Blepharitis is really 2 types of conditions.
Anterior blepharitis is usually caused by a staph infection of the eyelashes.. There is often crusting of the eyelid margin and red sore eyes.
Posterior blepharitis is a condition in which the oil glands in the eyelids become plugged with thicker than normal oil. The thicker oil plugs up the tear ducts, resulting in less oil on the tear film and faster evaporation leading to dry eyes.
Both forms result in dry, irritated eyes. Treatment consists of eyelid scrubs, warm compresses and OTC lubricant drops.Sometimes prescription drops are also prescribed.
See the "Dry Eye" sections on this web site for more detailed information.