Contact lenses and water: why you should never swim in them
Contact lenses, 5 min read, August 2026
It is the rule opticians repeat most and wearers ignore most. It deserves an explanation rather than another repetition.
A contact lens is a porous material sitting directly on the cornea. It absorbs what surrounds it and holds it against the eye for hours. That is exactly what makes it comfortable, and it is also what makes it a problem in contact with water: the lens does not simply get wet, it retains.
What actually happens
Any water that is not sterile contains micro organisms. Most are harmless to a healthy eye, because the tear film flushes them away within a few blinks and contains antibacterial substances.
A lens blocks that mechanism. It traps micro organisms between itself and the cornea, in a space that is warm, damp and shielded from tear renewal. At the same time, wearing lenses creates micro irritations on the corneal surface, and those become points of entry.
The most feared micro organism in this context is a free living amoeba found in fresh water and water networks, called acanthamoeba. The infection it causes is rare, but it is painful, slow to treat and can leave permanent damage to vision. The vast majority of documented cases involve lens wearers exposed to water.
Seawater poses a slightly different problem: salt dehydrates the lens, which shrinks and sticks to the cornea. Removing a stuck lens tears off surface cells, creating exactly the kind of lesion that invites infection.
"The risk is not high on any single swim. It is small every time, and it is never zero. Repetition is what makes it real."
The full list of waters concerned
The sea, the pool, even a well chlorinated one, since chlorine does not kill acanthamoeba, rivers, lakes and rice paddies, hot tubs and hot springs, where the temperature speeds up proliferation, the shower, often forgotten, and tap water, drinking water included.
That last point always surprises people. Drinking water is safe to drink, not to put in contact with a lens. This is why a lens is never rinsed in tap water, never stored in it, and why the case must be rinsed with solution then air dried, never filled with water.
What to do if it has already happened
If you have been swimming in your lenses, do not keep them in. Take them out as soon as you are out of the water, bin them if they are dailies, and for monthlies run a full disinfection with fresh solution, or replace them if you have any doubt.
Then keep an eye on things for a few days. Increasing pain, persistent redness, blurred vision, heavy watering or intense discomfort in light all justify a prompt consultation. A corneal infection caught early treats well, caught late far less so.
The alternatives when you live by the water
A dive mask made to your prescription. This is the best solution for snorkelling and diving. There are masks with standard corrective lenses, in half dioptre steps, and masks made to order from your prescription.
Corrective swimming goggles. For the pool and for swimming in the sea, they are easy to find in common corrections and cost very little.
Daily lenses, with discipline. Some wearers choose dailies and bin them the moment they leave the water. It is the least bad compromise, it is not a risk free method, and it remains inadvisable.
Accepting the blur. For a short swim, going in without correction is often the simplest answer. The risk of temporary blur is zero, the risk of an infection is not.
And surfing
The case is a specific one in Bali. Seawater, suspended sand, impacts and rubbing your eyes with your hand make the worst possible combination for a lens. Losing a lens on the first wave is in fact the most common outcome. Surfers who need correction generally use dailies binned straight away, knowing the risk, or swim without correction.
Review your lens use: our optometrists assess how you actually wear them and suggest the right setup, details on Free Eye Exams in Bali.
This article is informative and does not replace medical advice. Any pain, redness or drop in vision in a contact lens wearer must be examined urgently by a healthcare professional.
