الفهرس 
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Abstract
On examination, early there is bulbar and palpebral conjunctival hyperemia; occasional mucus strands may be present. With progression, conjunctival thickening with loss of translucency occurs. The upper tarsal conjunctiva will demonstrate macropapillae (0.3 to 1 mm in diameter) or giant papillae (more than 1 mm in diameter). The number of papillae can vary from a few to innumerable. More pronounced mucus strands can be found at the canthi, in the fornices, and among the papillae. The papillae often have a dome-shaped appearance with fibrotic whiteyellow tops. Horner-Trantas’ dots may be seen. Fluorescein staining of the papillae, which indicates ulceration of the conjunctival surface, reflects severity. There may also be corneal staining, but this is uncommon. Pseudoptosis may occur in more severe cases. There is often significant deposit formation on the surface of the contact lenses. (42)
Several factors may be involved in pathogenesis. Mechanical irritation by the contact lens probably plays a role, especially lenses with thick edges, as seen in myopes. Accumulated deposits of protein, lipid, and minerals on the contact lens surface act as a source of antigens that can sensitize the conjunctiva. Chronic microtrauma by the lens and its deposits disrupts tight junctions between conjunctival epithelial cells, allowing allergens to penetrate. Damage to conjunctival epithelial cells induced by contact lenses and their deposits stimulates the production of neutrophil chemotactic factors, which play a role in the inflammatory response.(67-69)Certain lens polymers (e.g., hydrogels) are more prone to accumulation of deposits. Also, larger lenses provide a greater surface area for deposits to accumulate and a greater surface area for antigens to contact the conjunctiva. Long wearing times allow a longer period of conjunctival exposure to antigen. Meibomian gland dysfunction may play a role in deposit formation and contact lens intolerance.(70-72)
The allergic mechanism in GPC is probably a basophil-rich delayed hypersensitivity (type IV) reaction with a possible IgE (type I) humoral component.(66,73) An abnormal distribution of inflammatory cells is seen. There are mast cells in the conjunctival epithelium (not seen in normals) and increased numbers of mast cells in the substantiaprop