Anti-oxidative capacity of various artificial tear preparations

Background: Increased UV radiation and ozone exposure may cause "dry eyes o f environmental origin". if the normal anti-oxidative capacity of the tear film can no longer cope with the oxidative stress. The use of artificial te ars with an adequate anti-oxidative effect may be beneficial in the treatme nt of dry eyes caused by environmental factors. Methods: The anti-oxidative capacity of various commercial artificial tear preparations was determined with a modified TRAP procedure. The two preparations with the strongest an ti-oxidative effect were then examined for their protective effects against UV or ozone exposure in a hyaluronate model. Results: Of 19 artificial tea r preparations tested, only 6 showed strong to moderate anti-oxidative effe cts. All others were at best weakly anti-oxidative or had no anti-oxidative effect at all. Some of them even acted as oxidants. Although the two most strongly anti-oxidative preparations performed somewhat differently on UV a nd ozone exposure, they were both found to be highly protective against the se important oxidative stress factors. Conclusions: The anti-oxidative capa city of artificial tear preparations varies widely. While some are strong a nti-oxidants, others are less active or even act as oxidants. If the carefu lly elicited history of patients with dry eyes suggests that noxious enviro nmental factors may be causally involved, artificial tears which are not ju st lubricants or contain wetting agents, but act as anti-oxidants, should b e chosen for treatment from the many commercially available preparations. S uch an etiology-oriented concept would probably improve the success rate of treatment for dry eyes.