Linoleic acid content of human meibum is associated with telangiectasia and plugging of gland orifices in meibomian gland dysfunction.

To examine the relation between changes in the free fatty acid (FFA) composition of human meibum and both objective signs and subjective symptoms of meibomian gland dysfunction (MGD), we analyzed the FFA content of meibum collected from both MGD patients and control subjects. Thirty-eight patients with MGD (13 men and 25 women; mean age ± SD, 66.9 ± 15.0 years) were evaluated. Various objective signs and subjective symptoms of MGD were assessed. Meibum was analyzed by liquid chromatography-Fourier transform mass spectrometry, and the relation between the FFA composition of meibum and each objective sign and subjective symptom was examined by principal component analysis (PCA). No relation was apparent between the FFA composition of meibum and individual subjective symptoms or objective signs of MGD. However, a PCA score plot for meibum samples grouped on the basis of the severity of both telangiectasia and plugging of meibomian gland orifices revealed clear separation of mild and severe groups. This separation of the two groups was largely due to a significantly increased linoleic acid content in meibum of the severe group (3.56%, versus 0.70% of total FFAs in the mild group). The relative amount of linoleic acid in meibum was thus associated with the severity of telangiectasia and plugging of gland orifices in MGD, suggesting that this FFA might contribute to the pathogenesis of these signs.