Abstract
Abstract: :
Purpose: To determine if patient wear had any effect on the attachment of Acanthamoeba to the new second–generation silicone hydrogel (S–H) lens, Acuvue Advance. Attachment was compared to that of the first generation S–H lenses and a conventional hydrogel lens. Methods: Unworn and worn (daily for one week) 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 each lens type were examined. Logarithmic transformation of data allowed the use of parametric ANOVA for statistical analysis. Results: Patient wear produced a significant increase in the number of Acanthamoeba attaching to the second–generation lens (p<0.001) and the conventional hydrogel lens (p=0.009). No such increase in attachment was found with the first generation S–H lenses, but attachment was significantly greater than to the unworn or worn second generation and conventional hydrogel lenses (p<0.001). Conclusions: Acanthamoeba demonstrated a significantly higher affinity for worn second generation S–H lenses compared with unworn lenses. Patient wear may therefore be considered as a risk factor for Acanthamoebal infection. However, as attachment to the worn second generation S–H was similar to that found with the worn conventionally hydrogel, this new lenses is at no more risk of promoting infection with Acanthamoeba than a conventional hydrogel. The same cannot be said for the first generation S–H lenses, which had significantly greater attachment than both the unworn and worn second generation S–H, and may be at greater risk of initiating infection through lens colonisation.
Keywords: contact lens • Acanthamoeba • keratitis