MEIBOMIAN GLAND DYSFUNCTION: A The meibomian glands are sebaceous glands of the posterior lamella of the eyelid margin that have a unique lipid content consisting of sterol esters and waxes without the high tri-glycerides levels found in sebum. Meibomian gland dysfunction implies an abnormal lipid composition and abnormal secretion of the meibomian glands and may be accompanied by abnormal function of the anterior eyelid margins. Some patients with meibomian gland dysfunction have rosacea or other sebaceous gland disorders. Meibomian gland dysfunction is characterized by enlargement, irregularity, inspissation, and plugging of the meibomian gland orifices. A thick, yellowish oil can be expressed from individual glands. 

B Concomitant involvement of the sebaceous glands of Zeis produces oily debris (scurf) along the eyelashes. Foam often accumulates along the lateral lower eyelid margin. Vascular dilation with telangiectasia may occur, and the eyelid margins may be thickened and erythematous. Symptomatic patients complain of chronic burning, foreign-body sensation, conjunctival redness, filmy Vision, tearing and crusting of the eyelids. Nonspecific changes of the ocular surface are produced by the irritating lipids and secondary tear film abnormalities. Conjunctivitis, and occasionally episcleritis, occur in chronic cases. The cornea may be normal, but it sometimes exhibits punctate epithelial erosions. Marginal subepithelial infiltrates and a vascularized pannus can occur with severe disease, but this is rare. 

STAPHYLOCOCCAL BLEPHARITIS: Acute or chronic staphylococcal blepharitis is usually caused by Staphylococcus aureus, but it can also be caused by coagulase-negative staphylococci, and occasionally other bacteria. These bacteria infect the lid margin, the lash bases and follicles, and the associated glands. The resultant lid inflammation causes burning, foreign-body sensation, redness and mattering of the lashes. Examination reveals lid margin erythema and ulceration, fibrin, collarettes, and crusts at the base of the lashes. The condition can also be associated with recurrent hordeola (see Hordeolum), conjunctivitis, and marginal corneal infiltrates. A coarse punctate epitheliopathy can involve the inferior third of the cornea. In cases of long-standing disease, the thickened and scarred lids can produce contour abnormalities as well as lost or misdirected lashes. Treatment of staphylococcal blepharitis is directed at eradicating the offending organism. Intensive lid hygiene can be effective. Hot soaks increase local vascular flow and help to loosen the attached debris. Lid scrubs with a dilute non-irritating shampoo remove the irritating scales and debris and eliminate some bacteria. A bactericidal antibiotic ointment applied to the lid margins can further decrease the bacterial population. In patients with symptomatic keratoconjunctivitis, limited and closely monitored use of topical cortico-steroids may be necessary in the initial treatment of the disease. 

ACUTE BLEPHARITIS: The characteristic signs of angular blepharitis are maceration and crusting of the skin at the lateral (and sometimes medial) canthus. Localized temporal injection of the conjunctival and epibulbar vessels may accompany the lid lesions. This disorder is most commonly associated with infections caused by Staphylococcus species or (shown) Moraxella species, with the former predominating. Proteolytic enzymes elaborated by these bacteria can produce the maceration. Herpes virus or even Candida infection can also cause angular blepharitis. Treatment consists of maintaining lid hygiene and eradicating the causative organism with an appropriate antibiotic ointment. 

HORDEOLUM :A hordeolum, sometimes called a stye, is a local infected abscess of a hair follicle or a gland on the margin of the eyelid. 
An external hordeolum is a focal, erythematous swelling of the anterior eyelid margin, often an infected gland of Zeis. An internal hordeolum is an acute focal inflammation / infection of a meibomian gland. 
Local treatment, including topical antibiotics and warm compresses, is. usually sufficient. Systemic antibiotics are sometimes considered when extensive eyelid cellulitis occurs.