Effect of Contact Lens Wear on the Release of Tear Mediators in Keratoconus

Objectives: The release of different cytokines and mediators in tears of patients with keratoconus (KC) wearing contact lenses (CLs) may contribute to the pathology of KC. Methods: Cohort study was established in patients with KC wearing rigid gas permeable (RGP) CL (group I), patients with ametropia wearing silicone hydrogel (Si-Hi) CL (group II) and ametropic patients wearing RGP CL (group III). Results: Our findings indicate that before CL wear, the release of epidermal growth factor (EGF) and tissue-type plasminogen activator (t-PA) was attenuated, whereas matrix metalloproteinase (MMP)-9, interleukin (IL)-6, chemokine (C-C motif) ligand 5 (CCL5), IL-13, and plasminogen activator inhibitor (PAI)-1 were enhanced in KC compared with ametropes. An increasing linear trend over time was found for MMP-9, EGF, and CXCL8 in KC and MMP-9, MMP-13, IL-6, and CXCL8 in group III. Significant differences were observed in the linear trend over time between groups I and III for MMP-13 and tissue inhibitor of metalloproteinases (TIMP)-1; between groups I and II for MMP-9 and CXCL8; and between groups III and II for MMP-9, CXCL8, and MMP-13. In KC, the release of MMP-9 at week 6 and nerve growth factor (NGF) at 10 min was higher, but NGF at week 2 was lower than that in group II. The release of MMP-13 and NGF at week 2 and 6 were lower in the KC group as compared with group III, and similarly, with IL-6 and CXCL8 at week 2 and PAI at all time points. Conclusions: Contact lens wear can influence the levels and dynamics of various mediators in the tears of patients with KC that might have an impact on the progression of the disease.