LC-MS/MS analyses of human meibum conducted in triple quadrupole mode. The species of ceramide (Cer), hexosyl-ceramide (Hex-Cer), and sphingomyelin (SM) were identified based on their retention time and m/z ratio and quantified as described in previous publications.30,31 The mole percent of species of Cer, Hex-Cer, and SM were compared across groups defined by clinical parameters. *Denotes statistical significance with p-value <0.05. Boxplots depicting the median, interquartile range, and range are shown. A. The mole percent of Cer species compared to meibum quality. B. The mole percent of Hex-Cer species compared to meibum quality. C. The mole percent of SM species compared to meibum quality.