Blepharitis is an inflammation of the free edge of the eyelid which can spread to all eyelids. Blepharitis manifests itself by a redness and swelling of the eyelid, with small scabs on the skin and at the root of the eyelashes. It often affects both eyes at the same time, and is accompanied by pain or itching of the eyelids. Other ocular signs are often associated: eye redness, sensations of grains of sand, burning, itching and/or secretions.
This inflammation can affect the outer part of the eyelids: the skin and eyelashes (anterior blepharitis), or even reach the rim of the eyelid, which is in contact with the eye, and the glands that are there (posterior blepharitis), or even affect both the external part and the edge of the eyelid (anterior and posterior blepharitis).
THE DIFFERENT TYPES OF BLEPHARITIS
Blepharitis can affect the outer part of the eyelids: the skin and eyelashes (anterior blepharitis). The eyelid is red, swollen often with small scabs at the root of the eyelashes.
It can also reach the rim and the inside of the eyelid, which is in contact with the eye, and the Meibomian glands that are there (posterior blepharitis): in this case, white dots, or styes or chalazions may appear on the edge of the eyelids.
Blepharitis can be both anterior and posterior, which means it can affect the skin, the rim and the inside of the eyelids.
[i] 2007 Report of the International Dry Eye WorkShop (DEWS). The Ocular Surface 2007; 5(2) / http://www.tearfilm.org/dewsreport/pdfs/TOS-0502-DEWS-noAds.pdf