Table 2.

Terminology of Blepharitis

Condition	Definition
Blepharitis	Blepharitis is a general term describing inflammation of the lid as a whole; marginal blepharitis is inflammation of the lid margin and includes both anterior and posterior blepharitis.
Anterior blepharitis	Anterior blepharitis describes an inflammation of the lid margin anterior to the gray line and concentrated around the lashes. It may be accompanied by squamous debris or collarettes around the lashes, and inflammation may spill onto the posterior lid margin.
Posterior blepharitis	Posterior blepharitis describes an inflammation of the posterior lid margin, which may have different causes, including MGD, conjunctival inflammation (allergic or infective), and/or other conditions, such as acne rosacea.7,12–15
MGD	MGD describes a chronic, diffuse abnormality of the meibomian glands, commonly characterized by terminal duct obstruction and/or qualitative/quantitative changes in the glandular secretion. It may result in alteration of the tear film, symptoms of eye irritation, clinically apparent inflammation, and ocular surface disease.