Acanthamoeba keratitis is a rare but serious eye infection that is painful and sight-threatening. It affects the clear front surface of the eye (the cornea) which becomes painful and swollen (inflamed).
Acanthamoeba are usually found in soil and in water, for example in hot and cold tap water, swimming pools, hot tubs and sea water. In the UK, most people who get Acanthamoeba keratitis wear contact lenses. About 1 in 30,000 contact lens wearers become infected. It’s also possible to become infected after an injury to the cornea. Using tap water to clean or store contact lenses or having poor contact lens hygiene increases the risk of infection. Examples of poor lens hygiene are not using disinfection solutions properly, reusing the solution in the contact lens case, failing to empty and dry the contact lens case after use and storing lenses in water overnight. Wearing contact lenses when swimming or taking a shower also increases risk. So does putting lenses in with wet hands from tap water.
Acanthamoeba keratitis is very painful for most people but it’s possible to have no pain at all. Other symptoms include red eyes that feel irritated or like they have something in them. Some people will get blurred or poor vision. Some people become sensitive to light and find it painful or uncomfortable.
Acanthamoeba keratitis needs immediate attention. Treatment is usually with antiseptic eye drops. It can be hard to treat and may also need antibiotics or steroids as well as painkillers. The most serious infections will mean the need for a corneal transplant. This involves surgery to remove the damaged cornea and replace it with a healthy one from a suitable donor.
Do make sure you have good contact lens hygiene. For example, clean and dry your hands well before touching your lenses. Take your lenses out before sleeping. Follow the advice from your optician and the manufacturer’s instructions for your lenses. Think about using daily disposable lenses instead of ones that need to be cleaned and stored to use again. Don’t wear contact lenses when you wash in the bath or shower, or when you go swimming at a pool or in the sea.