Objectives: To study changes in tear film inflammatory mediators following continuous wear of silicone-hydrogel lenses and corneal refractive therapy with reverse geometry contact lenses.
Design: A prospective, case-control study.
Methods: Twenty-eight subjects had worn silicone-hydrogel lenses on a 30-night continuous wear basis. Thirty-two subjects had worn corneal refractive therapy lenses on an overnight basis. Thirty-two matched control subjects were also recruited. Tear samples were obtained 12 months after initial fitting and assayed using ELISA for cytokines (interleukin (IL)-6 and IL-8), matrix metalloproteinase 9 (MMP-9) and epidermal growth factor (EGF).
Results: EGF was significantly increased 12 months after both interventions. IL-6, IL-8 and MMP-9 were significantly increased only after corneal refractive therapy. The inflammatory response for the corneal refractive therapy patients was found to be associated with the degree of myopia corrected and the presence of corneal staining. Moreover, an increased level of MMP-9 and EGF was found to be associated with the presence of corneal-pigmented arc in the corneal refractive therapy group.
Conclusions: This research showed long-term increased tear levels of inflammatory markers in subjects wearing corneal refractive therapy lenses when compared with continuous wear of silicone-hydrogel lenses or no lens wear.