Alcon Naphcon A Eye Drop, formerly prescribed by doctors, are now available without a prescription. Alcon Naphcon A Eye Drop combine a redness reliever and an antihistamine for temporary relief of itchy, red eyes from allergies caused by ragweed, pollen, grass, and animal dander and hair. A gentle, effective, thimerosalfree, preserved solution Recommended for rewetting lenses during wear .5 fl. oz. 15 mL bottle Consult a doctor before use if you have heart disease, high blood pressure, trouble urinating, or narrow angle glaucoma.