In a strong magnifying mirror, it is easy to see saponification, also called frothy tears, characterized by bubbles in the tear film. When the tear film pools in the lower sack, the bubbles are very visible at the lid margin. Sometimes bubbles can be seen in other areas of the eye in the tear film. Bubbles can be very uncomfortable. Because there is literally soap in the eye, the eyes can burn, and be quite red.
Saponification, a sign of poor quality meibum, is a result of enzymes reacting with tear lipids. When combined, they create a foamy, soapy material, that feels like soap in the eyes. Saponification can occur when there are demodex mites at the roots of the lashes, or in the meibomian glands. When the mites die, their bodies, and the bacteria they harbor, release enzymes that react with the tear film, creating soap. Saponification can also occur when there are infections for the same reasons. The enzymes released by the bacteria react with lipids in the tear film, creating soap.