THE EYE AND THE EOSINOPHIL

Recent work has highlighted the eosinophil's role as an effector cell in a wide array of disease entities, including parasitic infections an d allergic and nonallergic diseases. The eosinophil is filled with gra nules containing toxic cationic proteins, capable of harming tissue wh en released to the extracellular space. In the eye, toxic eosinophil c ationic granule proteins have been encountered in conjunctiva, cornea, tears, and contact lenses of patients suffering from ocular allergy, suggesting an effector role for the eosinophil in the ophthalmic manif estations of atopy. Laboratory investigations indicate that eosinophil granule major basic protein, the principal eosinophil granule protein , may adversely influence corneal epithelium, and promote corneal ulce ration in the severest forms of ocular allergy. Further, the eosinophi l may play a contributory pathophysiologic role in some nonallergic op hthalmic diseases such as Wegener's granulomatosis, orbital pseudotumo r, and histiocytosis X. The eosinophil's morphologic, immunologic, and biochemical characteristics will be reviewed and its role in certain ophthalmic diseases thoroughly examined.