Inflammatory Response to Contact Lenses in Patients With Keratoconus Compared With Myopic Subjects

PURPOSE: To determine the levels of inflammatory molecules in the tears of patients who wore rigid gas permeable (RGP) contact lenses (CLs) and who had either keratoconus or myopia. METHODS: A prospective, case-control study with 4 groups enrolled 20 RGP CL keratoconus wearers and 28 keratoconus non-lens wearers, 20 myopic CL wearers, and 20 subjects with myopia that were non-lens wearers (1 eye per patient). Fifteen microliters of tears were collected by capillary flow. The concentration of cytokines (interleukin-6 [IL-6], IL-10, and tumor necrosis factor [TNF]-alpha), cell adhesion molecules (intercellular adhesion molecule 1 [ICAM-1] and vascular cell adhesion molecule 1 [VCAM-1]), and matrix metalloproteinase (MMP-9) was measured by enzyme-linked immunosorbent assay. RESULTS: The most significant differences associated with the wearing of RGP CLs in patients with keratoconus were seen in increased levels of proinflammatory cytokines (IL-6, 23.7 vs. 6.4 pg/mL, P = 0.001; TNF-alpha, 21.3 vs. 3.8 pg/mL, P = 0.028) and cell adhesion molecules (ICAM-1, 32.8 vs. 7.7 ng/mL, P < 0.0001; VCAM-1, 57.4 vs. 29.3 ng/mL, P < 0.0001). In patients with myopia, increased levels of TNF-alpha (4.2 vs. 1.8 pg/mL, P < 0.0001) and MMP-9 (12.9 vs. 6.1 ng/mL, P < 0.0001) were associated with the wearing of RGP CLs. CONCLUSIONS: Wearing RGP CLs induces overexpression of IL-6, TNF-alpha, ICAM-1, and VCAM-1 in the tears of patients with keratoconus. These increased levels are higher in cases with severe keratoconus.