After these measurements we will ask you to stand inside a specially designed room where the environment can be controlled by a computer. The pollen that you were found to be allergic to will then be introduced into the atmosphere of the room, so that the signs and symptoms of SAC can be induced - this is intentional, but normally resolves within a few hours with no treatment. At each visit, you will experience a different duration (no longer than 10 minutes) and either no treatment, artificial tear supplement (ATS; preservative free ocular lubricant), cold compress (CC; cooled gel eye mask) or anti-allergic medication (epinastine hydrochloride 500μg/mL). The measurements will then be repeated even 5 minutes for an hour.