Eyeworld

62 | EYEWORLD | JULY 2023 C ORNEA of anterior blepharitis include irritation, itching, and redness and scaling of the eyelid skin. "B" is for bacteria and viruses. These are the infectious causes, which include bacteria such as staphylococci and blepharitis due to viruses such as Herpes simplex, Herpes zoster, or Molluscum contagiosum. "C" is for cancer, chemical, clogging, and complex. This group includes papilloma, seba- ceous cell carcinoma, melanoma, and basal cell carcinoma. Chemical refers to burns or thermal blepharitis. Clogging refers to the blockage of the meibomian glands in meibomian gland dysfunction. Complex refers to hybrid forms of blepharitis, which manifest both in the anterior and posterior lid. "D" is for Demodex and dermatologic. These etiologies include Demodex folliculorum (anterior blepharitis), Demodex brevis (posterior blepharitis), oculocutaneous rosacea, psoria- sis, Stevens-Johnson syndrome, and cicatricial pemphigoid. In 2011, the International Workshop on Meibomian Gland Dysfunction stratified blepha- ritis into anterior and posterior types. It defined anterior blepharitis as inflammation of the lid margin anterior to the gray line and centered around the eyelashes. The gray line represents the location of the marginal region of the or- bicularis muscle seen through the lid skin. The line divides the eyelid into an anterior lamella (eyelid skin and muscle) and posterior lamella (tarsus and conjunctiva). Anterior blepharitis may be accompanied by squamous debris or collarettes around the base of the lashes and vascular change. 3 The International Workshop defined poste- rior blepharitis as inflammatory conditions of the posterior lid margin, including meibomian gland dysfunction. The posterior lid margin contains the marginal mucosa, the mucocuta- neous junction, the meibomian gland orifices and the terminal ductules, and the neighboring keratinized skin. Posterior blepharitis is a term used to describe inflammatory conditions of the posterior lid margin, of which meibomian gland dysfunction is only one cause, Dr. de Luise said. Other causes include infectious or allergic conjunctivitis and systemic conditions, such as oculocutaneous rosacea. 3 will sometimes form caps of meibum over the gland openings. If left untreated, this will usual- ly cause chalazia or abscesses of the meibomian glands. Dr. Perry said one of the reasons that bleph- aritis is tricky to diagnose is because there are five main factors: a microbiologic factor, derma- tologic factor, allergic factor, nutritional factor, and meibum quality factor. Dr. de Luise said that anterior blepharitis due to staphylococcal organisms and posterior blepharitis due to meibomian gland dysfunction are among the most common forms. Another system is to describe the eyelid findings as ulcer- ative or non-ulcerative. Ulcerative blepharitis tends to be infectious in etiology, and non-ulcer- ative blepharitis is more likely inflammatory. Dr. de Luise offered a useful mnemonic device for the presentations and causations of blepharitis by remembering the letters ABCD. "A" is for anterior and allergic. This group includes allergic eczematoid blepharoderma- titis, contact dermatitis, and atopic dermatitis. Allergic anterior blepharitis usually manifests as an eczematoid blepharodermatitis. Symptoms continued from page 61 Foamy tear film Source: Henry Perry, MD

• Blank Page
• Blank Page (1)