Changes in Human Meibum Lipid Composition with Age Using Nuclear Magnetic Resonance Spectroscopy

Abstract

Purpose.: Human tear film stability decreases with increasing age. In this study, the changes in meibum composition were measured in search of markers of tear film instability. Methods.: ¹H NMR nuclear magnetic resonance (NMR) spectra of 43 normal donors aged 1 to 88 years were acquired. Results.: Compared with meibum from adolescents and adults, meibum from infants and children contains less CH₃ and C═C groups and an increased aldehyde-to-lipid hydroperoxide ratio. Conclusions.: It is reasonable that tear film stability is higher in infants than in adults. Their meibum contains less CH₃ and C═C groups and higher levels of protein, and as a result, the lipid is more ordered because of the tighter and stronger lipid–lipid interactions. For water to evaporate, it must first pass through the tight lipid–lipid barrier. For tears to break up, lipid–lipid interactions must be broken. It is reasonable that because the lipid–lipid interactions are stronger in infants' and children's tears compared with those of adolescents and adults, the tear film in the younger groups is more stable and provides a better barrier to evaporation than does the tear film of adults. Lipid saturation could be the critical feature in meibum that stabilizes tears in infants.