Abstract
Abstract: :
Purpose: To investigate the attachment of Acanthamoeba to the new second–generation silicone hydrogel (S–H) lens, Acuvue Advance, and determine if the presence of a bacterial biofilm coating affects attachment. Amoebal attachment will be compared to that of first generation S–H lenses and a conventional hydrogel lens. Methods: Unworn and Pseudomonas aeruginosa biofilm coated Acuvue Advance (Johnson & Johnson), Focus Night & Day (Ciba Vision), Purevision (Bausch & Lomb), and Acuvue (Johnson & Johnson) lens quarters were incubated for 90 minutes in suspensions of plate–cultured Acanthamoeba castellanii trophozoites. Trophozoites attached to one surface of each quarter were counted by direct light microscopy. Sixteen replicates of unworn and biofilm coated lenses of each type were examined. Logarithmic transformation of data allowed the use of parametric ANOVA for statistical analysis. Results: The presence of a bacterial biofilm on the Acuvue Advance lens (p<0.001) and the conventional hydrogel (p=0.009) lens produced a significant increase in attachment, compared with the unworn state. No such effect was noted with the first generation S–H lenses. Amoebal attachment to unworn or biofilm coated second generation S–H and the conventional hydrogels did not differ significantly, but both had significantly fewer attached organisms than the unworn or biofilm coated first generation S–H lenses (p<0.001). Conclusions: The similarity in amoebal attachment to the second generation S–H lens and the conventional hydrogel lens suggests that the Acuvue Advance lens poses no more of a risk of ocular infection with Acanthamoeba, as a result of amoebal colonisation, than a conventional hydrogel lens. The risk may actually be less due to the improved corneal oxygenation and metabolism achieved with this new lens material. However, the first generation S–H lenses, which had significantly more organisms attached, may provide a greater risk of infection if Acanthamoebal exposure occurs, for instance when showering, swimming or through non–continuous wear and inefficient lens care regimes.
Keywords: contact lens • Acanthamoeba • keratitis