<prompt> Answer this question truthfullyWhat classification does Blepharitis fall under?  <response>: <reason> A clinically useful approach is to classify blepharitis based on the affected location of the lid margin delineated by the gray line the muscle of Riolan, which divides the area into the anterior lamella skin, muscle, eyelash follicles, and glands of Zeis and posterior lamella tarsus, conjunctiva, and meibomian glands. According to the affected lid structure and the location of the predominant inflammation, marginal blepharitis can be divided into: Anterior blepharitisAnterior blepharitis describes an inflammation of the lid margin anterior to the gray line and concentrated around the lashes. It may be accompanied by squamous debris or collarettes around the lashes, and inflammation may spill onto the posterior lid margin.Posterior blepharitisPosterior blepharitis describes an inflammation of the posterior lid margin, which may have different causes, including meibomian gland dysfunction, conjunctival inflammation allergic or infective, andor other conditions, such as acne rosacea.Blepharitis can also be classified as acute or chronic, depending on the acuity of onset and time course of clinical presentation: Acute blepharitisAcute ulcerative blepharitis Acute ulcerative blepharitis is typically caused by staphylococcal infection. It may also be caused by herpes simplex virus or varicella zoster virus. Acute nonulcerative blepharitis is usually caused by an allergic reaction e.g., atopic blepharodermatitis and seasonal allergic blepharoconjunctivitis or contact hypersensitivity e.g., dermatoblepharoconjunctivitis.Chronic blepharitisChronic blepharitis refers to non-infectious inflammation of unknown cause.Alternatively, blepharitis may be classified based on three objective criteria meibomian gland morphology, tear osmolarity, and Schirmer test result: SeborrheicCharacterized by hypersecretion, normal gland morphology, and low or normal tear osmolarityObstructiveCharacterized by low excretion or high gland dropout on meibography, increased tear osmolarity, and normal Schirmer test resultObstructive with siccaCharacterized by low excretion or high gland dropout on meibography, increased tear osmolarity, and low Schirmer test resultSiccaCharacterized by normal gland morphology, increased tear osmolarity, and low Schirmer test result 