Conjunctiva PDF

Conjunctiva Karen Gil MD, MHSN Conjunctiva • Thin, translucent mucous membrane • Runs from the limbus over the anterior sclera forms a cul-de-sac at the superior and inferior fornices and turns anteriorly to line the eyelids • Ensures smooth movement of the eyelids over the globe 1- limbus 2- bul...

Conjunctiva Karen Gil MD, MHSN Conjunctiva • Thin, translucent mucous membrane • Runs from the limbus over the anterior sclera forms a cul-de-sac at the superior and inferior fornices and turns anteriorly to line the eyelids • Ensures smooth movement of the eyelids over the globe 1- limbus 2- bulbar conjunctiva 3- conjunctival fornix 4- tarsal conjunctiva 5- punctum 6 - marginal conjunctiva Conjunctiva • Divided: – Palpebral conjunctiva or tarsal conjunctiva (tissue lining the eyelids) – Bulbar conjunctiva (tissue covers the sclera) – Conjunctival Fornix , culde-sac (connects palpebral and bulbar sections) Conjunctiva Bulbar Conjunctiva • Translucent • Allow underlying sclera to shine trough • Two layers: – Stratified squamous epithelial layer • Continuous with the corneal epithelium • Superficial cells have: – microvilli – goblet cells (their cytoplasm contains melanin granules) – Submucosa (stroma) • Vascularized loose connective tissue Plica Semilunaris • Conjunctival fold at medial canthus that contains: – Smooth muscle – Goblet cells – Adipose tissue • Reduce stretching of conjunctiva on lateral movements Caruncle • Hill of tissue located on the medial side of plica semilunaris • Unknown function • Contains: – Goblet cells – Hair follicles – Sebaceous and sweat glands • Source for the collection of matter (awake in the morning) Conjunctival Blood Supply • The palpebral and forniceal portions are supplied by the peripheral arcades (upper and lower lids) • Bulbar conjunctiva are supplied by the anterior ciliary arteries Conjunctival Blood Supply Conjunctival Innervation Sensory innervation • Bulbar conjunctiva – long posterior ciliary nerves • Palpebral conjunctiva– Superior- frontal and lacrimal branches of the ophthalmic nerve – Inferior- lacrimal nerve and the infraorbital branch of the maxillary nerve • All sensory information is carried in the trigeminal nerve Clinical Applications • Conjunctivitis – Pink eye – Any inflammation of the conjunctiva – Cause by a variety of factors • Bacterial infection • Viral infection • Allergic reaction Clinical Applications • Chemosis – Accumulation of fluids in the loose stromal tissue (edema) – Seen in inflammatory conditions Clinical Applications • Conjunctival Injection – Dilatation and engorgement of the conjunctival blood vessels – Also seen in inflammation and irritation Clinical Applications • Pinguecula – Opaque, slightly elevated mass of modified conjunctival tissue in the interpalpebral area – Usually at 3 o’clock or 9 o’clock – Round, oval, yellowish – The epithelial layer stays intact – The submucosa changes: • Hyalinization (collagen degeneration) • Abnormal elastic fibers Clinical Applications • Pterygium – Fibrovascular overgrowth of bulbar conjunctiva into cornea – Usually progressive – 3 o’clock or 9 o’clock – Same connective tissue changes as pinguecula Follicles and Papillae Follicles Papillae Etiology Causes Lymphoid hyperplasia Viral disease*, Chlamydia (trachoma, conjunctivitis), catscratch disease (Parinaud’s), toxic drug reactions Allergic response Allergies**, Chlamydia (trachoma, conjunctivitis), bacterial conjunctivitis Composition Plasma cells, lymphocytes Blood vessel center surrounded by edema/inflammatory cells under the epithelium Size Generally smaller than papillae Generally larger than follicles Location Often the lower lid Blood vessels Avascular, but vessels may wrap Blood vessel tuft in center around them Follicles Often the upper lid Papillae Appearance Yellowish or gray/white, with surrounding blood vessels Red center