title: Intersubject and Interday Variability in Human Tear and Meibum Lipidomes: A Pilot Study.
abstract: OBJECTIVE
  Our aim was to quantitate day-to-day changes in the tear and meibum lipid profile of individual subjects in a pilot study of healthy humans.
  
  
  METHODS
  Matched tear and meibum samples were obtained from four subjects on three consecutive days. Quantitative lipid profiles of human basal tears and meibum were compared using multivariate analysis by principal components.
  
  
  RESULTS
  Substantial differences in the lipid profile between subjects were observed, while lipid profiles were steady across the three consecutive days of sampling. Multivariate principal component analysis demonstrated that lysophosphatidylcholine was the largest variant lipid class between subjects in tears, while wax esters comprised the most variation between subjects in meibum secretions.
  
  
  CONCLUSIONS
  Interday variability is shown to be much smaller than interpatient variability, suggesting that tears and meibum subjects both have unique profiles in humans.
authors.affiliation: Illawarra Health and Medical Research Institute and School of Medicine, University of Wollongong, Wollongong, NSW, Australia. Electronic address: simonb@uow.edu.au.
authors.forename: Simon H J
authors.initials: SH
authors.lastname: Brown
authors.affiliation: Vision CRC, Sydney, NSW, Australia; School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia; Brien Holden Vision Institute, Sydney, NSW, Australia.
authors.forename: Carolina M E
authors.initials: CM
authors.lastname: Kunnen
authors.affiliation: Vision CRC, Sydney, NSW, Australia; School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia; Brien Holden Vision Institute, Sydney, NSW, Australia.
authors.forename: Eric B
authors.initials: EB
authors.lastname: Papas
authors.affiliation: Vision CRC, Sydney, NSW, Australia; School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia; Brien Holden Vision Institute, Sydney, NSW, Australia.
authors.forename: Percy
authors.initials: P
authors.lastname: Lazon de la Jara
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Mark D P
authors.initials: MD
authors.lastname: Willcox
authors.affiliation: School of Chemistry, University of Wollongong, Wollongong, NSW, Australia; Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD, Australia.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Blanksby
authors.affiliation: Illawarra Health and Medical Research Institute and School of Medicine, University of Wollongong, Wollongong, NSW, Australia. Electronic address: toddm@uow.edu.au.
authors.forename: Todd W
authors.initials: TW
authors.lastname: Mitchell
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008055:Lipids / Q000032:analysis*; D008297:Male; D008537:Meibomian Glands / Q000737:chemistry*; D010865:Pilot Projects; D013666:Tears / Q000737:chemistry*; D055815:Young Adult
chemical_list: D008055:Lipids
keywords: lipidomics; lipids; meibum; multivariate analysis; tear