Background: The pH-values of artificial tears have not been examined up to now.
Materials and methods: The pH-values of 20 commercially available artificial tears were determined.
Results: pH-values measured from 4.82 to 8.39. One sixth showed pH-values above physiological values.
Conclusion: A remarkable proportion of commercially available artificial tears deviate from the physiological range of the pH. It does not seem advisable to apply those in eyes with damaged anterior segments.