histology* / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult