Allergic conjunctivitis is one of the most common disorders of the external eye. Hypersensitivity of the conjunctiva to foreign substances is characterized by discharge, redness, itching, irritation, swelling, light sensitivity, and tearing. The tear fluid contains a small amount of eosinophils and histamine. Allergic eye conditions can be classified into four categories. They are hay fever conjunctivitis, vernal conjunctivitis, atopic keratoconjunctivitis, and giant papillary conjunctivitis.