Evaluation of the microorganisms on the surface of the soft silicon hydrogel contact lenses after three months daily usage in Dargaz optometry clinic in 2012-2013

Increasing th usage of soft silicon hydrogel lenses and the usage of this kind of contact lenses as seasonal contact lenses for period of three months in Iran and the fact that this priod is longer than the recommended time the manufacturer determined، we decide to evaluate the effect of three month usage of soft silicon hydrogel contact lenses on microbial contamination. In this cross sectional study we took fifty samples from the surface of soft silicon hydrogel lenses after three months usage and the microorganisms on their surface was evaluated. Microorganisms grown in medium containing Staphylococcus epidermidis، Staphylococcus Saprophiticus، Micrococcus، Eshrishio coli، Klebsiella، Proteous، Citrobacter and Corynebacterium diphteriae. Microbial contamination was observed in 48% of cases and 52% were found to have no contamination. Results showed that three month usage of soft silicon hydrogel lens increased the bacterial adhesion and ocular infection risk and this type of contact lenses must be used exactly as long as specified by the manufacturer.