The symptoms of dry eyes can be quickly and easily relieved with lubricating eye drops. Preservatives in the preparations can, however, damage the eyes. That is why only preservative-free eye drops should be used.
What are preservatives in eye drops good for?
Preserving agents in eye drops are supposed to prevent germs from getting into the eye. Bacteria or fungi can quickly settle and reproduce in many eye drop bottles without a sterile closure. With drops, they then get into the eyes and can cause infections there.
Preserving agents should impede germs from growing. However, tests have shown that the preservatives do not offer comprehensive protection from germs. In a third of the eye drops tested, bacteria were detected in the bottles after 15 days – and that despite the addition of preserving agents. Therefore, the real benefit of preserving agents is questionable. In addition, these additives are not always well tolerated1.
Which preservatives are there in eye drops?
Above all, the preserving agent benzalkonium chloride comes under fire. The substance, which is also used in disinfectants, damages the delicate cornea and changes the composition of the tear film. The condition of dry eyes worsens as a result.
Eye drops with benzalkonium chloride can cause more harm than good if used over prolonged periods. In addition, benzalkonium chloride can cause allergies. Particularly someone who uses eye drops every day should definitely therefore turn to a preparation without preservatives.
Alongside benzalkonium chloride, there are other preserving agents with which eye drops are preserved. These include, for example, Polyquad®, PURITE® or the oxychloro complex. These agents are only slightly more tolerable than benzalkonium chloride. They, too, can irritate the eyes and give rise to allergies.
Other preserving agents that you should avoid are:
- Chlorhexidine gluconate
- Polidronium chloride
In daylight, PURITE® disintegrates into harmless ions and oxygen. It is, however, questionable how quickly that happens and whether PURITE® is therefore less harmful to cells than other preserving agents. Trials on living tissue have shown detrimental effects2.
The COMOD® system makes preservatives superfluous
The best alternatives for dry eyes for long-term users and contact lens wearers are eye drops without preservatives. The innovative multi-dose bottles from Ursapharm make preservative-free sterility possible; the products are fitted with the unique COMOD® system. Thanks to a refined airflow and a special pump, the system prevents the eye drop solution from coming into contact at any time with the surrounding air. Bacteria and fungal spores can therefore not gain access to the inside of the bottle and contamination is eliminated. Thanks to the COMOD® system the eye drops can be used for six months after opening.
1Source: Press release from Deutschen Ophthalmologischen Gesellschaft (DOG – German Ophthalmological Society), January 2013 (http://www.dog.org/wp-content/uploads/)
2Schrage, N.etal.: Graefes Arch Clin Exp Ophthalmol. 2012; 250 (9): 1333-40