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.
Why do some eye drops contain preservatives?
Eye drops in conventional squeeze bottles have to be preserved in order to prevent contamination of the solution and thereby avoid the risk of inflammation of the eye. 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 – 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, may damage the delicate cornea and change the composition of the tear film. The condition of dry eyes may worsen 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, 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 multidose bottles from URSAPHARM, the patented, unique COMOD® system, make possible preservative-free sterility. Thanks to a sophisticated ventilation duct, the AIRLESS application system prevents the eye drop solution from coming into contact at any time with the surrounding air when the dosing pump is operated. 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