In the United States, Acanthamoeba keratitis is nearly always associated with soft contact lens use.[6] Acanthamoeba spp. is most commonly introduced to the eye by contact lenses that have been exposed to the organism through the use of contaminated lens solution, using homemade saline-based solution or tap water, or from wearing contact lenses while bathing or swimming.[7][8][7] However, it may also be introduced to the eye by exposure to soil or vegetation, or by trauma.[1] In fact, the first case of Acanthamoeba keratitis described was due to ocular trauma.[1] Once on the contact lens, Acanthamoeba is able to survive in the space between the contact lens and the surface of the eye.[8][9][10] Soft contact lenses are more adherent to the corneal surface than hard lenses, which allows the Acanthamoeba organism to bind to mannosylated glycoproteins on the corneal surface.[11] Expression of these proteins on the corneal surface is increased by contact lens use.[10] This increase in glycoprotein content, along with microtrauma to the corneal epithelial surface due to contact lens use increases the risk for infection.[11][12] Once the organism has gained access to the surface of the eye, it is able to invade through the epithelium and Bowman's layer.