Participants, eligibility criteria, and settings
Eighty-two patients were included in this study. Two separate cohorts were recruited, one (A) to evaluate the immediate effect of a single application of two different lipid-based lubricants and a second (B) to assess the effect of a 12-week treatment with regular application five times per day.In cohort A (short term effect) after baseline measurement one single drop of study medication was applied. Both eyes were timed separately to ensure the same interval for all measurements. In 10 controls, one eye did not receive study medication. All measurements were taken immediately, 15 and 120 minutes after the application. To avoid disturbances of the tear film that would affect the continuous measurements, we resigned from further evaluation of other tear film parameters.In cohort B (long term effect) all participants applied the study medication 5 times per day for 12 weeks. All examinations were performed at baseline, and at 4- and 12-week follow-up as described above. They were advised to suspend the application of study medication 12 hours prior to the measurements. For cohort B an age- and sex-matched control group of healthy volunteers was recruited, which did not receive any treatment.Inclusion criteria were a lipid layer deficit, defined as less than 75 interferometric color units (ICU) measured with the LipiViewThe study took place at the Department of Ophthalmology at the University Hospital in Düsseldorf, Germany.