Meibomian glands are located along the border of the eyelids near the eyelashes, and secrete oils into the tears to prevent them from evaporating off the eye too quickly. When these do not function properly, the oils become thick and harden. These thickened secretions lead to blocked and inflamed glands and eyelids (blepharitis). In addition, the tears do not get the normal oils added into them, and evaporate off the eye surface quickly, leaving them dry and irritated (dry eye).
Treatment for MGD mainly revolves around antibiotic drops for infection (to treat blepharitis), and proper lid hygiene. This involves avoiding the use of eye make-up, warm compresses, and eyelid scrubs. Warm compresses should be done 1-2 times per day for at least 5 minutes each time. They can be made by wetting a towel with warm water, and placing it over your eyes for 5 minutes, reheating as needed. Eyelid scrubs are performed by closing your eyes and massaging during a warm shower. Sometimes it is necessary to perform a probing procedure in the office to open the glands.
Here is a video that presents an overview of meibomian gland dysfunction.
This video below gives an overview of MGD treatment.