CORNEA EWAP SEPTEMBER 2023 37 and slit lamp examination usually disclose eyelid margin erythema. Lid margin and eyelash crusts, scales, sleeves, scurf, or collarettes can be seen, depending on the type of blepharitis. The workup for blepharitis is similar to that for dry eye disease, Dr. de Luise said. Obtaining a comprehensive history is essential. What are the patient’s symptoms? Does the vision worsen during the day (more likely dry eye disease) or improve during the day (more likely blepharitis)? Testing should include visual acuity, symptom score such as SPEED, SANDE, or OSDI, tear film breakup time, analysis of the blink rate, vital dye corneal staining with fluorescein and conjunctiva with lissamine green, evaluation of tear film meniscus, analysis of eyelids and lashes to look for erythema, crusts, scales, scurf, sleeves, and collarettes, evaluation of meibomian gland orifices, and a careful analysis of the lash base under high magnification slit lamp to look for Demodex mites. 4,5 Dr. Perry noted that patients with infectious blepharitis may present with diffuse edema. That’s less common than a diffuse erythema along the upper lid margin associated with the presence of scurf, cylindrical dandruff, or other deposits on the lid margins or lashes. That is often associated with itching, redness, swelling, foreign body sensation, and burning. Symptoms may be very subtle, he added. “The most common reason for blepharitis is meibomian gland dysfunction, so the meibomian glands, instead of secreting long chain fatty acids that are compressible and expand and contract with each blink, start to secrete more free fatty acids.” This causes a premature break in the tear film. As time goes by, with the increase in free fatty acids, combined with inflammation, little bubbles start to form in the tear film. Even one or two little bubbles is significant for advanced meibomian gland disease, Dr. Perry said. When evaluating a patient for blepharitis, Dr. Perry will do a slit lamp evaluation to look at the lid margins and eyelashes and look at marginal tear strip and conjunctiva. “I’m looking at their eyelashes for cylindrical dandruff ( Demodex ) and lid margins for neovascularization and/or obscuration of the meibomian gland orifices to see if the lid margin has been covered by new vessels or if there’s capping of the meibomian glands,” Dr. Perry said. “I’m also looking at how the eyelid closes [to see] if there’s conjunctivochalasis.” He also looks for the presence of nocturnal lagophthalmos, which can be subtle. After making note of what is found on the slit lamp slit lamp examination and distinguish among the following observations. • Scales: Keratinized plaques on the eyelid surface often seen in staphylococcal blepharitis • cales: Greasy flakes seen in seborrheic blepharitis • Scurf: Dandruff-like excrescences seen in seborrheic blepharitis • leeves: Cylindrical tubes of material around the lash base • Collarettes (cylindrical dandruff): Cylindrical tubes of material that go higher up the eyelash base than sleeves, usually associated with Demodex infestation Anterior blepharitis is a nonspecific term that identifies the location of the eyelid inflammation, and it is usually caused by seborrhea or by staphylococcal overabundance. Demodex organisms have also been associated. The two most common bacteria that cause anterior blepharitis are Staphylococcus epidermidis and Staphylococcus aureus. Dr. de Luise said that staphylococcal blepharitis typically presents with crusting on the eyelid surface and debris in the tear film meniscus. Patients usually complain of eyelid irritation, and the eyelid margins are red and often crusted. If these crusts are removed, there is often oozing and bleeding. “In chronic and recurrent cases, there can be lid margin ulceration, misdirected eyelashes, trichiasis, whitening of the lashes, and loss of eyelashes, as well as an associated conjunctival hyperemia,” he said. “Severe cases often display an associated limbal keratitis or keratoconjunctivitis.” Patients with anterior blepharitis may present with visual blurring and irritation. External ocular evaluation Excessive meibum secretions in MGD. Source: Henry Perry, MD
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