British Contact Lens Association

Acanthamoeba and contact lenses

Problems with contact lenses are thankfully rare but are more likely to occur if the recommended hygiene procedures are not followed. That’s why it’s important to listen carefully to the advice of your contact lens practitioner and always follow instructions on lens wear and care.

One type of infection affecting the cornea, the transparent front part of the eye, is Acanthamoeba keratitis, a rare but very painful condition that can cause sight loss. The infection rate is approximately one in 30,000 contact lens wearers and in around 85% of cases the condition is associated with contact lens use.

The organism that causes the infection, Acanthamoeba, has been found in almost all environments, including soil, dust, fresh water and seawater. Acanthamoeba is found in chlorinated swimming pools, hot tubs, domestic tap water and even in bottled water. It is also present, without causing illness, in the nasal passages of healthy people.

Risk factors for infection in contact lens wearers include:

· Using tap water during lens care (to rinse lenses or the storage case) or inadequate hand drying prior to lens handling

· Wearing lenses while swimming (without goggles), showering or in hot tubs

· Using ineffective lens care solutions

· Failing to follow lens care instructions

Symptoms of Acanthamoeba keratitis include a sensation of having something in the eye, watery eyes, blurred vision, sensitivity to light, swelling of the upper eyelid and extreme pain. If you experience any of these symptoms, remove your contact lenses and consult your contact lens practitioner immediately, who will advise you what to do next.

If the disease is recognised early, when only the surface layer of the cornea is infected, it may respond rapidly to treatment. If the disease is not recognised until later then intensive treatment may be needed for up to 12 months. Infection can also reoccur after treatment.

Most cases of Acanthamoeba keratitis are preventable if contact lens wearers follow the instructions given to them by their contact lens practitioner and on their lens care products. Contact lens wearers not complying with these instructions may be increasing their risk of infection with Acanthamoeba and other organisms. Not all contact lens solutions have the same disinfecting ability, so changing solutions without the advice of your contact lens practitioner is not recommended.

More information on lens hygiene can be found under Dos and Don’ts of contact lenses and in the BCLA leaflet ‘Looking after contact lenses’