Blepharitis, which literally means “inflammation of the eyelids,” is an extremely common condition in which the eyelids become red and swollen, often leading to symptoms of burning, itching, irritation, foreign body sensation, sensitivity to light, and blurred vision. Although the condition is not an actual infection, toxins released by bacteria which normally live within the skin of the eyelids contribute to the associated inflammation. Blepharitis is often divided into two forms- anterior and posterior.
In anterior blepharitis, inflammation is most pronounced toward the front of the eyelids, involving the glands associated with the eyelashes. Usually caused by an overgrowth of staphylococcus bacteria, this condition is often seen in children and young adults. Bacterial toxins irritate the surface of the eye, causing conjunctivitis, or inflammation of the membrane which lines the eyeball. In more severe cases, the cornea becomes involved in a condition known as marginal keratitis. White inflammatory deposits develop in the periphery of the normally clear cornea, leading to significant pain, foreign body sensation, blurred vision, and often extreme sensitivity to light.
In posterior blepharitis, more commonly found in adults, inflammation involves the oil-producing Meibomian glands which line the back of the eyelid margins. The normal, smoothe oils produced by these glands, which serve to lubricate the eye, become thick and greasy, clogging the gland openings. The thick secretions are very irritating to the ocular surface, causing all of the symptoms noted above. This condition is often associated with the skin disease rosacea, in which the oil glands of the face become inflamed, leading to red, inflamed skin over the brows, nose, and cheeks.