Eye Doctors Warn 45 Million U.S. Contact Wearers Against 3 Common Habits

Q: Your tap water is safe to drink, so why could it cost a contact lens wearer their sight?

Tap water can threaten a contact lens wearer’s sight because it is safe to drink, but not sterile enough for the eye. It can contain microorganisms such as *Acanthamoeba*, along with bacteria, that are usually harmless when swallowed but can cause severe corneal infections when trapped under a lens. That risk rises because soft contact lenses absorb water like sponges. If tap water gets on the lenses during showering, rinsing, or storage, the lens can hold those organisms against the cornea. Doctors say this creates the conditions for infections such as *Acanthamoeba keratitis*, a rare but potentially blinding disease that can cause intense pain, corneal ulcers, scarring, and sometimes require a corneal transplant. Experts from the American Academy of Ophthalmology and the CDC warn that contact lenses should never touch tap water. Ophthalmologists also stress that even brief exposure matters: showering in lenses, swimming in them, or cleaning them with water all increase risk. Sleeping in lenses adds another danger by reducing oxygen to the cornea and increasing infection risk six- to eightfold. The practical advice is simple: never rinse or store lenses in tap water, remove lenses before showering or swimming, and use only sterile contact lens solution or sterile saline when appropriate. If redness, pain, discharge, blurred vision, or a foreign-body sensation develops, remove the lenses immediately and seek prompt eye care if symptoms do not quickly improve.

3 articles · Updated · The Washington Post · Jun 30

Eye specialists said contact lens users should not swim, shower or sleep in lenses because all three habits raise the risk of serious eye infection.
Water is a main concern: pools, lakes and even tap water can carry Acanthamoeba and other germs that stick to soft lenses and can cause vision loss, surgery or cornea transplants.
Sleeping in contacts increases infection risk six to eight times, according to the CDC, because closed eyes create a dark, low-oxygen environment where bacteria can thrive against the cornea.
Doctors said daily disposable lenses may lower overall risk, but they do not eliminate it; any pain, redness or discharge lasting more than 12 hours should be checked by an eye doctor.