title: Pilot study of the influence of eyeliner cosmetics on the molecular structure of human meibum.
abstract: OBJECTIVE
  It has been suggested that eye makeup could interact with human meibum causing a decrease in the stability of the tear film. The aim of this pilot study was to measure makeup-human meibum interactions in vitro.
  
  
  METHODS
  Human meibum-makeup interactions were quantified by measuring order-to-disorder lipid phase transitions using infrared spectroscopy.
  
  
  RESULTS
  Makeup products exhibited lipid phase transition temperatures that were much higher than those for meibum. One product increased the lipid phase transition temperature by 4.2°C when combined with human meibum causing a large increase (from 30 to 49%) in the order of the meibum-lipid hydrocarbon chains and significantly decreased the minimum frequency, enthalpy and entropy of the phase transition of human meibum. Another eyeliner caused no significant (p < 0.05) change in the phase transition parameters of human meibum.
  
  
  CONCLUSIONS
  Infrared spectroscopy may be used to measure interactions between human meibum and makeup. One makeup product increased the lipid order (viscosity) which could have adverse effects on tear film stability. Modern cosmetics are highly regulated and relatively safe to use; however, it could be beneficial to design makeup products that do not interact with meibum, especially since women have a higher prevalence of dry eye symptoms.
authors.affiliation: Department of Chemistry, University of Louisville, Louisville, Ky., USA.
authors.forename: Morgan
authors.initials: M
authors.lastname: Hunter
authors.forename: Rahul
authors.initials: R
authors.lastname: Bhola
authors.forename: Marta C
authors.initials: MC
authors.lastname: Yappert
authors.forename: Douglas
authors.initials: D
authors.lastname: Borchman
authors.forename: Dylan
authors.initials: D
authors.lastname: Gerlach
mesh_terms: D000328:Adult; D001831:Body Temperature; D003358:Cosmetics / Q000009:adverse effects* / Q000737:chemistry; D015352:Dry Eye Syndromes / Q000209:etiology; D019277:Entropy; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry*; D008297:Male; D008537:Meibomian Glands / Q000737:chemistry*; D015394:Molecular Structure; D044367:Phase Transition; D010865:Pilot Projects; D019265:Spectroscopy, Near-Infrared
chemical_list: D003358:Cosmetics; D008055:Lipids