rily relieving itchy, red eyes caused by allergies to things such as pollen, ragweed, grass, or animal hair and dander. Naphcon-A is a decongestant and antihistamine combination | The decongestant constricts (narrows) the blood vessels, which reduces eye redness | Pocket pack | The antihistamine works by blocking the action of histamine, which helps reduce symptoms such as watery, itchy eyes