blepharitis

blepharitis is the most common ocular disease encountered by an ophthalmologist constituting 37% of all ophthalmology clinics out patient visits. blepharitis is categorized into anterior and posterior, each classified as infectious or noninfectious. anterior blepharitis is mainly infectious and caused by staphylococcus sp., propyonibacterium acne, corynebacterium sp., moraxella catarrhalis, herpes simplex virus, phitirus pubis and mites. possible mechanisms working in anterior blepharitis are colonization of lid margins by microorganisms, an imbalance between pathogenic and non-pathogenic microorganisms, and inflammatory mediators released by microorganisms or immune cells. another form of anterior blepharitis is seborrheic which is characterized by greasy scales on the anterior lid margin. posterior blepharitis is mainly non-infectious and caused by alterations in the composition of meibomian secretions including an increase in free fatty acids and fatty wax leading to tear film instability, tear hyperosmolarity and evaporative dry eye. tear hyperosmolarity is an important reason for ocular inflammation and irritation leading to epitheliopathy. in all forms of blepharitis, subjective complaints are burning and discomfort which is typically worst in the morning and improving toward the end of the day, discomfort while working on a computer, discharge, and redness. additionally, patients may complain of contact lens intolerance or recurrent episodes of chalazia. clinical findings vary depending on the type of blepharitis and include collarets around eyelashes, hyperemia and thickening of the lid margins, madarosis, poliosis, trichiasis, telangectasia, lid margin irregularities, and pouting and plugging of meibomian gland orifices. these abnormalities may be complicated by corneal marginal ulceration, and conjunctival or corneal phlyctenulosis. treatment of blepharitis is aimed to reduce patient discomfort decrease, bacterial colonies and inflammation, as well as help meibomian glands release their secretions. these goals are achieved through different measures including hot, moist compresses and application of anti-bacterial and anti-inflammatory agents.