Optrex Allergy 2% w/v Eye Drops 10ml soothes and prevents itchy, allergy eyes. It contains 20 mg of Sodium Cromoglicate per 1 ml of eye drops. These eye drops are suitable for children aged six years and older, at the discretion of the pharmacist. Optrex Hayfever Eye Drops work by stopping the release of natural substances in your eyes that cause an allergic reaction, and can be used to prevent and treat symptoms such as red inflamed, itchy or watery eyes. To help prevent your eyes from becoming sore or itchy, wear sunglasses to reduce pollen exposure, wash your hair and change clothes after spending time outdoors, and dry washed clothes indoors when pollen levels are high.