Effects of Multipurpose Contact Lens Care Solutions on the Adhesion of Acanthamoeba to Silicone Hydrogel Contact Lenses

Purpose: To evaluate the effect of 7 multipurpose contact lens care solutions (MPSs) on the adhesion of Acanthamoeba (AC) to 5 silicone hydrogel contact lenses (SHCLs). Methods: Acanthamoeba castellanii (ATCC50370) trophozoites were inoculated onto disks trimmed from SHCLs, Asmofilcon A, Galyfilcon A, Senofilcon A, Lotrafilcon B, and Balafilcon A. After 4-hour incubation, the number of adherent AC trophozoites on SHCL was counted under phase contrast microscopy. AC trophozoites mixed with 7 MPSs were inoculated onto Balafilcon A and incubated for 24 hours followed by direct counting, phase contrast microscopy, and scanning electron microscopy. AC cysts were also inoculated onto Balafilcon A followed by counting using phase contrast microscopy. Results: Adhesion of AC trophozoites to Lotrafilcon B and Balafilcon A was 10 times higher in comparison with the other 3 SHCLs. Twenty four-hour treatment of AC trophozoites with Epica Cold, Epica Cold Aquamore, ReNu MultiPlus, OptiFree Plus, and Complete DoubleMoist reduced the numbers of adherent AC to less than 25% of control, whereas the numbers of AC treated with Complete AminoMoist and C3 SoftOne Moist was about 50% and 75% of control, respectively. Normal AC trophozoites without any treatments showed 25 times higher adhesion rates compared with normal AC cysts. Conclusions: The adhesion rates of AC trophozoites to SHCL varied depending on the type of MPSs used. Appropriate uses of MPS could reduce adhesion rates of AC to SHCL and potentially decrease clinical rates of Acanthamoeba keratitis.