Effect of Single Instillation of Three Different Topical Lubricants on Tear Film Thickness in Patients With Dry Eye Syndrome

The prevalence and incidence of dry eye syndrome (DES) is constantly increasing. Several therapeutic strategies have been proposed, but still no ideal regimen has been found. Recently, a new method for the non- invasive measurement of tear film thickness (TFT) based on optical coherence tomography (OCT) has been developed. It has been shown in previous studies that TFT correlates well with objective signs as well as with subjective symptoms of DES. In the present study the effects of three different topical lubricants (Neovis total multi®, Vismed multi® and Hydrabak® eye drops) on tear film thickness in patients with moderate to severe DES will be investigated using this device. Tear film thickness will be measured at baseline and at defined time points after single instillation. The course of tear film thickness during this study day will provide information about the corneal residency time of the three different eye drops. Patients with moderate to severe DES will be randomized to receive either Neovis total multi®, Vismed multi® or Hydrabak® eye drops. Assessment of lipid layer thickness of the tear film will be performed before and at pre-specified time points after instillation as secondary outcome. Other clinical measures for DES such as determination of tear film break up time (TFBUT), corneal fluorescein staining, Schirmer I test and subjective assessments will also be performed.