Blepharitis is a common and sometimes lifelong eyelid condition that is estimated to affect 30 million people worldwide. The exact underlying cause of blepharitis is not well defined or understood.
A blepharitis patient’s eyelids become irritated and swollen. The eyelid oil producing glands become infected and bacterial colonies layer at the base of the eyelashes at the eyelid margin. The combination of oil gland dysfunction and bacterial growth leads to the sensation of irritation, itchiness, stinging and burning. Blepharitis patient develop eye redness, light sensitivity and decreased visual clarity. Untreated scarring of the lids and eye structures can develop.
The offending germs can originate from the normal flora of the periocular skin (streptococcus and staphylococcus) but can be from skin conditions associated with bacteria like acne or rosacea.
Depending on the area of the eyelid that is affected we distinguish blepharitis as anterior blepharitis or posterior blepharitis.
Anterior blepharitis affects the base of the eyelids where the forward facing eyelashes exit the lid margin. If untreated anterior blepharitis produces scarring and eyelid disfigurement. Disfigurement can misalign the eyelashes and they no longer face outward but become misdirected inward toward the eyeball. This misdirection is called entropion. Entropion results in rubbing of the lashes on the eyeball during normal blinking. The rubbing can lead to redness, infection, scarring and loss of optical clarity of the cornea.
Posterior blepharitis is associated with dysfunction of the eyelid’s oil producing glands (meibomian glands). Meibomian glands become clogged from blepharitis germs. The clogged meibomian glands give a frothy and foamy look to the lid margin. If meibomian gland material becomes sealed off and cannot drain inflammatory styes and chalazia form along the eyelids.
Treatment of blepharitis is with good lid hygiene, topical or systemic medications. If lid misalignment, styes and chalazia develop surgery may be indicated.