11/13/2014 14:12 EST | Updated 01/13/2015 05:59 EST

Contact-lens care lapses linked to eye infections

Nearly one million eye infections occur each year in the U.S., say public health officials, who warn that wearing contact lenses is the main risk factor for developing an infection of the cornea.

For Thursday’s report from the U.S. Centers for Disease Control and Prevention, researchers looked at cases of keratitis — an infection of the cornea that causes pain and mild inflammation in most cases and can lead to blindness in a small number of cases.

Keratitis occurs when germs invade the cornea, the clear dome that covers the coloured part of the eye.

The infection is most likely to occur when contact lenses are worn too long or are not cared for correctly, the CDC said

To prevent eye infections, the agency recommends the following seven precautions for contact lens wearers:

- Wash hands with soap and water and dry well before touching contact lenses.

- Take contacts out before bed, showering or swimming.

- Rub and rinse contacts in disinfecting solution each time they are removed.

- Rub and rinse the case with contact lens solution, dry with a clean tissue and store upside down with the caps off after each use.

- Replace contact lens cases at least once every three months.

- Do not "top off" solution in lens case.

- Carry a backup pair of glasses in case contact lenses have to be taken out.

"Contact lenses can provide many benefits, but they are not risk-free — especially if contact lens wearers take shortcuts and don’t take care of their contact lenses and supplies," Dr. Jennifer Cope, a medical epidemiologist at CDC, said in a release.

The agency estimated that Americans made an estimated 930,000 visits to doctor’s offices and outpatient clinics and 58,000 emergency room visits each year because of eye infections.

About 38 million Americans wear contact lenses. Previously, other researchers have estimated one to 10 per cent suffer keratitis or other eye problems.