This is a long-term inflammatory disease of the eyelids caused by the overgrowth of normal bacteria living along the lid and base of the eyelashes. Anyone can get blepharitis, but the prevalence increases with age since as we get older we make fewer natural antibodies in our tears.
As the eyelids can be difficult to keep clean, overgrowth of bacteria, biofilm, scurf and debris can accumulate over the years and the toxins released from bacteria can cause irritation and subsequently damage the eyelids and tear glands.