Wearing contact lenses while showering or swimming — or sleeping with them in — may seem like harmless time-savers.
But these common habits increase the risk of agonising eye problems and even blindness, experts have warned.
The main concern is a microscopic parasite which is often found in water, including tap water, called acanthamoeba keratitis.
The bug is normally harmless, but wearing contacts can create microscopic tears in the front part of the ye, the cornea — through which acanthamoeba can enter.
They then multiply, causing eye pain, redness, blurred vision, light sensitivity, and watery eyes. In the worst cases, it can lead to blindness.
Acanthamoeba can get into the eye while bathing or showering, and if contacts are being worn during these activities, the chances of infection increases dramatically.
Even leaving contacts in overnight can increase the risk.
This is because small numbers of acanthamoeba can be transferred into the eyes if a person washes their hands then touches their face.
Nina Wang, 30, from London, fell victim to the parasite while on holiday in Bali in July 2019
At first, Ms Wang just felt irritation and stickiness, but her symptoms progressed into soreness, pain, and an unbearable sensitivity to light. Two days later on July 16, 2019, she went to hospital
If contacts are worn during sleep it creates the perfect environment in which acanthamoeba can thrive.
Lens manufacturers and opticians make these risks clear yet, hundreds of Britons suffer the infection each year, according to the College of Optometrists.
Meanwhile, an estimated 1,500 Americans get it each year, according to The Cleveland Clinic.
Nina Wang, 30, from London, fell victim to the parasite while on holiday in Bali in July 2019.
The businesswoman who has been wearing contact lenses since she was 11, first stared feeling irritation in her right eye, but assumed her symptoms were just mild conjunctivitis and would go away on their own.
‘I’ve dealt with many an irritations that are normally insignificant, but it got worse the next day,’ she told MailOnline.
She admitted to occasionally falling asleep with her contacts in, which she alternated between monthly and daily types to limit the number she had to carry on her six-week trip.
At first, Ms Wang just felt irritation and stickiness, but her symptoms progressed into soreness, pain, and an unbearable sensitivity to light.
The photograph (Left) shows the scar blocking the pupil and the vision, and the photograph on the Right shows how specialist treatment cleared the pupil area of scar and simultaneously reduced the myopia (short-sightedness) significantly
Two days later on July 16, 2019, she went to hospital.
When her symptoms escalated, she sought medical help at a local hospital in Bali, where she was diagnosed with microbial keratitis.
She was given antibiotics and the medical staff advised her to travel to Jakarta for more specialised treatment, but she decided to remain in Bali.
Ms Wang followed the hospital’s initial instructions, which included wearing an eye patch, avoiding sunlight, and using prescribed drops.
Upon returning to the UK three weeks later, on August 4, Ms Wang sought further care at Moorfields Eye Hospital, where specialists recognised the infection.
Over time, the infection caused a scar to develop that blocked the vision in her right eye, however she continued to wear her contacts for 18 months.
Eventually, she went to Professor Dan Reinstein, a specialist ophthalmic surgeon at London Vision Clinic, in November 2020.
She underwent laser eye surgery helping her regain 90 per cent of her vision.
McCasland was forced to stop working at the café as a result of the infection. The pain, which had persisted for a month and half, made it difficult to work, as did the lost of vision in her left eye, which caused changes to depth perception
McCasland has lost vision in her right eye, and is awaiting an expensive transplant that only has a small chance of restoring her sigh
Ms Wang said: ‘This has been a multiple year process, with a lot of time and money gone into correcting the scar, and Dan has done an incredible job.’
She added that her sight is now ‘completely manageable’.
But not everyone is as lucky as Ms Wang — for some the infection leaves them permanently blind.
Brooklyn McCasland, 23, from Texas US, lost all vision in her right eye after she contracted the parasites — which also lives in fresh and salt water — when she swam with her contact in.
The barista was first told by doctors she just had sand in her eye. Late they blamed a common infection and gave her eyedrops and antibiotics.
But the pain went on and the outer layer of her eye began clouding over, with what her doctor assumed was damage from an infection.
Ms McCasland is now blind in her right eye, and is awaiting an expensive corneal transplant that only has a small chance of restoring her sight.
In May 2019, Emily Kelleher, a high school English teacher in Massachusetts, was left feeling like her left eye was being stabbed by a ‘knife or an ice pick’ — she had also been infected with the parasite.
Ms Kelleher’s eye under the microscope (pictured here) in her doctors office revealed the presence of acanthamoeba parasites
Her doctors told her she likely got it when the parasites got into her eye while showering with contact, something she used to do every day.
Last year, Rachel Prochnow, an Austin, Texas-based lifestyle writer, went blind in her right eye after showering with her contacts in.
She had always been careful about taking care of her eyes, having worn contacts since she was 12.
Ms Prochnow claims she always took them out at night, cleaned them well and threw away her contact lens cases regularly — ensuring everything was sterile.
But she admits she did not realise that showering, swimming or getting in a hot tub with her contacts in could leave her vulnerable to infection.
If acanthamoeba keratitis is caught early, doctors can treat it easily with eyedrops.
Tina Patel, contact lens optician from Feel Good Contacts, stressed that the best way to avoid infection is to maintain a proper lens care routine.
She told MailOnline: ‘If you wear two weekly or monthly lenses, make sure your lenses are removed, cleaned and stored properly every night before going to sleep.
Ms Prochnow first noticed something was wrong when her eye felt a little scratchy and sensitive to light. Soon, she was in excruciating pain, and was unable to see anything besides light and hand movements
‘Contact lenses should also never be worn in swimming pools, hot tubs and showers.’
She warns that even any residual water left on the hands before inserting lenses could be enough to cause acanthamoeba keratitis.
Professor Reinstein told MailOnline: ‘Soft contact lenses are most prone to acanthamoeba keratitis, due to the higher water content which can attract and harbor microorganisms.
‘Additionally, extended-wear lenses, which are often worn overnight, limit oxygen to the cornea and can trap contaminants against the eye for prolonged periods, increasing the risk of infection.’
