Here’s a reminder to keep your contact lenses clean. A British man who lost his eye to a rare infection last year says he wants people to be more aware of the risks.

The infection’s called Acanthamoeba keratitis and it is caused by an amoeba found in ordinary tap water. While it is rare, it happens often enough to cause concern – almost always in contact lens wearers.

Andrew Carthew, 59, told several British newspapers he didn’t think the infection was severe when he first felt his eye becoming watery and irritated.

But it quickly became painful and antibiotics did not help. Neither did a cornea transplant. Surgeons removed the affected eye last November.

It’s one of the many reasons health officials say contact lens users have to be super-careful and clean.

"I never swam in them or showered in them or slept in them and I never washed them in tap water, which is all the things that you shouldn't do,” Carthew told the Bristol Post.

“I must have had a contaminated finger and rubbed my eye or put them in with a contaminated finger and the bacteria harbored in this case.”

A local eye health charity, IsightCornwall, confirmed the incident.

Nearly a third of the 41 million Americans who wear contact lenses has had to visit a doctor because of red or painful eyes. Shutterstock

It takes quick recognition and aggressive treatment to get rid of the microbe that causes the infection, ophthalmologists say. Patients may have to get their eyes scraped, with medications and disinfectants dripped into the eye every hour to save it.

“The ameba is found worldwide in the environment in water and soil. The ameba can be spread to the eyes through contact lens use, cuts, or skin wounds or by being inhaled into the lungs,” the Centers for Disease Control and Prevention says.

It caused an outbreak in at least 35 states in 2007, the CDC reported.

Symptoms include pain and redness of the eye, excessive tearing and sensitivity to light.

To avoid any eye infection, the CDC advises:

Never reuse or top off old solution. Use fresh cleaning or disinfecting solution each time lenses are cleaned and stored.

Never use saline solution or rewetting drops to disinfect lenses. Neither solution is an effective or approved disinfectant.

Be sure to clean, rub, and rinse your lenses each time you remove your lenses. Rubbing and rinsing your contact lenses will aid in removing harmful microbes and residues.

Store reusable lenses in the proper storage case.

Related: Wear contacts? The CDC says you're probably doing something wrong

The CDC says nearly a third of the 41 million Americans who wear contact lenses has had to visit a doctor because of red or painful eyes. The CDC says 90 percent of people who wear hard contact lenses admit to having occasionally rinsed them off in tap water.