Contact lens wear is quite safe as long as proper lens and storage case care are followed. Improper lens wear and care can put the lens wearer at risk for serious consequences. Sight-threatening microbial keratitis (corneal ulcer) is the most significant adverse event associated with contact lens wear and is largely preventable. The contact lens storage case is the most likely potential reservoir for contact lens related ocular infections. Contact lens storage cases should be replaced regularly, at least every 1-3 months.