I have been a big fan and user of very diluted Tea Tree Oil for years. I know it works on killing Demodex which a clear destroyer of meibomian gland structure and function.
New research from Dr. Sullivan, a well respected Harvard colleague, shows 2-4% of Tea Tree Oil used for a period of time can damage meibomian gland cells.
Dr. Sullivan outlines several alternatives available to practitioners that have shown to be effective against Demodex including microblepharoexfoliation, Intense Pulsed Light (IPL), and Manuka honey.
I would not give up, though, completely on Tea Tree Oil. Here are the take home messages I will be using personally:
1. Make sure it is very diluted tea tree oil: 1-2 % is likely effective and will likely do minimal damage if washed off completely afterwards. I will be using 1 drop of TTO with 9 drops of water to diluted TTO.
2. Always wash off tea tree oil.
3. Leave on for a few seconds and then wash off
4. Get meibography 2x/year if concerned about TTO’s effects on meibomian glands
5. Prefer to use IPL, Manuka honey (but wash off also in am): to kill Demodex
More info:
https://defocusmedia.com/optometry-podcast-teatree-oil-in-eyecare/