A study recently done in the US showed that contact-lens wearers have had an increased rate of serious eye infections*. An alarming 99% of contact lens wearers also reported at least one behaviour that could put them at risk for an eye infection caused by bacteria, fungi or viruses. Some of these infections could permanently damage vision.
The most common bad habits reported by contact lens wearers included the following:
• Failure to properly wash hands with soap and water and dry them before handling contact lenses
• Sleeping in contact lenses (only certain contact lenses are approved for overnight use)
• Showering or swimming with contact lenses
• Over-wearing contact lenses beyond the prescribed daily limit
• Failure to replace contacts according to the prescribed regimen
• Failure to use the proper disinfection/storage system (plain saline is not a disinfectant)
• Storing contact lenses in tap water (water is not sterile and may cause serious eye infections)
• Failure to use fresh solution daily (contact lens solution needs to be replaced after each use and not topped up)
• Failure to properly maintain contact lens cases (should be rinsed with contact lens disinfectant solution, not water, and should be replaced regularly)
Remember that contact lenses are categorized as medical devices that must be used only under the supervision of a licensed professional. If any adverse symptoms such as redness, discharge, pain, change in vision or discomfort are noticed while wearing contact lenses they should be discontinued and professional care sought immediately. Since eye health problems can also develop without any noticeable symptoms, annual eye exams are required for contact lens wearers.
(Source: http://www.pharmacytimes.com/contributor/jennifer-gershman-pharmd-cph/2016/09/contact-lens-hygiene-is-lacking