Water can introduce germs to the eyes through contact lenses

Water can cause soft contact lenses to change shape, swell, and stick to the eye. This is uncomfortable, and can scratch the cornea (the clear dome that covers the colored part of the eye), which makes it easier for germs to enter the eye and cause infection.

Most water is not germ-free. There are many different kinds of germs in water that can cause eye infections, but a particularly dangerous germ—an ameba called Acanthamoeba—is commonly found in tap water, lake water, well water, and other water sources 5. This germ can cause a very severe type of eye infection called Acanthamoeba keratitis, which is often very painful and difficult to treat—sometimes requiring a year or more of treatment 6-8. Although rare, this type of infection can result in the need for a corneal transplant, or blindness 9, 10.

Keep contact lenses away from all water

For contact lens wearers, it is best to remove lenses before showering, swimming, or using a hot tub—and contact lenses should never be rinsed or stored in water 1, 2, 11, 12. It is also important to wash and dry hands well before handling lenses 13-15, and to clean contact lens cases with solution rather than water to avoid contaminating the lenses with germs found in water.

For those who are actively involved in swimming or other water sports and concerned about being able to see well enough without wearing lenses, prescription goggles may be a good option—or possibly even a different form of vision correction, such as laser eye surgery.