Blepharitis, also referred to as meibomitis, is a chronic inflammatory condition of the eyelid margin. It is more common in individuals with light-skin phototypes and closely linked with dry eye syndrome. Patients will commonly describe foreign body sensation, burning, stinging, excessive tearing, eyelid erythema, and collections of matter around the eyelashes upon awakening. Although itching is more common in allergic eye disease, it can be present in blepharitis as well. Patients may also be prone to having multiple styes and chalazia on the eyelids.

Patients with chronic skin conditions such as rosacea, seborrheic dermatitis, and psoriasis are particularly prone to suffer from blepharitis. There are a number of causes of blepharitis in addition to the systemic skin conditions noted above, including meibomian gland dysfunction (meibomitis) and staphylococcal infection as well as infestation with Demodex mites (demodicosis).

Very severe blepharitis and associated dry eye can lead to ocular surface dysfunction and resultant progressive corneal and conjunctival scarring with peripheral vascularization of the cornea.