When you have itchy eyes from allergies, look to LASTACAFT Once Daily Relief Antihistamine Eye Drops. Prescription strength LASTACAFT is clinically proven to relieve eye itching due to allergies in as little as 3 minutes and lasts up to 24 hours. So how does LASTACAFT work When allergens in the air come into contact with your eyes, histamine is released which is the body's natural defense mechanism that causes an allergic response which can make your eyes itch. Once daily LASTACAFT works in minutes to relieve itchy allergy eyes by 1) blocking histamine H1 receptors and 2) preventing further release of more histamine in the eye. LASTACAFT provides eye itch relief from both seasonal and year round allergens: pollen, grass, ragweed, animal hair and pet dander. LASTACAFT is for use in adults and children ages 2 and older. It's also a great value―each bottle of LASTACAFT contains a 60 day supply and is FSA HSA eligible. So, no matter the season, IT'S LASTACAFT SEASON. Based on 16 24 hour studies.