Many thanks to our research fellow, Faith Kean who looked this one up:
What Determines the Color of the Meibomian Gland Oil (ie, Meibum)
Photos showing the difference are coming as well.
Free fatty acid composition of human meibum correlates with meibum color as determined with a slit-lamp microscope.
FFAs—were detected in meibum.
Free fatty acid composition differed between clear and colored (cloudy or yellow) meibum, with unsaturated FFAs tending to be more abundant in colored meibum.
Meibum Color and Free Fatty Acid Composition in Patients With Meibomian Gland Dysfunction