Page contents
- Why don’t water and contact lenses mix?
- Acanthamoeba: the most serious threat
- Pool or sea: is there a difference?
- How to swim safely if you wear contact lenses
- Red eye after swimming: conjunctivitis or keratitis?
- When to see an ophthalmologist urgently
- Is there an alternative to contact lenses?
- Frequently Asked Questions
Swimming with contact lenses in the sea, a pool or a lake increases the risk of a serious infection of the cornea, known as keratitis, because bacteria and parasites in the water, such as Acanthamoeba, become trapped between the lens and the eye. The safest practice is to take your lenses out before swimming or to wear watertight swimming goggles.
Why don’t water and contact lenses mix?
No swimming water is sterile. The sea, lakes and rivers, as well as chlorinated pools and hot tubs, can contain bacteria such as Pseudomonas, fungi and protozoa such as Acanthamoeba. Chlorine does not reliably kill all of these micro-organisms, particularly the resistant cysts of Acanthamoeba.
A soft contact lens acts like a sponge: it absorbs water and whatever the water carries, and holds it in close contact with the cornea for hours. In the fresh water of a pool the lens changes shape and “sticks” to the eye, while the salt and sand of the sea cause irritation and tiny abrasions on the surface. A small scratch in the corneal epithelium is the doorway through which infection gets in. On top of that, a wave can wash the lens away, and many people end up putting it back in hastily, with hands covered in sand and sun cream.
Acanthamoeba: the most serious threat
Acanthamoeba is a micro-organism that lives freely in water, soil and dust. In most people it never causes a problem. In contact lens wearers, however, it can cause Acanthamoeba keratitis, a rare but very serious infection:
- It usually causes pain that is far more severe than the appearance of the eye would suggest.
- At first it looks like simple irritation or a viral infection, so diagnosis is often delayed.
- Treatment is long, often lasting months, and needs close monitoring.
- In some cases it leaves a corneal scar and permanently reduced vision, and occasionally a corneal transplant is needed.
The main risk factor is contact between the lenses or their case and water: swimming, showering, or rinsing with tap water.
Bacterial keratitis
Bacterial keratitis is more common than Acanthamoeba keratitis, and its most typical cause is Pseudomonas. It develops quickly, within hours or a few days, with pain, redness, discharge and a white spot on the cornea. The risk rises sharply when someone sleeps in their lenses, which happens on holiday more often than we think.
Who is most at risk?
The risk of infection increases when more than one factor is combined. The most common are:
- Swimming or showering in lenses.
- Sleeping in lenses that are not designed for extended wear.
- Wearing lenses beyond their recommended replacement schedule.
- Poor case hygiene or reusing solution.
- Lenses bought without an eye examination, such as decorative coloured lenses.
Pool or sea: is there a difference?
| Environment | What increases the risk | Common symptoms |
|---|---|---|
| Swimming pool | Chlorine-resistant micro-organisms, a lens that “sticks” to the eye | Burning, redness from chlorine, blurring |
| Hot tub, heated pool | Warm water, where microbes multiply more easily | Irritation, higher risk of infection |
| Sea | Bacteria and protozoa, sand, irritating salt | Foreign body sensation, dryness, small abrasions |
| Lake, river | Fresh or stagnant water, often with a higher microbial load | As in the pool, with a greater risk of infection |
The conclusion is simple: none of these environments is safe for swimming in contact lenses without protection.
How to swim safely if you wear contact lenses
- Take your lenses out before getting in the water, if your vision allows it.
- Wear watertight swimming goggles. Prescription swimming goggles for short-sightedness are also available and solve the problem without lenses.
- If you must swim in lenses, choose daily disposables under well-fitting goggles and throw them away straight after swimming.
- Never rinse lenses or their case with tap or bottled water. Use only the solution recommended by your ophthalmologist, and always fresh.
- Do not sleep in your lenses, not even for a short nap on the beach.
- Wash and dry your hands thoroughly before touching your eyes or lenses.
- Take your glasses and a spare pair of lenses with you on holiday.
If your eyes are simply irritated after swimming, remove your lenses and use preservative-free lubricating drops. Do not put the lenses back in until the discomfort has completely gone. You will find more seasonal advice in our guide to protecting your eyes in summer.
The lens case matters as much as the lens
The case is often the source of contamination. Empty the case and rinse it with fresh solution every day, leave it to air-dry open and upside down, and replace it at least every three months. Never top up old solution with new. On holiday, with heat, sand and humidity, these rules become even more important.
Red eye after swimming: conjunctivitis or keratitis?
Irritation from chlorine or conjunctivitis after a swim in a pool is common and usually mild. Keratitis is a different matter, because it affects the cornea itself and can threaten sight. In a contact lens wearer, a red and painful eye is treated as possible keratitis until proven otherwise.
When to see an ophthalmologist urgently
Remove your lenses and get an examination the same day if you have:
- Eye pain that does not ease after taking the lens out.
- Marked sensitivity to light.
- Blurred vision.
- Redness that persists or gets worse.
- A white or greyish spot on the coloured part of the eye.
- Heavy watering or discharge.
Bring your lenses and their case with you, as they may be needed for a culture. Do not use old drops you have at home, especially steroid drops, without your doctor’s advice, as they can make some infections worse.
At the clinic, a slit lamp examination with a special dye shows whether the cornea is damaged. If keratitis is suspected, a sample may be taken for culture and treatment starts straight away, without waiting for the results, because every day of delay counts.
Is there an alternative to contact lenses?
For people who swim often or do water sports, depending on lenses is a daily concern. If your prescription is stable and your cornea is suitable, laser correction of short-sightedness is an option worth discussing after a full pre-operative assessment. It is not right for everyone, but for many people it settles the lenses or glasses dilemma at the beach for good.
If you wear contact lenses and want to use them safely, book an appointment at our clinic in Neo Psychiko, Athens.
Frequently Asked Questions
If I wear swimming goggles, can I keep my lenses in?
Watertight swimming goggles greatly reduce contact between the lens and the water, but they do not rule it out, as water can get in if they shift. If you swim in lenses under goggles, choose daily disposables and throw them away immediately afterwards. The safest option remains prescription swimming goggles, without lenses.
What should I do if water gets in my eye while I am wearing a lens?
Take the lens out as soon as possible, with clean, dry hands, and do not put it straight back in. If it is a daily lens, throw it away. If it is a monthly or two-weekly lens, disinfect it in fresh solution for the recommended time or, better still, replace it. If pain, blurred vision or sensitivity to light follow in the next few days, you need an eye examination without delay.
Are hard contact lenses safer in water?
No. Rigid gas permeable lenses do not absorb water like soft lenses, but micro-organisms can become trapped underneath them, and they are easily dislodged when swimming. Acanthamoeba keratitis has been described with all types of lenses. The rule is the same for every lens: as little contact with water as possible.
Can I shower with contact lenses in?
It is best to avoid it. Tap water is not sterile and may contain Acanthamoeba, which is why it is recommended to remove your lenses before a shower, a bath or washing your face. If that is not practical, keep your eyes closed and avoid water hitting your face directly.
Questions about your case?
Dr. Skouteris will examine you at his practice in Neo Psychiko and explain your options.
Ophthalmic surgeon trained at the John Radcliffe University Hospital in Oxford and Fellow of the European Board of Ophthalmology (FEBO).
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