Mucous is common when Dry Eye is accompanied by bacterial infection, when meibomian glands secrete poor quality meibum, and when there is aqueous tear deficiency, allergy, or trauma. In some cases, there is an overproduction of mucous without infection, and in others there is bacterial infection. Staphylococcus epidermidis colonies, for example, are characterized by stringy mucous.
Sometimes people pull at the mucous strings with their fingers. As the string is pulled, it causes trauma to the surface of the eye or the caruncula. Fishing for the strings with fingers becomes a cycle of disease all its own known as Mucous Fishing Syndrome. Irritation caused by pulling out the strings of mucous triggers the production of more mucous. Breaking the cycle may be difficult.
Small amounts of mucous, commonly referred to as “sleep,” may be found at the inner corners of the eyes at waking. Larger amounts of mucous accompanied by crusting may be a sign of infection, requiring medical treatment with topical antibiotics or other medications.