Blepharitis is an inflammation process affecting the eyelid margins, eyelash follicles or openings of the anteriorly-placed accessory lacrimal glands and the posteriorly-placed Meibomian glands that causes ocular irritation and redness acutely but usually chronically.
It may have periods of exacerbations and remissions.
It usually occurs in middle-aged adults but can also start in childhood.
Can affect vision by disrupting the surface of the cornea and the bulbar conjunctiva; may influence tear film composition.