Table 2.

Major characteristic features of meibum and meibomian lipids^*

Feature	Class of lipids with the feature
High levels of CE in meibum	saturated and unsaturated CE, Chl-OAHFA
High levels of WE in meibum	saturated and unsaturated WE
Low degree of unsaturation of fatty chains (mostly, one, wo, or three double bonds per FA and FAl chain)	All complex lipids
Branching of FA and FAl (predominantly "iso" and "anteiso")	WE (both FA and FAl moieties), FA, FAl, and CE
High levels of odd-numbered FA residues (mostly C17 and C15)	WE, CE, FFA
High levels of VLC and ELC FA residues (mostly C24–C34)	WE, CE, OAHFA, Chl-OAHFA, FFA
High levels of ELC FAl residues in lipids (mostly C24–C34)	WE, DiAD
High levels of ω– and a,ω-hydroxylation of FA and FAl residues, respectively	OAHFA, Chl-OAHFA, DiAD
Low levels of Chl, Sql, Cer, acyl-Cer, PL and SM	whole meibum

^*Modified from (Butovich et al., 2016)