BACTERIAL BIOFILM ON CONTACT-LENSES AND LENS STORAGE CASES IN WEARERSWITH MICROBIAL KERATITIS

Bacterial biofilm formation on contact lenses (CLs), and CL storage ca ses may be a risk factor for CL-associated corneal infection and may e xplain the persistence of organisms in CL storage cases. This study ev aluated biofilm formation on, and microbial contamination of, CLs and CT, storage cases from patients with microbial keratitis. Contact lens es and CL storage cases from 20 wearers with microbial keratitis were sampled microbiologically and visualized using scanning electron micro scopy (SEM). Culture results from the cornea were also noted. Bacteria l biofilm was present more frequently (P < 0.05) on CL storage case su rfaces (17/20) compared with CL surfaces (11/20) and biofilm density w as significantly greater on case surfaces (P < 0.05). There was no ass ociation between poor compliance and microbial contamination of the CL storage case, nor between poor compliance and biofilm formation or de nsity on the CL or CL storage case. Biofilm formation occurred equally frequently with hydrogen peroxide and chlorine release care systems. Microbial keratitis in CL wearers is frequently associated with bacter ial biofilm in the CL storage case. Despite the use of current CL disi nfection systems, the CL storage case is a favourable environment for proliferation of certain organisms. Biofilm on CLs may prolong the ret ention time of organisms at the ocular surface and increase their pote ntial pathogenicity.