Preservatives, which are supposed to keep eye drops free of germs during storage and application, damage the cells of the ocular surface. These substances destroy the natural tear film, and they can also be the cause of intolerance reactions. Therefore, modern tear substitute preparations are entirely free of preservatives. In HYLO-COMOD®, the patented COMOD® multiple dose system prevents a contamination of the solution by microorganisms. Apart from preservatives, eye drops often contain phosphates which can exert detrimental influence. Due to the reaction with calcium, which is released from the cells of the irritated cornea, practically insoluble crystals can be created, which deteriorate vision. Therefore, eye drops that are used for the treatment of dry and irritated eyes should not contain any phosphate. HYLO-COMOD® is entirely free from phosphates and thus excludes the risk of crystal formation.