Eye allergy diagnosis
To provide proper treatment, your ophthalmologist will check to see whether your symptoms are related to an eye infection or allergic conjunctivitis. He or she can usually diagnose allergic conjunctivitis easily by examining your eyes and discussing your medical history — including your history and your family's history of allergies.
Your ophthalmologist will examine your eyes with a slit lamp microscope to check for signs of eye allergies, such as swollen blood vessels on the surface of the eye. If your allergies are severe, or if it is not completely clear that you have allergic conjunctivitis, your ophthalmologist may choose to test for specific type of white blood cells (called eosinophils) that show up in areas of the eye where there is an allergic reaction to something. This test is done by gently scraping a tiny area of the conjunctiva and testing this tissue for eosinophils.